A proteomic approach for the characterization of C677T mutation of the human gene methylenetetrahydrofolate reductase.

Methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of methylenetetrahydrofolate (CH2H4folate) to methyltetrahydrofolate (CH3H4folate). The C677T mutation is a common polymorphism of the human enzyme that leads to the replacement of Ala222Val, thermolability of MTHFR, and mild elevation of plasma homocysteine levels. A mild hyperhomocysteinemia is known to be risk factor for cardiovascular and thrombotic diseases, ischemic stroke, neural tube defects, late on-set dementia, and pregnancy complications.

Reduced platelet thromboxane formation in uremia. Evidence for a functional cyclooxygenase defect.

A qualitative platelet abnormality and a bleeding tendency are frequently associated with renal failure and uremia. We demonstrated previously that uremic patients display an abnormal platelet aggregation to arachidonic acid and reduced malondialdehyde production in response to thrombin and arachidonic acid. The objectives of this investigation were: (a) to compare platelet prostaglandin (PG) and thromboxane (TX) production in whole blood and in platelet-rich plasma (PRP) of 21 uremic patients and 22 healthy subjects; (b) to evaluate the concentration and activity of platelet PG- and TX-forming enzymes; (c) to assess the functional responsiveness of the platelet TXA(2)/PGH(2) receptor; (d) to explore the hemostatic consequences of partially reduced TXA(2) production.

Pulmonary formation of prostacyclin in man.

The pulmonary formation of prostacyclin (PGI2), as reflected by the difference in concentration of pulmonary and systemic arterial radioimmunoassayed 6-keto-PGF1 alpha, was determined in six healthy waking subjects. The systemic arterial 6-keto-PGF1 alpha levels were low (less than or equal to 50 pg/ml), and no evidence of pulmonary formation and release of the compound was noted. In other experiments systemic arterial 6-keto-PGF1 alpha levels were determined in patients prior to and during artificial ventilation, as well as during and after occlusion of the pulmonary circulation (extra-corporeal circulation, ECC).

The synovial prostaglandin system in chronic inflammatory arthritis: differential effects of steroidal and nonsteroidal anti-inflammatory drugs.

1 The present study was undertaken to characterize the spectrum of arachidonic acid metabolites present in synovial effusions of patients with rheumatoid or psoriatic arthritis, and to compare changes in their concentration following a short-term treatment with 6alpha-methyl-prednisolone (6-MeP: 4-8 mg/day) or indoprofen (1.2 g/day), a nonsteroidal anti-inflammatory agent with proven synovial prostaglandin inhibitory effect.2 Measurements of prostaglandin E(2) (PGE(2)), thromboxane (TX) B(2), 6-keto-PGF(1alpha) and PGF(2alpha) were performed by radioimmunoassay techniques in synovial effusions obtained from 23 patients, and validated by thin-layer chromatographic analysis of the extracted immunoreactivity.

Prostacyclin stimulates the adenylate cyclase system of human thyroid tissue.

Since Prostacyclin (PGI2) is a major product of arachidonic acid metabolism in the human thyroid, we have studied the effects of PGI2 on cAMP accumulation in human thyroid slices and cultured thyrocytes. In both systems, PGI2 caused a dose- and time-dependent increase of cAMP accumulation with higher potency and efficacy than PGE2. Two optically active isomers of 5,6-dihydro-PGI2, i.