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  • Author: J. Bartos x
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Abstract

Background

In congenital adrenal hyperplasia (CAH), achieving the balance between overtreatment and undertreatment remains challenging. Final height (FH) can serve as a long-term outcome measure. We aimed to identify age-dependent factors that influence FH in CAH patients, resulting in age-specific treatment goals.

Methods

We retrospectively evaluated longitudinal data of 39 pediatric CAH patients born between 1980 and 1997 from the Radboudumc CAH database. We analyzed height and bone age (BA) at diagnosis or 4 years of age, at the start of puberty and at FH. Height data were corrected for parental height and secular trend. Hydrocortisone (HC) use and salivary steroid concentrations were studied longitudinally throughout childhood and puberty.

Results

Median FH standard deviation scores (SDSs) corrected for target height SDSs (THSDSs) was −1.63. Median height SDS corrected for THSDS (HSDS-THSDS) decreased from diagnosis/age 4 years to FH in both salt wasting (SW) CAH and simple virilizing (SV) CAH, and in both male and female patients. However, when height was corrected for BA, no height loss occurred from diagnosis/age 4 years to FH in any of the subgroups, while a height gain was seen in SV males. In the combined model analyzing both HC dose and salivary steroid concentrations, in childhood the androstenedione (A) concentration was negatively associated with FH, while in puberty the HC dose was negatively associated with FH.

Conclusions

In CAH, loss of growth potential already occurs in early childhood. In prepubertal children, exposure to elevated androgens is associated with decreased FH. In puberty, the growth suppressing effects of HC outweigh the negative effects of elevated androgens. Therefore, we suggest different treatment approaches in prepubertal and pubertal patients.

Abstract

Background: Choline is essential for mammalian cell function. It plays a critical role in cell membrane integrity, neurotransmission, cell signaling and lipid metabolism. Moreover, choline is involved in methylation in two ways: a) its synthesis requires methyl groups donated by S-adenosyl-methionine (AdoMet); and b) choline oxidation product betaine methylates homocysteine (Hcy) to methionine (Met) and produces dimethylglycine. This later donates one carbon units to tetrahydrofolate (THF).

Methods: To evaluate the correlations of choline and betaine with folate, AdoMet, S-anenosyl-homocysteine (AdoHcy), total homocysteine (tHcy), and DNA methylation, choline, betaine and dimethylglycine were measured by LC-MS/MS in plasma of 109 healthy volunteers, in whom folate, AdoMet, AdoHcy, tHcy, and DNA methylation have previously been reported.

Results: Using a bivariate model, choline and betaine showed strong positive correlations with folate (r=0.346 and r=0.226), AdoHcy (r=0.468 and r=0.296), and correlated negatively with AdoMet/AdoHcy ratio (r=–0.246 and r=–0.379). Only choline was positively correlated with AdoMet (r=0.453). Using a multivariate linear regression model, choline correlated strongly with folate (β=17.416), AdoMet (β=61.272), and AdoHcy (β=9.215). Betaine correlated positively with folate (β=0.133) and negatively with tHcy (β=–0.194) ratio. Choline is an integral part of folate and methylation pathways.

Conclusions: Our data highlight the importance of integrating choline in studies concerning addressing pathological conditions related to folate, homocysteine and methylation metabolism.

Abstract

Background: Alterations in global DNA methylation are implicated in various pathobiological processes. We describe a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for determination of cytosine and 5-methylcytosine in DNA.

Methods: DNA was hydrolyzed using formic acid. Cytosine and 5-methylcytosine were separated by gradient-elution reversed-phase chromatography with a mobile phase containing nonafluoropentanoic acid (NFPA) as ion-pairing reagent and quantified using stable isotope dilution LC-ESI-MS/MS. The method was applied to DNA isolated from leukocytes of healthy volunteers.

Results: Linear calibration curves were obtained in the range 0.111–4.422 ng/μL [mean correlation co-efficient 0.9983 (SD=0.0011), n=9] for cytosine and 0.0048–0.1936 ng/μL [mean correlation coefficient 0.9991 (SD=0.0010), n=9] for 5-methylcytosine. The intra- and inter-assay CVs for the 5-methylcytosine/total cytosine ratio (mCyt/tCyt) was 1.7% (n=9) and 3.5% (n=8) for calf thymus DNA (mean mCyt/tCyt ratio 6.5%), and 4.5% (n=6) and 6.5% (n=14), respectively for pBR322 DNA (mean mCyt/tCyt ratio 0.48%). The limit of detection (signal-to-noise ratio 3) was 2 pg on-column for cytosine and 5-methylcytosine. In healthy subjects (n=109), the mCyt/tCyt ratio varied from 2.6% to 4.8% (median 4.1%). DNA methylation was negatively correlated to age, but only in subjects with the methylenetetrahydrofolate reductase (MTHFR) 677 TT genotype (p=0.046). No association with B-vitamin status was observed.

Conclusions: This LC-ESI-MS/MS method is easy to perform and offers reproducibility, selectivity and sensitivity for studying DNA methylation. The method allows a sample throughput of approximately 200 samples/week. The MTHFR C677T genotype influences age-related changes in DNA methylation.

Clin Chem Lab Med 2007;45:903–11.

Abstract

Background: Treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency can be monitored by salivary androstenedione (A-dione) and 17α-hydroxyprogesterone (17OHP) levels. There are no objective criteria for setting relevant target values or data on changes of 17OHP and A-dione during monitoring.

Methods: We evaluated A-dione and 17OHP levels in nearly 2000 salivary samples collected during long-term treatment of 84 paediatric patients with classic 21-hydroxylase deficiency.

Results: A-dione and 17OHP levels and its ratio 17OHP/A-dione remained constant from 4 to 11 years with no sex-related differences. During puberty, A-dione and 17OHP levels both increased, starting at earlier age in girls than in boys. The ratio 17OHP/A-dione declined. Normalised A-dione concomitant with elevated 17OHP [1.43 nmol/L (0.46–4.41) during prepuberty; 2.36 nmol/L (0.63–8.89) for boys and 1.99 nmol/L (0.32–6.98) for girls during puberty] could be obtained with overall median glucocorticoid doses of 11–15 mg/m2/day. A-dione levels above the upper reference limit (URL), suggesting undertreatment, coincided with 17OHP levels ≥10 times URL. The percentage of A-dione levels above URL was 16% at ages 4–8 years, but increased to 31% for girls at 16 years and 46% for boys at 17 years.

Conclusions: Normalised A-dione consistent with 17OHP three times URL during prepuberty and normalised A-dione consistent with 4–6 times URL during puberty could be obtained by moderate glucocorticoid dosages. A constant 17OHP/A-dione ratio during prepuberty suggested absence of adrenarche. During puberty, a higher percentage of samples met the criteria for undertreatment, especially of boys.

By learning how to balance natural resource limitations and pollution prevention with economic growth, green chemistry will become the central science of sustainability. The elimination of persistent pollutants is vital for a sustainable civilization. To achieve this, the most important guiding concept is that the elemental composition of technology should be shifted toward the elemental composition of biochemistry. Oxidation chemistry is currently a prolific producer of persistent pollutants. Many arise from the use of chlorine, hypochlorite, or chlorine dioxide in large-scale oxidation processes. Oxidation chemistry can be greened by replacing these with catalyzed alternatives based on Nature's oxidizing agent, hydrogen peroxide. TAML® (TetraAmidoMacrocyclicLigand) iron catalysts, which were invented at Carnegie Mellon University, are widely patented and are being developed to activate H2O2 for commercial applications. TAML activators are water-soluble, easy to use, function well from neutral to basic pH, are not dominated by nonselective Fenton-like reactivity, are straightforward to synthesize, work effectively in minute concentrations, enable peroxide processes to occur at temperatures well below those of the processes targeted for replacement, and are amenable to modification for capturing novel selectivities. TAML activators are "dial-a-lifetime" catalysts: an activator can be chosen exhibiting a lifetime commensurate with the desired task.