Geotricosis: fungemia en paciente con leucemia linfoblástica aguda / Geotrichosis: fungemia in a patient with acute lymphoblastic leukemia

La fungemia por Geotrichum spp. es poco frecuente y altamente letal. En el Instituto Nacional de Cancerología de Bogotá solo se han reportado dos casos: uno entre el 2001 y el 2007, y el otro entre el 2012 y el 2018. Este tipo de infección es más común en pacientes con algún grado de compromiso del sistema inmunitario, por lo que puede presentarse en pacientes con neoplasias hematológicas malignas. Se presenta el caso de un hombre de 27 años con recaída de leucemia linfoblástica aguda, que ingresó con poliartralgias de cinco días de duración. También cursaba con neutropenia febril, celulitis sin abscesos y bacteriemia por Staphylococcus aureus resistente a la meticilina para lo cual recibió terapia con oxacilina y cefepime. Sin embargo, persistía la neutropenia febril por lo que se sospechó una infección fúngica invasora. Se tomó un nuevo set de hemocultivos y se inició tratamiento antifúngico. En los hemocultivos se identificaron artroconidias y mediante espectrometría de masas por láser de matriz asistida de ionización-desorción se confirmó la presencia de Geotrichum spp. Se ajustó el tratamiento antifúngico con deoxicolato de anfotericina B por 14 días y voriconazol por cuatro semanas. Luego de una estancia prolongada se le dio de alta. Aunque la incidencia de la fungemia por Geotrichum spp. es baja, en pacientes con neoplasias hematológicas malignas debe considerarse en el contexto de una neutropenia febril que es persistente a pesar del tratamiento antimicrobiano de amplio espectro. La identificación de los agentes causantes de fungemias con herramientas de proteómica, como la espectrometría de masas mencionada, permite ajustar el tratamiento dirigido y reducir las complicaciones, la estancia hospitalaria y la mortalidad.

Fungemia caused by Geotrichum spp. is rare and highly lethal. The Instituto Nacional de Cancerología in Bogotá reported just two cases: one in the period 2001-2007 and the other in 2012-2018. This type of infection is more common in any kind of immunocompromised patients, so it can occur in those with hematological malignancies. Here we present the case of a 27-year-old man, diagnosed with acute lymphoblastic leukemia in relapse and admitted with polyarthralgia for five days, febrile neutropenia, non- abscessed cellulitis, and bacteremia due to methicillin-sensitive Staphylococcus aureus. The patient received therapy with oxacillin and cefepime, but the febrile neutropenia persisted. A new set of blood cultures was taken, and antifungal treatment was started because of the suspicion of invasive fungal infection. Arthroconidia were identified in blood cultures and Geotrichum spp. was confirmed using matrix-assisted laser desorption-ionization mass spectrometry. The antifungal treatment was adjusted with amphotericin B deoxycholate for 14 days and voriconazole for four weeks, and after a prolonged stay, the patient was discharged. Although the incidence of fungemia caused by Geotrichum spp. is low, it must be considered in patients with hematological malignancies and persistent febrile neutropenia despite the broadspectrum antimicrobial treatment. The confirmation of fungemia causing agents, with proteomic tools such as the mentioned mass spectrometry, allows treatment adjustment and decreases complications, hospital stay, and mortality.

Fusariosis en pacientes con cáncer: serie de 13 casos y revisión de la literatura / Fusariosis in cancer patients: 13 case series report and literature review

La fusariosis es una micosis oportunista producida por Fusarium spp. Su presentación clínica depende del estado inmunológico del huésped, especialmente, el de aquellos con enfermedades hematooncológicas, cuyas manifestaciones varían desde formas localizadas hasta infección fúngica invasora. El cultivo de piel o de sangre permite orientar el tratamiento antifúngico combinado con anfotericina B y voriconazol. Se presentan 13 casos de pacientes con cáncer en un periodo de once años que desarrollaron fusariosis diseminada; asimismo, se hizo con una revisión extensa de la literatura. En esta serie de casos, la mortalidad fue del 61,5 % (8/13), a pesar del uso del antifúngico. De los 13 pacientes, 11 tenían neoplasia hematológica y 2 neoplasia sólida. El factor de riesgo más importante fue la neutropenia profunda. El compromiso de la piel y los hemocultivos positivos facilitaron la prescripción del tratamiento combinado en la mayoría de los casos. La neutropenia febril persistente asociada a lesiones cutáneas, la onicomicosis, los nódulos o las masas pulmonares permitieron sospechar una infección fúngica invasora por Fusarium spp. El objetivo de la presentación de esta serie de casos es recordar el diagnóstico de fusariosis a la comunidad médica en contacto con pacientes oncológicos, con neutropenia febril profunda y persistentes.

The fusariosis is an opportunistic mycosis caused by Fusarium spp. Its clinical presentation depends on the immunological status of the host, especially in patients with hemato-oncological diseases, whose manifestations vary from localized to invasive fungal infections. Skin or blood culture helps to guide combined antifungal treatment with amphotericin B and voriconazole. Here, we present 13 cases in a period of eleven years of patients with cancer who developed disseminated fusariosis and their outcomes, together with a review of the related literature. In this series of cases, mortality was 61.5 % (8/13), despite the use of the antifungal. Out of the 13 cases, 11 had hematological neoplasia and 2 solid neoplasia. The most determinant risk factor was profound neutropenia. Skin involvement and positive blood cultures in most cases allowed combined treatment prescription. Persistent febrile neutropenia associated with skin lesions, onychomycosis, nodules, or lung masses lead to suspicion of Fusarium spp. fungal invasive infection. The aim of this series of cases is to remind healthcare professionals that oncological patients with deep and persistent febrile neutropenia can develop fusariosis.

Identification,structure elucidation and origin of a common pyridinium-thiocyanate intermediate in electrospray mass spectrometry among the benziamidazole-class proton pump inhibitors / 药物分析学报

During the analysis of benziamidazole-class irreversible proton pump inhibitors,an unusual mass spectral response with the mass-to-charge ratio at[M+10]+intrigued us,as it couldn't be assigned to any literature known relevant structure,intermediate or adduct ion.Moreover,this mysterious mass pattern of[M+10]+has been gradually observed by series of marketed proton pump inhibitors,viz.omeprazole,pantoprazole,lansoprazole and rabeprazole.All the previous attempts to isolate the corresponding component were unsuccessful.The investigation of present work addresses this kind of signal to a pyridinium thiocyanate mass spectral intermediate(10),which is the common fragment ion of series of labile aggregates.The origin of such aggregates can be traced to the reactive intermediates formed by acid-promoted degradation.These reactive intermediates tend to react with each other and give raise series of complicated aggregates systematically in a water/acetonitrile solution by electrospray ioniza-tion.The structure of the corresponding pyridinium thiocyanate species of omeprazole(10a)has been eventually characterized with the help of synthetic specimen(10a').Our structural proposal as well as its origin was supported by in situ nuclear magnetic resonance,chemical derivatization and colorimetric experiments.

Rapid authentication of different herbal medicines by heating online extraction electrospray ionization mass spectrometry / 药物分析学报

The rapid and accurate authentication of traditional Chinese medicines(TCMs)has always been a key scientific and technical problem in the field of pharmaceutical analysis.Herein,a novel heating online extraction electrospray ionization mass spectrometry(H-oEESI-MS)was developed for the rapid and direct analysis of extremely complex substances without the requirement for any sample pretreatment or pre-separation steps.The overall molecular profile and fragment structure features of various herbal medicines could be completely captured within 10-15 s,with minimal sample(＜0.5 mg)and solvent consumption(＜20 μL for one sample).Furthermore,a rapid differentiation and authentication strategy for TCMs based on H-oEESI-MS was proposed,including metabolic profile characterization,characteristic marker screening and identification,and multivariate statistical analysis model validation.In an analysis of 52 batches of seven types of Aconitum medicinal materials,20 and 21 key compounds were screened out as the characteristic markers of raw and processed Aconitum herbal medicines,respectively,and the possible structures of all the characteristic markers were comprehensively identified based on Com-pound Discoverer databases.Finally,multivariate statistical analysis showed that all the different types of herbal medicines were well differentiated and identified(R2X＞0.87,R2Y＞0.91,and Q2＞0.72),which further verified the feasibility and reliability of this comprehensive strategy for the rapid authentication of different TCMs based on H-oEESI-MS.In summary,this rapid authentication strategy realized the ultra-high-throughput,low-cost,and standardized detection of various complex TCMs for the first time,thereby demonstrating wide applicability and value for the development of quality standards for TCMs.

Comparison of different approaches for direct coupling of solid-phase microextraction to mass spectrometry for drugs of abuse analysis in plasma / 药物分析学报

The direct coupling of solid-phase microextraction(SPME)to mass spectrometry(MS)(SPME-MS)has proven to be an effective method for the fast screening and quantitative analysis of compounds in complex matrices such as blood and plasma.In recent years,our lab has developed three novel SPME-MS techniques:SPME-microfluidic open interface-MS(SPME-MOI-MS),coated blade spray-MS(CBS-MS),and SPME-probe electrospray ionization-MS(SPME-PESI-MS).The fast and high-throughput nature of these SPME-MS technologies makes them attractive options for point-of-care analysis and anti-doping testing.However,all these three techniques utilize different SPME geometries and were tested with different MS instruments.Lack of comparative data makes it difficult to determine which of these methodologies is the best option for any given application.This work fills this gap by making a comprehensive comparison of these three technologies with different SPME devices including SPME fibers,CBS blades,and SPME-PESI probes and SPME-liquid chromatography-MS(SPME-LC-MS)for the analysis of drugs of abuse using the same MS instrument.Furthermore,for the first time,we developed different desorption chambers for MOI-MS for coupling with SPME fibers,CBS blades,and SPME-PESI probes,thus illustrating the universality of this approach.In total,eight analytical methods were developed,with the experimental data showing that all the SPME-based methods provided good analytical performance with R2 of linearities larger than 0.9925,accuracies between 81％and 118％,and good precision with an RSD％≤13％.

Exploration and advance of key techniques in MALDI mass spectrometry imaging / 药学学报

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a new imaging technique with label-free, rapid, and high throughput features. It has bloomed in the analysis on the spatial distribution of biomolecules such as drugs, metabolites, peptides and proteins on the tissue surface in virtue of providing high data throughput from non-targeted full analysis and high accuracy from targeted analysis. The acquisition of MSI signal response with high sensitivity, high spatial resolution, and good stability is directly depended on the appropriate sample preparation approaches, and flexible and various data processing tools will help the non-target data mining to meet the demands of visualization, spatial distribution and multiple index applications so as to reveal the scientific rules beneath the data. This review briefly summarizes the key advances in MALDI-MSI from aspects of sample preparation procedures, data processing and visualization. It also illustrates the characteristics, difficulties and probable solutions derived from these key techniques.

Chemical reaction mechanism of decoction of traditional Chinese medicines: a review / 中国中药杂志

Complicated chemical reactions occur in the decoction of traditional Chinese medicines(TCMs) which features complex components, influencing the safety, efficacy, and quality controllability of TCMs. Therefore, it is particularly important to clarify the chemical reaction mechanism of TCMs in the decoction. This study summarized eight typical chemical reactions in the decoction of TCMs, such as substitution reaction, redox reaction, isomerization/stereoselective reaction, complexation, and supramolecular reaction. With the "toxicity attenuation and efficiency enhancement" of aconitines and other examples, this study reviewed the reactions in decoction of TCMs, which was expected to clarify the variation mechanisms of key chemical components in this process and to help guide medicine preparation and safe and rational use of medicine in clinical settings. The current main research methods for chemical reaction mechanisms of decoction of TCMs were also summed up and compared. The novel real-time analysis device of decoction system for TCMs was found to be efficient and simple without the pre-treatment of samples. This device provides a promising solution, which has great potential in quantity evaluation and control of TCMs. Moreover, it is expected to become a foundational and exemplary research tool, which can advance the research in this field.

A peculiar case of onychomycosis caused by Cladosporium halotolerans

ABSTRACT A 49-year-old patient with changes in the nails of the hallux for 10 years was diagnosed with onychomycosis. The identity of the causative agent was confirmed as Cladosporium halotolerans from the Cladosporium sphaerospermum species complex using molecular techniques. MALDI-TOF identified the agent as C. sphaerospermum complex species. Overall, species such as onychomycosis agents should attract special attention to avoid mistakes in the identification process while considering a probable contaminant as responsible for the disease. These species deserve attention since there are rare descriptions of them as causes of onychomycosis. It is important to recognize them as causes of disease and not just as a probable contaminant.

Significance of Aspergillus spp. isolation in defining cases of COVID-19 Associated Pulmonary Aspergillosis - CAPA

ABSTRACT COVID-19-Associated Pulmonary Aspergillosis (CAPA) is a relatively common complication in patients with severe forms of the disease caused by the SARS-CoV-2 virus. Diagnosing and confirming CAPA is challenging. In this study, Aspergillus spp. isolation in respiratory specimens from patients with COVID-19 was evaluated for identifying cases of CAPA. In 2020-2021, 17 Aspergillus spp. were isolated from 15 COVID-19 patients admitted to a university hospital in Brazil. Patient records were retrospectively reviewed to obtain clinical-epidemiological data and other markers of Aspergillus spp. infection and then compared with the ECMM/ISHAM criteria for defining CAPA. Probable CAPA was defined in 5/10 patients, who had Aspergillus spp. isolated from Bronchoalveolar Lavage (BAL) or a positive galactomannan blood test. Additionally, anti-Aspergillus antibodies were detected in two of these patients, during active or follow-up phases of CAPA. In another seven patients with Aspergillus spp. isolated from tracheobronchial aspirate or sputum, CAPA was presumed, mainly due to deterioration of clinical conditions and new lung imaging suggestive of fungal infection. Antifungal agents to control CAPA, particularly voriconazole, were used in 9/15 cases. In cases of probable CAPA and remaining patients, clinical conditions and comorbidities were similar, with lethality being high, at 60% and 71%, respectively. The number of CAPA cases defined by scientific criteria was lower than that assumed in the clinical context. This was largely due to the lack of BAL collection for fungal culture and the non-intensive use of other markers of invasive aspergillosis. The isolation of Aspergillus spp. in different respiratory specimens should alert clinicians to the diagnosis of CAPA.

A case of Aspergillus salwaensis-induced spinal infection / 中国热带医学

@#Abstract: To report a case of Aspergillus salwaensis-induced spinal infection and its laboratory detection. The inflammatory granulation and necrotic tissue samples of a patient with spinal infection were collected from, the Affiliated Hospital of Chengde Medical College on June 17, 2020 for direct smear microscopy and culture, and the isolated strain was identified by microscopy by smear staining, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF-MS), molecular identification and in vitro antifungal susceptibility test. The patient was 62 years old female and presented with recurrent chest and back pain with no obvious cause. The initial diagnosis was spinal infection, after 7 days of treatment with levofloxacin, the effect was not good. Surgery was then performed remove the lesion via posterior thoracic debridement, and fungal hypha was observed under microscope in tissue specimens. The isolated strains had no typical structure, MALDI-TOF-MS was used for identification for many times, but there was no identification result. After 7 days of fluconazole treatment, the patient's condition improved, and her chest and back pain were alleviated compared to before surgery. The patient was discharged and followed up in the outpatient department, the fungus was later identified as Aspergillus salwaensis by sequence analysis of the internal transcribed spacer (ITS) gene sequencing, and the patient's antifungal medication was changed to voriconazole after with the attending physician. The patient consciously recovered well with no pain in the operative area and normal spinal activity at 1 year follow-up. The possibility of spinal fungal infection should be considered in patients with back pain without a clear cause and poor response to routine antibiotic treatment. Direct smear report of microscopic results are very important for guiding clinical antibiotic selection for rare filament fungi with atypical colony and microscopic morphology and unsuccessful MALDI-TOF-MS identification, molecular biological methods such as ITS sequence analysis can be helpful for early identification of the fungal species, improving identification speed.

Detection of common candidemia pathogens based on PCR combined with MALDI-TOF MS / 中华检验医学杂志

Objective:A high-throughput assay for the detection of five common clinical Candidaemia pathogens was established by combining polymerase chain reaction (PCR) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).Method:Establishment of methodology. We selected Candida albicans, Candida parapsilosis, Candida glabrata, Candida krusei, Candida tropicalis to be the target pathogens and the internal transcribed spacer (ITS) region as the target gene. Specific single base extension primers were designed to perform single base extension reaction in the same reaction system. MALDI-TOF MS was used to detect the characteristic peaks of each target pathogen. The sensitivity and specificity of the detection system were verified by using spiked blood samples. Totally 108 blood samples from proven or suspected candidaemia patients were collected from October 2021 to September 2022 in a hospital in Beijing. The results of nucleic acid mass spectrometry were compared with those of clinical blood culture. Results:The established nucleic acid mass spectrometry detection system can simultaneously detect five common clinical Candida species. Each strain can produce specific product peaks and there is no mutual interference between the strains. The detection limit of Candida albicans was 100 CFU/ml. The detection limit of Candida parapsilosis, Candida glabrata, Candida krusei and Candida tropicalis was 10 CFU/ml. For the 108 blood samples, the sensitivity, specificity, positive predictive value and negative predictive value of nucleic acid mass spectrometry were 94.74% (36/38), 97.14% (68/70), 92.31% (36/39) and 98.55% (68/69), respectively. The McNemar χ 2 test showed no significant difference between the two methods ( P>0.05), and the Kappa consistency test showed good consistency between the two methods ( Kappa=0.9, P<0.05). Conclusion:A nucleic acid mass spectrometry detection system suitable for clinical candida detection was successfully constructed, and the method validation results were consistent with the clinical blood culture.

Diagnosis of periprosthetic joint infection based on semi-quantitative detection of synovial fluid calprotectin by MALDI-TOF MS / 中华检验医学杂志

Objective:To explore the clinical value of synovial fluid calprotectin for the diagnosis of periprosthetic joint infection (PJI).Methods:Based on prospective cohort study design, a total of 82 patients suspected of PJI after hip and knee arthroplasty in the First Medical Center of the PLA General Hospital from July 2021 to June 2022 were selected. Patients were divided into infection group (PJI, n=39) and non-infection group (non-PJI, n=43) according to the diagnostic criteria proposed by the Second International Consensus Conference in 2018. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for double-blind detection of calprotectin and internal reference standard (IRS) in synovial fluid of patients. The peaks of target protein and IRS were recorded for further analysis. Mann-Whitney U test was used to compare the concentrations of S100A8 and S100A9 between the two groups, and receiver operating characteristic curve (ROC) was used to analyze the diagnostic efficacy of S100A8 and S100A9 for PJI. Results:Calprotectin was detected as monomers S100A8 and S100A9. Synovial fluid S100A8 was significantly higher in the PJI group than that in the non-PJI group [1.57 (0.48, 4.17) vs 0.00 (0.00, 0.05), Z=?7.221, P<0.05]. Synovial fluid S100A9 was also significantly higher in the PJI group than that in the non-PJI group [0.74 (0.29, 1.70) vs 0.06 (0.00, 0.10), Z=?6.255, P<0.05]. When using S100A8 and S100A9 to diagnose PJI, the sensitivity were 97.4% and 87.2%, the specificity were 86.0% and 88.4%, and the area under the ROC were 0.964 (95% CI 0.929-0.998) and 0.902 (95% CI 0.924-0.996), respectively. Conclusion:The detection of synovial fluid S100A8 and S100A9 by MALDI-TOF MS can make a satisfactory diagnosis for PJI.

Feasibility study of integrating medical Linac with electromagnet to measure magnetic factor of reference dosimetry for MRIgRT / 中华放射医学与防护杂志

Objective:To study the influence of intensive magnet fields on radiation dose measurement, and to demonstrate the feasibility of measuring magnet field correction factor by a combination of medical linac with variable magnet fields in view of needing for accurate measurement of the doses from reference beam arising in MR image-guided radiotherapy.Methods:A photon radiation field and a variable field with 6 MV nominal high voltage were produced by using conventional medical electron linear accelerator equipped with a pair of electromagnets with magnetic field strength up to 1.5 T. Both PTW30013 and PTW31010 ionization chambers were used to test the responses of ionization chambers under different magnetic field strengths at four orientations in which the angles between ionization chamber axis and magnetic field direction were 0°, 180°, 90° and 270°, respectively. The magnetic factors, kB, M was calculated and compared with the reported values in literature. Results:The response of ionization chamber was proportional to the magnetic field strength before it reached to a peak around 1 T, and then fell down as the magnetic field continued to rise. When the magnetic field was 0.35 T, the magnetic factors of PTW31010 were 0.988 2±0.000 3 and 0.997 4±0.000 4 corresponding to 90° and 0° directions, the discrepancy between 0° scenario and literature was 0.05% ± 0.04%. When the magnetic field reached 1.5 T, the magnetic factor of PTW30013 was 0.958 9±0.000 5 at the situation of 90°, which was 0.60% ± 0.05% different from the literature value.Conclusions:Conventional 6 MV medical accelerator equipped with electromagnet can be used to measure the magnetic field factor of reference dosimetry for MRIgRT.

Principles Of Ultrasound Technology In Medical Imaging Of Non Ionization Images

The X-ray tube is one of the most important components in any X-ray system. In the beginning, physicists and physicians used gas ion tubes. The so-called Coolidge tube applied a high vacuum and is still used today. Medical examinations have required continuously improved designs of X-ray tubes (smaller focal spots at a higher output). The principle of the Goetze line focus is still applied in any diagnostic X-ray tube. Different anode materials and the rotating anode contributed to an increased output and reduced exposure time. Bearings needed special attention. Spiral groove bearings are the most advanced design today. The heat storage capacity of the anode and the tube housing assembly influences examination time and patient throughput. Cardiac imaging required less motion blurring in cine film images and increasing radiation exposure in interventional procedures called for measures to reduce dose. Protection against radiation and electric shock has always been a concern of design engineers. Focal spot sizes dedicated to specific applications and heat management within the total tube housing assembly will be future issues. Even with the event of ultrasound and MR technology, X-ray procedures will still be applied for diagnostic and interventional purposes.

Detection of Microorganisms in Clinical Sonicated Orthopedic Devices Using Conventional Culture and qPCR / Detecção de microrganismos em dispositivos ortopédicos sonicados clínicos usando cultura convencional e qPCR

Abstract Objective To evaluate the sensitivity and specificity of the quantitative real-time polymerase chain reaction (qPCR) for 16S rDNA gene screening using sonicated fluid from orthopedic implants. Methods A retrospective study was conducted on 73 sonicated fluids obtained from patients with infection associated with orthopedic implants. The samples were subjected to conventional culture and molecular testing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and qPCR for 16S rDNA. The cycle threshold values were used to define a cut-off of the qPCR of the 16S rDNA for negative and positive cultures. Results No statistical differences were observed between the positive and negative culture groups based on the time from the first surgery to infection (p= 0.958), age (p =0.269), or general comorbidities. Nevertheless, a statistical difference was found between the mean duration of antibiotic use before device removal (3.41 versus 0.94; p =0.016). Bacterial DNA was identified in every sample from the sonicated fluids. The median cycle thresholds of the positive and negative cultures were of 25.6 and 27.3 respectively (p< 0.001). As a diagnostic tool, a cycle threshold cut-off of 26.89 demonstrated an area under the curve of the receiver operating characteristic of 0.877 (p≤ 0.001). Conclusion The presence of antimicrobial agents for more than 72 hours decreased culture positivity, but did not influence the qPCR results. Despite this, amplification of the 16S rDNA may overestimate infection diagnosis.

Resumo Objetivo Avaliar a sensibilidade e a especificidade da reação em cadeia de polimerase em tempo real quantitativa (quantitative real-time polymerase chain reaction, qPCR, em inglês) para a triagem do gene rDNA 16S, com a utilização do fluido sonicado de implantes ortopédicos. Métodos Um estudo retrospectivo foi realizado em 73 fluidos sonicados obtidos de pacientes com infecção associada aos implantes ortopédicos. As amostras foram submetidas a cultura convencional e a teste molecular utilizando ionização e dessorção a laser assistida por matriz com espectrometria de massa por tempo de voo (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF MS, em inglês) e qPCR para o gene rDNA 16S. Os valores limiares do ciclo foram usados para definir um ponto de corte para a qPCR do gene rDNA 16S para culturas negativas e positivas. Resultados Não foram observadas diferenças estatísticas entre os grupos de cultura positiva e negativa com base no tempo desde a primeira cirurgia até a infecção (p= 0,958), na idade (p= 0,269), ou nas comorbidades em geral. No entanto, uma diferença estatística foi encontrada entre a duração média do uso de antibióticos antes da remoção do dispositivo (3,41 versus 0,94; p= 0,016). O DNA bacteriano foi identificado em todas as amostras dos fluidos sonicados. Os limiares do ciclo médio de culturas positivas e negativas foram de 25,6 e 27,3, respectivamente (p< 0,001). Como uma ferramenta de diagnóstico, um corte do limite do ciclo de 26,89 demonstrou uma área sob a curva da característica de operação do receptor de 0,877 (p ≤ 0,001). Conclusão A presença de agentes antimicrobianos por mais de 72 horas diminuiu a positividade da cultura, mas não influenciou os resultados da qPCR. Apesar disso, a amplificação do rDNA 16S pode sobrestimar o diagnóstico de infecção.

Principles & Functions Of Conventional & Digital X-Rays Imaging Systems In Diagnosis

Digital radiography (DR) is an advanced form of x-ray inspection which produces a digital radiographic image instantly on a computer. This technique uses x-ray sensitive plates to capture data during object examination, which is immediately transferred to a computer without the use of an intermediate cassette. The incident x-ray radiation is converted into an equivalent electric charge and then to a digital image through a detector sensor. Compared to other imaging devices, flat panel detectors, also known as digital detector arrays (DDAs) provide high quality digital images. They can have better signal-to-noise ratio and improved dynamic range, which, in turn, provides high sensitivity for radiographic applications. Flat panel detectors work on two different approaches, namely, indirect conversion and direct conversion. Indirect conversion flat panel detectors have a scintillator layer which converts x-ray photons to photons of visible light and utilise a photo diode matrix of amorphous silicon to subsequently convert the light photons into an electrical charge. This charge is proportional to the number and energy of x-ray photons interacting with the detector pixel and therefore the amount and density of material that has absorbed the x-rays. Direct conversion flat panel detectors use a photo conductor like amorphous selenium (a-Se) or Cadmium telluride (Cd-Te) on a multi-micro electrode plate, providing the greatest sharpness and resolution. The information on both types of detectors is read by thin film transistors. In the direct conversion process, when x-ray photons impact over the photo conductor, like amorphous Selenium, they are directly converted to electronic signals which are amplified and digitised. As there is no scintillator, lateral spread of light photons is absent here, ensuring a sharper image. This differentiates it from indirect construction.

PRINCIPLES OF X-RAY TECHNOLOGY IN MEDICAL IMAGING AND IMPROVEMENT OF RADIOLOGICAL IMAGES (2nd Part)

Radioisotopes are unstable nuclei of elements (eg Molybdenum 99), which are transformed into stable nuclei while emitting radiation (particles, photons). This phenomenon is characterized as radioactivity. Radioactivity can be natural or artificial. Artificial radioactivity is that observed in isotopes produced artificially in a laboratory. The study of radioactive isotopes in combination with the development of systems for the detection of emitted radiation, was the trigger for the investigation of possible applications of radioisotopes in medicine. This research resulted in the creation of a new science, Nuclear Medicine, whose main purpose is to apply the properties of radioisotopes in the diagnosis and treatment of human diseases.

PRINCIPLES OF X-RAY TECHNOLOGY IN MEDICAL IMAGING AND IMPROVEMENT OF RADIOLOGICAL IMAGES (1st Part)

The X-ray tube is one of the most important components in any X-ray system. In the beginning, physicists and physicians used gas ion tubes. The so-called Coolidge tube applied a high vacuum and is still used today. Medical examinations have required continuously improved designs of X-ray tubes (smaller focal spots at a higher output). The principle of the Goetze line focus is still applied in any diagnostic X-ray tube. Different anode materials and the rotating anode contributed to an increased output and reduced exposure time. Bearings needed special attention. Spiral groove bearings are the most advanced design today. The heat storage capacity of the anode and the tube housing assembly influences examination time and patient throughput. Cardiac imaging required less motion blurring in cine film images and increasing radiation exposure in interventional procedures calling for measures to reduce dose. Protection against radiation and electric shock has always been a concern of design engineers. Focal spot sizes dedicated to specific applications and heat management within the total tube housing assembly will be future issues. Even in the event of ultrasound and MR technology, X-ray procedures will still be applied for diagnostic and interventional purposes.

PRINCIPLES OF MAGNETIC RESONANCE TECHNOLOGY IN MEDICAL IMAGING OF NON IONIZATION IMAGES

The X-ray tube is one of the most important components in any X-ray system. In the beginning, physicists and physicians used gas ion tubes. The so-called Coolidge tube applied a high vacuum and is still used today. Medical examinations have required continuously improved designs of X-ray tubes (smaller focal spots at a higher output). The principle of the Goetze line focus is still applied in any diagnostic X-ray tube. Different anode materials and the rotating anode contributed to an increased output and reduced exposure time. Bearings needed special attention. Spiral groove bearings are the most advanced design today. The heat storage capacity of the anode and the tube housing assembly influences examination time and patient throughput. Cardiac imaging required less motion blurring in cine film images and increasing radiation exposure in interventional procedures called for measures to reduce dose. Protection against radiation and electric shock has always been a concern of design engineers. Focal spot sizes dedicated to specific applications and heat management within the total tube housing assembly will be future issues. Even with the event of ultrasound and MR technology, X-ray procedures will still be applied for diagnostic and interventional purposes.

Simulation calculation of wall correction factor of 192Ir gamma-ray spherical graphite cavity ionization chamber / 中华放射医学与防护杂志

Objective:To study the correction factor of the chamber wall of the reference air kerma rate reference ionization chamber (NIM-Ir-SG-100 type) for 192Ir radioactive source. Methods:The photon spectrum and ionization chamber wall correction factor of the radioactive source housing and irradiator model are calculated by Monte Carlo code. And then the photon energy, wall thickness and ionization chamber diameter, which affect the result of the chamber wall correction factor, are simulated.Results:After calculation, the simulation result of the correction factor of spherical graphite cavity ionization chamber wall was 1.037 7. Controlling a single variable, photon energy (0.3-1.3 MeV), wall thickness (0.2-0.5 cm), inner diameter (0.5 -15 cm), the maximum deviations of wall correction result were 1.62%, 3.30% and 2.86%, respectively.Conclusions:The self-made spherical graphite cavity ionization chamber has good performance, and the corrected kwall value of the chamber wall is within a reasonable range. The completion of the chamber wall correction factor is an important step to measure the reference air kerma rate of the 192Ir radioactive source and establish the measurement benchmark.