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BACKGROUND: In this paper, we present organ donation and transplantation activities in Poland from 2017 to 2022. Data came from registries maintained by the Polish Transplant Coordinating Center Poltransplant and consisted of the national waiting list, deceased donor registry, transplant registry, and the live donor registry. Poltransplant is the Competent Authority in Organs, with tasks related to preparing assessments, analyses, information, and reports in transplantation medicine and publishing and disseminating these results in the country and abroad. Poltransplant edits the Poltransplant Bulletin on its web pages and presents its activities at Polish Transplantation Society congresses, published consecutively as professional papers.
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Trasplante de Órganos , Sistema de Registros , Obtención de Tejidos y Órganos , Polonia , Humanos , Obtención de Tejidos y Órganos/estadística & datos numéricos , Trasplante de Órganos/estadística & datos numéricos , Donantes de Tejidos/provisión & distribución , Donantes de Tejidos/estadística & datos numéricos , Listas de Espera , Donadores VivosRESUMEN
We propose a novel type of electronic tongue based on four types of monodispersed chemosensory microparticles (MPs) with a lipophilic core stabilized by a nonionic poloxamer surfactant. The lipophilic core composition was designed to achieve cross-sensitivity toward various ions and to enable spectrophotometric and/or spectrofluorimetric detection. Thus, generic anion-selective MPs, generic cation-selective MPs, as well as two types of metalloporphyrin-based MPs were fabricated and their morphology was characterized. Next, their differential sensing ability toward the discrimination of five l-tyrosine derivatives (dopamine, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxy-l-phenylalanine, normetanephrine, 4-hydroxy-3-methoxymandelic acid) was assessed. Comparison with the respective ion-selective electrode (ISE) responses was also provided to verify if the results from the potentiometric e-tongue correspond to outputs of the developed MP optode array. The recognition of dietary supplements containing l-tyrosine (l-Tyr) derivatives with the use of the MP-based e-tongue proved the potential of the developed sensing assay in pharmaceutical analysis.
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This paper focuses on the current state of art as well as on future trends in electrochemical aptasensors application in medical diagnostics. The origin of aptamers is presented along with the description of the process known as SELEX. This is followed by the description of the broad spectrum of aptamer-based sensors for the electrochemical detection of various diagnostically relevant analytes, including metal cations, abused drugs, neurotransmitters, cancer, cardiac and coagulation biomarkers, circulating tumor cells, and viruses. We described also possible future perspectives of aptasensors development. This concerns (i) the approaches to lowering the detection limit and improvement of the electrochemical aptasensors selectivity by application of the hybrid aptamer-antibody receptor layers and/or nanomaterials; and (ii) electrochemical aptasensors integration with more advanced microfluidic devices as user-friendly medical instruments for medical diagnostic of the future.
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Aptámeros de Nucleótidos , Técnicas Biosensibles , Nanoestructuras , Anticuerpos , Biomarcadores , HumanosRESUMEN
INTRODUCTION: Most life-threatening diabetes-related complications involve the kidneys, eyes, cardiovascular system, and autonomic nervous system. Clinical islet transplantation (CITx) may be a therapeutic option for some patients. In this study, we analyzed the progression of diabetic complications after CITx and in patients waiting for islet transplantation. METHODS: From 2008 to 2015, 67 patients were listed for pancreatic or islet transplantation. We compared beta scores, islet scores, and secondary complications between patients who underwent islet allotransplantation (CITx group, n = 6) and the patients awaiting islet transplantation (wait group, n = 19) at baseline and during the 1-year follow-up. RESULTS: In the CITx group, good islet function was observed in 80% of patients 1 month post-transplantation and 40% of patients 1 year post-transplantation; however, no patient achieved insulin independence. One patient who underwent simultaneous islet-kidney transplantation died on day 8 because of severe bleeding in the retroperitoneal space. In 1 case, islet primary nonfunction was observed. Mean islet score in the CITx group 1 year post-transplantation was significantly higher than the pretransplant score and wait group scores at enrollment and 1 year later (P < .01). Increased albuminuria was observed in 3 of 11 (27%) patients in the wait group and 0 patients in the CITx group (P = .08). One patient (9%) in the wait group developed chronic renal failure requiring hemodialysis. Ophthalmologic procedures were required by 47% of patients in the wait group and 0 patients in the CITx group in the first year after transplantation (P < .01). CONCLUSION: Successful islet transplantation slows the progression of diabetic complications.
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Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/cirugía , Insulina , Trasplante de Islotes Pancreáticos , Adulto , Glucemia/análisis , Diabetes Mellitus Tipo 1/sangre , Femenino , Humanos , Insulina/sangre , Insulina/uso terapéutico , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: Donors with acute kidney injury (AKI) are generally accepted as a valuable source of kidneys for transplant. The aim of this study was to assess the risk of developing AKI based on deceased kidney donor parameters. MATERIALS AND METHODS: The data of 162 kidneys procured from deceased donors after brain death were collected. These included clinical characteristics of donors and histologic assessment in organ biopsy specimens. The donors' kidney terminal function was classified according to the Acute Kidney Injury Network criteria. All biopsies were performed with the use of a 16G automatic needle, and the 20-mm tissue specimen was available in all cases. Biopsy specimens were secured and prepared in a routine way with hematoxylin and eosin. The presence of chronic changes was analyzed according to the Banff 2009 classification by 1 experienced nephropathologist. The logistic regression model was used to assess the risk of AKI regarding donor characteristics and histologic findings. RESULTS: There were 50 kidneys (30.9%) with AKI identified. The risk of AKI increased with donor age (P = .002; odds ratio [OR], 1.02; 95% CI, 1.01-1.03), body mass index (P = .003; OR, 1.05; 95% CI, 1.01-1.09), and male sex (P = .001; OR, 1.79; 95% CI, 1.31-2.27). Regarding the histologic findings, the interstitial fibrosis presence was a risk factor of AKI (P = .004; OR, 1.04; 95% CI, 1.01-1.06). CONCLUSIONS: Older donor age, male sex, higher body mass index, and presence of interstitial fibrosis in kidney graft biopsy specimen are risk factors of AKI.
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Lesión Renal Aguda , Muerte Encefálica , Trasplante de Riñón , Donantes de Tejidos/provisión & distribución , Lesión Renal Aguda/etiología , Adulto , Factores de Edad , Femenino , Humanos , Riñón/fisiopatología , Masculino , Persona de Mediana Edad , Factores de Riesgo , Factores SexualesRESUMEN
BACKGROUND: Hypothermic machine perfusion (HMP) has become a standard method of preservation for kidneys procured from expanded-criteria donors and donors after cardiac death. There are different systems and approaches to the HMP preservation period, with cold storage prior to HMP sometimes taking several hours. This study evaluated whether the time at which kidneys receive HMP had any influence on the outcomes of kidney transplantation. METHODS: In this analysis, patient and graft survival were evaluated over a 1-year post-transplantation period. Patients who received HMP kidneys (n = 379) were divided into 2 groups: those who received kidneys with a cold ischemia time (CIT) prior to HMP <295 minutes (group G1; n = 254) and those who received kidneys with CIT prior to HMP >295 minutes (group G2; n = 125). RESULTS: Delayed graft function was observed in 31.8% (81/254) of patients in group G1 vs 46.4% (58/125) of patients in group G2 (P = .007). One-year graft survival was statistically higher in the group G1 (93.2%; 233/254) vs group G2 (86.5%; 105/125, P = .029). Mean 1-year estimated glomerular filtration rate was significantly better in the group G1. CONCLUSIONS: In conclusion, introduction of HMP up to 295 minutes from procurement led to better early and 1-year graft results. Kidneys should receive HMP as soon as possible after retrieval, preferably during procurement.
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Isquemia Fría/efectos adversos , Criopreservación/métodos , Trasplante de Riñón/efectos adversos , Riñón , Preservación de Órganos/efectos adversos , Perfusión/efectos adversos , Adulto , Isquemia Fría/métodos , Muerte , Funcionamiento Retardado del Injerto/etiología , Femenino , Tasa de Filtración Glomerular , Supervivencia de Injerto , Humanos , Hipotermia Inducida , Trasplante de Riñón/métodos , Masculino , Persona de Mediana Edad , Preservación de Órganos/métodos , Perfusión/métodos , Factores de Tiempo , Donantes de Tejidos , Resultado del TratamientoRESUMEN
INTRODUCTION: Painful chronic pancreatitis (CP) is the main indication for analgesic pancreatectomy with simultaneous islet autotransplantation to prevent postoperative diabetes mellitus (DM). However, advanced CP may lead to insulin secretion disorders and DM. There are doubts as to whether islet autotransplantation in such cases is an appropriate procedure. The aim of this study was to analyze the results of islet autotransplantation in patients with CP with already diagnosed with DM. METHOD: Between 2008 and 2015, at the Department of General and Transplantation Surgery, patients with CP and unsatisfying pain treatment with positive fasting C-peptide ( > 0.3 ng/mL) level were qualified for simultaneous pancreatectomy and islet autotransplantation. Eight procedures were performed. In 5 cases patients had DM diagnosed prior to the procedure (DM group n = 5). Three patients without DM diagnosed prior to surgery were the control group (n = 3). RESULT: There were no cases of procedure-related deaths in either group. Pain relief without analgesics was reported by all patients. Good islet function was observed in 80% (4/5) of the DM group vs 100% (3/3) in the control group (P = ns). Brittle diabetes was diagnosed in 1 patient in the DM group as a result of islet primary non-function. CONCLUSION: Patients with CP-related severe pain and DM patients with positive C-peptides should be considered for pancreatectomy and islet autotransplantation.
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Diabetes Mellitus Tipo 1/cirugía , Trasplante de Islotes Pancreáticos/métodos , Pancreatectomía , Pancreatitis Crónica/cirugía , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pancreatectomía/métodos , Trasplante AutólogoRESUMEN
BACKGROUND: There are many doubts with regards to accepting deceased kidneys with acute kidney injury (AKI) for transplantation. PURPOSE: The aim of this study was to present the 5-years outcome of kidney transplantation cases where deceased donors developed AKI before organ procurement. METHODS: Two hundred twenty-six deceased renal transplants were analyzed. Data regarding donors and recipients were collected. Terminal AKI was defined as terminal serum creatinine concentration higher than 1.99 mg/dL and 66 such cases were diagnosed. All kidney transplant recipients were followed for 60 months. RESULTS: AKI group presented more episodes of delayed graft function (DGF) compared to the non-AKI group (56% vs 35%, p < .05). No differences were observed between the groups in the rate of acute rejection episodes, kidney function as well as patient and graft survival. CONCLUSIONS: Transplants with AKI present more often DGF and comparable graft survival to transplants without AKI. Kidneys with AKI can be a valuable source of organs provided attentive selection and appropriate care of deceased donors.
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Lesión Renal Aguda/mortalidad , Funcionamiento Retardado del Injerto/epidemiología , Selección de Donante/normas , Rechazo de Injerto/epidemiología , Fallo Renal Crónico/cirugía , Trasplante de Riñón/efectos adversos , Adolescente , Adulto , Anciano , Aloinjertos/patología , Aloinjertos/provisión & distribución , Funcionamiento Retardado del Injerto/patología , Femenino , Estudios de Seguimiento , Tasa de Filtración Glomerular , Rechazo de Injerto/patología , Supervivencia de Injerto , Humanos , Riñón/patología , Fallo Renal Crónico/mortalidad , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Tasa de Supervivencia , Donantes de Tejidos , Resultado del Tratamiento , Adulto JovenRESUMEN
C-reactive protein (CRP) is a crucial biomarker of cardiovascular diseases and for its detection both optical and electrochemical techniques were applied. This study concerns the application of DNA aptamer as recognition layer for CRP detection. For that purpose aptamer immobilization method on gold surface was selected and the content of receptor layer was optimized to ensure an efficient binding to target protein. The quality of the monolayer was verified by the application of chronocoulometry and atomic force microscopy. Using thiolated aptamers provided the formation of layers of highest density and stability. The square-wave voltammetry experiments performed in the presence of methylene blue redox indicator revealed a linear response of aptasensor towards CRP in the range from 1 to 100â¯pM. Moreover, a DNA aptamer - based sensor showed good selectivity towards C-reactive protein in comparison to interfering proteins including BSA and IgE. Finally, the analysis of CRP in serum sample was conducted using the developed aptasensor.
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Aptámeros de Nucleótidos/metabolismo , Técnicas Biosensibles/métodos , Proteína C-Reactiva/análisis , Aptámeros de Nucleótidos/genética , Secuencia de Bases , Proteína C-Reactiva/química , Proteína C-Reactiva/metabolismo , Electroquímica , Oxidación-ReducciónRESUMEN
A novel electrochemical PNA-based biosensor for the determination of Hg2+ is described. The receptor layer, containing single strands of polythymine PNA (peptide nucleic acid), was formed at the surface of gold electrode. Due to the presence of thymine bases and peptide bonds, an interaction between Hg2+ ion and receptor layer occurs. The influence of chain modification - PNA vs. DNA - and type of redox marker - anionic AQMS-Na (sodium salt of anthraquinone-2-sulfonic acid) and FeII/III (potassium ferri/ferrocyanide) or cationic MB (methylene blue) and RuHex (hexaammineruthenium(III) chloride) - were studied. Proposed PNA-based biosensor with anionic AQMS-Na as a redox marker demonstrated significantly better analytical parameters, as compared to results obtained for other tested redox markers (for measurements at pH6.0). The linear response towards Hg2+ was in the range from 5 to 500nmol·L-1 with the detection limit of 4.5nmol·L-1. The developed sensor distinguishes itself with high selectivity towards Hg2+, even for solutions containing several interfering cations. Interactions between Hg2+ and PNA receptor layer were studied using square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS).
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Técnicas Biosensibles/métodos , Mercurio/análisis , Ácidos Nucleicos de Péptidos/química , Técnicas Biosensibles/instrumentación , Electroquímica , Electrodos , Oro/química , Límite de Detección , Mercurio/química , Oxidación-Reducción , Agua/químicaRESUMEN
A simple and cost effective method for the determination of restriction endonuclease activity is presented. dsDNA immobilized at a gold electrode surface is used as the enzymatic substrate, and an external cationic redox probe is employed in voltammetric measurements for analytical signal generation. The assessment of enzyme activity is based on a decrease of a current signal derived from reduction of methylene blue which is present in the sample solution. For this reason, the covalent attachment of the label molecule is not required which significantly reduces costs of the analysis and simplifies the entire determination procedure. The influence of buffer components on utilized dsDNA/MCH monolayer stability and integrity is also verified. Electrochemical impedance spectroscopy measurements reveal that due to pinhole formation during enzyme activity measurement the presence of any surfactants should be avoided. Additionally, it is shown that the sensitivity of the electrochemical biosensor can be tuned by changing the restriction site location along the DNA length. Under optimal conditions the proposed biosensor exhibits a linear response toward PvuII activity within a range from 0.25 to 1.50 U/µL.
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Técnicas Biosensibles/instrumentación , Enzimas de Restricción del ADN/metabolismo , ADN/metabolismo , Técnicas Electroquímicas/instrumentación , Pruebas de Enzimas/instrumentación , Ácidos Nucleicos Inmovilizados/metabolismo , Proteus vulgaris/enzimología , ADN/química , Enzimas de Restricción del ADN/análisis , Espectroscopía Dieléctrica , Electrodos , Diseño de Equipo , Oro/química , Ácidos Nucleicos Inmovilizados/química , Límite de DetecciónRESUMEN
Voltammograms recorded on the glassy carbon electrode (GCE) may be a chemical fingerprints of food samples, enabled distinguishing the origin of the considered products. In this work the objects of the study was 5 Polish ciders of various brands. For each sample 10 scans were recorded by DPV in the potential range between -0.2 and 1.0 V in Britton-Robinson buffer at pH 2.0. The signals preprocessing realized by baseline correction with 4-th degree polynomial and normalization (in 0 to 1 interval), performed to reduce problems with insufficient signal's repeatability associated with mechanical renovation of the electrode surface before each measurement. The PLS-DA classification models were built using the training set and then validated using the samples absent in the learning process. The final multi-class model with optimized complexity enables classification of the ciders with 100% sensitivity and specificity, with the exception of one cider, where specificity was 95% (for validation set).
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Bebidas/clasificación , Electroquímica/métodos , Carbono/química , Análisis Discriminante , Electroquímica/instrumentación , Electrodos , Vidrio/química , Análisis de los Mínimos CuadradosRESUMEN
The possibility of utilization of gold electrodes modified with short guanine-rich ssDNA probes for determination of Pb(2+) was examined. Interaction between guanine residues and lead ion followed by formation of G-quadruplex structures was confirmed by electrochemical impedance spectroscopy investigations. An external cationic redox label, methylene blue, was employed in voltammetric measurements for analytical signal generation. It was shown that due to the G-quadruplex formation, the oligonucleotides in the recognition layer fold, which enhances the electron transfer between methylene blue and the electrode surface. The MB current signal rises proportionally to the lead ion concentration in the range from 0.05 to 1µmol/L. The developed biosensor demonstrated high selectivity towards Pb(2+) ion, with only minor response towards interfering metal cations. The calculated limit of detection was of 34.7nmol/L. The utilization of the biosensor for Pb(2+) determination in real samples of water was also tested.
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Técnicas Biosensibles/métodos , Ácidos Nucleicos Inmovilizados/química , Plomo/análisis , Técnicas Biosensibles/instrumentación , Calibración , Cationes Bivalentes/análisis , ADN de Cadena Simple/química , Espectroscopía Dieléctrica/métodos , Electrodos , Oro/química , Límite de Detección , Metales/química , Azul de Metileno/química , Ácidos Nucleicos Heterodúplex/química , Agua/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
The present study aims at the further development of the uranyl oligonucleotide-based voltammetric biosensor, which takes advantage of strong interaction between UO2(2+) and phosphate DNA backbone. Herein we report the optimization of working parameters of previously elaborated electrochemical DNA biosensor. It is shown that the sensor sensitivity is highly dependent on the oligonucleotide probe length and the incubation time of sensor in a sample solution. Consequently, the highest sensitivity was obtained for 10-nucleotide sequence and 60 min incubation time. The lower detection limit towards uranyl cation for developed biosensor was 30 nM. The influence of mixed monolayers and the possibility of developing a non-calibration device were also investigated. The selectivity of the proposed biosensor was significantly improved via elimination of adenine nucleobases from the DNA probe. Moreover, the regeneration procedure was elaborated and tested to prolong the use of the same biosensor for 4 subsequent determinations of UO2(2+).
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Técnicas Biosensibles/métodos , Sondas de ADN/química , Electroquímica/métodos , Sondas de Oligonucleótidos/química , Compuestos de Uranio/análisis , Compuestos de Uranio/química , Secuencia de Bases , Técnicas Biosensibles/instrumentación , Sondas de ADN/genética , Electroquímica/instrumentación , Electrodos , Equipo Reutilizado , Sondas de Oligonucleótidos/genéticaRESUMEN
Reduced physical activity and high calories up-take along with carbohydrates based diet are considered to be a leading cause of diabetes mellitus rise in western countries. Together with rise in DM morbidity, increase of complicated diabetes is also observed. Pancreas transplantation occurred to be a milestone in diabetic patient management. Guine pig pancreatic islets isolation performed for the first time by Moskalewski in 1965 and updates of his method have given an opportunity to introduce allogenic isolated islets transplantation to clinical usage. For the first time in Poland clinical allotransplantation of isolated pancreatic islets took place in Department of General Surgery and Transplantology of Medical University of Warsaw in 12's June 2008. Unfortunately, unsatisfying results of islet transplantation, specially short period of insulin independence after successful transplantation related with multifactor islet function lost, reduce clinical indications. In this publication we have analyzed known and potential factors of islet lost and we have tried to find way to prevent them, with a long period insulin-independence after transplantation as a main goal.
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Complicaciones de la Diabetes/prevención & control , Diabetes Mellitus Tipo 1/cirugía , Trasplante de Islotes Pancreáticos/métodos , Animales , Cobayas , Humanos , Insuficiencia del TratamientoRESUMEN
Studies have shown beneficial effects of machine perfusion (MP) on early kidney function and long-term graft survival. The aim of this study was to investigate whether the type of perfusion device could affect outcome of transplantation of deceased donor kidneys. A total of 50 kidneys retrieved from 25 donors were randomized to machine perfusion using a flow-driven (FD) device (RM3; Waters Medical Inc) or a pressure-driven (PD) device (LifePort; Organ Recovery Systems), 24 of these kidneys (n = 12 pairs; 48%) were procured from expanded criteria donors (ECD). The primary endpoints were kidney function after transplantation defined using the incidence of delayed graft function (DGF), the number of hemodialysis sessions required, graft function at 12 months, and analyses of biopsy. DGF was similar in both groups (32%; 8/25). Patients with DGF in the FD group required a mean of 4.66 hemodialysis sessions versus 2.65 in the PD group (P = 0.005). Overall, 1-year graft survival was 80% (20/25) vs. 96% (24/25) in the FD and PD groups. One-year graft survival of ECD kidneys was 66% (8/12) in the FD group versus 92% (11/12) in the PD group. Interstitial fibrosis and tubular atrophy were significantly more common in the FD group - 45% (5/11) vs. 0% (0/9) (P = 0.03) in PD group. There were no differences in creatinine levels between the groups. Machine perfusion using a pressure-driven device generating lower pulse stress is superior to a flow-driven device with higher pulse stress for preserving kidney function.
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Trasplante de Riñón/métodos , Preservación de Órganos/instrumentación , Perfusión/instrumentación , Adulto , Anciano , Biomarcadores/análisis , Funcionamiento Retardado del Injerto/fisiopatología , Femenino , Supervivencia de Injerto , Humanos , Riñón/fisiopatología , Masculino , Persona de Mediana Edad , Preservación de Órganos/métodos , Perfusión/métodos , Estudios Prospectivos , Donantes de Tejidos , Obtención de Tejidos y ÓrganosRESUMEN
This work considers the problem of lack of bilinearity in multivariate calibration. In voltammetry this issue especially relies on the analysis of overlapping signals, which change the shape, sensitivity or shift along the potential axis, causing a significant loss of linearity. It limits the quality of many chemometric models designed for linear data. Improvement of the predictive ability of multivariate calibration models is achieved by pre-processing of the raw data. In this work we proposed the application of a technique called orthogonal signal correction (OSC). We demonstrated that orthogonal correction enables the removal of almost all non-linear effects, disturbing voltammetric signals that impede the building of effective PLS models. The methodology was presented using simulated signals, and also in determination of the nanomolar concentration of scandium in the presence of a high and changing excess of nickel.
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BACKGROUND: Kidney transplantation (KTx) is a widely accepted method of renal function replacement therapy. Surgical site infections (SSIs), along with urinary tract infections, are among the most common infective complications after KTx. The purpose of this study was to assess the incidence of SSI in patients after KTx, identify risk factors for SSI, and classify patients in which standard antibiotic prophylaxis could be avoided. METHODS: Between January 2010 and December 2011, 262 KTxs were performed in our center. Deceased donors', recipients' data, and data related to surgical procedures were collected. SSIs were diagnosed in accordance with the guidelines published by the U.S. Centers for Disease Control and Prevention. RESULTS: SSIs were diagnosed in 7.25% (19/262) of patients. Of nineteen SSI patients, two (10.5%) were diagnosed with organ-specific SSIs, which eventually led to graft loss; six (31.5%) developed deep incisional SSIs; and eleven (58%) developed superficial incisional SSIs. Through analysis of this extensive data set, we determined the following risk factors for the development of SSI: kidney from extended criteria donors, a cold ischemia time of more than 30 hr, time of surgical procedure longer than 200 min, confirmed diabetes in the recipients, a recipient body mass index higher than 27 kg/m, and occurrence of delayed graft function. CONCLUSIONS: It may be possible to reduce standard antibiotic prophylaxis to a single dose in patients without known risk factors for SSI. Any opportunity to reduce antibiotic use is crucial in preventing the development of multi-drug-resistant pathogens.
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Antibacterianos/uso terapéutico , Trasplante de Riñón/efectos adversos , Trasplante de Riñón/métodos , Infección de la Herida Quirúrgica/epidemiología , Adulto , Anciano , Antiinfecciosos/farmacología , Profilaxis Antibiótica/métodos , Índice de Masa Corporal , Femenino , Supervivencia de Injerto , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Infección de la Herida Quirúrgica/prevención & control , Resultado del TratamientoRESUMEN
The feasibility of using gold electrodes modified with short-chain ssDNA oligonucleotides for determination of uranyl cation is examined. Interaction between UO(2)(2+) and proposed recognition layer was studied by means of voltammetric and quartz crystal microbalance measurements. It was postulated that ssDNA recognition layer functions via strong binding of UO(2)(2+) to phosphate DNA backbone. The methylene blue was used as a redox marker for analytical signal generation. Biosensor response was based on the difference in electrochemical signal before and after subjecting it to sample containing uranyl ion. The lower detection limit of 30 nmol L(-1) for UO(2)(2+) was observed for a sample incubation time of 60 min. Proposed ssDNA-modified electrodes demonstrated good selectivity towards UO(2)(2+) against common metal cations, with only Pb(2+) and Ca(2+) showing considerable interfering effect.
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Técnicas Biosensibles , ADN/química , Electroquímica/métodosRESUMEN
The evaluation of novel electrochemically active label for electrochemical detection of DNA hybridization is presented. Metallacarborane units modified with iron, cobalt or chromium were investigated. The value of redox potential and relatively strong current signal facilitate usage of Fe-carborane as marker covalently attached to the ssDNA. In electrochemical genosensor the sequence complementary to UL55 gene was labeled and used as a target for biosensor device. Interactions were investigated using electrochemical and piezoelectric methods. Obtained results confirm usefulness of the designed label in electrochemical detection of DNA hybridization.