Within- and between-subject biological variation data for serum zinc, copper and selenium obtained from 68 apparently healthy Turkish subjects

Postponed access: the file will be available after 2022-10-22Objectives: Trace elements (TrEL) are nutritionally essential components in maintaining health and preventing diseases. There is a lack of reliable biological variation (BV) data for TrELs, required for the diagnosis and monitoring of TrEL disturbances. In this study, we aimed to provide updated within- and between-subject BV estimates for zinc (Zn), copper (Cu) and selenium (Se). Methods: Weekly serum samples were drawn from 68 healthy subjects (36 females and 32 males) for 10 weeks and stored at −80 °C prior to analysis. Serum Zn, Cu and Se levels were measured using inductively-coupled plasma mass spectrometry (ICP-MS). Outlier and variance homogeneity analyses were performed followed by CV-ANOVA (Røraas method) to determine BV and analytical variation estimates with 95% CI and the associated reference change values (RCV) for all subjects, males and females. Results: Significant differences in mean concentrations between males and females were observed, with absolute and relative (%) differences for Zn at 0.5 μmol/L (3.5%), Cu 2.0 μmol/L (14.1%) and Se 0.06 μmol/L (6.0%). The within-subject BV (CVI [95% CI]) estimates were 8.8% (8.2–9.3), 7.8% (7.3–8.3) and 7.7% (7.2–8.2) for Zn, Cu and Se, respectively. Within-subject biological variation (CVI) estimates derived for male and female subgroups were similar for all three TrELs. Marked individuality was observed for Cu and Se. Conclusions: The data of this study provides updated BV estimates for serum Zn, Cu and Se derived from a stringent protocol and state of the art methodologies. Furthermore, Cu and Se display marked individuality, highlighting that population based reference limits should not be used in the monitoring of patients.publishedVersio

Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion

Evaluation of the Bactec 9240 system for blood cultures

Purpose: This study was carried out in order to determine species of bacteria causing sepsis and the rate of false positives and negatives in the results obtained in the evaluation of blood cultures by the Bactec 9240 system. Method: For a period of one year, from September 1994 to September 1995, 8022 blood cultures which were taken by various clinics from patients with fever or sepsis were evaluated using the Bactec 9240 system. For this purpose, Bactec plus Aerobic/F and Bactec Peds plus/F vials were examined for 7 days. Identification of the bacteria was made using the Sceptor system. Results: Out of the 8022 blood cultures, 1763 were positive with the Bactec 9240 system and of these, 1727 grew in the subcultures (2.05% false positives). As a result of subculturing of the 6259 blood cultures negative in the Bactec system, various bacteria and fungi were isoleted in 11 cultures (0.18% false negatives). The majority of the bacteria isolated were Staphylococcus species. Besides this, out of the 1763 cultures that were positive with Bactec 9240, 19 (1.08%) were positive after the 5th day. Conclusion: The time involved in the evaluation of blood cultures is shortened when the Bactec 9240 system is used. Also, there is less contamination of the blood cultures since subculturing is done only once

Leukocyte telomere length as a compensatory mechanism in vitamin D metabolism

Vitamin D deficiency is common among postmenopausal women. Telomere length can be a potential protective mechanism for age-related diseases. The objective of our study is to examine the association of vitamin D supplementation on leukocyte telomere length (LTL) in healthy postmenopausal women with vitamin D deficiency. The study was designed as a placebo-controlled study to investigate the short-term effects of vitamin D supplementation and seasonal changes on vitamin D related parameters, including 25(OH)D, 1,25(OH)(2)D parathormone (PTH), Vitamin D binding protein (VDBP), vitamin D receptor (VDR), and telomere length in a cohort of postmenopausal women (n = 102). The group was divided as supplementation (n = 52) and placebo groups (n = 50). All parameters were measured before and after treatment. Serum VDBP levels were measured by ELISA method and VDR, GC (VDBP) gene expressions and relative telomere lengths were measured in peripheral blood mononuclear cells (PBMC) using a quantitative real-time PCR method. The results demonstrate that baseline levels were similar between the groups. After vitamin D supplementation 25(OH)D, 1,25(OH)(2)D, PTH and VDBP levels were changed significantly compared to the placebo group. At the end of the study period, LTL levels were significantly increased in both groups and this change was more prominent in placebo group. The change in GC expression was significant between treatment and placebo groups but VDR expression remained unchanged. Even though the study was designed to solely assess the effects of vitamin D supplementation, LTL was significantly increased in the whole study group in summer months suggesting that LTL levels are affected by sun exposure and seasonal changes rather than supplementation. The study displayed the short-term effect of Vitamin D supplementation on vitamin D, PTH levels, LTL and vitamin D associated gene expressions. The relation between Vitamin D and LTL is not linear and could be confounded by several factors such as the population differences, regional and seasonal changes in sun exposure