Protection against Diarrhea Associated with Giardia intestinalis Is Lost with Multi-Nutrient Supplementation: A Study in Tanzanian Children

Giardia intestinalis is a well-known cause of diarrhea in industrialized countries. In children in developing countries, asymptomatic infections are common and their role as cause of diarrhea has been questioned. In a cohort of rural Tanzanian pre-school children, we assessed the association between the presence of Giardia at baseline and subsequent diarrhea risk. The study was conducted in the context of a randomised trial assessing the effect of supplementation with zinc and other micro-nutrients on malaria, and half of the children daily received a multi-nutrient supplement. Surprisingly, we found that the presence of Giardia at baseline was associated with a substantial reduction in diarrhea risk. Multivariate statistical analysis showed that this protection could not be explained by differences in age or walking distance to the dispensary between children with and without Giardia. Because we cannot exclude that children differed in other (unmeasured) characteristics, we cannot draw firm conclusions about the causality of the observed association, but our findings support the view that the parasite is not an important cause of diarrhea in highly endemic settings. Striking was that the Giardia-associated protection was lost when children received multi-nutrients. Our data do not provide information about the mechanisms involved, but suggest that multi-nutrients may influence the compositionor pathogenicity of intestinal biota

Inherited Chronic Obstructive Pulmonary Disease: New Selective-Sequencing Workup for 1-Antitrypsin Deficiency Identifies 2 Previously Unidentified Null Alleles

disposes individuals to chronic obstructive pulmonary disease (COPD) and/or liver disease. Phenotyping of the protein by isoelectric focusing is often used to char-acterize 1AT deficiency, but this method may lead to misdiagnosis (e.g., by missing null alleles). We evalu-ated a workup that included direct sequencing of the relevant parts of the gene encoding 1AT, SERPINA1 [serpin peptidase inhibitor, clade A (alpha-1 antipro-teinase, antitrypsin), member 1], for patients with 1AT concentrations1.0 g/L. METHODS: During a 5-year period, we identified 66 pa-tients with 1AT concentrations 1.0 g/L and ampli-fied and sequenced exons 2, 3, and 5 of the 1AT gene in these patients. To ensure that no relevant geno-types were missed, we sequenced the same exons in 48 individuals with 1AT concentrations between 1.0 and 1.5 g/L. RESULTS: Sequence analysis revealed 18 patients with combinations of disease-associated 1AT alleles: 8 homozygous for the deficient Z allele and 10 com-pound heterozygotes for various deficient or null al-leles. We identified and named 2 new null alleles, Q0soest (Thr 1023delA, which produces a TGA stop sig-nal at codon 112) and Q0amersfoort (Tyr 1603stop). No relevant disease-associated allele combinations were missed at a 1.0-g/L threshold. CONCLUSIONS: Up to 22 % of the alleles in disease-asso-ciated1AT allele combinationsmay bemissed by con-ventional methods. Genotyping by direct sequencing of samples from patients with 1AT concentrations 1.0 g/L detected these alleles and identified 2 newnull alleles

Inherited Chronic Obstructive Pulmonary Disease: New Selective-Sequencing Workup for � 1-Antitrypsin Deficiency Identifies 2 Previously Unidentified Null Alleles

individuals to chronic obstructive pulmonary disease (COPD) and/or liver disease. Phenotyping of the protein by isoelectric focusing is often used to characterize � 1AT deficiency, but this method may lead to misdiagnosis (e.g., by missing null alleles). We evaluated a workup that included direct sequencing of the relevant parts of the gene encoding � 1AT, SERPINA1 [serpin peptidase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 1], for patients with � 1AT concentrations �1.0 g/L. METHODS: During a 5-year period, we identified 66 patients with � 1AT concentrations �1.0 g/L and amplified and sequenced exons 2, 3, and 5 of the � 1AT gene in these patients. To ensure that no relevant genotypes were missed, we sequenced the same exons in 4

Toward standardization of carbohydrate-deficient transferrin (CDT) measurements: I. Analyte definition and proposal of a candidate reference method.

An alcohol-associated change in the serum transferrin glycoform pattern, carbohydrate-deficient transferrin (CDT), is used as a biomarker of chronic moderate to heavy alcohol consumption. A current limitation in CDT analysis is the lack of standardization, which hampers clinical and analytical comparison between studies. This situation prompted initiation of a Working Group (WG) on CDT Standardization under the auspices of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). The standardization work aims to define and validate the analyte, select a reference method, work out procedures for the production of reference materials, and make suggestions for the clinical usage of CDT. The first recommendation of the WG is that disialotransferrin should be the primary target molecule for CDT measurement and the single analyte on which CDT standardization is based. It is further recommended that HPLC should be the analytical principle considered as the basis of an interim reference method until a suitable mass spectrometric reference method is established. In clinical use, CDT should be expressed in a relative amount (% CDT), to compensate for variations in the total transferrin concentration

Toward standardization of carbohydrate-deficient transferrin (CDT) measurements: II. Performance of a laboratory network running the HPLC candidate reference measurement procedure and evaluation of a candidate reference material

Carbohydrate-deficient transferrin (CDT) is a descriptive term used for a temporary change in the transferrin glycosylation profile caused by alcohol, and used as a biomarker of chronic high alcohol consumption. The use of an array of methods for measurement of CDT in various absolute or relative amounts, and sometimes covering different transferrin glycoforms, has complicated the comparability of results and caused confusion among medical staff. This situation prompted initiation of an IFCC Working Group on CDT standardization. This second publication of the WG-CDT covers the establishment of a network of reference laboratories running a high-performance liquid chromatography (HPLC) candidate reference measurement procedure, and evaluation of candidate secondary reference materials. The network laboratories demonstrated good and reproducible performance and thus can be used to assign target values for calibrators and controls. A candidate secondary reference material based on native human serum lyophilized with a cryo-/lyoprotectant to prevent protein denaturation was found to be commutable and stable during storage. A proposed strategy for calibration of different CDT methods is also presented. In an external quality assurance study involving 66 laboratories and covering the current routine CDT assays (HPLC, capillary electrophoresis and immunoassay), recalculation of observed results based on the nominal values for the candidate calibrator reduced the overall coefficient of variation from 18.9% to 5.5%. The logistics for distribution of reference materials and review of results were found to be functional, indicating that a full reference system for CDT may soon be available. Clin Chem Lab Med 2010;48:1585-92

Clinical evaluation of geriatric outpatients with suspected heart failure:value of symptoms, signs, and additional tests

Aims Heart failure (HF) is common in geriatric patients. Clinicians face diagnostic challenges primarily due to comorbidity and limited access to echocardiography. The purpose of this study was to identify independent determinants of the presence of HF in geriatric outpatients and to determine the optimal diagnostic strategy. Methods and results Geriatric outpatients [mean age 82 (+/- 6) years, 30% men] with suspected HF underwent an extensive standardized diagnostic work-up. An expert consensus panel determined the presence of HF. Heart failure was present in 94 of 206 participants (46%). Male sex [odds ratio (OR) 2.0], age per 10 years (OR 1.6), nocturnal dyspnoea (OR 1.7), absence of wheezing (OR 2.1), loss of appetite (OR 1.7), and lower body mass index (BMI; OR 0.9) were independently associated with the presence of HF: the c-statistic of the model containing these items was 0.75. Of all additional tests, N-terminal pro-B-type natriuretic peptide (NT-proBNP) improved the diagnostic accuracy the most (OR ln NT-proBNP 2.8; c-statistic 0.92). A diagnostic rule, consisting of six clinical variables and NT-proBNP, showed good negative and positive predictive values. Conclusion Half of geriatric patients suspected of HF actually have HF. Apart from age, gender, and nocturnal dyspnoea, absence of wheezing, loss of appetite, and lower BMI were independently associated with the presence of HF. Symptoms and signs in combination with NT-proBNP reliably identified the presence or absence of HF in the vast majority of patients. Additional diagnostic tests, in particular echocardiography, can be targeted at those in whom the presence of HF remains uncertain and to ascertain the cause of HF

Toward standardization of carbohydrate-deficient transferrin (CDT) measurements: III. Performance of native serum and serum spiked with disialotransferrin proves that harmonization of CDT assays is possible

Carbohydrate-deficient transferrin (CDT) is a generic term that refers to the transferrin glycoforms whose concentration in blood is temporarily increased by sustained alcohol consumption. Due to high clinical specificity, CDT was proposed as a biomarker of heavy alcohol use and has been available for about 20 years. A number of methods have been developed for CDT measurement based on different analytical techniques and principles and without any harmonization or calibration to a reference method. As a consequence, neither the reference limits nor the cut-off values have been similar across assays, hampering understanding of the diagnostic value of CDT and its routine use. This prompted the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) to initiate a Working Group on Standardization of CDT (WG-CDT). This third publication of the WG-CDT is devoted to testing the commutability of native and disialotransferrin-spiked serum panels as candidate secondary reference materials, in order to prove the harmonization potential of commercial CDT methods. The results showed that assay harmonization reduced the inter-laboratory imprecision in a network of reference laboratories running the HPLC candidate reference method. In the seven commercial methods evaluated in this study, the use of multi-level secondary calibrators of human serum origin significantly reduced the between-method imprecision. Thus, harmonization of CDT measurements by different methods can be achieved using this calibration system, opening the way for a full standardization of commercial methods against a reference method by use of certified reference materials

Prevalence and determinants of vitamin D deficiency in infants and toddlers in the Netherlands: a pilot study

Background: Little is known of the vitamin D status of young infants and toddlers and its determinants in West Europe. The prevalence and determinants of vitamin D deficiency of children aged 6–48 months in the centre of the Netherlands (52°N) is investigated. Methods: In a cross-sectional population study, randomly recruited infants and toddlers (n = 150) were studied using an online questionnaire and a physical examination either in late summer (n = 52) or in late winter (n = 98). Vitamin D analysis was performed by capillary blood sampling using dried bloodspots plus LC-MS/MS. Results: In late winter, 32% of the children were vitamin D deficient (<50 nmol/L 25OH vitamin D3) with 5% severely deficient (<25 nmol/L). In late summer, 2% were deficient. The odds of vitamin D deficiency were higher in children aged 24–48 months, for those not using formula milk and those not adhering to the supplementation guidelines. Conclusion: One-third of Dutch infants and toddlers were found to be vitamin D deficient in late winter. Suggested strategies for raising the vitamin D status may include improving the adherence to supplementation, a sensible sun exposure or the use of fortified foods. Special attention is needed for the children aged 24–48 months