Analytical determination of homocysteine: a review

Nekrassova, Olga; Lawrence, Nathan S.; Compton, Richard G.

doi:10.1016/s0039-9140(03)00173-5

Cited by 306 publications

(156 citation statements)

References 61 publications

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“…The shift of the unknown electroactive species could be attributed to the silver quasi-reference electrode built into the screen-printed electrode. Since human plasma alone contains contents of homocysteine and glutathione, 1,5,8,16,18,20,[37][38] we can expect to see an adduct peak signal associated with the thiol-catechol reaction. To definitively determine the peak observed at ca.…”

Section: Detection In Human Plasmamentioning

confidence: 99%

“…This value is reasonable and practical for the range thiols that are typically seen in human plasma. [1][2]5,18,39 The standard addition method was also performed on the plasma sample in the presence of 1.0 mM catechol (pH 7.2). Using the square-wave parameters (frequency, 10 Hz; amplitude, 5.0 mV; step potential, 10 mV) the human plasma was spiked separately with either homocysteine or glutathione at different concentrations of up to 20 μM.…”

Section: Detection In Human Plasmamentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11] Thiols, such as homocysteine (HCy) and glutathione (GSH), are ubiquitous in physiological fluids as they play an important role in maintenance, antioxidation protection and metabolism. 9,[12][13] Levels of these thiols have been reported to be important as changes at the cellular role may have implications to conditions such as arteriosclerosis, 5,12,14 leukaemia, [14][15] cancer, 14,16 Alzheimer's, 5,[17][18][19] and/or Parkinson's disease. 5,[17][18] As such, selective detection is valuable for the biomedical community as it may provide a versatile diagnostic pathway to monitor various conditions.…”

Section: Introductionmentioning

confidence: 99%

“…9,[12][13] Levels of these thiols have been reported to be important as changes at the cellular role may have implications to conditions such as arteriosclerosis, 5,12,14 leukaemia, [14][15] cancer, 14,16 Alzheimer's, 5,[17][18][19] and/or Parkinson's disease. 5,[17][18] As such, selective detection is valuable for the biomedical community as it may provide a versatile diagnostic pathway to monitor various conditions. However, many electroanalyses of biological samples require the prior use of a separation technique as samples may contain many reactive species that may impede the electrochemical detection.…”

Section: Introductionmentioning

confidence: 99%

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Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

Lee

Compton

2015

ANAL. SCI.

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A selective voltammetric determination of homocysteine and glutathione was applied to cell tissue culture media and human plasma via a single two-step method. The two-step method relies on the 1,4-Michael addition reaction between electro-oxidized catechol and the target thiol. Furthermore, the procedure relies on the differing reaction kinetics of the ortho-quinone with various thiol species giving different responses as a function of the scan rate. At faster scan rates homocysteine is only detected, while at slower scan rates the adduct signal reflects both homocysteine and glutathione. As a result, the quantification of both homocysteine and glutathione can be determined with a combination of both sets of data. The previous proof-of-concept (P. T. Lee, D. Lowinsohn, and R. G. Compton, Sensors, 2014, 14, 10395), is applied to the quantification of thiols in both tissue culture media and human plasma alone. Analytical parameters were determined for both homocysteine and glutathione in the respective media and the linear range. The sensitivities in tissue culture media are ca. 3 nA μM -1 and ca. 1 nA μM -1 and the limits of detections are ca. 2 μM and ca. 1 μM for homocysteine and glutathione, respectively. In human plasma, the sensitivities were determined to be 94 and 39 nA μM -1 , and the limit of detections are ca. 0.8 μM and ca. 0.8 μM for homocysteine and glutathione, respectively.

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Section: Detection In Human Plasmamentioning

confidence: 99%

Section: Detection In Human Plasmamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

Lee

Compton

2015

ANAL. SCI.

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“…Total plasma homocysteine: working ranges. Nekrassova et al, (2003). The analytical parameters obtained for the various detection methodologies of homocysteine after a Page 12 15 separating technique has been applied to the sample.…”

Section: List Of Tablesmentioning

confidence: 99%

An evaluation of plasma homocysteine in the assessment of vitamin B₁₂status of pasture-fed sheep

Furlong

Sedcole

Sykes

2010

New Zealand Veterinary Journal

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of a thesis submitted in partial fulfilment of the requirements for the Degree ofM.Appl.Sc. Improvement of HPLC methodology was carried out to resolve peak integrity, precision, run time and stability issues encountered previously in the assay ofHcy. An Evaluation ofEighty two pregnant ewes, half of which were supplemented with a Co bullet, were grazed together on a Southland property known to be Co deficient. Half of the lambs from each group were supplemented with 3mg microencapsulated Cbl (SMARTShot™) one month after lambing (day 0), providing four groups. Lambs were blood sampled and weighed, at monthly intervals, until approximately 210 days of age and were weaned at day 89.A 40% difference in mean liveweight was recorded between the supplemented and unsupplemented lamb groups. Mean monthly total homocysteine (tHcy) concentration ranged from 1.5 to 4.5 ~mol/l. On day 0 tHey concentrations in lambs from supplemented 11 and unsupplemented ewe groups were 4.0 and 2.2 /lmol/l; a difference which was significant (p <0.001). Subsequently there were no differences between unsupplemented and supplemented lamb groups.This lack of effect occurred despite plasma concentrations of MMA and Cbl at which response to supplementation could be expected and L WG responses to Cbl supplementation were observed. Unsupplemented lamb MMA and Cbl concentrations (> 16 /lmol/l and <170 pmol/l, respectively, compared to the deficient status thresholds from reference ranges of > 13 /lmol/l and <200 pmol/l respectively) were attained on day 57. No correlation between Hcy and MMA or Cbl concentrations was detected even in individual animals whose performance was severely compromised by deficiency. This suggested that the biological importance of the Hcy pathway means that it is highly conserved, even in extreme deficiency.To purSue this further, data 'from a previous supplementation trial in which 34 individual unsupplemented animals had been removed due to welfare issues, due to severe ill-health, were examined. Mean tHcy concentrations ranging from 6 -13 /lmolll were recorded, in association with Cbl concentrations below 200 pmol/l throughout and steady rise in MMA concentration to very high values (from 10 -26 /lmol/l). The severity of the deficiency at onset was characterised by rapid response to supplementation although tHcy showed no associated change as a consequence.In conclusion, the measurement of tHcy as a metabolic indicator of Cbl deficiencyIn sheep on typical New Zealand pasture appears to have no value in detecting the incidence or assessment of the severity of the disease. The possibility that diet and other factors such as alternative pathways, including the betaine -methionine metabolic pathways, may regulate and conserve methylation pathways is discussed, but a conclusion that MMA is the first rate limiting pathway and the metabolic indicator of choice in predicting the clinical Cbl status in sheep, seems most plausible.

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Nanoelectrochemistry Applications Based on Electrospinning

Scampicchio

Cosio

Mengistu

et al. 2015

Agricultural and Food Electroanalysis

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Analytical determination of homocysteine: a review

Cited by 306 publications

References 61 publications

Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

An evaluation of plasma homocysteine in the assessment of vitamin B₁₂status of pasture-fed sheep

Nanoelectrochemistry Applications Based on Electrospinning

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Analytical determination of homocysteine: a review

Cited by 306 publications

References 61 publications

Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

Selective Thiol Detection in Authentic Biological Samples with the Use of Screen-printed Electrodes

An evaluation of plasma homocysteine in the assessment of vitamin B12status of pasture-fed sheep

Nanoelectrochemistry Applications Based on Electrospinning

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An evaluation of plasma homocysteine in the assessment of vitamin B₁₂status of pasture-fed sheep