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1.
Lancet Microbe ; 5(4): e317-e325, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38359857

RESUMEN

BACKGROUND: There has been high uptake of rapid antigen test device use for point-of-care COVID-19 diagnosis. Individuals who are symptomatic but test negative on COVID-19 rapid antigen test devices might have a different respiratory viral infection. We aimed to detect and sequence non-SARS-CoV-2 respiratory viruses from rapid antigen test devices, which could assist in the characterisation and surveillance of circulating respiratory viruses in the community. METHODS: We applied archival clinical nose and throat swabs collected between Jan 1, 2015, and Dec 31, 2022, that previously tested positive for a common respiratory virus (adenovirus, influenza, metapneumovirus, parainfluenza, rhinovirus, respiratory syncytial virus [RSV], or seasonal coronavirus; 132 swabs and 140 viral targets) on PCR to two commercially available COVID-19 rapid antigen test devices, the Panbio COVID-19 Ag Rapid Test Device and Roche SARS-CoV-2 Antigen Self-Test. In addition, we collected 31 COVID-19 rapid antigen test devices used to test patients who were symptomatic at The Royal Melbourne Hospital emergency department in Melbourne, Australia. We extracted total nucleic acid from the device paper test strips and assessed viral recovery using multiplex real-time PCR (rtPCR) and capture-based whole genome sequencing. Sequence and genome data were analysed through custom computational pipelines, including subtyping. FINDINGS: Of the 140 respiratory viral targets from archival samples, 89 (64%) and 88 (63%) were positive on rtPCR for the relevant taxa following extraction from Panbio or Roche rapid antigen test devices, respectively. Recovery was variable across taxa: we detected influenza A in nine of 18 samples from Panbio and seven of 18 from Roche devices; parainfluenza in 11 of 20 samples from Panbio and 12 of 20 from Roche devices; human metapneumovirus in 11 of 16 from Panbio and 14 of 16 from Roche devices; seasonal coronavirus in eight of 19 from Panbio and two of 19 from Roche devices; rhinovirus in 24 of 28 from Panbio and 27 of 28 from Roche devices; influenza B in four of 15 in both devices; and RSV in 16 of 18 in both devices. Of the 31 COVID-19 devices collected from The Royal Melbourne Hospital emergency department, 11 tested positive for a respiratory virus on rtPCR, including one device positive for influenza A virus, one positive for RSV, four positive for rhinovirus, and five positive for SARS-CoV-2. Sequences of target respiratory viruses from archival samples were detected in 55 (98·2%) of 56 samples from Panbio and 48 (85·7%) of 56 from Roche rapid antigen test devices. 98 (87·5%) of 112 viral genomes were completely assembled from these data, enabling subtyping for RSV and influenza viruses. All 11 samples collected from the emergency department had viral sequences detected, with near-complete genomes assembled for influenza A and RSV. INTERPRETATION: Non-SARS-CoV-2 respiratory viruses can be detected and sequenced from COVID-19 rapid antigen devices. Recovery of near full-length viral sequences from these devices provides a valuable opportunity to expand genomic surveillance programmes for public health monitoring of circulating respiratory viruses. FUNDING: Australian Government Medical Research Future Fund and Australian National Health and Medical Research Council.


Asunto(s)
COVID-19 , Gripe Humana , Metapneumovirus , Infecciones por Paramyxoviridae , Virus Sincitial Respiratorio Humano , Humanos , COVID-19/diagnóstico , SARS-CoV-2/genética , Gripe Humana/diagnóstico , Prueba de COVID-19 , Australia , Metapneumovirus/genética , Virus Sincitial Respiratorio Humano/genética , Secuenciación Completa del Genoma
3.
Lancet Microbe ; 4(10): e800-e810, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37722405

RESUMEN

BACKGROUND: The 2022 outbreak of mpox (formerly known as monkeypox) led to the spread of monkeypox virus (MPXV) in over 110 countries, demanding effective disease management and surveillance. As current diagnostics rely largely on centralised laboratory testing, our objective was to develop a simple rapid point-of-care assay to detect MPXV in clinical samples using isothermal amplification coupled with CRISPR and CRISPR-associated protein (Cas) technology. METHODS: In this proof-of-concept study, we developed a portable isothermal amplification CRISPR-Cas12a-based assay for the detection of MPXV. We designed a panel of 22 primer-guide RNA sets using pangenome and gene-agnostic approaches, and subsequently shortlisted the three sets producing the strongest signals for evaluation of analytical sensitivity and specificity using a fluorescence-based readout. The set displaying 100% specificity and the lowest limit of detection (LOD) was selected for further assay validation using both a fluorescence-based and lateral-flow readout. Assay specificity was confirmed using a panel of viral and bacterial pathogens. Finally, we did a blind concordance study on genomic DNA extracted from 185 clinical samples, comparing assay results with a gold-standard quantitative PCR (qPCR) assay. We identified the optimal time to detection and analysed the performance of the assay relative to qPCR using receiver operating characteristic (ROC) curves. We also assessed the compatibility with lateral-flow strips, both visually and computationally, where strips were interpreted blinded to the fluorescence results on the basis of the presence or absence of test bands. FINDINGS: With an optimal run duration of approximately 45 min from isothermal amplification to CRISPR-assay readout, the MPXV recombinase polymerase amplification CRISPR-Cas12a-based assay with the selected primer-guide set had an LOD of 1 copy per µL and 100% specificity against tested viral pathogens. Blinded concordance testing of 185 clinical samples resulted in 100% sensitivity (95% CI 89·3-100) and 99·3% specificity (95% CI 95·7-100) using the fluorescence readout. For optimal time to detection by fluorescence readout, we estimated the areas under the ROC curve to be 0·98 at 2 min and 0·99 at 4 min. Lateral-flow strips had 100% sensitivity (89·3-100) and 98·6% specificity (94·7-100) with both visual and computational assessment. Overall, lateral-flow results were highly concordant with fluorescence-based readouts (179 of 185 tests, 96·8% concordant), with discrepancies associated with low viral load samples. INTERPRETATION: Our assay for the diagnosis of mpox displayed good performance characteristics compared with qPCR. Although optimisation of the assay will be required before deployment, its usability and versatility present a potential solution to MPXV detection in low-resource and remote settings, as well as a means of community-based, on-site testing. FUNDING: Victorian Medical Research Accelerator Fund and the Australian Government Department of Health.

4.
J Med Virol ; 95(8): e29029, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37565686

RESUMEN

The impact and frequency of infectious disease outbreaks demonstrate the need for timely genomic surveillance to inform public health responses. In the largest known outbreak of mpox, genomic surveillance efforts have primarily focused on high-incidence nations in Europe and the Americas, with a paucity of data from South-East Asia and the Western Pacific. Here we analyzed 102 monkeypox virus (MPXV) genomes sampled from 56 individuals in Melbourne, Australia. All genomes fell within the 2022 MPXV outbreak lineage (B.1), with likely onward local transmission detected. We observed within-host diversity and instances of co-infection, and highlight further examples of structural variation and apolipoprotein B editing complex-driven micro-evolution in the current MPXV outbreak. Updating our understanding of MPXV emergence and diversification will inform public health measures and enable monitoring of the virus' evolutionary trajectory throughout the mpox outbreak.


Asunto(s)
Monkeypox virus , Mpox , Humanos , Monkeypox virus/genética , Mpox/epidemiología , Genómica , Brotes de Enfermedades , Australia/epidemiología
6.
Am J Pathol ; 192(11): 1496-1505, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36030837

RESUMEN

Lungs often present tissue calcifications and even ossifications, both in the context of high or normal serum calcium levels. Precise mechanisms governing lung calcifications have not been explored. Herein, we emphasize recent advances about calcification processes in other tissues (especially vascular and bone calcifications) and discuss potential sources of calcium precipitates in the lungs, involvement of mineralization promoters and crystallization inhibitors, as well as specific cytokine milieu and cellular phenotypes characteristic for lung diseases, which may be involved in pulmonary calcifications. Further studies are necessary to demonstrate the exact mechanisms underlying calcifications in the lungs, document homologies in biomineralization processes between various tissues in physiological and pathologic conditions, and unravel any locally specific characteristics of mineralization processes that may be targeted to reduce or prevent functionally relevant lung calcifications without negatively affecting the skeleton.

8.
Euro Surveill ; 27(22)2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35656835

RESUMEN

Rapid diagnosis and whole genome sequencing confirmed a case of monkeypox in an HIV-positive individual receiving antiretroviral therapy. The patient had a normal CD4+ T-cell count and suppressed HIV viral load and presented with a genital rash in Melbourne, Australia after return from Europe in May 2022. He subsequently developed systemic illness and disseminated rash and 11 days after symptom onset, he was hospitalised to manage painful bacterial cellulitis of the genital area.


Asunto(s)
Exantema , Infecciones por VIH , Mpox , Exantema/etiología , Genitales , Infecciones por VIH/complicaciones , Infecciones por VIH/diagnóstico , Infecciones por VIH/tratamiento farmacológico , Humanos , Masculino , Mpox/diagnóstico , Carga Viral
9.
PeerJ ; 10: e13055, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35287344

RESUMEN

Background: Connexins are transmembrane proteins forming gap junctions between the cells, which allow intercellular communication. Significance of gap junctions and connexins in lung carcinoma is not yet understood. The objective of the study was to investigate immunohistochemical expression and the localization of connexin-43 (Cx43) in primary lung carcinoma and its lymphatic metastases. Methods: Surgical specimens of excised tumors from 88 patients (45 men and 43 women, 61.9 ± 7.4 years) with lung carcinoma (52 adenocarcinoma (AC), 36 squamous cell carcinoma (SqCC)) who were operated on at the University Hospital "Bezanijska Kosa" in a five-year period (2012-2016) were used. We conducted immunohistochemical staining for Cx43 and measured the degree of expression (percentage of positive cells and staining intensity) as well as localization of Cx43 in primary tumor and in lymphatic metastases. Results: Immunohistochemical analysis of the primary tumors revealed that SqCC showed significantly higher percentage of tumor cells expressing Cx43 as well as higher staining intensity than AC (p < 0.001). Almost 70% of samples with SqCC showed high Cx43 expression, whereas AC showed no expression in more than 50% of cases. Localization of Cx43 expression was most often cytoplasmic (AC and SqCC) and combined membranous and cytoplasmic (SqCC) with very rare instances of nuclear localization (AC). Almost the same pattern in distribution, intensity, and localization of Cx43 expression was observed in the lymph node metastases; however, almost a third of AC cases changed the pattern of Cx43 expression in the metastasis compared to primary tumor. Conclusion: The results of this study showed that lung carcinomas express Cx43 in more than 65% of cases and that it was aberrantly localized (not membranous localization). We highlighted that SqCC expressed Cx43 more than did AC, both in primary tumor and lymphatic metastases. Further research is needed to establish whether Cx43 could be used as a prognostic biomarker in lung carcinoma.


Asunto(s)
Adenocarcinoma , Carcinoma de Células Escamosas , Neoplasias Pulmonares , Masculino , Humanos , Femenino , Conexina 43/análisis , Metástasis Linfática , Estudios Retrospectivos , Conexinas/metabolismo , Carcinoma de Células Escamosas/cirugía , Adenocarcinoma/cirugía , Neoplasias Pulmonares/cirugía , Pulmón/química
10.
J Clin Med ; 11(3)2022 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-35160164

RESUMEN

Cardiac involvement in drug reaction with eosinophilia and systemic symptoms (DS) is rare but associated with high mortality. The aim of this research was to systematically review case reports by PRISMA guidelines in order to synthetize the knowledge of cardiac manifestations of DS. We identified 42 cases from 36 case reports. Women were two times more affected than men. Two-thirds of patients had cardiac manifestation in the initial phase of the disease, while in one-third of cases cardiac manifestations developed later (mean time of 70 ± 63 days). The most common inciting medications were minocycline (19%) and allopurinol (12%). In 17% of patients, the heart was the only internal organ affected, while the majority (83%) had at least one additional organ involved, most commonly the liver and the kidneys. Dyspnea (55%), cardiogenic shock (43%), chest pain (38%), and tachycardia (33%) were the most common cardiac signs and symptoms reported. Patients frequently had an abnormal ECG (71.4%), and a decrease in left ventricular ejection fraction was the most common echocardiographic finding (45%). Endomyocardial biopsy or histological examination at autopsy was performed in 52.4%, with the predominant finding being fulminant eosinophilic myocarditis with acute necrosis in 70% of those biopsied. All patients received immunosuppressive therapy with intravenous steroids, while non-responders were more likely to have received IVIG, cyclosporine, mycophenolate, and other steroid-sparing agents (60%). Gender and degree of left ventricular systolic dysfunction were not associated with outcomes, but short latency between drug exposure and the first DRESS symptom onset (<15 days) and older age (above 65 years) was associated with death. This underscores the potential importance of heightened awareness and early treatment.

11.
Acta Med Acad ; 50(1): 197-208, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34075773

RESUMEN

In this review, we summarize current approaches to diagnosis of malignant pleural mesothelioma, focusing on the distinction from benign mesothelial proliferations and other malignant tumors. Current recommendations for reporting histological sub-type and tumor grade are also reviewed. Particular emphasis is placed on immunohistochemical and molecular tools that may help in establishing the diagnosis of mesothelioma with greater confidence. Immunohistochemical stains for BRCA1-associated protein (BAP1) and methylthioadenosine phosphorylase (MTAP) and homozygous deletion of p16 using fluorescence in situ hybridization (FISH) are emphasized as important methods for distinguishing benign from malignant mesothelial proliferations. CONCLUSIONS: Diffuse malignant pleural mesothelioma is a heterogeneous group of aggressive pleural tumors for which histological classification plays an increasingly important role in patient management. Stage and resectability remain key drivers of therapeutic strategies and outcomes. There is an increasingly robust suite of diagnostic tools, including immunohistochemical stains for BAP1 and MTAP and p16 FISH, for differentiating benign from malignant mesothelial proliferations in cytology and tissue specimens.


Asunto(s)
Neoplasias Pulmonares , Mesotelioma Maligno , Biomarcadores de Tumor , Diagnóstico Diferencial , Homocigoto , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Eliminación de Secuencia , Proteínas Supresoras de Tumor/genética , Ubiquitina Tiolesterasa/genética
13.
Commun Biol ; 4(1): 666, 2021 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-34079053

RESUMEN

Calcium dynamics control synaptic transmission. Calcium triggers synaptic vesicle fusion, determines release probability, modulates vesicle recycling, participates in long-term plasticity and regulates cellular metabolism. Mitochondria, the main source of cellular energy, serve as calcium signaling hubs. Mitochondrial calcium transients are primarily determined by the balance between calcium influx, mediated by the mitochondrial calcium uniporter (MCU), and calcium efflux through the sodium/lithium/calcium exchanger (NCLX). We identified a human recessive missense SLC8B1 variant that impairs NCLX activity and is associated with severe mental retardation. On this basis, we examined the effect of deleting NCLX in mice on mitochondrial and synaptic calcium homeostasis, synaptic activity, and plasticity. Neuronal mitochondria exhibited basal calcium overload, membrane depolarization, and a reduction in the amplitude and rate of calcium influx and efflux. We observed smaller cytoplasmic calcium transients in the presynaptic terminals of NCLX-KO neurons, leading to a lower probability of release and weaker transmission. In agreement, synaptic facilitation in NCLX-KO hippocampal slices was enhanced. Importantly, deletion of NCLX abolished long term potentiation of Schaffer collateral synapses. Our results show that NCLX controls presynaptic calcium transients that are crucial for defining synaptic strength as well as short- and long-term plasticity, key elements of learning and memory processes.


Asunto(s)
Discapacidad Intelectual/genética , Discapacidad Intelectual/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Intercambiador de Sodio-Calcio/genética , Intercambiador de Sodio-Calcio/metabolismo , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Señalización del Calcio , Cardiomiopatías/genética , Cardiomiopatías/metabolismo , Femenino , Hipocampo/metabolismo , Humanos , Técnicas In Vitro , Potenciación a Largo Plazo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Mitocondriales/química , Proteínas Mitocondriales/deficiencia , Plasticidad Neuronal , Neuronas/metabolismo , Linaje , Mutación Puntual , Terminales Presinápticos/metabolismo , Intercambiador de Sodio-Calcio/química , Transmisión Sináptica/genética , Transmisión Sináptica/fisiología
14.
Am J Case Rep ; 21: e926433, 2020 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-33268763

RESUMEN

BACKGROUND Kaposi Sarcoma Inflammatory Cytokine Syndrome (KICS) is a relatively new syndrome described in patients co-infected with Human Immunodeficiency Virus (HIV) and Kaposi Sarcoma (KS) Herpes Virus (KSHV). KICS clinically resembles Multicentric Castleman disease (MCD) and both present with various degrees of lymphadenopathy, pancytopenia, HIV and KSHV viremia, and signs of systemic inflammatory syndrome (SIRS). KICS has higher mortality than MCD and is rarely recognized. Lymph node, bone marrow, or splenic biopsy can help differentiate between the 2 entities. CASE REPORT We present a case of a 28-year-old African American man with advanced acquired immunodeficiency syndrome (AIDS) who was diagnosed with disseminated pulmonary and cutaneous KS. Following initiation of combined antiretroviral therapy (cART), rapid immunologic recovery occurred followed by rapid clinical deterioration (IRIS) with multiorgan failure, overwhelming SIRS, and ultimately death. The patient's symptoms, signs, and laboratory findings during this episode could not be solely explained by KS-IRIS, and MCD versus KICS was diagnosed. CONCLUSIONS SIRS in patients with uncontrolled HIV viremia and CD4 lymphopenia has a broad differential diagnosis, including infectious and noninfectious causes. It encompasses sepsis due to common bacterial pathogens, various HIV-specific opportunistic infections, immunological conditions such as hemophagocytic lymphohistiocytosis (HLH), and IRIS, malignancies such as primary effusion lymphoma (PEL) and MCD, and finally KCIS. Clinicians involved in treatment of these patients should have a high index of suspicion for less-known and recently described syndromes such as KICS to recognize it early and initiate timely treatment, which might improve the high mortality associated with KICS.


Asunto(s)
Enfermedad de Castleman , Infecciones por VIH , Herpesvirus Humano 8 , Síndrome Inflamatorio de Reconstitución Inmune , Sarcoma de Kaposi , Adulto , Enfermedad de Castleman/complicaciones , Enfermedad de Castleman/diagnóstico , Citocinas , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Humanos , Síndrome Inflamatorio de Reconstitución Inmune/complicaciones , Síndrome Inflamatorio de Reconstitución Inmune/diagnóstico , Masculino , Sarcoma de Kaposi/complicaciones , Sarcoma de Kaposi/diagnóstico
15.
Phys Rev Lett ; 123(8): 087401, 2019 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-31491230

RESUMEN

We present a first-principles method for the calculation of the temperature-dependent relaxation of symmetry-breaking atomic driving forces in photoexcited systems. We calculate the phonon-assisted decay of the photoexcited force on the low-symmetry E_{g} mode following absorption of an ultrafast pulse in Bi, Sb, and As. The force decay lifetimes for Bi and Sb are of the order of 10 fs and in agreement with recent experiments, demonstrating that electron-phonon scattering is the primary mechanism relaxing the symmetry-breaking forces. Calculations for a range of absorbed photon energies suggest that larger amplitude, symmetry-breaking atomic motion may be induced by choosing a pump photon energy which maximizes the product of the initial E_{g} force and its lifetime. The high-symmetry A_{1g} force undergoes a partial decay to a nonzero constant on similar timescales, which has not yet been measured in experiments. The average imaginary part of the electron self-energy over the photoexcited carrier distribution provides a crude indication of the decay rate of symmetry-breaking forces.

16.
Ann Saudi Med ; 36(1): 42-50, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26922687

RESUMEN

BACKGROUND: Miliary tuberculosis (TB) usually presents with atypical clinical manifestations; thus it is often recognized only at autopsy. OBJECTIVES: Our objectives were to study the frequency of MT diagnosed at autopsy and determine clinical diagnoses that masked TB, as well as causes of death and comorbidities. DESIGN: Retrospective study of all autopsies performed between 2008 and 2014. SETTING: Institute of Pathology, Belgrade, Serbia. SUBJECTS AND METHODS: in subjects where autopsy showed the presence of MT that was not recognized clinically, we recorded the clinical diagnoses (presumed causes of death) as reported in autopsy request forms, as well as actual cause of death and comorbidities as determined at autopsy. MAIN OUTCOME MEASURES: Clinically unrecognized MT. RESULTS: The total number of autopsies in this period was 6206. thirty-five individuals showed clinically unrecognized MT (0.56% of all autopsies, age: 62.2 [17.2] years, M:F=2:3). Common clinical diagnoses masking pulmonary MT were exacerbation of COPD (25%) and pulmonary thromboembolism (25%), with common radiological presentation of diffuse pulmonary infiltrates (56.3%). Dominant clinical diagnoses in patients with generalized MT were adult respiratory distress syndrome, sepsis, gastrointestinal bleeding and meningoencephalitis. Disseminated MT was often associated with secondary anemia or thrombocytopenia (15.8%) and recent surgery (15.8%). Frequent comorbidities included chronic renal failure and malignancies, whereas MT was a dominant cause of death. CONCLUSION: Greater awareness of MT is needed to improve recognition in clinical settings. In particular, MT should be considered in patients with atypical clinical presentation and diffuse pulmonary infiltrates on chest X-ray, particularly if they have chronic renal failure, malignancy, hematological disorders or a history of recent surgery. LIMITATIONS: None.


Asunto(s)
Diagnóstico Tardío/mortalidad , Tuberculosis Miliar/diagnóstico , Anciano , Autopsia , Causas de Muerte , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Serbia/epidemiología , Tuberculosis Miliar/mortalidad
17.
Expert Opin Drug Discov ; 8(10): 1253-63, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23919882

RESUMEN

INTRODUCTION: Copper is an essential element in the human organism. Furthermore, copper deficiency is rare; however, the hematologic manifestations associated with copper deficiency, such as anemia, leukopenia, neutropenia, myeloneuropathy and osteoporosis, are well known. AREAS COVERED: The authors present an overview of the various commercially available drugs used in the treatment of copper deficiency. Furthermore, the authors offer a description of copper complexes, as potential pharmaceutically active compounds, that can be used in the design of new formulations with therapeutic potential. EXPERT OPINION: Progress in the synthesis of new metallo-organic complexes (such as the copper-pullulan complex) and the chelated form of copper have provided new avenues for drug design that combat copper deficiency. The copper-pullulan complex, as an active compound, has been designed in its solid dosage form, and its optimization in the treatment of copper deficiency has been furthered through advancements in experimental design methodology. The authors believe that the numerous ongoing studies, evaluating the synthesis of these complexes, should produce new additions to the copper deficiency therapeutic armamentarium in the future.


Asunto(s)
Quelantes/uso terapéutico , Cobre/deficiencia , Cobre/uso terapéutico , Diseño de Fármacos , Glucanos/química , Compuestos Organometálicos/uso terapéutico , Disponibilidad Biológica , Quelantes/síntesis química , Quelantes/química , Quelantes/farmacocinética , Cobre/química , Humanos , Compuestos Organometálicos/síntesis química , Compuestos Organometálicos/química , Compuestos Organometálicos/farmacocinética
18.
Drug Dev Ind Pharm ; 39(7): 1084-90, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22871119

RESUMEN

New formulation for treatment a copper deficiency in human organism was developed and optimized by application of mathematical modeling. This formulation contained copper (II) complex with polysaccharide pullulan, as active substance. The binder concentration [polyvinyl pyrrolidone (PVP %)], the disintegrant concentration (corn starch %) and the resistance to crushing (hardness) were taken as independent variables. In vitro measured drug release characteristics of the tablets at pH 1.20 and 7.56 were studied as response variables. Initially, the created full factorial 2(3) model showed that the resistance to crushing has the most significant effect on copper (II) complex release from the formulation. Optimal tablet formulation F2, with lower Hardness (50 N), lower Starch (20.0%) and higher PVP (2.7%) concentrations, is selected using the partial least squares (PLS) regression modeling. The selected formulation F2 has expressed the best drug release profile at both pH (98.66% pH = 1.20; 93.35% pH = 7.56), and the lowest variation of tablets weight. The presented theoretical approach and created PLS model can be readily applied in future copper complexes studies and formulation design.


Asunto(s)
Cobre/química , Química Farmacéutica , Concentración de Iones de Hidrógeno , Análisis de los Mínimos Cuadrados , Modelos Teóricos , Povidona/química , Solubilidad , Comprimidos
19.
Phys Chem Chem Phys ; 14(47): 16209-22, 2012 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-23060011

RESUMEN

This paper presents a theoretical investigation of the microscopic mechanisms responsible for heat transport in bulk Si, Ge and SiGe alloys, with the goal of providing insight into design rules for efficient Si-based nanostructured thermoelectric semiconductors. We carried out a detailed atomistic study of the thermal conductivity, using molecular dynamics and the Boltzmann transport equation. We investigated in detail the effects of the physical approximations underlying each approach, as well as the effect of the numerical approximations involved in the implementation of the two different methods. Our findings permitted us to understand and reconcile apparently conflicting results reported in the literature.

20.
Acta Pol Pharm ; 69(4): 739-49, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22876618

RESUMEN

The aim of this study was to design and optimize a new tablet formulation for treatment of copper deficiency in human organism by using an experimental design. The new no-veneered tablets, prepared by a wet granulation technique, are containg active substance, a copper(II) complex with polysaccharide pullulan. The binder concentration, the disintegrant concentration and the resistance to crushing were used as independent variables in the formulation, while in vitro measured drug release characteristics of the tablets was response variable in a full factorial design 2(3) modeling. A cubic model for data fitted was used to examine the obtained results. They showed that the resistance to crushing has the most significant effect on copper(II) complex release from the formulation, while the disintegrant concentration has smaller influence on dissolution profile of copper(II) complex and the binder concentration had minor impact in this study. Lower value of resistance to crushing has influence on better dissolution profile. Furthermore, physical characteristics of the tablets were evaluated, viz., drug content, hardness, thickness, friability, disintegration time, mass variation, particle size and size distribution.


Asunto(s)
Cobre/química , Cobre/deficiencia , Enfermedades Carenciales/tratamiento farmacológico , Glucanos/química , Compuestos Organometálicos/química , Química Farmacéutica , Enfermedades Carenciales/metabolismo , Composición de Medicamentos , Excipientes/química , Dureza , Humanos , Cinética , Modelos Estadísticos , Tamaño de la Partícula , Povidona/química , Solubilidad , Almidón/química , Comprimidos , Tecnología Farmacéutica/métodos
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