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Quantitative automated particle-enhanced immunonephelometric assay for the routinary measurement of human cystatin C.
No full textHuman cystatin C is a low molecular mass protein of 13359 Dalton recently proposed as a new very sensitive marker of changes in glomerular filtration rate. Serum cystatin C concentration correlates negatively with glomerular filtration rate as well as or better than creatinine. We evaluated a recently introduced automated nephelometric immunoassay for cystatin C in serum or EDTA-plasma samples on the Behring Nephelometer System. The assay consists of incubating the 100-fold diluted sample for 6 minutes with latex particles covalently coated with anti-human cystatin C antibodies, and then quantifying the change of light-scatter produced. Method reproducibility is satisfactory, the intra- and inter-assay coefficients of variation ranging from 1.58% to 3.77% and from 5.6% to 11.47% respectively. Rheumatoid factor (< or = 1116 IU/ml), bilirubin (< or = 418 micrommol/l), triglycerides (10.47 mmol/), and haemoglobin (12 g/l) do not significantly interfere in the assay. No significant difference was found in cystatin C concentration between serum and EDTA-plasma samples. Cystatin C is stable in serum samples stored under different conditions up to one month. This method correlates well (mean difference=-0.536+/-0.307 mg/l) with another commercially available particle-enhanced turbidimetric immunoassay. Cystatin C offers better clinical sensitivity than creatinine for discriminating patients with normal renal function and those with mild-to-moderate reduction in renal function. This method is suitable for routine cystatin C measurement, including emergencies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Cystatin C in healthy women at term pregnancy and in their infant newborns: relationship between maternal and neonatal serum levels and reference values.
No full textHuman cystatin C, a basic low molecular mass protein with 120 amino acid residues, is freely filtered by the glomerulus and almost completely reabsorbed and catabolized by the proximal tubular cells. Cystatin C has been recently proposed as a new sensitive endogenous serum marker for the early assessment of changes in the glomerular filtration rate. To define a reference basis for future clinical investigations in the perinatal period, we investigated the relationship between maternal and neonatal serum cystatin C in comparison with that of creatinine. We also defined reference values in healthy women at full-term pregnancy and in full-term newborns over the first 5 days of life. Seventy-eight women with uncomplicated pregnancy, aged between 19 and 40 years, and their infant newborns (43 males, 35 females) were enrolled in the study. The gestational age ranged from 37 to 43 weeks, and the birth weight from 2.50 to 4.15 kg. Blood samples were taken from all the women immediately before delivery and from their newborns at birth, 72 and 96 h after birth. Maternal and neonatal renal function was evaluated by standards parameters and by calculating creatinine clearance. In all serum samples, we measured cystatin C, creatinine, and urea. At term gestation, serum cystatin C ranged from 0.64 to 2.30 mg/L. At birth, serum cystatin C values ranged from 1.17 to 3.06 mg/L, significantly decreasing after 3 and 5 days of life. No correlation was found between maternal and neonatal serum cystatin C values (r = 0.09). As cystatin C serum levels in newborns are not significantly correlated with the respective maternal levels, neonatal serum cystatin C may originate almost exclusively in the neonate
Is serum cystatin C a sensitive marker of glomerular filtration rate (GRF)? A preliminary study on renal transplant patients
No full textHuman cystatin C is a basic low molecular mass protein (13,359 Dalton) freely filtered through the glomerulus and almost completely re-absorbed and catabolized by proximal tubular cells. We measured serum cystatin C in 38 kidney transplant patients (23 males, 15 females) aged between 6 and 32 years. To assess renal function, serum and urinary creatinine were also determined in all patients, and creatinine clearance was finally calculated Cystatin C was determined by a particle-enhanced turbidimetric assay, and creatinine was measured by gas chromatography-mass spectrometry. To compare the diagnostic efficiency of cystatin C with that of creatinine, inulin clearance was performed on 12 renal transplant patients, and receiver operating characteristic (ROC) analysis was applied. The results of this study demonstrate that serum cystatin C significantly increases in renal transplant patients with reduced creatinine clearance (< 70 mL/min per 1.73 m2) and that the diagnostic accuracy of serum cystatin C is better than of serum creatinine. Cystatin C may be utilized as a very marker of reduced GFR
Immunoturbidimetric assay of glycated hemoglobin
No full textWe investigated the performances of HbA1c determination by a latex enhanced turbidimetric immunoassay using the specific monoclonal antibodies (Unimate, Roche) against the β-N-terminal fragments. The coefficients of variation ranges from 1.7 to 3.8% within assay (n = 30) and from 3.9 to 4.9% between assay (n = 20). The assay was linear from 2.5 to 14.9% of HbA1c. No interferences was found from fetal, carbamylated, or variant (S) hemoglobins and from labile Schiff adduct with glucose. The following relationship was derived from fresh sample comparison between HPLC (Diamat-BioRad) (x) and immunoassay (y) method: y = 0.971 x + 0.87%, r= 0.98, n = 115. The immunoassay provides a highly precise and specific method for HbA1c
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
[Determination of blood cystatin C in pregnant women during labor and in their newborns].
No full textINTRODUCTION:
Human cystatin C is a basic low molecular mass protein (M(r) = 13,359) freely filtered by the glomerulus and almost completely reabsorbed and catabolized by the proximal tubular cells. In this study, we determined maternal and neonatal serum cystatin C levels both in a group of healthy pregnant women and in their newborns over the first five days of life.
PATIENTS AND METHODS:
Fifty healthy pregnant women, aged from 19 to 40 years, were selected. Newborns (31 males, 19 females) demonstrated the 1-min Apgar score ranging between 8 and 10, and the 5-min between 9 and 10. Their gestational age (GA) ranged between 37 and 43 weeks. Cystatin C was determined by using the cystatin C PET kit (Dako, Milano, Italy). We also determined serum creatinine and urea in all patients by using the Ektachem enzymatic assay (Ortho Diagnostic Division, Milano, Italy).
RESULTS:
In pregnant women, serum cystatin C was 1.52 +/- 0.39 mg/L, ranging from 0.69 to 2.30 mg/L. Serum creatinine was 58.9 +/- 11.5 mumol/L, and serum urea was 3.117 +/- 0.729 mmol/L. In newborns, serum cystatin C was at birth 2.29 +/- 0.52 mg/L, ranging from 1.17 to 4.84 mg/L. Subsequently, cystatin C significantly decreased over the first five days of life. Serum creatinine was at birth 80.08 +/- 14.26 mumol/L. By using analysis of variance (ANOVA) we found a statistically significant difference between maternal and neonatal cystatin C (p < 0.001) as well as between maternal and neonatal creatinine (p +/- 0.001). However, no correlation has been demonstrated by simple linear regression between maternal and neonatal cystatin C (r = 0.05), while maternal and neonatal creatinine significantly correlated (r = 0.45).
CONCLUSIONS:
Our preliminary findings suggest that cystatin C does not cross the placental barrier. Thus, in the neonate cystatin C serum levels may solely derived from himself
[Determination of blood cystatin C in pregnant women during labor and in their newborns]
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