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1.
BMC Med Inform Decis Mak ; 23(1): 187, 2023 09 18.
Article in English | MEDLINE | ID: mdl-37723450

ABSTRACT

BACKGROUND: Mobile health is gradually revolutionizing the way medical care is delivered worldwide. In Mozambique, a country with a high human immunodeficiency virus prevalence, where antiretroviral treatment coverage is 77% accompanied by a 67% of retention rate, the use of mobile health technology may boost the antiretroviral treatment, by delivering care beyond health facilities and reaching underrepresented groups. Leveraging new technologies is crucial to reach the 95-95-95 United Nations target by 2030. The design, development, implementation, and evaluation of a mobile health platform called Infomóvel were covered in this article. Its intended use involves collaboration with community health workers and aims to increase human immunodeficiency virus patient access, adherence, and retention to care. METHODS: Using the Design Science Research Methodology, Infomóvel was created, as well as this publication. The explanation of various actions includes everything from problem description to observational study and goal-following for a solution, which results in the design and development of a platform proposal. Before the utility assessment of Infomóvel was conducted to make adjustments, a demonstration phase was conducted in one region of Mozambique. RESULTS: The initial subjects of the Infomóvel flowchart and physical process design were patients receiving antiretroviral medication who were enrolled in the patients tracking system and who had consented to home visits. The case manager examines the file before importing it into the Infomóvel database stored on a cloud server using the website www.commcarehq.org . The case manager application synchronises with the Infomóvel server database, enabling the import of latest data and access to the lists of new patients and community health workers. The community health worker uses his phone to access his application, which allows him to record the geographic coordinates and sort the list of patients by priority and type of visit. CONCLUSION: Results from Infomóvel add to the growing body of data showing that mobile health techniques are beneficial for managing stable individuals with chronic conditions in Mozambique. These approaches can be scaled up and better utilised. However, additional studies should be conducted to quantify the resources needed to implement on a larger scale.


Subject(s)
Acquired Immunodeficiency Syndrome , HIV , Humans , Male , Mozambique , Acquired Immunodeficiency Syndrome/drug therapy , Acquired Immunodeficiency Syndrome/epidemiology , Biomedical Technology , Databases, Factual
2.
J Clin Microbiol ; 57(3)2019 03.
Article in English | MEDLINE | ID: mdl-30626662

ABSTRACT

The iconic koala (Phascolarctos cinereus) is host to two divergent gammaherpesviruses, phascolarctid gammaherpesviruses 1 and 2 (PhaHV-1 and -2), but the clinical significance of the individual viruses is unknown and current diagnostic methods are unsuitable for differentiating between the viruses in large-scale studies. To address this, we modified a pan-herpesvirus nested PCR to incorporate high-resolution melt analysis. We applied this assay in a molecular epidemiological study of 810 koalas from disparate populations across Victoria, Australia, including isolated island populations. Animal and clinical data recorded at sampling were analyzed and compared to infection status. Between populations, the prevalence of PhaHV-1 and -2 varied significantly, ranging from 1% to 55%. Adult and older animals were 5 to 13 times more likely to be positive for PhaHV-1 than juveniles (P < 0.001), whereas PhaHV-2 detection did not change with age, suggesting differences in how these two viruses are acquired over the life of the animal. PhaHV-1 detection was uniquely associated with the detection of koala retrovirus, particularly in females (P = 0.008). Both viruses were significantly associated (P < 0.05) with the presence of genital tract abnormalities (uterine/ovarian cysts and testicular malformation), reduced fertility in females, urinary incontinence, and detection of Chlamydia pecorum, although the strength of these associations varied by sex and virus. Understanding the clinical significance of these viruses and how they interact with other pathogens will inform future management of threatened koala populations.


Subject(s)
Gammaherpesvirinae/genetics , Herpesviridae Infections/veterinary , Molecular Diagnostic Techniques/veterinary , Phascolarctidae/virology , Polymerase Chain Reaction/veterinary , Animals , Animals, Wild , Australia/epidemiology , Female , Gammaherpesvirinae/isolation & purification , Genetic Variation , Herpesviridae Infections/diagnosis , Herpesviridae Infections/epidemiology , Herpesviridae Infections/virology , Male , Molecular Epidemiology , Prevalence , Risk Factors
3.
Biomacromolecules ; 19(4): 1305-1313, 2018 04 09.
Article in English | MEDLINE | ID: mdl-29565567

ABSTRACT

This work explores the dynamics of hydrogen bond networks in cellulose through inelastic neutron scattering (INS) and periodic CASTEP calculations. Estimated spectra were based on the crystal structure of cellulose Iα and Iß and replicate the INS spectrum of cellulose samples with remarkable similarity, allowing a reliable assignment of INS bands to vibrational modes of cellulose. Comparison of cellulose samples from varied sources, from bacterial to kraft pulp, allows the identification of characteristic INS bands, arising from C2-OH torsional motions, which easily identify which allomorph-Iα or Iß-is prevalent. A high crystallinity index is revealed by the presence of well-defined INS bands associated with highly cooperative CH bending modes along the chain. Hydrating kraft cellulose samples clearly affects those INS bands related with the hydroxymethyl group, identified as the preferred binding site for water molecules. At high humidity content level, a significant proportion of the water molecules is aggregated in clusters within the amorphous cellulose domains. The formation of ice microcrystals leads to a partial disruption of the hydrogen-bond network, as can be concluded from the observed red-shift of the torsional OH vibrational modes. The full assignment and interpretation of cellulose's INS spectra herein provided is a sound basis for future use of INS spectroscopy in the characterization of functionalized cellulose fibers and composite materials.


Subject(s)
Cellulose/chemistry , Hydrogen Bonding , Models, Chemical , Compression Bandages , Crystallography, X-Ray , Dynamic Light Scattering , Ice , Neutrons , Vibration
4.
Phys Chem Chem Phys ; 19(27): 17998-18009, 2017 Jul 21.
Article in English | MEDLINE | ID: mdl-28665431

ABSTRACT

The solids choline chloride and urea, mixed in a 1 : 2 molar proportion, form the iconic deep eutectic solvent "Reline". A combination of computational and vibrational spectroscopy tools, including inelastic neutron scattering (INS), have been used to probe intermolecular interactions in the eutectic mixture. Reline's experimental spectra were estimated using discrete and periodic ab initio calculations of a molecular aggregate with two choline chloride and four urea units. This is the minimum size required to achieve satisfactory agreement with experiment, as smaller clusters cannot represent all of reline's significant intermolecular interactions. The INS spectrum of reline, compared with that of pure choline chloride, reveals a displacement of chloride anions away from their preferred positions on top of choline's methyl groups, whose torsional movement becomes less hindered in the mixture. Urea, which adopts a planar (sp2) shape in the crystal, becomes non-planar (sp3) in reline, a feature herein discussed for the first time. In reline, urea molecules form a wide range of hydrogen bonds, from soft contacts to stronger associations, the latter being responsible for the deviation from ideality. The chloride's interactions with choline are largely conserved at the hydroxyl end while becoming weaker at the cationic headgroup. The interplay of soft and strong interactions confers flexibility to the newly formed hydrogen-bond network and allows the ensemble to remain liquid at room temperature.

5.
J Gen Virol ; 97(3): 747-755, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26691326

ABSTRACT

Recombination in alphaherpesviruses allows evolution to occur in viruses that have an otherwise stable DNA genome with a low rate of nucleotide substitution. High-throughput sequencing of complete viral genomes has recently allowed natural (field) recombination to be studied in a number of different alphaherpesviruses, however, such studies have not been applied to equine herpesvirus 1 (EHV-1) or equine herpesvirus 4 (EHV-4). These two equine alphaherpesviruses are genetically similar, but differ in their pathogenesis and epidemiology. Both cause economically significant disease in horse populations worldwide. This study used high-throughput sequencing to determine the full genome sequences of EHV-1 and EHV-4 isolates (11 and 14 isolates, respectively) from Australian or New Zealand horses. These sequences were then analysed and examined for evidence of recombination. Evidence of widespread recombination was detected in the genomes of the EHV-4 isolates. Only one potential recombination event was detected in the genomes of the EHV-1 isolates, even when the genomes from an additional 11 international EHV-1 isolates were analysed. The results from this study reveal another fundamental difference between the biology of EHV-1 and EHV-4. The results may also be used to help inform the future safe use of attenuated equine herpesvirus vaccines.


Subject(s)
Herpesviridae Infections/veterinary , Herpesvirus 1, Equid/genetics , Herpesvirus 4, Equid/genetics , Horse Diseases/virology , Recombination, Genetic , Animals , Base Sequence , Genome, Viral , Herpesviridae Infections/virology , Herpesvirus 1, Equid/classification , Herpesvirus 1, Equid/isolation & purification , Herpesvirus 4, Equid/classification , Herpesvirus 4, Equid/isolation & purification , Horses , Molecular Sequence Data , New Zealand , Phylogeny
6.
Int J Risk Saf Med ; 35(1): 19-24, 2024.
Article in English | MEDLINE | ID: mdl-37718852

ABSTRACT

BACKGROUND: Medication reconciliation is advocated to ensure the continuity, safety, and effective use of medicines across transitions of care. CASE REPORT: In this report, we describe the case of a 90-year-old female with previous diagnoses of atrial fibrillation and cutaneous metastatic breast cancer presenting with bilateral ulcerative lesions on the chest wall. The patient was diagnosed with Deep Vein Thrombosis at the Emergency Department and started on rivaroxaban, although the patient was already taking edoxaban. This therapeutic duplication was noticed only one week later, even though she was already experiencing significant bleeding managed through a prescribing cascade. Despite the technical error (action-based), it is possible to identify several weaknesses in the organisation's structure, which provided a trajectory of accident opportunity. CONCLUSION: Anticoagulants are ranked first for the highest priority to receive a medication reconciliation. To achieve an optimal level of medication reconciliation, we ought to recognise and correct latent failures.


Subject(s)
Atrial Fibrillation , Breast Neoplasms , Skin Neoplasms , Thoracic Wall , Female , Humans , Aged, 80 and over , Medication Reconciliation , Anticoagulants , Atrial Fibrillation/drug therapy , Breast Neoplasms/drug therapy
7.
Clin Infect Dis ; 54 Suppl 4: S369-74, 2012 May.
Article in English | MEDLINE | ID: mdl-22544205

ABSTRACT

Between 2007 and 2008, the Mozambique Ministry of Health conducted an assessment of human immunodeficiency virus drug resistance (HIVDR) using World Health Organization (WHO) methods in a cohort of children initiating antiretroviral therapy (ART) at the main pediatric ART referral center in Mozambique. It was shown that prior to ART initiation 5.4% of children had HIVDR that was associated with nevirapine perinatal exposure (P < .001). Twelve months after ART initiation, 77% had viral load suppression (<1000 copies/mL), exceeding the WHO target of ≥ 70%; 10.3% had HIVDR at 12 months. Baseline HIVDR (P = .04), maternal prevention of mother-to-child transmission (P = .02), and estimated days of missed medication (P = .03) predicted HIVDR at 12 months. As efforts to eliminate pediatric AIDS are intensified, implementation of ritonavir-boosted protease inhibitor regimens in children with prevention of mother-to-child transmission exposure may reduce risk of virological failure in our setting.


Subject(s)
Anti-Retroviral Agents/pharmacology , HIV Infections/drug therapy , HIV Infections/epidemiology , Anti-Retroviral Agents/therapeutic use , Chi-Square Distribution , Child , Child, Preschool , Cohort Studies , Drug Resistance, Viral , Female , HIV/drug effects , HIV/genetics , HIV Infections/virology , Humans , Infant , Male , Mozambique/epidemiology , Pilot Projects , Prevalence , Treatment Outcome , World Health Organization
8.
Med Phys ; 39(1): 415-23, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22225311

ABSTRACT

PURPOSE: The most recent Varian(®) micro multileaf collimator (MLC), the High Definition (HD120) MLC, was modeled using the BEAMNRC Monte Carlo code. This model was incorporated into a Varian medical linear accelerator, for a 6 MV beam, in static and dynamic mode. The model was validated by comparing simulated profiles with measurements. METHODS: The Varian(®) Trilogy(®) (2300C/D) accelerator model was accurately implemented using the state-of-the-art Monte Carlo simulation program BEAMNRC and validated against off-axis and depth dose profiles measured using ionization chambers, by adjusting the energy and the full width at half maximum (FWHM) of the initial electron beam. The HD120 MLC was modeled by developing a new BEAMNRC component module (CM), designated HDMLC, adapting the available DYNVMLC CM and incorporating the specific characteristics of this new micro MLC. The leaf dimensions were provided by the manufacturer. The geometry was visualized by tracing particles through the CM and recording their position when a leaf boundary is crossed. The leaf material density and abutting air gap between leaves were adjusted in order to obtain a good agreement between the simulated leakage profiles and EBT2 film measurements performed in a solid water phantom. To validate the HDMLC implementation, additional MLC static patterns were also simulated and compared to additional measurements. Furthermore, the ability to simulate dynamic MLC fields was implemented in the HDMLC CM. The simulation results of these fields were compared with EBT2 film measurements performed in a solid water phantom. RESULTS: Overall, the discrepancies, with and without MLC, between the opened field simulations and the measurements using ionization chambers in a water phantom, for the off-axis profiles are below 2% and in depth-dose profiles are below 2% after the maximum dose depth and below 4% in the build-up region. On the conditions of these simulations, this tungsten-based MLC has a density of 18.7 g cm(- 3) and an overall leakage of about 1.1 ± 0.03%. The discrepancies between the film measured and simulated closed and blocked fields are below 2% and 8%, respectively. Other measurements were performed for alternated leaf patterns and the agreement is satisfactory (to within 4%). The dynamic mode for this MLC was implemented and the discrepancies between film measurements and simulations are within 4%. CONCLUSIONS: The Varian(®) Trilogy(®) (2300 C/D) linear accelerator including the HD120 MLC was successfully modeled and simulated using the Monte Carlo BEAMNRC code by developing an independent CM, the HDMLC CM, either in static and dynamic modes.


Subject(s)
Models, Theoretical , Particle Accelerators/instrumentation , Radiometry/instrumentation , Radiometry/methods , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, High-Energy/instrumentation , Computer Simulation , Radiotherapy Dosage
9.
Clin Oral Implants Res ; 23(12): 1404-13, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22092925

ABSTRACT

OBJECTIVES: This study aimed to analyse the association between polymorphisms in the IL1 gene cluster and failure of dental implants in a Portuguese population. MATERIAL AND METHODS: A total of 155 Caucasian Portuguese subjects were divided into two groups: 100 with successful dental implants and 55 with unsuccessful dental implants. DNA was obtained through an oral mucosa scraping. PCR was used to identify the polymorphisms: single nucleotide changes in positions -889 of IL1A gene and +3953 of IL1B gene. RESULTS: The prevalence of the polymorphisms -889IL1A gene and +3953IL1B gene, determined by the positive result of TGP (Genetic Test for Periodontitis; CGC, Genetics, Portugal), in the studied population rehabilitated with dental implants was of 33.50%. Allele 1 of the IL1B gene was the most prevalent (62.20%), followed by allele 1 of the IL1A gene (54.80%) and the least frequent was allele 2 of IL1B gene (37.40%). Success of dental implants was mainly associated with a negative TGP result, whereas no success was found to be related to a positive result. There were no statistically significant differences between the alleles 1 and 2 of the genes IL1A and IL1B and the tobacco and alcohol consumption for the success or no success of the dental implants. CONCLUSIONS: The alleles 1 and 2 of IL1A gene and the alleles 1 and 2 of IL1B gene were statistically associated with the success or no success of the dental implants. Tobacco habit and alcohol consumption showed no statistically significant association with success or no success of the dental implants.


Subject(s)
Dental Implants , Dental Restoration Failure , Interleukin-1alpha/genetics , Interleukin-1beta/genetics , Polymorphism, Single Nucleotide , Adult , Aged , Alcohol Drinking/epidemiology , Alleles , Female , Humans , Male , Middle Aged , Polymerase Chain Reaction , Portugal/epidemiology , Risk Factors , Smoking/epidemiology , Surveys and Questionnaires
10.
Eur J Radiol ; 151: 110278, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35430441

ABSTRACT

According to the World Health Organization (WHO), at the end of 2020, 7.8 million women alive were diagnosed with breast cancer in the past 5 years, making it the world's most prevalent cancer. It is largely recognized and demonstrated that early detection represents the first strategy to follow in the fight against cancer. The effectiveness of mammography screening for early breast cancer detection has been proven in several surveys and studies over the last three decades. The estimation of the Mean Glandular Dose (MGD) is important to understand the radiation-associated risk from breast x-ray imaging exams. It continues to be the subject of numerous studies and debates, since its accuracy is directly related to risk estimation and for optimizing breast cancer screening programs. This manuscript reviews the main dosimetry formalisms used to estimate the MGD in mammography and to understand the continuing efforts to reduce the absorbed dose over the last forty years. The dosimetry protocols were formulated initially for mammography. Digital breast tomosynthesis (DBT) either in conjunction with synthesized digital mammogram (SDM) or with digital mammography (DM), is routinely used in many breast cancer screening programs and consequently the dosimetry protocols were extended for these techniques.


Subject(s)
Breast Neoplasms , Breast/diagnostic imaging , Breast Neoplasms/diagnostic imaging , Early Detection of Cancer/methods , Female , Humans , Mammography/methods , Mass Screening , X-Rays
11.
Eur J Radiol ; 155: 110509, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36087425

ABSTRACT

In X-ray breast imaging, Digital Mammography (DM) and Digital Breast Tomosynthesis (DBT), are the standard and largely used techniques, both for diagnostic and screening purposes. Other techniques, such as dedicated Breast Computed Tomography (BCT) and Contrast Enhanced Mammography (CEM) have been developed as an alternative or a complementary technique to the established ones. The performance of these imaging techniques is being continuously assessed to improve the image quality and to reduce the radiation dose. These imaging modalities are predominantly used in the diagnostic setting to resolve incomplete or indeterminate findings detected with conventional screening examinations and could potentially be used either as an adjunct or as a primary screening tool in select populations, such as for women with dense breasts. The aim of this review is to describe the radiation dosimetry for these imaging techniques, and to compare the mean glandular dose with standard breast imaging modalities, such as DM and DBT.


Subject(s)
Breast Neoplasms , Breast , Breast/diagnostic imaging , Breast Density , Breast Neoplasms/diagnostic imaging , Female , Humans , Mammography/methods , Radiometry/methods , X-Rays
12.
Radiography (Lond) ; 28(2): 333-339, 2022 05.
Article in English | MEDLINE | ID: mdl-34565679

ABSTRACT

INTRODUCTION: Digital Mammography (DM-2D) and more recently Digital Breast Tomosynthesis (DBT), are two of the most effective imaging modalities for breast cancer detection, often used in screening programmes. It may happen that exams using these two imaging modalities are inadvertently performed to pregnant women. The objective of this study is to assess the dose in the uterus due to DM-2D and DBT exams, according to two main irradiation scenarios: in the 1st scenario the exposure parameters were pre-selected directly by the imaging system, while in the 2nd scenario, the maximum exposure parameters were chosen. METHODS: The mammography equipment used was a Siemens Mammomat Inspiration. A physical anthropomorphic phantom, PMMA plates (simulating a breast thickness of 6 cm) and thermoluminescent dosimeters (TLDs) were used to measure entrance air kerma values on the phantom's breast and abdomen in order to successively estimate the mean glandular dose (MGD) and the dose in the uterus. For the two irradiation scenarios chosen, two-breast imaging modalities were selected: 1) DBT in Cranio-Caudal (CC) view (with 28 kV and 160 mAs as exposure parameters), 2) DBT and DM in Medio Lateral-Oblique (MLO) and CC views (with 34 kV and 250 mAs as exposure parameters). RESULTS: In the 1st scenario, the TLD measurements did not detect significant dose values in the abdomen whereas the MGD estimated using the D.R. Dance model was in close agreement with data available in the literature. In the 2nd scenario, there was no significant difference in MGD estimation between the different views, whereas the air kerma values in the abdomen (in DBT mode, CC and MLO) were 0.049 mGy and 0.004 mGy respectively. In CC DM-2D mode the abdomen air kerma value was 0.026 mGy, with no significant detected value in MLO view. CONCLUSIONS: For the dose in the uterus, the obtained values seem to indicate that DM-2D and DBT examinations inadvertently performed during pregnancy do not pose a significant radiological risk, even considering the case of overexposure in both breasts. IMPLICATIONS FOR PRACTICE: The accurate knowledge of the doses in DM-2D and DBT will contribute to raise the awareness among medical practitioners involved in breast imaging empowering them to provide accurate information about dose levels in the uterus, improving their radiation risk communication skills and consequently helping to reduce the anxiety of pregnant women undergoing this type of examinations.


Subject(s)
Breast , Mammography , Breast/diagnostic imaging , Female , Humans , Mammography/methods , Phantoms, Imaging , Pregnancy , Radiation Dosage , Uterus/diagnostic imaging
13.
Aust Vet J ; 100(11): 562-565, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36042563

ABSTRACT

A molecular survey of herpesviruses in Australian native mammals was conducted, spanning 260 individuals from 27 species. Among the herpesviruses detected, a putative new gammaherpesvirus species was detected in the yellow-bellied glider (Petaurus australis), and another in the critically endangered Leadbeater's possum (Gymnobelideus leadbeateri). In addition, the known host range of the putative species macropodid gammaherpesvirus 3 (MaHV-3) is herein extended to the western grey kangaroo (Macropus fuliginosus). These findings expand our understanding of herpesviruses in Australian mammals and may inform biosecurity protocols for captive and translocated populations.


Subject(s)
Macropodidae , Animals , Australia
14.
Int J Tuberc Lung Dis ; 26(7): 641-649, 2022 07 01.
Article in English | MEDLINE | ID: mdl-35768920

ABSTRACT

SETTING: Antenatal care (ANC) and postpartum care (PPC) clinic in Manhiça District, Mozambique.OBJECTIVE: To estimate the prevalence of TB among pregnant and post-partum women and describe the clinical characteristics of the disease in a rural area of Southern Mozambique.METHODS: We conducted a cross-sectional TB prevalence study among pregnant and post-partum women recruited from September 2016 to March 2018 at the Manhiça Health Care Center (MHC). We recruited two independent cohorts of women consecutively presenting for routine pregnancy or post-partum follow-up visits.RESULTS: A total of 1,980 women from the ANC clinic and 1,010 from the PPC clinic were enrolled. We found a TB prevalence of 505/100,000 (95% CI: 242-926) among pregnant women and 297/100,000 (95% CI: 61-865) among post-partum women. Among HIV-positive pregnant women, TB prevalence was 1,626/100,000 (95% CI: 782-2,970) and among postpartum HIV-positive women, TB prevalence was 984/100,000 (95% CI: 203-2,848).CONCLUSIONS: The burden of TB was not higher in postpartum women than in pregnant women. Most TB cases were detected in HIV-positive women. TB screening and diagnostic testing among pregnant and postpartum women attending ANC and PPC clinics in Manhiça District is acceptable and feasible.


Subject(s)
HIV Infections , Pregnancy Complications, Infectious , Tuberculosis, Pulmonary , Cross-Sectional Studies , Female , HIV Infections/diagnosis , HIV Infections/epidemiology , Humans , Postpartum Period , Pregnancy , Pregnancy Complications, Infectious/diagnosis , Pregnancy Complications, Infectious/epidemiology , Prenatal Care , Prevalence , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/epidemiology
15.
Microbiol Resour Announc ; 10(2)2021 Jan 14.
Article in English | MEDLINE | ID: mdl-33446587

ABSTRACT

We present the genome sequences of macropodid alphaherpesviruses 2 and 4, two closely related pathogens of macropods. Both encoded 68 nonredundant open reading frames (ORFs) and share 90.6% genome-wide nucleotide identity. These viruses are associated with fatal outbreaks of disease in multiple marsupial species. These sequences will be important for the development of new diagnostic tools.

16.
Ann Intensive Care ; 11(1): 180, 2021 Dec 23.
Article in English | MEDLINE | ID: mdl-34950977

ABSTRACT

BACKGROUND: Stratifying patients with sepsis was the basis of the predisposition, infection, response and organ dysfunction (PIRO) concept, an attempt to resolve the heterogeneity in treatment response. The purpose of this study is to perform an independent validation of the PIRO staging system in an international cohort and explore its utility in the identification of patients in whom time to antibiotic treatment is particularly important. METHODS: Prospective international cohort study, conducted over a 6-month period in five Portuguese hospitals and one Australian institution. All consecutive adult patients admitted to selected wards or the intensive care, with infections that met the CDC criteria for lower respiratory tract, urinary, intra-abdominal and bloodstream infections were included. RESULTS: There were 1638 patients included in the study. Patients who died in hospital presented with a higher PIRO score (10 ± 3 vs 8 ± 4, p < 0.001). The observed mortality was 3%, 15%, 24% and 34% in stage I, II, III and IV, respectively, which was within the predicted intervals of the original model, except for stage IV patients that presented a lower mortality. The hospital survival rate was 84%. The application of the PIRO staging system to the validation cohort resulted in a positive predictive value of 97% for stage I, 91% for stage II, 85% for stage III and 66% for stage IV. The area under the receiver operating characteristics curve (AUROC) was 0.75 for the all cohort and 0.70 if only patients with bacteremia were considered. Patients in stage III and IV who did not have antibiotic therapy administered within the desired time frame had higher mortality rate than those who have timely administration of antibiotic. CONCLUSIONS: To our knowledge, this is the first external validation of this PIRO staging system and it performed well on different patient wards within the hospital and in different types of hospitals. Future studies could apply the PIRO system to decision-making about specific therapeutic interventions and enrollment in clinical trials based on disease stage.

17.
Appl Radiat Isot ; 66(4): 435-40, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18222694

ABSTRACT

The Monte Carlo simulation programs PENELOPE and MCNPX have been used for simulating the dose rate distribution in a (60)Co gamma irradiator. The simulated isodose curves obtained for each simulation code were validated comparing them to the dose measurements performed with a Fricke solution, which is a standard dosemeter widely used in radiation processing for calibration purposes. The agreement between the simulated values and the measurements indicates the effectiveness of both codes in performing the dose-mapping simulation for gamma irradiators.

18.
Phys Med ; 52: 9-17, 2018 Aug.
Article in English | MEDLINE | ID: mdl-30139615

ABSTRACT

Biokinetic data from the administration of radiopharmaceuticals is essential in nuclear medicine dosimetry. It has particular significance in children, as their metabolism is very different from adults. Biokinetic models for paediatric patients could therefore need to be adapted to better reflect their absorption, retention and excretion functions, when compared to adults. Obtaining quality in vivo infant or paediatric biokinetic data is then essential to improve the available reference models, which in turn can lead to the optimization of paediatric procedures and protocols in clinical practice. This study analyses the biokinetic behaviour of 99mTc-dimercaptosuccinic acid (DMSA), in 8 infants aged 4 months to 2 years old, through an imaging study using a gamma camera, and compares the obtained values with those obtained with the reference ICRP biokinetic model. The in vivo data was treated using an adapted methodology from the MIRD 16 pamphlet. Activity curves for the liver, the kidney and the whole body, were built, and new effective absorption, retention and excretion half-lives were estimated, and compared with the reference biokinetic parameters of ICRP 128. The obtained residence time in the kidneys of 2.56 h, has a deviation of 30.8% to the ICRP 128 value of 3.70 h. The obtained maximum uptake in the kidneys was of 0.22/A0, which compares to the value of 0.31/A0 for ICRP. The obtained biokinetic parameters were used to estimate the absorbed dose. The obtained dose values are smaller than the reference ICRP 128 ones by 32.1% in the kidneys, and 18.4% in the liver.


Subject(s)
Gamma Cameras , Radionuclide Imaging , Radiopharmaceuticals/pharmacokinetics , Technetium Tc 99m Dimercaptosuccinic Acid/pharmacokinetics , Calibration , Child, Preschool , Female , Humans , Infant , Kidney/diagnostic imaging , Kidney/metabolism , Liver/diagnostic imaging , Liver/metabolism , Male , Models, Biological , Radiometry , Radionuclide Imaging/instrumentation , Time Factors
19.
Appl Radiat Isot ; 135: 72-77, 2018 May.
Article in English | MEDLINE | ID: mdl-29413839

ABSTRACT

The distribution of radiopharmaceuticals in tumor cells represents a fundamental aspect for a successful molecular targeted radiotherapy. It was largely demonstrated at microscopic level that only a fraction of cells in tumoral tissues incorporate the radiolabel. In addition, the distribution of the radionuclides at sub-cellular level, namely inside each nucleus, should also be investigated for accurate dosimetry estimation. The most used method to perform cellular dosimetry is the MIRD one, where S-values are able to estimate cellular absorbed doses for several electron energies, nucleus diameters, and considering homogeneous source distributions. However the radionuclide distribution inside nuclei can be also highly non-homogeneous. The aim of this study is to show in what extent a non-accurate cellular dosimetry could lead to misinterpretations of surviving cell fraction vs dose relationship; in this context, a dosimetric case study with 99mTc is also presented. METHODS: The state-of-art MCNP6 Monte Carlo simulation was used in order to model cell structures both in MIRD geometry (MG) and MIRD modified geometries (MMG), where also entire mitotic chromosome volumes were considered (each structure was modeled as liquid water material). In order to simulate a wide energy range of Auger emitting radionuclides, four mono energetic electron emissions were considered, namely 213eV, 6keV, 11keV and 20keV. A dosimetric calculation for 99mTc undergoing inhomogeneous nuclear internalization was also performed. RESULTS: After a successful validation step between MIRD and our computed S-values for three Auger-emitting radionuclides (99mTc, 125I and 64Cu), absorbed dose results showed that the standard MG could differ from the MMG from one to three orders of magnitude. These results were also confirmed by considering the 99mTc spectrum emission (Auger and internal conversion electrons). Moreover, considering an inhomogeneous radionuclide distribution, the average electron energy that maximizes the absorbed dose was found to be different for MG and MMG. CONCLUSIONS: The modeling of realistic radionuclide localization inside cells, including a inhomogeneous nuclear distribution, revealed that i) a strong bias in surviving cell fraction vs dose relationships (taking to different radiobiological models) can arise; ii) the alternative models might contribute to a more accurate prediction of the radiobiological effects inherent to more specific molecular targeted radiotherapy strategies.

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