Peritoneal Transport Kinetics of Glucose, Urea, and Creatinine during Infancy and Childhood

1991 ◽  
Vol 11 (4) ◽  
pp. 322-325 ◽  
Author(s):  
Cornelis H. Schröder ◽  
Marie-José Van Dreumel ◽  
Roel Reddingius ◽  
Ad G.M. Theeuwes ◽  
Hans L. Willems ◽  
...  
Keyword(s):  
Young Children ◽  
Transport Kinetics ◽  
Age Dependency ◽  
Older Children ◽  
Peritoneal Equilibration Test ◽  
Peritoneal Transport ◽  
Infancy And Childhood ◽  
Reference Curves ◽  
Kinetics Of

Peritoneal handling of glucose and metabolites is reported to be higher in young children treated with CAPD than in older children. Reference curves for the standardized peritoneal equilibration test (PET) are not available for younger ages. The present study describes the results of the PET in 19 children (mean age 5.0 years, ranging from 0.3–15) during the first month of CAPD treatment. No age dependency for the handling of glucose, urea, and creatinine could be established when the group was subdivided into 1. children below the age of 3 years, and 2. children above that age. There was, however, a significant correlation between equilibration of creatinine and age, indicating more rapid equilibration at younger ages.

scholarly journals Peritoneal equilibration test results are different in infants, children, and adults.

1995 ◽  
Vol 6 (4) ◽  
pp. 1309-1312
Author(s):  
S R Mendley ◽  
N L Majkowski
Keyword(s):  
Peritoneal Dialysis ◽  
Young Children ◽  
Analysis Of Variance ◽  
Clinical Care ◽  
Test Results ◽  
Older Children ◽  
Peritoneal Equilibration Test ◽  
Very Young Children

Peritoneal equilibration test (PET) curves have been standardized in adult peritoneal dialysis (PD) patients. However, it appears that norms for pediatric PD patients may be different. A series of PET in 29 stable, chronic PD patients < or = 14 yr old performed at dwell volumes of 33 +/- 6 mL/kg with 2.5% Dianeal is reported. PET results for glucose and creatinine transport were compared between patients age < or = 2 and those 3 to 14 and published adult values by analysis of variance. Children < or = 2 transport glucose and creatinine more rapidly than do children 3 to 14 and adults. Children 3 to 14 transport glucose more rapidly than do adults; creatinine transport is not significantly different. These data demonstrate that transport characteristics differ between very young children, older children, and adults. Because PET are usually performed to plan mode of therapy, to address inadequate ultrafiltration, or to increase clearance, awareness of these results should assist in the clinical care of children on PD.

Instruction Helps and Hinders Young Children’s Feature Learning

2018 ◽  
Author(s):  
Charles Kalish ◽  
Nigel Noll
Keyword(s):  
Young Children ◽  
Feature Learning ◽  
Irrelevant Information ◽  
Diagnostic Feature ◽  
Older Children ◽  
Prediction Task ◽  
Feature Correlation ◽  
The Future

Existing research suggests that adults and older children experience a tradeoff where instruction and feedback help them solve a problem efficiently, but lead them to ignore currently irrelevant information that might be useful in the future. It is unclear whether young children experience the same tradeoff. Eighty-seven children (ages five- to eight-years) and 42 adults participated in supervised feature prediction tasks either with or without an instructional hint. Follow-up tasks assessed learning of feature correlations and feature frequencies. Younger children tended to learn frequencies of both relevant and irrelevant features without instruction, but not the diagnostic feature correlation needed for the prediction task. With instruction, younger children did learn the diagnostic feature correlation, but then failed to learn the frequencies of irrelevant features. Instruction helped older children learn the correlation without limiting attention to frequencies. Adults learned the diagnostic correlation even without instruction, but with instruction no longer learned about irrelevant frequencies. These results indicate that young children do show some costs of learning with instruction characteristic of older children and adults. However, they also receive some of the benefits. The current study illustrates just what those tradeoffs might be, and how they might change over development.

scholarly journals Multilab Direct Replication of Flavell, Beach, and Chinsky (1966): Spontaneous Verbal Rehearsal in a Memory Task as a Function of Age

2021 ◽  
Vol 4 (2) ◽  
pp. 251524592110181
Author(s):  
Emily M. Elliott ◽  
Candice C. Morey ◽  
Angela M. AuBuchon ◽  
Nelson Cowan ◽  
Chris Jarrold ◽  
...  
Keyword(s):  
Cognitive Development ◽  
Young Children ◽  
Memory Performance ◽  
Critical Role ◽  
Memory Task ◽  
Older Children ◽  
Continuous Increase ◽  
Verbal Rehearsal ◽  
Picture Memory ◽  
Spontaneous Production

Work by Flavell, Beach, and Chinsky indicated a change in the spontaneous production of overt verbalization behaviors when comparing young children (age 5) with older children (age 10). Despite the critical role that this evidence of a change in verbalization behaviors plays in modern theories of cognitive development and working memory, there has been only one other published near replication of this work. In this Registered Replication Report, we relied on researchers from 17 labs who contributed their results to a larger and more comprehensive sample of children. We assessed memory performance and the presence or absence of verbalization behaviors of young children at different ages and determined that the original pattern of findings was largely upheld: Older children were more likely to verbalize, and their memory spans improved. We confirmed that 5- and 6-year-old children who verbalized recalled more than children who did not verbalize. However, unlike Flavell et al., substantial proportions of our 5- and 6-year-old samples overtly verbalized at least sometimes during the picture memory task. In addition, continuous increase in overt verbalization from 7 to 10 years old was not consistently evident in our samples. These robust findings should be weighed when considering theories of cognitive development, particularly theories concerning when verbal rehearsal emerges and relations between speech and memory.

scholarly journals A New Method to Increase Ultrafiltration in Peritoneal Dialysis: Steady Concentration Peritoneal Dialysis

2016 ◽  
Vol 36 (5) ◽  
pp. 555-561 ◽  
Author(s):  
Vicente Pérez-Díaz ◽  
Alfonso Pérez-Escudero ◽  
Sandra Sanz-Ballesteros ◽  
Guadalupe Rodríguez-Portela ◽  
Susana Valenciano-Martínez ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Glucose Concentration ◽  
Fluid Overload ◽  
Glucose Solution ◽  
Osmotic Gradient ◽  
Single Session ◽  
Peritoneal Equilibration Test ◽  
Peritoneal Transport ◽  
Constant Rate ◽  
Limited Power

Background Peritoneal dialysis (PD) has limited power for liquid extraction (ultrafiltration), so fluid overload remains a major cause of treatment failure. Methods We present steady concentration peritonal dialysis (SCPD), which increases ultrafiltration of PD exchanges by maintaining a constant peritoneal glucose concentration. This is achieved by infusing 50% glucose solution at a constant rate (typically 40 mL/h) during the 4-hour dwell of a 2-L 1.36% glucose exchange. We treated 21 fluid overload episodes on 6 PD patients with high or average-high peritoneal transport characteristics who refused hemodialysis as an alternative. Each treatment consisted of a single session with 1 to 4 SCPD exchanges (as needed). Results Ultrafiltration averaged 653 ± 363 mL/4 h — twice the ultrafiltration of the peritoneal equilibration test (PET) (300 ± 251 mL/4 h, p < 0.001) and 6-fold the daily ultrafiltration (100 ± 123 mL/4 h, p < 0.001). Serum and peritoneal glucose stability and dialysis efficacy were excellent (glycemia 126 ± 25 mg/dL, peritoneal glucose 1,830 ± 365 mg/dL, D/P creatinine 0.77 ± 0.08). The treatment reversed all episodes of fluid overload, avoiding transfer to hemodialysis. Ultrafiltration was proportional to fluid overload ( p < 0.01) and inversely proportional to final peritoneal glucose concentration ( p < 0.05). Conclusion This preliminary clinical experience confirms the potential of SCPD to safely and effectively increase ultrafiltration of PD exchanges. It also shows peritoneal transport in a new dynamic context, enhancing the influence of factors unrelated to the osmotic gradient.

Age Effects in the Processing of Typical and Distinctive Faces

1995 ◽  
Vol 48 (2) ◽  
pp. 447-465 ◽  
Author(s):  
Robert A. Johnston ◽  
Hadyn D. Ellis
Keyword(s):  
Young Children ◽  
Recognition Memory ◽  
Memory Task ◽  
Age Effects ◽  
Decision Task ◽  
Older Children ◽  
Cognitive Architectures ◽  
Differential Processing ◽  
Four Dimensions ◽  
Adults And Children

Two experiments exploring the differential processing of distinctive and typical faces by adults and children are reported. Experiment 1 employed a recognition memory task. On three out of four dimensions of measurement, children of 5 years of age did not show an advantage for distinctive faces, whereas older children and adults did. In Experiment 2, however, subjects of all ages classified typical faces faster than distinctive ones in a face/non-face decision task: the 5-year-olds performed exactly as did adults and older children. The different patterns in performance between these two tasks are discussed in relation to possible cognitive architectures for the way young children represent faces in memory. Specifically, we examine two alternative architectures proposed by Ellis (1992) as precursors for Valentine's (1991a) multidimensional adult face-space and discuss whether implementations of these spaces should be based on a norm-based or an exemplar-based framework.

Do Monkeys and Young Children Understand Exclusive “Or” Relations? A Commentary on Ferrigno et al. (2021)

2021 ◽  
pp. 095679762110246
Author(s):  
Shalini Gautam ◽  
Thomas Suddendorf ◽  
Jonathan Redshaw
Keyword(s):  
Young Children ◽  
Response Pattern ◽  
Compelling Evidence ◽  
Experimental Task ◽  
Older Children ◽  
Disjunctive Syllogism ◽  
Identical Response ◽  
Exclusive Or

Ferrigno et al. (2021) claim to provide evidence that monkeys can reason through the disjunctive syllogism (given A or B, not A, therefore B) and conclude that monkeys therefore understand logical “or” relations. Yet their data fail to provide evidence that the baboons they tested understood the exclusive “or” relations in the experimental task. For two mutually exclusive possibilities—A or B—the monkeys appeared to infer that B was true when A was shown to be false, but they failed to infer that B was false when A was shown to be true. In our own research, we recently found an identical response pattern in 2.5- to 4-year-old children, whereas 5-year-olds demonstrated that they could make both inferences. The monkeys’ and younger children’s responses are instead consistent with an incorrect understanding of A and B as having an inclusive “or” relation. Only the older children provided compelling evidence of representing the exclusive “or” relation between A and B.

Kinetics of the multidrug transporter (P-glycoprotein) and its reversal

1997 ◽  
Vol 77 (2) ◽  
pp. 545-590 ◽  
Author(s):  
W. D. Stein
Keyword(s):  
Final Section ◽  
Transport Kinetics ◽  
Multidrug Transporter ◽  
Chemotherapeutic Drugs ◽  
Multidrug Resistance Proteins ◽  
Binding Properties ◽  
Membrane Pump ◽  
Resistance Proteins ◽  
P Glycoprotein ◽  
Kinetics Of

Most cancer deaths result from the cancer's either being intrinsically resistant to chemotherapeutic drugs or becoming resistant after being initially sensitive. Often, in cells grown in cell culture, drug resistance correlates with the presence of one or more of the so-called P-glycoproteins or multidrug resistance proteins, products of the mdr family of genes. This review is largely concerned with the transport kinetics of the P-glycoproteins. We first present a brief overview of the P-glycoproteins, their properties, and their clinical significance. Later sections of the review expand on this material with special emphasis on the substrates of P-glycoprotein and how they cross the cell membrane, on the transport kinetics of the P-glycoprotein, on reversers of its action, and on its activity as an ATPase. In a final section, we consider the mechanism of action of P-glycoprotein as an actively transporting membrane pump. The characteristic of P-glycoprotein considered the most difficult to explain is its very broad specificity (or lack of specificity), but there are precedents for this property in well-known proteins such as serum albumin, which binds a range of molecular types, including substrates and reversers of P-glycoprotein, seemingly as broad as does P-glycoprotein. Pointing out this analogy does not provide a molecular explanation for the substrate-binding properties of P-glycoprotein but does make those properties more assimilable.

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