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Biomedical subjects

B Roussel

Publications and source records attributed to B Roussel.

At least 55 records · Page 3Linked to original sources
PubMed1991

Autoimmune haemolytic anaemia due to anti-phospholipid antibodies.

The clinical course and laboratory findings of a patient with autoimmune haemolytic anaemia due to anti-phospholipid antibodies and secondary to a systemic lupus erythematosus-like syndrome are described. IgG and IgM with anti-phospholipid activity coexisted in both sera and acid eluates prepared from the patient's red cells, as demonstrated by ELISA using a panel of anionic and neutral phospholipids. The anti-erythrocyte binding activity of eluted autoantibodies, determined by a radioactive antiglobulin technique, was totally inhibited by absorption with phospholipid micelles. The patient's serum also contained an IgM warm haemolysin detectable with enzyme-treated cells only, as well as anti-C, -E and -S alloantibodies.

Anemia, Hemolytic, Autoimmune↗
PubMed1991

Reactivity patterns of anti-phospholipid antibodies in systemic lupus erythematosus sera in relation to erythrocyte binding and complement activation.

We studied 51 sera from patients with systemic lupus erythematosus to determine the relationship of their anti-phospholipid activity to their anti-erythrocyte and complement activation properties. Forty-nine per cent of the sera had anti-phospholipid activity as demonstrated by ELISA using a panel of anionic phospholipids, and most of these also bound to neutral phospholipids, albeit to a lesser extent. A cellular radioimmunoassay was used for the detection of immunoglobulin and C3 binding to normal erythrocytes (intact, enzyme-treated or glutaraldehyde-fixed) following incubation with patient sera. The levels of IgG anti-phospholipid correlated with hypocomplementaemia and with immunoglobulin binding (paralleled by a deposition of C3 fragments) to the three types of erythrocytes, although most strongly to fixed cells. Immunoglobulin binding to intact erythrocytes correlated primarily with reactivity against neutral phospholipids. The specificity for phospholipid epitopes of immunoglobulin adsorbed onto erythrocytes was confirmed by acid elution followed by testing in ELISA. These data suggest that some anti-phospholipid antibody subsets may bind to erythrocytes in vivo, thus accounting for the observed association of these antibodies with positive direct antiglobulin tests.

Antibodies, Antinuclear↗
PubMed1990

A human monoclonal IgM with autoantibody activities against heparan sulphate and the mitotic spindle.

A monoclonal IgM kappa from a patient with Waldenström's macroglobulinaemia (IgM-Rod) was found to react at temperatures below 28 degrees C with all tissue basement membranes and the cell coat of non-haematopoietic cells. IgM-Rod antibody was directed against heparan sulphate side chains of heparan sulphate proteoglycans as shown by binding in a solid-phase ELISA to heparan sulphate glycosaminoglycans but not to other purified subcomponents of the extracellular matrix; and by specific inhibition of the observed reactivity by heparitinase treatment. IgM-Rod showed cross-reactivity by indirect immunofluorescence with an as yet unidentified structure expressed in the nucleus during cell division and becoming associated with the mitotic spindle apparatus. The co-existence of both binding activities for heparan sulphate and nuclei determinants in the same IgM molecule was deduced from adsorption-elution experiments and from the inhibitory effect of a mouse monoclonal anti-idiotypic antibody directed against the paratope of IgM-Rod.

Antibodies, Anti-Idiotypic↗
PubMed1990

[Parameters of hemostasis during treatments associating fractionated heparin administered subcutaneously to standard and fractionated heparin administered intravenously in the chronic hemodialysis patient].

The hemorrhagic risk of an association of fractioned heparin (Fraxiparine) injected intravenously at the dose of 7500 AXaICU or of unfractionned heparin (UFH) injected intravenously at the usual dose used for a priming dose for hemodialysis (3750 +/- 1280 IU + 1000 IU after 2 hours of dialysis) to the subcutaneous administration of a thrombo-embolism preventive dose of Fraxiparine (7500 AXaICU) was evaluated on the modifications of the following hemostasis parameters: thrombin time, Activated Partial Thrombin Time (APTT), prothrombin time, anti Xa activity in 13 uremic patients on hemodialysis. The association of intravenous and subcutaneous Fraxiparine prevents efficiently the clotting of the extracorporeal circulation without inducing a detectable antithrombinic activity. In contrast, the association of I.V. UFH to subcutaneous Fraxiparine induces a significant increase of the thrombin time and of the APTT. This latter is exclusively explained by the activity of UFH. It is concluded that subcutaneous Fraxiparine at the thromboembolism preventive dose can be associated as well to I.V. Fraxiparine as to UFH without increasing the antithrombinic activity of the plasma.

Aged↗
PubMed1989

Low-molecular-weight heparin Fraxiparin in chronic hemodialysis. A dose-finding study.

A two-step dose-ranging study was undertaken with CY216 (Fraxiparin) in 8 patients on 7 sessions each. The different doses were administered each time as a single bolus injection at the start of hemodialysis without heparinized priming nor further administration during the 4-hour session. In the first step, the clinical efficacy of 4 different doses of Fraxiparin was compared with that of standard heparin on the percentage of sessions free of clot formation in the extracorporeal circulation (ECC). Safety was evaluated by the compression time for hemostasis at the puncture sites. The second step was a randomized comparison of 3 Fraxiparin dosages. In addition to the clinical assessment of efficacy, the following biological parameters were measured: fibrinopeptide A (FPA), anti-Xa (AXa) activity calibrated against Fraxiparin, thrombin time (TT), activated partial thromboplastin time, blood counts, hemoglobin, hematocrit, plasma creatinine and urea, and residual blood volume in the dialyzer. A 'standard' dosage of 10,000 AXa Institut Choay units of Fraxiparin was shown to prevent clot formation in the ECC. It resulted in a marked increase in TT, without any lengthening of the puncture site compression time. After 4 h, AXa and FPA levels in the venous line were related to the doses used (p less than 0.05). After 48 h AXa activity was very low. Dialysance and tolerance were excellent. Thus, a single dose of Fraxiparin unrelated to body weight and not determined by the measurement of the whole-blood activated clotting time appeared to be a safe and effective means for preventing fibrin formation in 4-hour dialysis sessions.

Adult↗
PubMed1988

[NMR spectrometry in vivo with a resistive magnet at 1,2 T].

A resistive magnet, operating at 1.2 T, intended to magnetic resonance spectroscopy in man was set up and evaluated in the hospital of Chamonix. Drusch S.A. in collaboration with Institut d' Electronique fondamentale built the system with the following characteristics: weight: 12 t, pole diameter: 55 cm, distance between coils: 36 cm. Cooling the magnet was provided by water flowing at 50 l/min. The magnetic field homogeneity was 3 X 10(-7) in a 60 mm diameter sphere. Stability was regulated at +/- 1 mGs. Five correcting circuits were used (X, Y, Z, Z2, XY). For experiments in man useful window was 120 X 20 cm and allowed measurements in brain and limbs. With this type of magnet, 1H, 31P and 23Na NMR spectra equalled in quality those obtained with superconducting magnets which work at a very higher cost.

Electromagnetic Fields↗
PubMed1987

[Anticoagulation in hemodialysis sessions with a low molecular weight heparin (CY 222, Choay). Dosage studies in chronic hemodialysis. Its use in patients at high risk of hemorrhage].

Efficacy of CY 222 for providing anticoagulation during hemodialysis was evaluated in three successive trials by rating quality of blood restitution (degree of coagulum formation in extracorporeal circulation) and by assay of fibrinopeptide A. Its safety was assessed by measurement of manual compression time necessary to ensure hemostasis of puncture points at end of session. Details of the first preliminary study were: 60 sessions in 11 chronic uremia patients; CY 222: 75, 150 and 300 A-Xa IC U/kg + 1,000 A-Xa IC U/h, then 150 and 300 A-Xa IC U/kg without continuous injection, compared with standard heparin (SH) at the usual dosage for each patient (60 +/- 13 IU/kg). Results showed CY 222 at 150 U/kg + 1,000 U/h to possess the same efficacy as SH and to give a shorter compression test time: for 150 U/kg the efficacy was satisfactory, although less than with SH, and compression times were shorter (interest in patients at risk of hemorrhage). For 300 U/kg, efficacy was superior (improved restitution and lower FPA level at end of seance: 6 ng/ml instead of 15 ng/ml.p less than 0.002) and compression times were identical. The second study to evaluate optimal dosage of CY 222 in chronic hemodialysis (CHD) involved: 10 patients; CY 222: 200 A-Xa IC U/kg and 250 A-Xa IC U/kg by single-dose injection. Results failed to demonstrate any significant difference in evolution of FPA levels, but restitution was better at 250 U/kg. In addition, investigation of the effect of rinsing of ECC with standard heparin before the session showed that its suppression did not alter effectiveness but improved tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation↗
PubMed1987

[Low molecular weight heparin (CY 222) levels during hemodialysis sessions. Comparison of various chromogenic and chronometric methods. Problem of standardization].

Current evaluation of biological activity of low molecular weight heparins (LMWH) is dependent solely on technics determining Xa inhibition. Comparison of these technics was carried out during 2 studies of the use of CY 222 during hemodialysis. In the first study, 66 plasma samples from 11 patients treated with 200 or 250 U A Xa IC kg/i.v. at start of session (sample collections at 2-4 h) were tested using a chronometric technic (Hepaclot Stago-plasma diluted to 1/3) and 2 chromogenic technics on microplates using C.B.S. 31-39 substrates (Stachrom-modified Stago: incubation time 90" for a wide range) and S 2222 (Coatest-modified Kabi: incubation time 180"). In the second, 28 plasma samples from 7 patients (sample collection 2-4 h, TO following session; anticoagulation CY 222 10,000-15,000-20,000 U A Xa IC) were studied by 2 chronometric methods: Hepaclot (Stago) and Heptest (Hemachem). Standardization was with CY 222 in each case (results expressed as U A Xa IC). Mean blood heparin in the first study was 2.39 +/- 0.7 with Hepaclot, 2.50 +/- 0.55 with Stachrom and 1.94 +/- 0.37 with Coatest. Student's test failed to show any difference between results with Strachrom and Hepaclot (t = 1.48 NS) whereas the difference was very significant between Hepaclot and Coatest and Stachrom and Coatest (p less than 10(-9).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation Tests↗
PubMed1987

[Plasma variation of atrial natriuretic peptide in central hypervolemia (diurnal or nocturnal) induced by antiorthostatic decubitus at -6 degrees].

Plasma levels of ANP were measured during a 4 hrs head-down tilt at -6 degrees in 5 healthy male volunteers (aged 20-22 M.2). The experiments took place from 8 to 14 hrs, (day), and from 22 to 7 hrs (night). The control period was 1 hr. in a seated position (8 to 9 hrs. for day and 22 to 23 hrs. for night). Blood samples were collected at 9 and 23 hrs. and every 20 min. during the first hours, and every hours thereafter. Electroencephalograms were continuously recorded during night. Our results showed a similar increase in ANP during both experimental conditions. During night there was no correlations between ANP and sleep stages. Finally the differences observed in renal responsiveness to central volume expansion during day or night could not be explained by a difference in renin, aldosterone, vasopressin (previously demonstrated in several studies) or ANP secretion.

Adult↗
PubMed1987

[Congenital nephrotic syndrome associated with congenital toxoplasmosis].

The authors report the case of a 1 month-old infant presenting with congenital toxoplasmosis associated with nephrotic syndrome and microscopic hematuria. Percutaneous renal biopsy showed a diffuse mild increase in mesangial cells and matrix, but immunofluorescence was negative. Electron microscopy revealed the presence of extensive fusion of foot processes. A review of the nephropathy of congenital toxoplasmosis is presented. Outcome seems to be favorable under steroid therapy. The pathophysiology of nephropathy is discussed, as well as the relationships or coincidence between congenital toxoplasmosis and nephrotic syndrome.

Female↗
PubMed1986

A once-repeated study of nocturnal plasma melatonin patterns and sleep recordings in six normal young men.

The concentration of melatonin was determined, using a sensitive and reliable radioimmunoassay, in plasma samples obtained at 20 min intervals during a 12 hr period (from 20.00 to 8.00) from six normal men. Polygraphic sleep recording was simultaneously performed. Each subject was studied twice at a 1 week interval. For each session, the plasma melatonin profile showed an episodic secretion: a mean frequency of 4.5 peaks and 4.0 troughs per night in the first study and a mean frequency of 4.0 peaks and 3.5 troughs in the second study. The two nocturnal melatonin profiles obtained from each subject were very similar. However, considerable interindividual variation was found (areas under the curve [AUC] from 15.3 to 125 pg X hr/ml). No relationship could be obtained between AUC and body weight. Apparent melatonin half-life calculated from the semilogarithmic plots of the melatonin pattern was 57 +/- 34 min. Chi-square testing revealed that the nocturnal pattern of melatonin levels was not related to sleep stages. Our data do not favor a direct relationship between melatonin secretion and the sleep-waking cycle in humans.

Adult↗
PubMed1986

Thermal and metabolic adaptation to first cold-water immersion in juvenile penguins.

Juvenile king and macaroni penguins are terrestrial seabirds and must face an intensive and prolonged energetic demand during their passage from shore to marine life in cold subantarctic seawater. Evidence for progressive thermal adaptation was sought by measurement of metabolic rate (MR) and body (Tb) and skin (Tsk) temperatures in unrestrained, fully immersed penguins. Steady-state responses obtained after the 3rd h of immersion in never-immersed (NI) penguins were compared with those of penguins acclimatized to seawater temperature (A). NI macaroni penguins, unlike NI king penguins, showed a fall in Tb on their first immersion but, once acclimatized, were able to maintain their homeothermy due to an increase (greater than 3.2 W/kg) in regulatory thermogenesis. In NI king penguins, during a simulation of seawater adaptation by 10 successive immersions, MR at 7 degrees C water temperature (Tw) rose from 6.0 to 9.4 W/kg (becoming 3-5 times higher than in air), whereas Tb rose from 37.6 to 38.4 degrees C. In both species occurrence of peak MR at much lower Tw, progressive increase in thermogenesis capacity, and lower conductance in water after adaptation to marine life (28 and 36% less in A king and macaroni penguins, respectively) showed that the passage from shore to marine life consisted of a true cold acclimatization.

Acclimatization↗
PubMed1986

Nocturnal continuous infusion of growth hormone (GH)-releasing hormone results in a dose-dependent accentuation of episodic GH secretion in normal men.

Fluctuations in plasma GH levels have been found in patients with acromegaly who have continuously elevated levels of ectopically produced GH-releasing hormone (GHRH). Likewise, plasma GH fluctuations have been found in normal subjects receiving continuous GHRH infusions. We report the effects of two doses of GHRH, administered by constant infusion, on nocturnal GH secretion in six normal young men. Each received, in random order, 2.5 ng/kg X min GHRH, 15 ng/kg X min GHRH, and 0.15 M NaCl. During both GHRH doses, a highly significant increase in total nocturnal GH secretion was found (P less than 0.001) as well as an increase in GH secretion during different periods of the night. Nocturnal GH secretion was episodic during the GHRH infusions, with an increase in the number and magnitude of the peaks compared to those during the NaCl infusion. Plasma immunoreactive GHRH concentrations plateaued at 1 h during the high dose and at 3 h during the low dose GHRH infusion. Sleep parameters, including total sleep time, sleep latency, and duration and timing of the different sleep stages, were not affected by GHRH infusions. We conclude that GHRH, continuously infused, increases nocturnal GH secretion according to the dose, while the episodic pattern of GH secretion is maintained.

Adult↗
PubMed1986

[Familial esophageal leiomyomatosis associated with Alport's syndrome in a 9-year-old boy].

The authors describe a family in which the mother and one son are affected by oesophageal leiomyomatosis and nephritis with haematuria. The mother also presents hypertrophy of vulva and clitoris, and her son has perceptive deafness and congenital cataract. In the medical literature only 15 cases of oesophageal leiomyomatosis in children and adolescents could be found. The association with Alport's syndrome was first described by Torres and Guarner in 1983.

Adult↗
PubMed1985

Diurnal administration of human growth hormone-releasing factor does not modify sleep and sleep-related growth hormone secretion in normal young men.

hGRF (iv 50 micrograms) was administered to 6 normal young adult males at 09.00 and 20.00 h on different days. Nocturnal GH secretion was monitored during polygraphic sleep recordings on both control nights and nights following hGRF administration. Sleep-related GH secretion and sleep parameters were not affected by diurnal hGRF administration.

Adult↗