Evaluation of a shorter methionine loading test

2004 ◽  
Vol 42 (9) ◽  
Author(s):  
Robert De Jonge ◽  
Pieter H. Griffioen ◽  
Bertrand van Zelst ◽  
R. Montserrate Brouns ◽  
Willy Visser ◽  
...  
Keyword(s):  
Body Weight ◽  
Methylenetetrahydrofolate Reductase ◽  
Plasma Homocysteine ◽  
Loading Test ◽  
Homocysteine Concentration ◽  
Methionine Load ◽  
History Of ◽  
Edta Blood ◽  
Methionine Loading Test

AbstractWe validated whether a shorter methionine loading test is as accurate as the original 6-h test in identifying hyperhomocysteinemic patients and investigated determinants of fasting and post-load homocysteine concentration. Plasma homocysteine was determined in EDTA-blood from women with a history of preeclampsia (n=106) after 12 h fasting and 3 and 6 h after an oral methionine load (0.1 g/kg body weight). The 677C > T polymorphism in the methylenetetrahydrofolate reductase (

Variability of the Methionine Loading Test: No Effect of a Low Protein Diet

1996 ◽  
Vol 33 (6) ◽  
pp. 551-554 ◽  
Author(s):  
Martin den Heijer ◽  
Gerard M J Bos ◽  
Ingeborg A Brouwer ◽  
Wim B J Gerrits ◽  
Henk J Blom
Keyword(s):  
Protein Diet ◽  
Low Protein Diet ◽  
Vitamin B ◽  
Standard Diet ◽  
Loading Test ◽  
Homocysteine Concentration ◽  
Low Protein ◽  
Transsulfuration Pathway ◽  
The Mean ◽  
Methionine Loading Test

The methionine loading test is used for the diagnosis of impaired methionine/homocysteine metabolism, in particular the transsulfuration pathway. Usually this test is performed on a low protein diet to control the intake of methionine. However, this is inconvenient and relatively expensive. In this study we compared the effects of a low protein diet and a standard diet on methionine loading test in 28 subjects (crossover design). The mean difference in homocysteine concentration after methionine loading between the two diets was 1.3 [confidence interval (CI) 95%-1.0–3.6]μmol/L which demonstrates that a special low protein diet is not essential in the performance of the methionine loading test. We also observed that 3 weeks after the first methionine loading test, fasting serum concentration of folate was higher and vitamin B12 concentration was lower.

The effect of excess daily methionine intake on plasma homocysteine after a methionine loading test in humans

1990 ◽  
Vol 192 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Anders Andersson ◽  
Lars Brattström ◽  
Bo Israelsson ◽  
Anders Isaksson ◽  
Björn Hultberg
Keyword(s):  
Plasma Homocysteine ◽  
Loading Test ◽  
Methionine Loading Test

High plasma homocysteine levels contribute to the risk of stroke recurrence and all-cause mortality in a large prospective stroke population

2009 ◽  
Vol 118 (3) ◽  
pp. 187-194 ◽  
Author(s):  
Weili Zhang ◽  
Kai Sun ◽  
Jinxing Chen ◽  
Yuhua Liao ◽  
Qin Qin ◽  
...  
Keyword(s):  
Methylenetetrahydrofolate Reductase ◽  
Mthfr C677t ◽  
Threshold Level ◽  
Plasma Homocysteine ◽  
Stroke Recurrence ◽  
Stroke Patients ◽  
Vascular Events ◽  
Homocysteine Concentration ◽  
Increased Risk ◽  
All Cause Mortality

Plasma homocysteine concentrations have been associated with the risk of stroke, but its relevance to secondary vascular events and mortality after stroke remains unclear because of inconsistent results from clinical trials. The aim of the present study was to investigate whether plasma homocysteine levels and the MTHFR (methylenetetrahydrofolate reductase) variant C677T contributed to the risk of stroke recurrence and all-cause mortality in a large prospective cohort of stroke patients in a Chinese population. A total of 1823 stroke patients (age, 35–74 years) were recruited during 2000–2001 and prospectively followed-up for a median of 4.5 years. During the follow-up, 347 recurrent strokes and 323 deaths from all-causes were documented. After adjustment for age, gender and other cardiovascular risk factors, a high homocysteine concentration was associated with an increased risk of 1.74-fold for stroke recurrence {RR (relative risk), 1.74 [95% CI (confidence interval), 1.3–2.3]; P<0.0001} and 1.75-fold for all-cause mortality [RR, 1.75 (95% CI, 1.3–2.4); P<0.0001] when highest and lowest categories were compared. Spline regression analyses revealed a threshold level of homocysteine for stroke recurrence. By dichotomizing homocysteine concentrations, the RRs were 1.31 (95% CI, 1.10–1.61; P=0.016) for stroke recurrence and 1.47 (95% CI, 1.15–1.88; P<0.0001) for all-cause mortality in patients with homocysteine levels ≥16 μmol/l relative to those with levels <16 μmol/l. The association of elevated plasma homocysteine concentrations with all-cause mortality was mainly due to an increased risk of cardiovascular deaths. No significant association was found between MTHFR C677T and stroke recurrence or mortality. In conclusion, our findings suggest that elevated homocysteine concentrations can predict the risk of stroke recurrence and mortality in patients with stroke.

Very Low Prevalence of Hyperhomocysteinemia among US Children with Personal/Family History of Thrombosis. Towards Reconsideration of the Recommendation for Routine Testing.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 730-730 ◽  
Author(s):  
Marilyn J. Manco-Johnson ◽  
Neil A. Goldenberg ◽  
Sally Stabler
Keyword(s):  
Family History ◽  
Familial Risk ◽  
Mthfr C677t ◽  
Study Groups ◽  
Mthfr Gene ◽  
Plasma Homocysteine ◽  
Laboratory Assessment ◽  
Homocysteine Concentration ◽  
History Of ◽  
The Impact

Abstract Background: Comprehensive thrombophilia laboratory testing is recommended for the evaluation of children with thrombosis by the Perinatal and Pediatric Subcommittee of the International Society on Thrombosis and Haemostasis (ISTH). The C677T thermolabile variant of the methylene tetrahydrofolate reductase (MTHFR) gene is highly prevalent in Caucasians, carried in heterozygous form in 45% and homozygously in 10%. The thrombogenicity of the MTHFR C667T mutation is mediated via elevation in plasma homocysteine concentration. However, in the U.S., folate fortification of food products may circumvent the impact of this mutation upon plasma homocysteine. Objective: To determine the prevalence of hyperhomocysteinemia among U.S. children with a personal history of thrombosis (thrombosis group) or a first-degree family history of thrombosis or thrombophilia (familial risk group). Methods: All children comprising the two study groups had been referred to the Thrombosis/Thrombophilia Program at The Children’s Hospital, Denver, and were consecutively recruited for participation in collection of laboratory and clinical data for this research. Plasma homocysteine, performed clinically as part of the ISTH recommended thrombophilia laboratory assessment, was determined by gas chromatograph mass spectroscopy. Results: Homocysteine concentration was normally distributed within the study population, and did not vary with age or differ significantly between the two study groups. Table 1 displays the results relative to age and study group. In 100% of subjects, homocysteine level was either low or normal with respect to the previously-established reference range for healthy individuals. Conclusions: Despite a high historical prevalence of the MTHFR C677T mutation in Caucasians, the prevalence of hyperhomocysteinemia among U.S. children with thrombosis or a familial risk of thrombosis is extremely low, being absent among nearly 200 children studied. Because other mutations that do result in hyperhomocysteinemia and thrombosis occur rarely, homocysteine testing as part of a comprehensive thrombophilia assessment in U.S. children should be targeted to those patients in whom metabolic disease is suspected clinically. Plasma Homocysteine Levels (UMl/L) in Children. Category Total < 1 year 1 - < 7 years 7 - < 13 years 13 - < 24 years + Thrombosis − Thrombosis N 193 25 48 44 76 128 65 Mean 5.6 4.4 5.0 5.3 6.6 5.6 5.6 Median 5.6 4.8 5.0 5.3 6.2 5.8 5.4 Std. Dev. 2.4 2.2 2.3 2.6 2.1 2.6 1.9

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