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1.
Sensors (Basel) ; 20(8)2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32316211

RESUMO

Real-time sensing of proteins, especially in wearable devices, remains a substantial challenge due to the need to convert a binding event into a measurable signal that is compatible with the chosen analytical instrumentation. Impedance spectroscopy enables real-time detection via either measuring electrostatic interactions or electron transfer reactions while simultaneously being amenable to miniaturization for integration into wearable form-factors. To create a more robust methodology for optimizing impedance-based sensors, additional fundamental studies exploring components influencing the design and implementation of these sensors are needed. This investigation addresses a sub-set of these issues by combining optical and electrochemical characterization to validate impedance-based sensor performance as a function of (1) biorecognition element density, (2) self-assembled monolayer chain length, (3) self-assembled monolayer charge density, (4) the electrochemical sensing mechanism and (5) the redox reporter selection. Using a pre-existing lysozyme aptamer and lysozyme analyte combination, we demonstrate a number of design criteria to advance the state-of-the-art in protein sensing. For this model system we demonstrated the following: First, denser self-assembled monolayers yielded substantially improved sensing results. Second, self-assembled monolayer composition, including both thickness and charge density, changed the observed peak position and peak current. Third, single frequency measurements, while less informative, can be optimized to replace multi-frequency measurements and in some cases (such as that with zwitterionic self-assembled monolayers) are preferred. Finally, various redox reporters traditionally not used in impedance sensing should be further explored. Collectively, these results can help limit bottlenecks associated with device development, enabling realization of next-generation impedance-based biosensing with customize sensor design for the specific application.

2.
ACS Sens ; 5(1): 13-18, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31833351

RESUMO

Environmental hazards typically are encountered in the gaseous phase; however, selective sensing modalities for identifying and quantitating compounds of interest in an inexpensive, pseudo-real-time format are severely lacking. Here, we present a novel proof-of-concept that combines an Air2Liquid sampler in conjunction with an oil-in-water microfluidic assay for detection of organophosphates. We believe this proof-of-concept will enable development of a new platform technology for semivolatile detection that we have demonstrated to detect 50 pmoles (2 ppb) of neurotoxic organophosphates.

3.
Sensors (Basel) ; 19(18)2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31500135

RESUMO

Simultaneous measurement of skin physiological and physical properties are important for the diagnosis of skin diseases and monitoring of human performance, since it provides more comprehensive understanding on the skin conditions. Current skin analysis devices, however, require each of probes and unique protocols for the measurement of individual skin properties, resulting in inconvenience and increase of measurement uncertainty. This paper presents a pen-type skin analyzing device capable tomeasure three key skin properties at the same time: transepidermal water loss (TEWL), skin conductance, and skin hardness. It uses a single truncated hollow cone (THC) probe integrated with a humidity sensor, paired electrodes, and a load cell for the multimodal assessment of the skin properties. The present device measured TEWL with a sensitivity of 0.0068 (%/s)/(g/m2/h) and a linearity of 99.63%, conductance with a sensitivity of 1.02 µS/µS and a linearity of 99.36%, and hardness with a sensitivity of 0.98 Shore 00/Shore 00 and a linearity of 99.85%, within the appropriate ranges for the human skin. The present pen-type device has a high potential for the skin health diagnosis as well as the human performance monitoring applications.


Assuntos
Resposta Galvânica da Pele/fisiologia , Dermatopatias/diagnóstico , Fenômenos Fisiológicos da Pele , Pele/química , Dureza , Humanos , Água/química
4.
Acc Chem Res ; 52(2): 297-306, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30688433

RESUMO

Physiological sensors in a wearable form have rapidly emerged on the market due to technological breakthroughs and have become nearly ubiquitous with the Apple Watch, FitBit, and other wearable devices. While these wearables mostly monitor simple biometric signatures, new devices that can report on the human readiness level through sensing molecular biomarkers are critical to optimizing the human factor in both commercial sectors and the Department of Defense. The military is particularly interested in real-time, wearable, minimally invasive monitoring of fatigue and human performance to improve the readiness and performance of the war fighter. However, very few devices have ventured into the realm of reporting directly on biomarkers of interest. Primarily this is because of the difficulties of sampling biological fluids in real-time and providing accurate readouts using highly selective and sensitive sensors. When additional restrictions to only use sweat, an excretory fluid, are enforced to minimize invasiveness, the demands on sensors becomes even greater due to the dilution of the biomarkers of interest, as well as variability in salinity, pH, and other physicochemical variables which directly impact the read-out of real-time biosensors. This Account will provide a synopsis not only on exemplary demonstrations and technological achievements toward implementation of real-time, wearable sweat sensors but also on defining problems that still remain toward implementation in wearable devices that can detect molecular biomarkers for real world applications. First, the authors describe the composition of minimally invasive biofluids and then identify what biomarkers are of interest as biophysical indicators. This Account then reviews demonstrated techniques for extracting biofluids from the site of generation and transport to the sensor developed by the authors. Included in this discussion is a detailed description on biosensing recognition elements and transducers developed by the authors to enable generation of selective electrochemical sensing platforms. The authors also discuss ongoing efforts to identify biorecognition elements and the chemistries necessary to enable high affinity, selective biorecognition elements. Finally, this Account presents the requirements for wearable, real-time sensors to be (1) highly stable, (2) portable, (3) reagentless, (4) continuous, and (5) responsive in real-time, before delving into specific methodologies to sense classes of biomarkers that have been explored by academia, government laboratories, and industry. Each platform has its areas of greatest utility, but also come with corresponding weaknesses: (1) ion selective electrodes are robust and have been demonstrated in wearables but are limited to detection of ions, (2) enzymatic sensors enable indirect detection of metabolites and have been demonstrated in wearables, but the compounds that can be detected are limited to a subset of small molecules and the sensors are sensitive to flow, (3) impedance-based sensors can detect a wide range of compounds but require further research and development for deployment in wearables. In conclusion, while substantial progress has been made toward wearable molecular biosensors, substantial barriers remain and need to be solved to enable deployment of minimally invasive, wearable biomarker monitoring devices that can accurately report on psychophysiological status.


Assuntos
Biomarcadores/análise , Técnicas Biossensoriais/métodos , Monitorização Fisiológica/métodos , Suor/química , Dispositivos Eletrônicos Vestíveis , Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Humanos , Monitorização Fisiológica/instrumentação
5.
ACS Omega ; 3(6): 6230-6236, 2018 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31458805

RESUMO

Breathing-air quality within commercial airline cabins has come under increased scrutiny because of the identification of volatile organic compounds (VOCs) from the engine bleed air used to provide oxygen to cabins. Ideally, a sensor would be placed within the bleed air pipe itself, enabling detection before it permeated through and contaminated the entire cabin. Current gas-phase sensors suffer from issues with selectivity, do not have the appropriate form factor, or are too complex for commercial deployment. Here, we chose isopropyl alcohol (IPA), a main component of de-icer spray used in the aerospace community, as a target analyte: IPA exposure has been hypothesized to be a key component of aerotoxic syndrome in pre, during, and postflight. IPAs proposed mechanism of action is that of an anesthetic and central nervous system depressant. In this work, we describe IPA sensor development by showing (1) the integration of a polymer as an IPA capture matrix, (2) the adoption of a redox chemical additives as an IPA oxidizer, and (3) the application of carbon nanotubes as an electronic sensing conduit. We demonstrate the ability to not only detect IPA at 100-10 000 ppm in unfiltered, laboratory air but also discriminate among IPA, isoprene, and acetone, especially in comparison to a typical photoionization detector. Overall, we show an electronic device that operates at room temperature and responds preferentially to IPA, where the increase in the resistance corresponds directly to the concentration of IPA. Ultimately, this study opens up the pathway to selective electronic sensors that can enable real-time monitoring in a variety of environments for the force health prevention and protection, and the potential through future work to enable low parts-per-million and possibly high parts-per-billion selective detection of gas-phase VOCs of interest.

6.
ACS Nano ; 11(5): 4899-4906, 2017 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-28448717

RESUMO

The water/graphene interface has received considerable attention in the past decade due to its relevance in various potential applications including energy storage, sensing, desalination, and catalysis. Most of our knowledge about the interfacial water structure next to graphene stems from simulations, which use experimentally measured water contact angles (WCAs) on graphene (or graphite) to estimate the water-graphene interaction strength. However, the existence of a wide spectrum of reported WCAs on supported graphene and graphitic surfaces makes it difficult to interpret the water-graphene interactions. Here, we have used surface-sensitive infrared-visible sum frequency generation (SFG) spectroscopy to probe the interfacial water structure next to graphene supported on a sapphire substrate. In addition, the ice nucleation properties of graphene have been explored by performing in situ freezing experiments as graphitic surfaces are considered good ice nucleators. For graphene supported on sapphire, we observed a strong SFG peak associated with highly coordinated, ordered water next to graphene. Similar ordering was not detected next to bare sapphire, implying that the observed ordering of water molecules in the former case is a consequence of the presence of graphene. Our analysis indicates that graphene behaves like a hydrophobic (or negatively charged) surface, leading to enhanced ordering of water molecules. Although liquid water orders next to graphene, the ice formed is proton disordered. This research sheds light on water-graphene interactions relevant in optimizing the performance of graphene in various applications.

7.
Biointerphases ; 11(4): 041003, 2016 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-27814665

RESUMO

Recognition and manipulation of graphene edges enable the control of physical properties of graphene-based devices. Recently, the authors have identified a peptide that preferentially binds to graphene edges from a combinatorial peptide library. In this study, the authors examine the functional basis for the edge binding peptide using experimental and computational methods. The effect of amino acid substitution, sequence context, and solution pH value on the binding of the peptide to graphene has been investigated. The N-terminus glutamic acid residue plays a key role in recognizing and binding to graphene edges. The protonation, substitution, and positional context of the glutamic acid residue impact graphene edge-binding. Our findings provide insights into the binding mechanisms and the design of peptides for recognizing and functionalizing graphene edges.


Assuntos
Grafite/metabolismo , Peptídeos/metabolismo , Propriedades de Superfície , Substituição de Aminoácidos , Biologia Computacional , Ácido Glutâmico/genética , Ácido Glutâmico/metabolismo , Concentração de Íons de Hidrogênio , Peptídeos/genética , Ligação Proteica
8.
Nat Commun ; 7: 11771, 2016 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27249579

RESUMO

The fabrication of nanoscale devices requires architectural templates on which to position functional molecules in complex arrangements. Protein scaffolds are particularly promising templates for nanomaterials due to inherent molecular recognition and self-assembly capabilities combined with genetically encoded functionalities. However, difficulties in engineering protein quaternary structure into stable and well-ordered shapes have hampered progress. Here we report the development of an ultrastable biomolecular construction kit for the assembly of filamentous proteins into geometrically defined templates of controllable size and symmetry. The strategy combines redesign of protein-protein interaction specificity with the creation of tunable connector proteins that govern the assembly and projection angles of the filaments. The functionality of these nanoarchitectures is illustrated by incorporation of nanoparticles at specific locations and orientations to create hybrid materials such as conductive nanowires. These new structural components facilitate the manufacturing of nanomaterials with diverse shapes and functional properties over a wide range of processing conditions.


Assuntos
Proteínas Arqueais/química , Nanopartículas Metálicas/química , Chaperonas Moleculares/química , Nanofios/química , Engenharia de Proteínas/métodos , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Cinética , Nanopartículas Metálicas/ultraestrutura , Methanocaldococcus/química , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Simulação de Dinâmica Molecular , Nanotecnologia/métodos , Nanofios/ultraestrutura , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Estabilidade Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Termodinâmica
9.
ACS Nano ; 9(12): 11509-39, 2015 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-26544756

RESUMO

The isolation of graphene in 2004 from graphite was a defining moment for the "birth" of a field: two-dimensional (2D) materials. In recent years, there has been a rapidly increasing number of papers focusing on non-graphene layered materials, including transition-metal dichalcogenides (TMDs), because of the new properties and applications that emerge upon 2D confinement. Here, we review significant recent advances and important new developments in 2D materials "beyond graphene". We provide insight into the theoretical modeling and understanding of the van der Waals (vdW) forces that hold together the 2D layers in bulk solids, as well as their excitonic properties and growth morphologies. Additionally, we highlight recent breakthroughs in TMD synthesis and characterization and discuss the newest families of 2D materials, including monoelement 2D materials (i.e., silicene, phosphorene, etc.) and transition metal carbide- and carbon nitride-based MXenes. We then discuss the doping and functionalization of 2D materials beyond graphene that enable device applications, followed by advances in electronic, optoelectronic, and magnetic devices and theory. Finally, we provide perspectives on the future of 2D materials beyond graphene.

10.
Sci Rep ; 5: 14374, 2015 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-26395160

RESUMO

Heterostructures consisting of two-dimensional materials have shown new physical phenomena, novel electronic and optical properties, and new device concepts not observed in bulk material systems or purely three dimensional heterostructures. These new effects originated mostly from the van der Waals interaction between the different layers. Here we report that a new optical and electronic device platform can be provided by heterostructures of 2D graphene with a metal oxide (TiO2). Our novel direct synthesis of graphene/TiO2 heterostructure is achieved by C60 deposition on transition Ti metal surface using a molecular beam epitaxy approach and O2 intercalation method, which is compatible with wafer scale growth of heterostructures. As-grown heterostructures exhibit inherent photosensitivity in the visible light spectrum with high photo responsivity. The photo sensitivity is 25 times higher than that of reported graphene photo detectors. The improved responsivity is attributed to optical transitions between O 2p orbitals in the valence band of TiO2 and C 2p orbitals in the conduction band of graphene enabled by Coulomb interactions at the interface. In addition, this heterostructure provides a platform for realization of bottom gated graphene field effect devices with graphene and TiO2 playing the roles of channel and gate dielectric layers, respectively.

11.
ACS Appl Mater Interfaces ; 7(36): 20447-53, 2015 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-26305504

RESUMO

Understanding the factors that influence the interaction between biomolecules and abiotic surfaces is of utmost interest in biosensing and biomedical research. Through phage display technology, several peptides have been identified as specific binders to abiotic material surfaces, such as gold, graphene, silver, and so forth. Using graphene-peptide as our model abiotic-biotic pair, we investigate the effect of graphene quality, number of layers, and the underlying support substrate effect on graphene-peptide interactions using both experiments and computation. Our results indicate that graphene quality plays a significant role in graphene-peptide interactions. The graphene-biomolecule interaction appears to show no significant dependency on the number of graphene layers or the underlying support substrate.


Assuntos
Grafite/química , Peptídeos/química , Adsorção , Ouro/química , Microscopia de Força Atômica , Simulação de Dinâmica Molecular , Espectroscopia Fotoeletrônica , Técnicas de Microbalança de Cristal de Quartzo , Prata/química , Análise Espectral Raman , Propriedades de Superfície
12.
Small ; 11(41): 5520-7, 2015 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-26313027

RESUMO

2D transition metal dichalcogenides (TMDCs) are nanomanufactured using a generalized strategy with self-assembled DNA nanotubes. DNA nanotubes of various lengths serve as lithographic etch masks for the dry etching of TMDCs. The nanostructured TMDCs are studied by atomic force microscopy, photoluminescence, and Raman spectroscopy. This parallel approach can be used to manufacture 2D TMDC nanostructures of arbitrary geometries with molecular-scale precision.


Assuntos
Calcogênios/química , DNA/química , Metais/química , Nanotubos/química , Impressão Tridimensional , DNA/ultraestrutura , Teste de Materiais , Nanotubos/ultraestrutura
13.
ACS Nano ; 8(7): 6805-13, 2014 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-24988046

RESUMO

Focused electron-beam-induced deposition (FEBID) is a promising nanolithography technique using "direct-write" patterning by carbon line and dot deposits on graphene. Understanding interactions between deposited carbon molecules and graphene enables highly localized modification of graphene properties, which is foundational to the FEBID utility as a nanopatterning tool. In this study, we demonstrate a unique possibility to induce dramatically different adsorption states of FEBID-produced carbon deposits on graphene, through density functional theory calculations and complementary Raman experiments. Specifically, an amorphous carbon deposit formed by direct irradiation of high energy primary electrons exhibits unusually strong interactions with graphene via covalent bonding, whereas the FEBID carbon formed due to low-energy secondary electrons is only weakly interacting with graphene via physisorption. These observations not only are of fundamental importance to basic physical chemistry of FEBID carbon-graphene interactions but also enable the use of selective laser-assisted postdeposition ablation to effectively remove the parasitically deposited, physisorbed carbon films for improving FEBID patterning resolution.

14.
ACS Appl Mater Interfaces ; 5(15): 7470-7, 2013 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-23869852

RESUMO

In this work, to explain doping behavior of single-layer graphene upon HSSYWYAFNNKT (P1) and HSSAAAAFNNKT (P1-3A) adsorption in field-effect transistors (GFETs), we applied a combined computational approach, whereby peptide adsorption was modeled by molecular dynamics simulations, and the lowest energy configuration was confirmed by density functional theory calculations. On the basis of the resulting structures of the hybrid materials, electronic structure and transport calculations were investigated. We demonstrate that π-π stacking of the aromatic residues and proximate peptide backbone to the graphene surface in P1 have a role in the p-doping. These results are consistent with our experimental observation of the GFET's p-doping even after a 24-h annealing procedure. Upon substitution of three of the aromatic residues to Ala in (P1-3A), a considerable decrease from p-doping is observed experimentally, demonstrating n-doping as compared to the nonadsorbed device, yet not explained based on the atomistic MD simulation structures. To gain a qualitative understanding of P1-3A's adsorption over a longer simulation time, which may differ from aromatic amino acid residues' swift anchoring on the surface, we analyzed equilibrated coarse-grain simulations performed for 500 ns. Desorption of the Ala residues from the surface was shown computationally, which could in turn affect charge transfer, yet a full explanation of the mechanism of n-doping will require elucidation of differences between various aromatic residues as dependent on peptide composition, and inclusion of effects of the substrate and environment, to be considered in future work.


Assuntos
Grafite/química , Peptídeos/química , Adsorção , Sequência de Aminoácidos , Eletrônica , Elétrons , Modelos Estatísticos , Simulação de Dinâmica Molecular , Dados de Sequência Molecular , Ligação Proteica , Especificidade por Substrato , Propriedades de Superfície , Água/química
15.
Nanoscale ; 5(11): 4931-6, 2013 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-23624632

RESUMO

Achieving highly enriched single wall carbon nanotubes (SWNTs) is one of the major hurdles today because their chirality-dependent properties must be uniform and predictable for use in nanoscale electronics. Due to the unique wrapping and groove-binding mechanism, DNA has been demonstrated as a highly specific SWNT dispersion and fractionation agent, with its enrichment capabilities depending on the DNA sequence and length as well as the nanotube properties. Salmon genomic DNA (SaDNA) offers an inexpensive and scalable alternative to synthetic DNA. In this study, SaDNA enrichment capabilities were tested on SWNT separation with varying degrees of metallicity that were formulated from mixtures of commercial metallic (met-) and semiconducting (sem-) abundant SWNTs. The results herein demonstrate that the degree of metallicity of the SWNT sample has a significant effect on the SaDNA enrichment capabilities, and this effect is modeled based on deconvolution of the near-infrared (NIR) absorption spectra and verified with photoluminescence emission (PLE) measurements. Using molecular dynamics and circular dichroism, the preferential SaDNA mediated separation of the (6, 5) sem-tube is shown to be largely influenced by the presence of met-SWNTs.


Assuntos
DNA/química , Nanotubos de Carbono/química , Animais , Dicroísmo Circular , Simulação de Dinâmica Molecular , Salmão/genética , Espectroscopia de Luz Próxima ao Infravermelho , Estereoisomerismo
16.
J Clin Endocrinol Metab ; 97(3): E393-9, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22188741

RESUMO

CONTEXT: Cryptorchidism is the most frequent congenital malformation among males, the major established risk factor for testicular germ cell tumors, and a presumed infertility risk factor. Androgens are essential for testicular descent, and functional genetic polymorphisms in the androgen receptor gene (AR) are postulated to influence cryptorchidism risk. OBJECTIVE: The aim of the study was to investigate whether the CAG repeat length polymorphism in exon 1 of the AR is associated with cryptorchidism risk. DESIGN AND SETTING: We conducted a family-based genotype-risk association study employing the transmission disequilibrium test for genotypic variants transmitted on the X-chromosome at a university-affiliated regional children's hospital. PARTICIPANTS: We studied 127 Hispanic boys with persistent cryptorchidism and comorbidities described in detail and their biological mothers. INTERVENTION: Genotypes defined by number of CAG repeats were measured for each member of participating son-mother pairs. MAIN OUTCOME MEASURE: Associations between CAG tract length genotype and cryptorchidism risk were estimated using matched-pairs logistic regression. RESULTS: Cryptorchidism risk was significantly associated with shorter CAG repeats [CAG≤19 vs. CAG≥20, odds ratio (OR)=0.44; 95% confidence interval (CI), 0.23-0.88]. This association was restricted to cryptorchidism with accompanying comorbidities, which was primarily hernia [CAG≤19 vs. CAG≥20, OR=0.35 (95% CI, 0.16-0.78)], and was strongest for bilateral cryptorchidism [CAG≤19 vs. CAG≥20, OR=0.09 (95% CI, 0.010-0.78)]. CONCLUSIONS: Androgen receptor genotypes encoding moderate functional variation may influence cryptorchidism risk, particularly among boys with bilateral nondescent or congenital hernia, and may explain in part the elevated risk of testicular seminoma experienced by ex-cryptorchid boys. Mechanistic research is warranted to examine both classical and nonclassical mechanisms through which androgens may influence risk of cryptorchidism and related conditions.


Assuntos
Criptorquidismo/genética , Hispano-Americanos/genética , Polimorfismo Genético , Receptores Androgênicos/genética , Repetições de Trinucleotídeos/genética , Adolescente , Criança , Pré-Escolar , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Humanos , Lactente , Masculino , Risco
17.
Artigo em Inglês | MEDLINE | ID: mdl-23423470

RESUMO

INTRODUCTION: Risk of testicular germ cell tumors (TGCT) is consistently associated with a history of cryptorchidism (CO) in epidemiologic studies. Factors modifying the association may provide insights regarding etiology of TGCT and suggest a basis for individualized care of CO. To identify modifiers of the CO-TGCT association, we conducted a comprehensive, quantitative evaluation of epidemiologic data. MATERIALS AND METHODS: Human studies cited in PubMed or ISI Web of Science indices through December 2011 and selected unpublished epidemiologic data were reviewed to identify 35 articles and one unpublished dataset with high-quality data on the CO-TGCT association. Association data were extracted as point and 95% confidence interval estimates of odds ratio (OR) or standardized incidence ratio (SIR), or as tabulated data. Values were recorded for each study population, and for subgroups defined by features of study design, CO and TGCT. Extracted data were used to estimate summary risk ratios (sRR) and evaluate heterogeneity of the CO-TGCT association between subgroups. RESULTS: The overall meta-analysis showed that history of CO is associated with four-fold increased TGCT risk [RR = 4.1(95% CI = 3.6-4.7)]. Subgroup analyses identified five determinants of stronger association: bilateral CO, unilateral CO ipsilateral to TGCT, delayed CO treatment, TGCT diagnosed before 1970, and seminoma histology. CONCLUSIONS: Modifying factors may provide insight into TGCT etiology and suggest improved approaches to managing CO. Based on available data, CO patients and their parents or caregivers should be made aware of elevated TGCT risk following orchidopexy, regardless of age at repair, unilateral vs. bilateral non-descent, or position of undescended testes.

18.
BJU Int ; 109(6): 910-5, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21883858

RESUMO

OBJECTIVE: To compare the perioperative parameters of paediatric patients who underwent nephrectomy via laparo-endoscopic single site (LESS) surgery (also known as single incision laparoscopic surgery or SILS) with those who underwent nephrectomy via conventional laparoscopy (LAP), robotic-assisted laparoscopy (RALN), and open surgery (OPEN). PATIENTS AND METHODS: The medical records of 69 paediatric patients at a single institution who underwent nephrectomies for non-functioning kidneys in 72 renal units (39 OPEN, 11 LAP, 11 RALN and 11 LESS) were reviewed for patient demographics and perioperative clinical parameters. RESULTS: The minimally invasive modalities in children, including LESS nephrectomy, were associated with shorter lengths of hospital stay (P < 0.001) and decreased postoperative pain medication usage (P < 0.001) than with open surgery. Similar surgical times were noted with LESS and the other minimally invasive modalities (LAP and RALN) (P= 0.056). However, the minimally invasive modalities (LESS, LAP and RALN) were associated with slightly longer surgical times when compared with open surgery (P < 0.001), which may, in part, be secondary to learning curve factors. No differences were noted among the minimally invasive modalities for postoperative pain medication usage (P= 0.354) and length of hospital stay (P= 0.86). CONCLUSIONS: The minimally invasive modalities for nephrectomy in children, including LESS nephrectomy, are associated with shorter lengths of hospital stay and decreased postoperative pain medication use when compared with open surgery. LESS nephrectomy in children is associated with similar surgical times, lengths of hospital stay and postoperative pain medication use as the other minimally invasive modalities (LAP and RALN). Slightly longer surgical times are noted with the minimally invasive modalities, including LESS nephrectomy, when compared with open surgery, which may, in part, be secondary to learning curve factors.


Assuntos
Nefropatias/cirurgia , Laparoscopia/métodos , Nefrectomia/métodos , Robótica , Adolescente , Criança , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Tempo de Internação/estatística & dados numéricos , Masculino , Nefrectomia/efeitos adversos , Dor Pós-Operatória/etiologia , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
19.
J Urol ; 186(4 Suppl): 1734-9, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21855900

RESUMO

PURPOSE: The prevalence of obesity and urolithiasis in children has increased with time. We evaluated the relationship between body mass and urolithiasis in children. MATERIALS AND METHODS: We performed a matched case-control study in a network of 30 primary care pediatric practices. Cases included subjects with ICD-9 codes for urolithiasis and controls were matched on age, duration of observation before the index date and clinical practice. Age and sex specific body mass index z scores at the time of the stone episode were calculated. Continuous body mass index z scores and clinical weight categories were evaluated with covariates, including race, ethnicity, gender and payer status. The OR and 95% CI were calculated using multivariate conditional logistic regression. RESULTS: We identified 110 cases and 396 matched controls, of whom 1.9% and 4.3% were overweight, and 3.7% and 4.5% were obese, respectively. On multivariate conditional logistic regression analysis the continuous body mass index z score (OR 0.84, 95% CI 0.63-1.12, p = 0.18), overweight status (OR 0.13, 95% CI 0.01-1.18) and obese status (OR 0.18, 95% CI 0.02-1.40) were not associated with urolithiasis. However, black race (OR 0.35, 95% CI 0.15-0.85) and Medicaid payer status (OR 0.47, 95% CI 0.24-0.93) were associated with a significant decrease in the odds of urolithiasis. CONCLUSIONS: High body mass was not associated with urolithiasis in our primary care pediatric practice network. However, black race and Medicaid payer status were associated with decreased odds of urolithiasis.


Assuntos
Índice de Massa Corporal , Obesidade/epidemiologia , Urolitíase/epidemiologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Masculino , Obesidade/complicações , Prevalência , Estudos Retrospectivos , Fatores de Risco , Estados Unidos/epidemiologia , Urolitíase/etiologia
20.
J Urol ; 186(4 Suppl): 1663-7, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21862079

RESUMO

PURPOSE: Robotic assisted laparoscopic pyeloplasty is an emerging, minimally invasive alternative to open pyeloplasty in children for ureteropelvic junction obstruction. The procedure is associated with smaller incisions and shorter hospital stays. To our knowledge previous outcome analyses have not included human capital calculations, especially regarding loss of parental workdays. We compared perioperative factors in patients who underwent robotic assisted laparoscopic and open pyeloplasty at a single institution, especially in regard to human capital changes, in an institutional cost analysis. MATERIALS AND METHODS: A total of 44 patients 2 years old or older from a single institution underwent robotic assisted (37) or open (7) pyeloplasty from 2008 to 2010. We retrospectively reviewed the charts to collect demographic and perioperative data. The human capital approach was used to calculate parental productivity losses. RESULTS: Patients who underwent robotic assisted laparoscopic pyeloplasty had a significantly shorter average hospital length of stay (1.6 vs 2.8 days, p <0.05). This correlated with an average savings of lost parental wages of $90.01 and hospitalization expenses of $612.80 per patient when excluding amortized robot costs. However, cost savings were not achieved by varying length of stay when amortized costs were included. CONCLUSIONS: Robotic assisted laparoscopic pyeloplasty in children is associated with human capital gains, eg decreased lost parental wages, and lower hospitalization expenses. Future comparative outcome analyses in children should include financial factors such as human capital loss, which can be especially important for families with young children.


Assuntos
Efeitos Psicossociais da Doença , Rim/cirurgia , Laparoscopia/métodos , Robótica , Ureter/cirurgia , Obstrução Ureteral/cirurgia , Procedimentos Cirúrgicos Urológicos/métodos , Adolescente , Criança , Pré-Escolar , Custos e Análise de Custo , Feminino , Seguimentos , Humanos , Laparoscopia/economia , Tempo de Internação/economia , Masculino , Pais , Procedimentos Cirúrgicos Reconstrutivos/economia , Procedimentos Cirúrgicos Reconstrutivos/métodos , Estudos Retrospectivos , Fatores Socioeconômicos , Estados Unidos , Obstrução Ureteral/economia , Procedimentos Cirúrgicos Urológicos/economia , Adulto Jovem
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