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Biomedical subjects

M Leclercq

Publications and source records attributed to M Leclercq.

At least 73 records · Page 4Linked to original sources
PubMed1985

Serum vitamin K1 concentration and vitamin K-dependent clotting factor activity in maternal and fetal cord blood.

The serum concentration of phylloquinone (vitamin K1) was measured in 34 healthy mothers and in the arterial cord blood of their newborn infants. In addition, the activities of factor II and of factors VII plus X were determined simultaneously in 16 paired maternal and fetal bloods. The serum vitamin K1 concentration was similar to that of control subjects in 27 mothers: 9.03 +/- 4.9 micrograms/L (mean and SD), with a simultaneous concentration of 10.4 +/- 5.3 micrograms/L in cord blood. Six mothers exhibited high serum vitamin K1 concentrations from 40 to 240 micrograms/L (median, 82) and the concentration in cord blood ranged from 25 to 115 micrograms/L (median, 71). One mother had a normal concentration of vitamin K1: 9 micrograms/L while no vitamin K1 was detectable in the serum of her infant. The activity of factor II and factors VII plus X was 7% and 7%, respectively, in this infant and 100% in the mother. All other mothers showed normal factor II and factors VII plus X activity, while the median activity was 47% (28%-56%) for factor II and 65% (35%-100%) for factors VII plus X in cord blood. These data suggest that vitamin K1 can cross the placental barrier but not in every case. Therefore the systematic administration of vitamin K1 to the newborn infant seems to be required to prevent the occurrence of the hemorrhagic disease.

Blood Coagulation Factors↗
PubMed1985

Pharmacokinetics of vitamin K1 in low-birth-weight neonates.

The pharmacokinetics of vitamin K1 was studied in 21 newborn infants. 11 neonates had received no parenteral loading dose prior to the study (group I), while 10 had been injected 5-10 mg vitamin K1 at birth (group II). At postnatal age 2-9 h, 1 mg of vitamin K1 was injected intravenously, and small samples of blood (less than or equal to 500 microliter) were collected at different times during 6 h. Serum vitamin K1 and its epoxide were assayed by high-performance liquid chromatography (HPLC). In both groups, the disappearance curve showed two exponential components: a fast distribution component during the 1st h and a slower elimination component during the next 5 h. In group I, the plasma half-life of the first component was between 18 and 52 min (median 23 min), and the half-life of the second was between 67 and 179 min (median 109 min). Both half-lives were significantly higher in group II. The volumes of distribution were suggestive of distribution into plasma during the first phase and roughly into the extracellular water for the second component. Epoxide was detected in most patients 15 min after vitamin K1 injection, and after 3 h its concentration was higher than the concentration of vitamin K1. These data suggest that the kinetics of vitamin K1 in neonates is not very different from that in adults. The newborn infant is able to oxidize vitamin K1, a phenomenon in keeping with the gamma carboxylation of glutamic acid.

Adult↗
PubMed1985

Does vitamin K excess induce ectopic calcifications in hemodialysis patients?

Vitamin K promotes the formation of gamma-carboxylated glutamic acid (Gla) residues within different protein classes such as vitamin K-dependent clotting factors, bone Gla-protein (BGP or osteocalcin), and atherocalcin. Gla-containing proteins have a high affinity for the Ca2+ ion. In addition to bone and atheromatous plaques they are also regularly found in ectopic calcifications, but not in uncalcified soft tissue. In the present study we investigate the possibility that vitamin K and BGP, in addition to previously recognized factors, may play a role in soft tissue calcification of chronic hemodialysis patients. Patients without radiovisible ectopic calcifications (group A) are compared to patients with such Ca deposits (group B). Both patient groups have comparable values of predialysis plasma Ca, P, alkaline phosphatases, parathyroid hormone (PTH) and 25 hydroxyvitamin D. The CaxP product is slightly higher in group B than in group A patients. Plasma vitamin K1 levels of group B patients are increased to more than twice the values observed in group A patients. Plasma BGP, even though not significantly different, shows a trend towards decreased levels in group B patients. A positive correlation exists between plasma vitamin K1 and BGP for patient group A alone, but not for group B alone. A correlation is also observed between plasma PTH and BGP (all patients) and between serum alkaline phosphatases and plasma BGP (all patients). Taken together, these results favor the hypothesis that in addition to an increased CaxP product a vitamin K excess may induce soft tissue calcification in hemodialysis patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Gamma-carboxyglutamic acid in urine of newborn infants.

Gamma-Carboxyglutamic acid (GLA) was measured in the urines obtained from 11 full-term infants, 48 pre-term infants appropriate for gestational age (AGA), and 25 small-for-gestational age (SGA) infants. Separation was performed by high resolution anion exchange chromatography. The results were similar in both AGA and SGA infants. During the first 3 days of life, urinary GLA mean (and range) was 1.66 (0.34-4.60) in the low birth weight infants versus 0.88 (0.26-1.38) in the full-term infants and 0.76 (0.62-1.15) mumol . kg-1 X 24 h-1 in the control adults. In the low birth weight infants, urinary GLA fell from 2.79 (0.61-5.75) at age 1-3 days, to 1.55 (0.26-4.04) mumol/24 h at day 8 (p less than 0.01); it then rose again slowly to 2.12 (0.65-3.93) mumol/24 h at day 45. In these infants there was no correlation between urinary GLA excretion and birth weight or gestational age, or urinary hydroxyproline or serum alkaline phosphatase. Despite the well-known reduced blood levels of vitamin K dependent coagulation factors in neonates, these results show that urinary GLA excretion is at least similar to the excretion in adults. These data suggest that these neonates can carboxylate glutamic acid and that the newborn infant has a high bone turnover.

1-Carboxyglutamic Acid↗
PubMed1984

Skin disorders and vitamin A metabolism disturbances in chronic dialysis patients: the role of zinc, retinol-binding protein, retinol and retinoic acid.

The authors have studied--in the plasma--the changes of zinc, retinol binding protein (RBP), retinol and retinoic acid with reference to the dermatological status of fifty chronically haemodialysed renal insufficiency patients divided into four subgroups (normal skin, dry skin, dry skin with keratosis, and only keratosis). The results of these groups were compared to those of thirty healthy subjects. The values of these variables do not show any significant difference in function of the dermatological subgroups; but, despite the considerable rise in the retinol binding protein and retinol levels in comparison with the controls (haemodialysis patients: RBP = 11.77 +/- 2.83 mumol X l(-1), retinol = 7 +/- 2.57 mumol X l(-1); controls; RBP = 2.76 +/- 0.62 mumol X l(-1), retinol = 2.16 +/- 0.53 mumol X l(-1] the electromicroscopic examination of skin biopsy samples from some of the patients did not reveal any sign of hypervitaminosis A in the lesions.

Humans↗
PubMed1984

[Osteoarthritis and tenosynovitis of the finger due to Mycobacterium intracellulare. A case report and review of the literature].

The authors present one case of osteo-arthritis and tenosynovitis of the right forefinger due to Mycobacterium intracellulare, in a 61-year old woman. The treatment consists of a synovectomy of the finger's proximal interphalangeal joint and of the sheath of the flexor tendons and a drug regimen associating erythromycin and cotrimoxazole for 2 1/2 months. This therapy proves successful, as the patient is clinically cured. A literature review records 19 similar osteo-articular and peri-articular infections due to the Mycobacterium avium-intracellulare group, reported during these last 25 years.

Arthritis, Infectious↗
PubMed1984

[Hepatic fibrosis and portal hypertension in chronic vitamin A poisoning].

The authors report the case of a 36-year-old man who was hospitalized for portal hypertension. The patient had been receiving 200 millions units of vitamin A for ten years duration as treatment of psoriasis. There were no extrahepatic signs of hypervitaminosis A and the serum concentration of vitamin A was low. Microscopic examination of a liver specimen showed: a) spontaneous fluorescence due to vitamin A accumulation in sinusoidal cells; b) portal, periportal and perisinusoidal fibrosis; c) hyperplasia and hypertrophy of Ito cells. Hepatic vitamin A concentration was markedly increased. Hemodynamic study showed increased wedged hepatic venous pressure. Low serum concentration of retinol binding protein, which could be due to severe denutrition, explained the low serum vitamin A. This case report emphasizes that severe hepatic injury due to chronic hypervitaminosis A may be observed in the absence of extrahepatic signs of vitamin A intoxication and increase in serum vitamin A concentration. In such cases, histologic examination of a liver specimen and determination of hepatic vitamin A concentration are the only means of diagnosis.

Adult↗
PubMed1982

Determination of rifampicin, desacetylrifampicin, isoniazid and acetylisoniazid by high-performance liquid chromatography: application to human serum extracts, polymorphonucleocytes and alveolar macrophages.

A method for the determination of rifampicin, desacetylrifampicin, isoniazid, and acetylisoniazid by high-performance liquid chromatography and using the same extract of the same sample is reported. After protein precipitation and extraction of these antituberculous drugs, two reversed-phase chromatographies were necessary. The technique was applied to serum extracts, polymorphonucleocytes and alveolar macrophages from patients treated for tuberculosis.

Chromatography, High Pressure Liquid↗