Effects of sieved particle size and equilibration time on the measurement of radionuclides in soil by gamma-ray spectrometer / 中国辐射卫生

Objective The effect of sieved particle size and equilibration time of soil samples on the measurement of radionuclides was studied to improve the accuracy of the specific activity of radionuclides in soil samples measured by gamma spectrometer. Methods The collected soil samples were dried and divided into four parts. After sieved with width of the mesh 2.0 mm, 1.0 mm, 0.5 mm and 0.25 mm respectively, they were filled into sample containers and sealed. The activity concentrations of 226Ra, 210Pb, 228Ra, 40K and 137Cs in different sieved soil samples were then measured at the sealed interval of 0, 4, 8, 12, 16, 21, 25 and 29 days by HPGe gamma-ray spectrometry respectively. Results The coefficients of variation ofthe specific activities of 226Ra, 210Pb, and 228Ra in soil samples measured at different equilibration intervals range from 0.9% to 4.3%. The coefficients of variation of the specific activities of 226Ra, 210Pb, 228Ra, 40K and 137Cs in soil samples with different sieved particle sizes range from 3.7% to 14.1%. Conclusion When the specific activities of radionuclides are determined by gamma-ray spectrometer, the effect of the sieved particle size on the measurement result must be considered, and its impact is higher than the equilibration time. This study is very useful for improving the accuracy of the determination of radionuclides in soil sample using gamma-ray spectrometer.

Abstração reflexionante em estudantes: implicações pedagógicas e psicopedagógicas / Reflective abstraction in students: Pedagogical and psycho-pedagogical implications

A partir da teoria piagetiana, a abstração reflexionante pode ser entendida como um motor para o desenvolvimento cognitivo, ao passo que atua diretamente no processo de equilibração. Dito isso, a pesquisa apresentada teve por objetivo investigar o desempenho de escolares frente às solicitações de uma situação operatória, contida no instrumento piagetiano "Abstrações, Diferenciações e Integrações no emprego de Operações Aritméticas Elementares", específico para a observação do mecanismo da abstração reflexionante. Para isso, empregou-se um estudo evolutivo com 80 sujeitos, distribuídos da seguinte forma: 20 estudantes de 6 anos, 20 estudantes de 11 anos, 20 de 16 anos e 20 alunos de 21 anos, sendo que, para cada faixa etária, 10 participantes estavam matriculados em escolas públicas e 10 em escolas da rede privada. Os dados foram analisados à luz dos níveis da prova operatória, acrescidos de análise estatística pela aplicação do teste de Mann-Whitney, para comparação dos resultados entre escolas públicas e particulares. Destaca-se que os estudantes, em grande maioria, não atingiram respostas mais avançadas do instrumento utilizado, revelando dificuldade em diferenciar e integrar os elementos da situação proposta, mesmo no caso dos participantes com idade mais avançada. Ainda, não houve diferença entre os alunos de escolas públicas e particulares. Afirma-se a importância de tais resultados e das discussões desenvolvidas ao longo do texto no âmbito pedagógico e psicopedagógico no que diz respeito a intervenções que coloquem em marcha o mecanismo da abstração reflexionante, imprescindível à evolução cognitiva.

From Piagetian theory, reflective abstraction can be understood as an engine for cognitive development, while acting directly in the equilibration process. That said, the research presented was aimed to investigate student's performance in response to requests for an operative situation, contained in the Piagetian instrument "Abstractions, Differences and Integrations in the Use of Elementary Arithmetic Operations", specific to the mechanism observation of reflective abstraction. For this, an evolutionary study was carried out with 80 subjects, distributed as follows: 20 six-year-old students, 20 eleven-year-old students, 20 sixteen-year-old and 20 twenty-one-year-old students, enrolled 10 of each age group in public schools and 10 in private schools. The data were analyzed according to the levels of the operative test, plus statistical analysis by the Mann-Whitney test, to compare the results between public and private schools. It is worth mentioning that the majority of students did not reach more advanced answers of the instrument used, revealing difficulty in differentiating and integrating the elements of the proposed situation, even in the case of older participants. Still, there was no difference between the participants of public and private schools. The importance of such results and the discussions developed throughout the text in the pedagogical and psycho-pedagogical context is affirmed with regard to interventions that put in motion the mechanism of reflective abstraction, essential to cognitive evolution.

Comparison of three PET methods to assess peritoneal membrane transport

The peritoneal equilibration test (PET) is the most widespread method for assessing water and solute transport across the peritoneal membrane. This study compared three methods: traditional PET (t-PET), mini-PET, and modified PET (mod-PET). Non-diabetic adults (n=21) who had been on peritoneal dialysis (PD) for at least three months underwent t-PET (glucose 2.5%-4 h), mini-PET (glucose 3.86%-1 h), and mod-PET (glucose 3.86%-4 h) to determine dialysate-to-plasma concentration ratio (D/P) for creatinine and dialysate-to-baseline dialysate concentration ratio (D/D0) for glucose. Agreement between methods regarding D/P creatinine and D/D0 glucose was assessed using analysis of variance (ANOVA), Pearson's correlation coefficient, and Bland-Altman analysis. D/P creatinine differed between t-PET and mini-PET (P<0.001) and between mod-PET and mini-PET (P<0.01) but not between t-PET and mod-PET (P=0.746). The correlation of D/P creatinine with t-PET vs mod-PET was significant (r=0.387, P=0.009) but not that of t-PET vs mini-PET (r=0.088, P=0.241). Estimated bias was −0.029 (P=0.201) between t-PET and mod-PET, and 0.206 (P<0.001) between t-PET and mini-PET. D/D0 glucose differed between t-PET and mod-PET (P=0.003) and between mod-PET and mini-PET (P=0.002) but not between t-PET and mini-PET (P=0.885). The correlations of D/D0 glucose in t-PET vs mod-PET (r=−0.017, P=0.421) or t-PET vs mini-PET (r=0.152, P=0.609) were not significant. Estimated bias was 0.122 (P=0.026) between t-PET and mod-PET, and 0.122 (P=0.026) between t-PET and mini-PET. The significant correlation of D/P creatinine between t-PET and mod-PET suggested that the latter is a good alternative to t-PET. There was no such correlation between t-PET and mini-PET.

Adecuación en diálisis peritoneal pediátrica: Del test de equilibrio peritoneal a las aquaporinas / Peritoneal dialysis adequacy in pediatrics: From the peritoneal equilibration test to the aquaporins

La evaluación de las características de transporte de solutos y agua del peritoneo es esencial para adecuar la prescripción dialítica en pacientes portadores de enfermedad renal crónica. Existen una serie de modelos para realizar esta evaluación. El test de equilibrio peritoneal (PET) evalúa la capacidad de transporte del peritoneo clasificando a los pacientes en 4 categorías de transportador: alto, promedio alto, promedio bajo y bajo. El short PET realiza la misma evaluación en solo 2 h, y ha sido validado en pacientes pediátricos. Por otro lado, el MiniPET otorga información adicional al evaluar la capacidad de transporte de agua libre por los poros ultrapequeños, y el Accelerated Peritoneal Examination Time (APEX) evalúa el punto de intersección de las curvas de equilibrio de urea y glucosa, y ha sido propuesto como el tiempo de permanencia óptimo para lograr una UF adecuada. Se analiza la información actual sobre estos métodos diagnósticos, en particular los últimos aportes de la literatura respecto al transporte de agua libre vía aquaporinas, que podrían representar una herramienta importante para optimizar el transporte de agua y solutos en pacientes en diálisis peritoneal crónica, en particular respecto al pronóstico cardiovascular.

An evaluation of the characteristics of peritoneal solute and water transport is essential to assess the suitability of prescribing dialysis in patients suffering from chronic renal disease. There are currently a series of models to perform this evaluation. The peritoneal equilibration test (PET) evaluates the peritoneal transport capacity, classifying the patients into four transport categories: high, high-average, low-average, and low. The short PET enables the same evaluation to be made in only 2 hours, and has been validated in paediatric patients. On the other hand, the MiniPET provides additional information by evaluating the free water transport capacity by the ultra-small pores, and the Accelerated Peritoneal Examination Time (APEX) evaluates the time when the glucose and urea equilibration curves cross, and has been proposed as the optimum dwell time to achieve adequate ultrafiltration. An analysis is presented on the current information on these diagnostic methods as regards free water transport via aquaporins, which could be an important tool in optimising solute and water transport in patients on chronic peritoneal dialysis, particularly as regards the cardiovascular prognosis.

Aulas investigativas e a construção de conceitos de matemática: um estudo a partir da teoria de Piaget / Investigative classes and construction of concepts of mathematics: a study of Piaget's theory / Des cours investigatifs et la construction des concepts de mathématiques: une étude de la théorie de Piaget / Clases investigativas y la construcción de conceptos de matemáticas: un estudio a partir de la teoría de Piaget

O estudo é uma pesquisa qualitativa e colaborativa que tem o objetivo de compreender o processo de construção dos conceitos de Matemática dos estudantes por meio de atividades de investigação, pois pesquisas apontam que essas atividades mobilizam os estudantes a aprender de acordo com sua idade e amadurecimento. A fundamentação teórica foi a teoria de Piaget no que tange aos conceitos de equilibração e abstração reflexionante. O método constituiu-se da observação das aulas e atividades investigativas e das resoluções destas, realizadas em conjunto por seis estudantes do 6º ano do Ensino Fundamental de uma escola municipal de Porto Alegre, em 2013. Os dados foram organizados em categorias relativas à interpretação, à resolução e à argumentação, articulando os elementos do cenário investigativo com o Método Clínico de Piaget. Destaca-se como resultado da pesquisa a compreensão da forma como os estudantes constroem o conceito de múltiplos e divisores de um número natural nessas aulas...

The study is a qualitative and collaborative research that aims to understand the construction process of concepts of mathematics students through research activities, as the research indicates that these activities mobilize students to learn according to their age and maturity. The theoretical framework was Piaget's theory in relation to concepts of equilibration and reflective abstraction. The method consisted of observation of classes and investigative activities and its resolutions collectively done by six students from the 6^th grade of a public school in Porto Alegre, in 2013. The data were organized into categories relating to interpretation and argument resolution, articulating the elements of investigative scenario with Piaget's Clinical Method. It stands out as a result of research, the understanding of how students construct the concept of multiple divisors of a natural number in these classes...

Cette étude est une recherche collaborative et qualitative, qui vise à comprendre le processus de construction des concepts d'étudiants en mathématiques à travers les activités d'investigation, car les recherches indiquent que ces activités encouragent les étudiants à apprendre en fonction de leur âge et maturité. Le cadre théorique a été la théorie de Piaget concernant les concepts d'équilibre et d'abstraction réfléchissante. On a utilisé la méthode d'observation des cours et d'activités d'enquête et résolutions realisées par six élèves ensemble, étudiants d'une école primaire publique à Porto Alegre, en 2013. Les données ont été organisés en catégories liées à l'interprétation, la résolution et l'argumentation, en articulant les éléments du scénario d'investigation avec la Méthode Clinique de Piaget. Comme résultat de la recherche, on met en évidence la compréhension de la façon dont les élèves construisent le concept de multiples et diviseurs d'un nombre naturel dans ces cours...

Este estudio es una investigación cualitativa y colaborativa, que tiene como objetivo comprender el proceso de construcción de los conceptos de matemáticas de los estudiantes mediante actividades de investigación, pues pesquisas indican que esas actividades movilizan los estudiantes a aprender de acuerdo a su edad y madurez. La fundamentación teórica fue la teoría de Piaget sobre los conceptos de equilibrio y la abstracción reflexionante. El método utilizado fue la observación de clases, actividades de investigación y resoluciones de seis estudiantes agrupados del 6º año de la educación primaria de una escuela municipal de Porto Alegre en 2013. Los datos fueron organizados en categorías relativas a interpretación, resolución y argumentación, articulando los elementos del escenario investigativo con el Método Clínico de Piaget. El resultado de la pesquisa fue la comprensión de cómo los estudiantes construyen el concepto de múltiplos y divisores de un número natural en las clases...

Analysis of the characteristics of mouthguards that affect isokinetic muscular ability and anaerobic power

PURPOSE: The purpose of this study was to estimate the effects of occlusal stability to identify action mechanisms of mouthguards, known to have a modulatory effect on limb muscle function. MATERIALS AND METHODS: This study included 20 male subjects to perform the isokinetic muscle tests and the Wingate anaerobic power test on both knee joints under five closed-mouth conditions: without or with 4 types of mouthguards with thickness of 2 mm based on premolar area: (1) full-coverage, (2) anterior partial-coverage, (3) right posterior partial-coverage, and (4) left posterior partial-coverage. The obtained results were subjected to One-way ANOVA with repeated measures, followed by post hoc test of the contrast method (alpha=.05). RESULTS: There was no significant difference between the closed position with and without a full-coverage mouthguard in all variables. However, significant differences were observed between with and without a partial-coverage mouthguard in muscular endurance during extension of the left knee, muscular power and endurance during flexion of the right knee. Additionally, significant differences were found between occlusal states with full- and partial-coverage mouthguards in muscular power and endurance during extension of the left knee. CONCLUSION: These findings indicate the elevation of vertical dimension by 2 mm or the inducement of occlusal stability had little effect on isokinetic muscle strength and anaerobic performance, while uneven distribution of occlusal force might have some positive effects.

Erros e equilibração em psicologia genética / Errors and equilibrium in the genetic psychology / Errores y equilibrio en psicología genética

Os erros presentes nas tarefas de um sujeito construtor de conhecimento são importantes porque, ao se constituírem como observáveis, favorecem os processos de equilibração. Para o pesquisador, clínico ou professor, a observação construtivista dos erros pode garantir uma objetividade mínima nos processos de diagnóstico e intervenção. Nossa intenção neste trabalho de revisão teórica (ilustrado por comentários sobre um estudo de caso) é caracterizar o erro como parte inerente à atividade do sujeito construtor que, quando colocado a solucionar um problema, aproveita-se desse erro para promover a abertura de novos possíveis e, em seguida, dialeticamente, reduzi-los a um único possível, garantindo assim sua condição de necessário. Tentamos atualizar a caracterização dos erros como parte do processo de aprendizagem e reveladores da lógica infantil, criticando posições que os consideram meramente indícios de incapacidades e dificuldades em resolver tarefas.

The errors present in the tasks of a subject builder of knowledge are important because, tthey are observable and promote the process of balancing. For the researcher, clinician or teacher, the observation of constructivist errors can guarantee a minimum objectivity in the process of diagnosis and intervention. Our intention in this review of theoretical work is to characterize the error inherent in the activity as part of the subject construction that, when placed to resolve a problem, taking advantage of this error is to promote the opening of new possibilities. We try to update the characterization of errors as part of the learning process and highlight the logic of children. We criticiz the positions that consider the error as evidence of disability and difficulties in solving tasks.

Los errores presentes en las tareas de un sujeto constructor de conocimiento son importantes porque, al constituirse observables, favorecen los procesos de equilibrio. Para el investigador, clínico o profesor, la observación constructivista de los errores puede garantizar una objetividad mínima en los procesos de diagnóstico e intervención. Nuestra intención en este trabajo de revisión teórica (ilustrado por comentarios sobre un estudio de caso) es caracterizar el error como parte inherente a la actividad del sujeto constructor que, cuando llamado a solucionar un problema, se aprovecha del error para promover la apertura de nuevos posibles y, en seguida, dialécticamente reducirlos a un único posible, garantizando así su condición de necesario. Intentamos actualizar la caracterización de los errores como parte del proceso de aprendizaje y como reveladores de la lógica infantil, criticando posiciones que los consideran meros indicios de incapacidades y dificultades al resolver tareas.

Equilibração e tomada de consciência: análise do jogo Cara a Cara / Equilibration and grasp of consciousness: an analysis of the game

O objetivo deste estudo é demonstrar teoricamente a viabilidade da utilização do jogo Cara a Cara para o estudo dos seguintes processos de desenvolvimento: equilibração e tomada de consciência, próprios do referencial piagetiano. O processo de construção do conhecimento passa, inclusive, pela interação sujeito/objeto e observáveis/coordenações, que são pares dialéticos envolvidos na adaptação do sujeito ao meio. Ao ter suas estruturas cognitivas desequilibradas, o sujeito precisa tentar compreender suas estratégias e as características do objeto. Fazendo isso, caminha para tomadas de consciências mais centrais, até o ponto em que consegue resolver a questão e, por algum tempo, manter suas estruturas equilibradas. O jogo Cara a Cara, conforme demonstrado ao longo desta discussão, se apresenta como um instrumento adequado para o entendimento de processos de construção do conhecimento, na medida em que permite a observação e o relato verbal acerca do que o sujeito compreende de si e do jogo.

The goal of this study is to demonstrate theoretically the utilization viability of the game ôGuess Who?õ for the study of the following development processes: equilibration and grasp of consciousness, particular of the piagetian referential. The knowledge construction process passes, besides, by the interaction subject/object and observable/coordinations, which are dialectic pairs involved in the subject adaptation to the environment. By having unbalanced cognitive structures, the subject must try to comprehend his/her strategies and the characteristics of the object. By doing so, he walks to more central grasps of consciousness to the point in which he/she can solve the issue and for some time, maintain their structure balanced. The game ôGuess Who?õ, as demonstrated throughout this discussion is presented as an appropriate tool for understanding processes of knowledge construction, in that it enables the observation and verbal report about what the subject understands of himself/herself and the game.

La dialéctica en la psicologia del desarrollo: relevancia y significacion en la investigacion / Dialectic in developmental psychology: its importance and significance in research

El presente artículo examina la significación y la relevancia de la dialéctica en la obra psicológica de Piaget y de Vigotsky. Por un lado se analiza una metodología dialéctica común, presente en las unidades de análisis de las investigaciones. Por otro, se exponen los rasgos peculiares que adquiere la dialéctica en la explicación del desarrollo en ambos desarrollo. Finalmente, en base a los análisis realizados, se caracterizan los rasgos de la dialéctica. También se discute su unicidad y su carácter apriori en la Psicología del Desarrollo y en las Ciencias Humanas, justificándose su diversidad, en función de las temáticas que se indagan, así como a ciertos límites en el uso de esa categoría en la indagación empírica. Su implementación exige que adopte formas diferentes, pertinentes a los distintos problemas y focos teóricos.

The present article analyses the signficance and relevance of dialectic in Piaget's and Vigotsky's psychological studies. On one hand, it highlights the common dialectical methodology present in units of analysis in research. On the other hand, it focuses on the peculiar features dialectic acquires within both authors' explanation of psychological development. Lastly, a characterization of dialectic features based on previous analysis is introduced. The present article argues against the unique dialectic and its a priori features in Developmental Psychology and Human Sciences areas. It also justifies its diversity in relation to the subject matters under investigation as well as the existence of certain limits in the use of that category in empirical research. The use of dialectics requires the adoption of diverse forms regarding different issues and theoretical focuses.

High Peritoneal Transport Status is Not an Independent Risk Factor for High Mortality in Patients Treated with Automated Peritoneal Dialysis

We undertook this study to elucidate whether baseline peritoneal membrane transport characteristics are associated with high mortality in incident automated peritoneal dialysis (APD) patients. This retrospective study includes 117 patients who started APD at Yonsei University Health System from 1996 to 2008 and had a PET within 3 months of APD initiation. High transporters were significantly older and had a higher incidence of cardiovascular disease. Patient survival for years 1, 3, and 5 were 85%, 64%, and 35% for high transporter and 94%, 81%, and 68% for non-high transporter group (P<0.01). Multivariate analysis revealed that age, diabetes, cardiovascular disease, serum albumin level, and residual renal function were independently associated with high mortality in APD patients. In contrast, high transport status was not a significant predictor for mortality in this population when the other covariates were included. Even though high transport was significantly associated with mortality in the univariate analysis, its role seemed to be influenced by other comorbid conditions. These findings suggest that the proper management of these comorbid conditions, as well as appropriate ultrafiltration by use of APD and/or icodextrin, must be considered as protective strategies to improve survival in peritoneal dialysis patients with high transport.

Influence of VEGF Genetic Polymorphism on Peritoneal Solute Transport in Pediatric Dialysis Patients

PURPOSE: Genetic and clinical factors can influence the permeability of the peritoneal membrane. The peritoneal equilibration test (PET) is helpful in measuring peritoneal permeability in peritoneal dialysis (PD). We investigated the influence of genetic polymorphism of vascular endothelial growth factor (VEGF) on the PET parameters. METHODS: Pediatric patients who underwent PET within 12 months of initiating PD at Seoul National University Children's Hospital and Samsung Medical Center were selected. The patients with positive history of peritonitis before PET were excluded. The VEGF -2578C/A, -14978T/C, -1154G/A, -634G/C, and +936C/T single-nucleotide polymorphisms were genotyped. RESULTS: The mean 4-hour dialysate-to-plasma ratio for creatinine (D/P creatinine) and the mean 4-hour dialysate glucose to baseline dialysate glucose ratio (D/D0 glucose) were 0.56+/-0.13 and 0.43+/-0.11, respectively. The patients with haplotype CTGGC showed higher 4-hour D/P creatinine (0.67+/-0.12 vs 0.50+/-0.09, P=0.007) and lower 4-hour D/D0 glucose (0.35+/-0.12 vs 0.47+/-0.08, P=0.037) than those without haplotype CTGGC. CONCLUSION: The VEGF genetic polymorphism may influence the peritoneal solute transport.

Factors Related to Baseline Peritoneal Solute Transport Rate in Incident Peritoneal Dialysis Patients:Results from Modified Peritoneal Equilibration Test Using 3.86% Glucose Solution / 대한신장학회잡지

BACKGROUND:The present study was designed to determine factors related to baseline peritoneal small solute transport rate (PSTR) from incident Korean peritoneal dialysis (PD) patients using modified peritoneal equilibration test (PET). METHODS:Incident PD patients whose duration of PD is between 4 weeks and 6 months were enrolled from four major university hospitals in Seoul. Modified PET with 3.86% glucose solution and adequacy test were performed. RESULT: 1) Our PET result from incident Korean PD patients showed results similar to that from the Caucacian patients. 2) The patients were divided into four groups based on the PSTR:serum albumin at time of PET, dip dialysate/plasma sodium, dialysate/plasma albumin ratio and peritoneal albumin excretion were significantly different among the four transport types (p<0.05). 3) D/PAlb was significantly higher in the high transport group than in the low transport. Serum albumin concentration before the onset of PD was not different among the four groups but was significantly different at the time of PET. 4) There was no difference of D/PCr4 between the diabetic (0.72+/-0.10) and the non-diabetic (0.72+/-0.11) groups. 5) PSTR in incidental PD patients was correlated with D/PAlb and dip D/P(Na). CONCLUSION:Our PET results from incidental Korean PD patients turned out to be showed results similar to those from Caucacian patients. There were no differences in age, BSA, BMI, nutrition index, CRP, residual renal function among four transport types in incidental PD patients. PSTR in incidental PD patients was correlated with D/PAlb and dip D/P(Na).

Peritoneal Equilibration test (PET) in Korean Patients - Single Center Experience / 대한신장학회잡지

BACKGROUND: Peritoneal solute transport rate, assessed by PET, varies widely among patients and has been shown to differ significantly among different ethnic groups. The aim of the present study is to investigate the peritoneal transport characteristics in Korean peritoneal dialysis (PD) patients and factors that predict peritoneal transport status. METHODS: Between May 2001 and February 2006, 141 patients on PD performed a standard 4-hour PET within the first 6 months after initiation of PD therapy. RESULTS: Of these 141 patients, there were 71males and 70 females. The mean age of the patients was 51.2+/-12.5 years and the etiology of renal failure was diabetes in 67 patients (47.5%). The mean 4-hour D/P creatinine ratio was 0.68+/-0.11. Compared with a mean of 0.65+/-0.15 as determined by Twardowski et al, our patients have significantly higher mean solute transport rate (p<0.05). Numbers of low (L), low-average (LA), high-average (HA), and high (H) transporters were 15 (10.6%). 68 (48.2 %), 53 (37.6%) and 5 (3.5%), respectively. However, according to our own data, the number of L, LA, HA and H were 18 (12.8%), 42 (29.8%), 64 (45.4%) and 17 (12.1%), respectively, significantly different from those classified by Twardowski et al. In univariate analysis, older age, hypoalbuminemia and lower BMI were predictive of high transport status. Using multiple linear regression, only hypoalbuminemia was independently predictive of higher 4-hour D/Pcr (p=0.000). CONCLUSION: Korean PD patients have a higher mean solute transport rate than Twardowskis data, and serum albumin is an independent predictor of high transport status. Further prospective studies with a large number of patients are needed for evaluating the diversity of peritoneal transport characteristics in different ethnic populations.

Peritoneal Equilibration test (PET) in Korean Patients - Single Center Experience / 대한신장학회잡지

BACKGROUND: Peritoneal solute transport rate, assessed by PET, varies widely among patients and has been shown to differ significantly among different ethnic groups. The aim of the present study is to investigate the peritoneal transport characteristics in Korean peritoneal dialysis (PD) patients and factors that predict peritoneal transport status. METHODS: Between May 2001 and February 2006, 141 patients on PD performed a standard 4-hour PET within the first 6 months after initiation of PD therapy. RESULTS: Of these 141 patients, there were 71males and 70 females. The mean age of the patients was 51.2+/-12.5 years and the etiology of renal failure was diabetes in 67 patients (47.5%). The mean 4-hour D/P creatinine ratio was 0.68+/-0.11. Compared with a mean of 0.65+/-0.15 as determined by Twardowski et al, our patients have significantly higher mean solute transport rate (p<0.05). Numbers of low (L), low-average (LA), high-average (HA), and high (H) transporters were 15 (10.6%). 68 (48.2 %), 53 (37.6%) and 5 (3.5%), respectively. However, according to our own data, the number of L, LA, HA and H were 18 (12.8%), 42 (29.8%), 64 (45.4%) and 17 (12.1%), respectively, significantly different from those classified by Twardowski et al. In univariate analysis, older age, hypoalbuminemia and lower BMI were predictive of high transport status. Using multiple linear regression, only hypoalbuminemia was independently predictive of higher 4-hour D/Pcr (p=0.000). CONCLUSION: Korean PD patients have a higher mean solute transport rate than Twardowskis data, and serum albumin is an independent predictor of high transport status. Further prospective studies with a large number of patients are needed for evaluating the diversity of peritoneal transport characteristics in different ethnic populations.

The Effect of Equilibration Temperature and Time Prior to Cryopreservation on the Outcome of Cryopreservation of 2-Cell Mouse Embryos / 대한산부인과학회잡지

OBJECTIVE: One-cell human zygotes have been successfully frozen and thawed using 1,2-propanediol (PROH) during freezing and thawing. This study was performed to assess the effect of equilibration temperature and time on cryopreservation of 2-cell mouse embryos by investigating the equilibration temperature and time during initial PROH exposure prior to cryopreservation. MATERIALS AND METHODS: The late 2-cell mouse embryos were obtained from 5-6 week old ICR mice and were exposed to 1.5 M PROH in phosphate-buffered saline (PROH-PBS) at 37degrees C, room temperature (22- 24degrees C), and 4degrees C for 30 min. The PROH was washed off the 2-cell mouse embyos by incubating them for 5 min each in 1, 0.5, and then 0 M PROH-PBS in the order named. The 2-cell mouse embryos were subsequently cultured in Ham's F-10 medium and embryo development was assessed at 24, 48, and 96 hours. RESULTS: Incubation of 2-cell mouse embryos at 37degrees C for 30 min significantly impaired embryo development to blastocysts. Embryo development after exposure to PROH at 37degrees C for 10 min was 8.3% (P=0.047) and embryo development for 30 min was 5.4% (P=0.038). Incubation of 2-cell mouse embryos at room temperature or 4degrees C for up to 30 min did not significantly reduce embryo development. Cryosurvival of 2-cell mouse embryos exposed to PROH at room temperature or 4degrees C was similar. CONCLUSION: These findings suggested that pronanediol is toxic to 2-cell mouse embryos in a temperature- and time-dependent fashion. Cryopreservation of 2-cell mouse embryos after exposure at 4degrees C appears to be no better than after exposure at room temperature.

Analysis of the Timing of PET and Factors Influencing PET Results / 대한신장학회잡지

The peritoneal equilibration test(PET) is used as a tool for determining the characteristics of the peritoneal membrane. Initial PET is recommended at least 1 month after peritoneal dialysis, but PET after 1 month may be difficult to perform on an out- patients basis. Two standard PETs(D/P4Cr) were per- formed in 60 CAPD patients(DM:non DM=22:38). Initial PETs, within one week after starting CAPD and follow up PETs, at least 3 months after CAPD were performed. The initial PET values were compared with subsequent PET values. Clinical data (age, sex, body surface area, BMI, presence of diabetes mellitus, ascites) and laboratory indices(serum albumin, dialysate creatinine clearance, KT/V, protein catabolic rate) were compared with the results of the PETs. In initial PET result, there was negative correlation between D/P4Cr and serum albumin(r=-0.522, p<0.001 N=60). There was no significant difference between initial and follow up(mean+/-S.D.:8.84+/-5.2months after CAPD) D/P4Cr(0.68+/-0.14 vs 0.68+/-0.13). But with passage of time, delta D/P4Cr and delta serum albumin were also negatively correlated (r=-0.459, p<0.001). According to the linear regression analysis, the factor significantly associated with D/P4Cr was serum albumin(coefficients -0.111). In conclusion, serum albumin level is the most important predictor of the peritoneal membrane transport characteristics, and it seems that the timing of PET does not matter, rather the changes of with time are strongly correlated with the changes of the serum albumin level.

Peritoneal Equilibration Tests on Continuous Ambulatory Peritoneal Dialysis patients / 대한내과학회지

OBJECTIVES: The peritoneal equilibration test(PET) is routinely performed in adults treated with chronic peritoneal dialysis to assess the peritoneal transport rate and to optimize treatment prescription. This study focuses on the evaluation of characteristics of peri toneal solute transport rates and physical and serological factors affecting peritoneal transport rate performed in our continuous ambulatory peritoneal dialysis(CAPD) patients due to guide adequate peri toneal dialysis form. METHODS: We analyzed 95 PET results which had been tested on the 28th day of CAPD and physical and serological values, such as age, sex, diabetes mellitus, height, weight, body surface area, arterial blood pressure, blood urea nitrogen, creatinine, glucose, cholesterol, triglyceride, total protein, albumin, hematocrit, hemoglo bin, sodium, potassium, phosphate which had been ob tained on the day of PET. RESULTS: 1) According to transport rate, high transport rate group was 9 cases(9.5%), high average transport group 26 cases(27.4%), low average transport rate group 32 cases(33.6%), and low transport rate group 28 cases (29.5%) respectivly. 2) The average of 4hour D/PCr was 0.60, 4hour D/Do glucose was 0.46, and drain volume was 2480ml. Thus the average of peritoneal solute transport rate of total patients was low average transport rate. 3) Factors affecting peritoneal solute transport rate were age, body surface area, plasma albumin, serum creatinine and triglyceride level. CONCLUSION: These findings suggest that high dose peritoneal dialysis form should be used in our CAPD patients because most of them have low average peritoneal transport rate, and age, body surface area, plasma albumin, serum creatinine, and triglyceride level should be consid ered when select the adequate peritoneal dialysis form.

Peritoneal Equilibration Test in Korean Patients Undergoing Continuous Ambulatory Peritoneal Dialysis / 대한신장학회잡지

In order to evaluate the peritoneal transport characteristics in Korean non-diabetic and diabetic end- stage renal disease patients, peritoneal equilibration test(PET) proposed by Twardowski et al. were performed on patients who had been on continuous ambulatory peritoneal dialysis(CAPD) for 2 to 6 months. The results were as follows : 1) Fifty four patients(including 24 diabetics) on CAPD were studied with a mean age of 48.7 years. And male/female ratio was 1 : 1.08. 2) In non-diabetics, the dialysate to dialysate prior to infusion ratio for glucose(D/D0 glu) at 2-, and 4-hour dwell times were 0.61+/-0.09, and 0.39+/-0.10, and the dialysate-to-plasma ratio for creatinine (D/P cr) at 2-, and 4-hour dwell times were 0.40+/-0.11, 0.63+/-0.12, respectively. 3) In diabetic patients, D/D0 glu at 2-, and 4- hour dwell times were 0.60+/-0.09, 0.39+/-0.08, respectively, and D/P cr at same dwell times were 0.50+/-0.08, and 0.71+/-0.08, which were significantly higher than in non-diabetics(por=150mg/dL) and normoglycemic(<150mg/ dL) patients. The values of D/Pcr at 2-, and 4-hour dwell times in hyper-glycemic patients were signficantly higher than in non-diabetic patients (D2/P2 cr : 0.50+/-0.09 vs. 0.40+/-0.11, D4/P4 cr : 0.72+/-0.07 vs 0.63+/-0.12, respectively, p<0.05). 5) Net ultrafiltration did not differ between any of subgroups. 6) In non-diabetic patients, the ranges of D4/P4 cr and D4/D0 glu for high, high average, low average, and low transporters were defined as D4/P4 cr : 0.87-0.75, 0.75-0.63, 0.63-0.51, 0.51-0.39, D4/D0 glu : 0.19-0.29 0.29-0.39, 0.39-0.49, 0.49-0.59, respectively, which were remarkably simliar as suggested by Twardowski et al. In conclusion, the creatinine and glucose transfers assessed by dialysate-plasma ratio of creatinine and glucose are remarkably similar between Korean and North American patients. And the creatinine transport rate in Korean diabetic patient is higher than non-diabetic patient while ultrafiltration is achievable in non-diabetic patient.

Double-equilibration technique for measuring liquid/gas partition coefficients of isoflurane / 中华麻醉学杂志

This study was designed to establish methods to measure partition coefficients of inhaled anesthetics at 1 atmosphere and 37 C by using syringe-flask double equilibration technique. Olive oil/gas (O/G), saline/gas (S/G), and water/gas (W/G) partition coefficients of isoflurane were 90.20?2.01, 0.6256?0.109, and 0. 741?0.025, respectively. Even though O/G was 150 folds of S/G,coefficients of variation for both O/G and S/G were less than 3%. The results indicate that the established double-equilibration technique has a very high repeatability and is applicable to wide ranges of inhaled anesthetics' solubilities.

Re-evaluation of solute transport groups of peritoneal dialysis patients using peritoneal equilibration test / 中华肾脏病杂志

Objective To clarify whether the peritoneal equilibration test (PET)-determined solute transport groups defined by Twardowski fits patients in our medical center. Methods 158 initial standardized PET data since 1995 was selected and proportions of four transport groups were calculated according to Twardowski's criterion. Using the mean and standard deviations of 4-hour dialysis/plasma ratio of creatinine (D/Pcr), transport groups of our patients were re-determined. Patients were classified as follow: according to both two criteria, patients whose 4-hour D/Pcr in the range of high transport, low transport and average transport were classified as group H1, group L1 and group A, respectively; several average transport patients who changed to low transport after re-evaluation were classified as group L2; high transport patients who changed to average transport were classified as group H2. Every group was compared with clinical status in order to evaluate which criterion fit our patients. Results The 4-hour D/Pcr was 0. 70 ?0. 14 in our patients. The proportion of high, high-average, low-average and low transport were 21.5%, 44.9%, 17.8% and 5. 7% according to Twardowski's and 14. 6% , 33.5%, 33.5% and 18. 4% after re-evaluation. The ultrafiltration volume in group L2 was significantly higher than that in group A ( P