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Biomedical subjects

H J Parra

Publications and source records attributed to H J Parra.

47 records · Page 3Linked to original sources

[Quantitative analysis of apolipoproteins and lipoprotein particles in patients with head injuries].

By head-injured patients, apo A-I and apo A-II concentrations were more decreased in HDL3 than in HDL2. Then, the plasmatic concentrations of the main lipoprotein particles present in HDL fraction were modified. For example, a significant decrease of Lp A-I: A-II particles was observed and this variation was similar to that of total apo A-I (r = 0.78). On the other hand, the concentration of Lp A-I particles was slightly modified, apo C-III concentration was markedly decreased whereas apo E concentration was significantly increased (p less than 0.05); in plasma samples obtained 10 days after a severe head injury, apo E reached three times the normal value.

Adolescent↗

Lipoprotein abnormalities in chronic haemodialysis patients.

Measurement of lipids, apolipoproteins A-I, A-II, B, C-III, Lp(a) and cholesterol, phospholipids, apo C-III in lipoprotein with and without apolipoprotein B was made in 49 patients (18 women and 31 men; mean age 50 +/- 15 years) undergoing maintenance haemodialysis for chronic renal failure. A group of 49 healthy people, matched for sex and age, acted as controls. In the haemodialysis group, special attention was placed upon the comparison of patients who had evident cardiovascular alterations (n = 17) with the residual group (n = 32). The concentration of apo C-III in apolipoprotein B containing lipoproteins was statistically higher in the patients with arterial disease than in the remaining subjects, whereas the ratio apo C-III from Lp no B/apo C-III from Lp B was decreased. Compared to controls, haemodialysis patients had significantly higher values of triglycerides, apolipoproteins C-III, Lp(a), and apolipoprotein C-III from apolipoprotein B-containing lipoproteins (LpB); in contrast, concentrations of phospholipids and cholesterol from lipoproteins without apolipoprotein B (Lp no B) and apolipoprotein A-II were significantly reduced in patients. Discriminant analysis indicated that the levels of apolipoprotein C-III and apolipoprotein C-III from LpB were the best indicators of deranged lipid transport in patients with chronic renal failure. Our data suggest that chronic haemodialysis patients tend to exhibit qualitative abnormalities of serum apolipoprotein-B triglyceride rich particles containing apolipoprotein C-III or (a).

Adolescent↗

Black-white differences in serum Lp(a) lipoprotein levels.

Serum Lp(a) lipoprotein was determined in 81 black and 81 white healthy men and women matched for sex and age. The results show a highly significant increase of Lp(a) concentrations in blacks as compared to whites, and confirm the notion that Lp(a) lipoprotein levels are race-dependent. Whether high values of Lp(a) play an atherogenic role in blacks remains to be established in further studies.

Adult↗

[Multivariate analysis of biological markers of excessive consumption of alcohol. Value of lipoprotein parameters].

In order to investigate the usefulness of lipid, lipoprotein and apolipoprotein parameters for detection of intemperate drinkers, 90 adult male subjects with an alcohol consumption above 400 g weekly were compared to 90 matched (age, body weight index) male subjects with an alcohol consumption below 250 g weekly. GGT and MCV were also evaluated. Univariate analysis showed GGT, apolipoprotein A-II and phospholipid-LP no B levels to be parameters the most significantly different between drinkers and controls. Discriminant analysis using six parameters in addition to apolipoprotein A-II allowed to classify correctly 80% of subjects (efficacy) with respect to their alcohol consumption. However, sensitivity of the parameters remains relatively low and a good efficacy is obtained only with a composite index of several parameters.

Adult↗

[The mysteries of lipoprotein (a): a bridge between thrombosis and atheroma].

Nearly 30 years have elapsed since Berg discovered a genetic variant of low density lipoproteins (LDL) which he called lipoprotein (a), abbreviated Lp (a). Lp (a) rapidly appeared as an independent factor of atherosclerosis. Its physico-chemical characteristics are well-known, but this cannot be said of its function, its metabolism and the exact mechanism of its contribution to atherogenesis. The plasma Lp (a) concentration is determined genetically and its seems that few factors can lower it. Owing to its structural analogy with plasminogen, Lp (a) has been suspected to bind fibrin by a competitive mechanism, thereby facilitating thrombosis, a necessary step in the progression of atherosclerosis. However, these results remain controverted, and indeed there is some evidence of a possible interaction between Lp (a) and alpha-2-antiplasmin, a physiological inhibitor of fibrinolysis, an effect that would accentuate fibrinolysis. This paradoxical action of Lp (a) and the various mysteries which still shroud this lipoprotein are perhaps due to the diversity of its isotypes.

Arteriosclerosis↗

Natural infection of chimpanzees with new lentiviruses related to HIV-1/SIVcpz.

To determine newly identified lentiviruses, termed simian immunodeficiency virus (SIV)cpz97CG4 and SIVcpz97CG6, from two wild-captured juvenile brother chimpanzees in the Republic of Congo, subgenomic pol (integrase, 288 bp), 5'tat/rev-env Cl (including vpu, 354 bp) and env (C2-C4, 544 bp) gene fragments were amplified and sequenced. The analysis revealed significantly discordant phylogenetic positions of SIVcpz97CG in each genomic region. In the trees derived from partial env sequences (V3), both SIVcpz strains clustered in human immunodeficiency virus type 1 (HIV-1) subtype A. However, in the trees derived from partial pol (integrase) and 5'tat/rev-env C1 (including vpu) sequences, they clustered independently from any of the known HIV-1 subtypes. Especially, in the 5'tat/rev-vpu tree, they branched before the root of HIV-1 group M. These findings suggest that these Congolese SIVcpz genomes are mosaic, probably due to a recombinational event in the recent past, and it provides evidence for a rather recently occurring cross-species transmission between humans and chimpanzees.

Amino Acid Sequence↗

[Study of the protein profile of the Adélé tribe of Togo].

Plasma proteins provide precise information about the physiological status of an individual. In this study, we compared the plasma protein profiles of 168 individuals from the Adélé ethnic group, from an isolated rural area of Togo, with those of 159 individuals from an urban population from the capital, Lomé. The Adélé villages are located in the Atakora mountains. The subjects were volunteers, all apparently healthy and aged between 18 and 65 years. We separated serum proteins by electrophoresis and identified proteins specific for nutritional, inflammatory and immune status. The Adélé significantly higher total serum protein concentrations than the urban individuals, with higher concentrations of a1 globulins (2.35 +/- 0.57 g/L versus 1.94 +/- 0.52 g/L) and g globulins (22.19 +/- 5.67 g/L versus 16.98 +/- 5.23 g/L) and lower concentrations of b globulins (6.83 +/- 1.56 g/L versus 7.34 +/- 1. 52 g/L). The Adélé also had lower plasma concentrations of albumin (41.91 +/- 5.74 g/L versus 44.56 +/- 6.32 g/L), tranferrin (2.5 +/- 0.52 g/L versus 3.03 +/- 0.6 g/L), haptoglobin (0.57 +/- 0.59 g/L versus 1.32 +/- 0.89 g/L) and IgA (2.3 +/- 0.89 g/L versus 2.88 +/- 1.12 g/L) and higher plasma concentrations of orosomucoid (0.85 +/- 0.26 g/L versus 0.69 +/- 0.27 g/L); IgG (25.3 +/- 7.11 g/L versus 21. 79 +/- 6.5 g/L) and IgM (4.25 +/- 2.83 g/L versus 2.25 +/- 1.0 g/L). The data obtained for the Adélé and urban populations were similar to those obtained for European populations except for IgM (higher in the Adélé than in the urban and European populations), IgG and CRP (higher for the Adélé and urban populations than for European populations). Nutritional status, as estimated by albumin and transferrin concentrations, was higher in the urban population of Lomé than in the Adélé population but the Adélé population suffered no malnutrition problems. These results are consistent with those of a previous study, using apo A-I concentrations as an index of nutritional status. Apo A-I has also been shown to be a reliable indicator of nutritional status, as prealbumin concentration alone is sufficient for the early diagnosis of protein malnutrition. The very high concentrations of plasma CRP obtained indicate the presence of an inflammatory syndrome in the Adélé and urban populations, as this protein is the first acute phase protein to be detected. However, the orosomucoid concentrations obtain-ed provide no evidence of significant inflammation. The high affinity of haptoglobin (Hp) for hemoglobin (Hb) results in the formation of soluble Hp-Hb complexes, reducing the value of Hp as a marker of the acute phase of inflammation. The frequency os sickle cell disease was higher in the Adélé population than in the urban population (10-25% versus 2-6%). Hemoglobinopathies are correlated with haptoglobin concentration and thus plasma haptoglobin concentration was lower in the Adélé population than in the urban population. The plasma concentrations of a1-antitrypsin in this study were similar to those reported for Europeans. The plasma concentration of protease inhibitors, such as a1-antitrypsin, increased as protease levels increased. These data confirm that the Adélé and urban populations suffer no disease due to high levels of protease release into the bloodstream. They also show that a1-antitrypsin is of some value as an acute phase marker protein. The acute nature of the inflammatory syndrome (as assessed by CRP concentration) in the Adélé and urban populations was confirmed by the hyperglobulinemia (high levels of production of IgM and IgG antibodies) observed in these populations. The Adélé and Lomé urban populations live in a tropical environment in which they are continuously in contact with infectious agents. This results in repeated stimulation of the immune system in both these populations. This study of plasma proteins in the Adélé provides insight into the physiological conditions of this ethnic group, w

Adolescent↗

Serum amyloid A concentrations in giant-cell arteritis and polymyalgia rheumatica: a useful test in the management of the disease.

A prospective clinical study of 23 patients with giant-cell arteritis (GCA) and/or polymyalgia rheumatica (PMR) was undertaken in order to assess the behaviour of the non-specific markers of the disease activity, the erythrocyte sedimentation rate (ESR) and other acute phase markers, particularly the C-reactive protein (CPR) and serum amyloid A apolipoprotein (apo SAA) levels during induction of disease remission by prednisone therapy, and possible further recurrence of GCA and/or PMR. The apo SAA measurement is more sensitive than the CRP measurement in determining disease activity (97% and 61%, respectively). The specificity of apo SAA is greater than ESR in the determination of inactive disease (86% and 77%, respectively). In some cases with clinically active disease the ESR and CRP were normal, whereas the apo SAA was always elevated. We conclude that the apo SAA measurement in combination with clinical data and other laboratory parameters may be useful in the management of GCA and/or PMR.

Acute-Phase Proteins↗

Depletion in choline containing phospholipids of LpB particles in adequately controlled type I insulin-dependent diabetes mellitus.

The aim of the present study was to evaluate the serum and lipoprotein levels of choline--containing phospholipids (lecithin, lysolecithin and sphingomyelin) in a group of type I diabetic patients in fair metabolic control. Forty-eight male adult diabetic patients without macroproteinuria were compared with 48 healthy controls matched for age and body weight. Total cholesterol and phospholipids were assessed in plasma and in apolipoprotein B (apoB) and non apoB containing lipoprotein particles (Lp B and Lp non B particles) separated using precipitation with Concanavalin A. When compared to the control group, diabetic patients have significantly lower serum phospholipids and phospholipids and cholesterol content of LpB particles. All the other parameters studied were similar in the two groups. The phospholipids/cholesterol ratio, calculated in LpB particles is also significantly reduced in the diabetic group. These results strongly suggest a depletion in the choline containing phospholipid content of LpB particles and therefore an alteration of the surface components of atherogenic particles in type I diabetes mellitus.

Adult↗