PubMed Health⌕ Search

Biomedical subjects

J Raynaud

Publications and source records attributed to J Raynaud.

At least 19 recordsLinked to original sources
PubMed2001

Natural and synthetic benzophenones: interaction with the cytosolic binding domain of P-glycoprotein.

A benzophenone glycoside has been isolated from Davallia solida. Its structure was elucidated by chemical and spectral means as 4-O-beta-D-glucopyranosyl-2,6,4'-trihydroxybenzophenone. It bound with moderate affinity to the purified C-terminal cytosolic domain of P-glycoprotein, but the binding affinity was 6- to 10-fold increased for its aglycone derivative and other related benzophenones.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

[Heparin-induced thrombopenia during hemodialysis in intensive care: use of a low molecular weight heparinoid, ORG 10172 (Orgaran)].

A 48-yr-old patient was admitted to the ICU for cardiogenic shock and acute renal failure after coronary artery bypass graft surgery. A heparin-induced thrombocytopenia (HIT) occurred during haemodialysis with unfractioned heparin (UFH) as the anticoagulant. The dialysers, the circuits and the catheters were recurrently thrombosing and the platelet count decreased to 9 G.L-1 on postoperative day 7. UFH was discontinued. Attempts to substitute UFH with a low molecular weight heparin (LMWH) failed, due to the presence of a high cross-reactivity rate of LMWH with the heparin-dependent antibody. Intermittent haemodialysis without anticoagulation using a predilution of the dialysers failed also and resulted in recurrent clotting. After informed consent of the patient, a new natural heparinoid Orgaran (Org 10172, Organon, Oss Holland) was administered. This agent is a mixture of several non heparin low molecular weight glycosaminoglycans, with proven anticoagulant efficacy, low cross-reactivity with the HIT antibody, and a half-time prolonged over 18-25 hours. The treatment regimen consisted in a i.v. bolus of 40-45 IU.kg-1 prior to each dialysis procedure, performed every two days. The platelet count increased to 200 G.L-1, seven days after discontinuing heparin injection, and remained stable during the administration of Orgaran. No other thrombosis occurred again. Each procedure of four hours duration was monitored with the plasma anti-Xa activity and APTT test. The mean anti-Xa plasma concentrations (0.44 +/- 0.55 IU.mL-1, 30 min after injection of Orgaran) were well correlated with APTT test (r = 0.73, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗
PubMed1993

[Markers of hemostasis and myocardial infarction in persons under 40 years of age].

Coronary disease before the age of 40 has special clinical and pathogenic features. The authors sought evidence of the existence of abnormalities of hemostasis markers in 39 patients aged under 40, several weeks after a myocardial infarction (MI). Blood samples were drawn a mean of 8 months after the MI. These laboratory studies included assay of C and S proteins, fibrinogen, clotting factors VII and VIII and antithrombin III, as well as detection of any possible circulating anticoagulant. Plasma levels of platelet factor 4 (PT4) and of beta-thromboglobulin (BTG) were measured in the same sample, enabling determination of the BTG/PF4 ratio. Only fibrinogen and plasma levels of platelet proteins were abnormal, revealing a significant difference between patients with multi-vessel disease and those with single vessel disease or free of severe angiographic lesions. Platelet activation appeared to persist some time after the MI, chiefly in patients with multi-vessel disease, and showing no relation to either age or treatment. Conclusions require prudence in view of difficulties in interpreting plasma assays of PF4 and of BTG.

Adult↗
PubMed1992

Sleep apneas in high altitude residents (3,800 m).

The question is: to what extent periodic breathing usually observed in translocated subjects at high altitude affects normal and polycythemic residents of high altitude? Standard sleep parameters, chest wall movements, temperature of ventilated gas and arterial O2 saturation (SaO2) were continuously recorded in 7 normal highlanders (mean hematocrit: 51%) and 14 polycythemic highlanders (mean hematocrit: 68%) during one night in La Paz, 3,850 m, Bolivia. The patterns of breathing instability were analysed by two ways: measuring duration of apneas and counting all the oscillations of SaO2 greater than 1%. Normal and polycythemic highlanders displayed a wide intersubject variability with regard to breathing instability, hence no significant difference in the total number of apneas and oscillations of SaO2 could be evidenced between the 2 groups. However, the longest apneas and the highest number of oscillations of SaO2 were found in the polycythemic highlanders.

Adaptation, Physiological↗
PubMed1990

Does arterial PCO2 interfere with hypoxia in muscular metabolism in man?

To answer the question whether PCO2 affects the muscular metabolism, PO2, PCO2, pH, lactic acid concentration and hemoglobin were measured in the efferent muscular venous blood from common flexor digitorum, during forearm rhythmic exercise corresponding to VO2max. Exercise was carried out either in hypocapnic hypoxia i.e. in permanent high altitude residents and translocated lowlanders, or in hypercapnic hypoxia i.e. in chronic obstructive lung disease (COLD) patients. The results show that, during exercise: i) PO2 in muscular venous blood remains around 20 Torr in normoxia and hypocapnic hypoxia and even higher (25 torr) in COLD patients, despite low arterial PaO2, and ii) arterial and/or local PCO2 play a role in the control of the muscular blood flow. But we cannot conclude that a change in PaCO2 affects muscular metabolism itself, because lactic acid in the muscular venous blood, that we used to check this effect, is likely dependent on mechanisms other than anaerobic glycolysis, such as a change in lactic acid efflux from the myocytes. The increase in muscular venous PCO2 may enhance the myocyte permeability to lactic acid during exercise.

Acclimatization↗
PubMed1990

Periodic breathing and O2 saturation in relation to sleep stages at high altitude.

This study was designed to compare sleep organization at high altitude (HA) and sea level (SL) and to estimate the extent periodic breathing (PB) negatively influences arterial O2 saturation (SaO2). Six lowlanders were studied at SL and after 3 weeks spent at 3,800 m (La Paz, Bolivia). Three EEG leads, EOG, submental EMG, chest and abdominal motion, temperature of ventilated gas, and SaO2 were polygraphically recorded. Comparison of HA and SL data disclosed that: 1) Sleep organization was identical, with the same percentage of REM and stage 4. 2) PB (cycle length: 20 s; central apnea: 9 s) occurred in three subjects during all stages of sleep except REM (43-60% of total sleep). A periodic lowering in heart rate occurred during ventilatory oscillation. 3) During PB, SaO2 oscillated very regularly from 78-90%, which resulted in a mean SaO2 value calculated during oscillations similar to that of the non-periodic breathers. We conclude that lung O2 uptake during PB is preserved.

Altitude↗
PubMed1988

Muscular venous blood metabolites during rhythmic forearm exercise while breathing air or normoxic helium and argon gas mixtures.

The effects of breathing normoxic helium or argon gas mixture on the local muscular metabolism during exercise were compared to those of room air in four healthy subjects. For this purpose, PO2, PCO2, pH, the concentrations of lactate (LA), glucose (Gl) haemoglobin (Hb) and K+ and osmolarity were repeatedly measured in efferent muscular venous blood during 12 min of rhythmic forearm exercise and 16 min of recovery. The time courses and magnitude of the changes in PCO2, pH, [Gl], [Hb], [K+] and osmolarity during exercise and recovery were similar for breathing both the helium and argon gas mixtures. The main finding was that during exercise, the [LA] curve reached a peak value significantly higher by 25% under normoxic helium than under room air or normoxic argon breathing. This rise in [LA] was accompanied by a slight reduction in muscular venous PO2, too small to signify muscular hypoxia. The possibility that this decline in PO2 might be due to a shift in muscular metabolism towards lipid oxidation was confirmed by the lower muscular respiratory quotient observed during helium breathing. However, such a shift did not explain why [LA] rose during this breathing. The probable explanation is that helium facilitates LA diffusion out of the myocytes.

Adult↗
PubMed1987

[Biochemical study of pollens of the genus Artemisia].

Pollens of three Artemisia: Artemisia vulgaris, Artemisia absinthium, Artemisia annua were separated by ion exchange chromatography and amino acids concentrations were measured. In any cases, the most important amino acid was proline, then asparagine + glutamine group, then gamma aminobutyric acid and alanine. An important level of histidine (8.1%) and hydroxyproline (6.2%) was found in Artemisia annua relative to the two other Artemisia species. The high histidine level, the precursor of histamine, found in the three kinds of Artemisia might be correlated with allergenic power of these weeds.

Amino Acids↗
PubMed1986

Time course of muscular blood metabolites during forearm rhythmic exercise in hypoxia.

O2 concentration, PO2, PCO2, pH, osmolarity, lactate (LA), and hemoglobin (Hb) concentrations in deep forearm venous blood were repeatedly measured during submaximal exercise of forearm muscles. Concentrations of arterial blood gases were determined at rest and during exercise. Experiments were conducted under normoxia and hypobaric hypoxia (PB = 465 Torr). In arterial blood, data obtained during exercise were the same as those obtained during rest under either normoxia or hypoxia. In venous muscular blood, PO2 and O2 concentration were lower at rest and during exercise in hypoxia. The muscular arteriovenous O2 difference during exercise in hypoxia was increased by no more than 10% compared with normoxia, which implied that muscular blood flow during exercise also increased by the same percentage, if we assume that exercise O2 consumption was not affected by hypoxia. Despite increased [LA], the magnitude of changes in PCO2 and pH in hypoxia were smaller than in normoxia during exercise and recovery; this finding is probably due to the increased blood buffer value induced by the greater amount of reduced Hb in hypoxia. Hence all the changes occurring in hypoxia showed that local metabolism was less affected than we expected from the decrease in arterial PO2. The rise in [Hb] that occurred during exercise was lower in hypoxia. Possible underlying mechanisms of the [Hb] rise during exercise are discussed.

Adult↗
PubMed1986

Bioenergetic and cardiovascular responses to exercise in residents at 2.850 m, with asymptomatic Chagas' disease.

Cardiovascular and energetic responses at rest, during 30 min of exercise (mechanical output: 125 watts) and for a subsequent recovery period of 5 min were compared in two groups, each comprising 21 residents at an altitude of 2.850 m. One group was in the asymptomatic phase of Chagas' disease with positive serological tests for T. cruzi, whereas the other was without Chagas' disease (negative serological tests). The two groups were similar as regards age, weight-for-height, blood parameters, nutritional status and heart and lung functions, including heart rate and frontal plane QRS axis determinations. At rest, they differed in that maximal and minimal arterial blood pressures were slightly but significantly lower in the group with Chagas' positive serological tests than in the controls. During exercise and recovery, the only differences between them and the controls were that their minimal diastolic arterial blood pressure was significantly lower. In absolute values, the rises in arterial pressure due to exercise were exactly the same in the two groups. Maximal O2 uptake was identical in both groups, as was exercise steady state VO2. These findings indicate that the asymptomatic subjects with Chagas' disease had a normal work capacity and were not affected by high altitude.

Adult↗
PubMed1984

Changes in rectal and mean skin temperature in response to suggested heat during hypnosis in man.

Rectal temperature, mean skin temperature and heart rate were recorded in 7 subjects during hypnosis, induced either alone or while sensations of heat were suggested. During hypnosis alone, a fall in the heart rate of about 10 beat X min-1 was the only autonomic response observed; body temperatures were unaltered. In contrast, during hypnosis with suggestion of heat, the following changes occurred: (1) Mean rectal temperature decreased 0.20 degrees C (p less than 0.05) within 50 min. Its mean time course differed significantly from that for hypnosis alone (p less than 0.001). (2) Comparison of individual rectal temperature time sequences showed that in fact this temperature only declined in 4 subjects out of 7, and tended to form a plateau located 0.35 degrees C below the value of the preceding waking state. Despite reinforcement of heat suggestion, the plateau continued until the end of the hypnotic trance. (3) Mean skin temperature tended to rise. (4) When hypnosis with suggestion ceased, both rectal and skin temperatures very slowly returned to their levels during the preceding waking state.

Adult↗
PubMed1984

[Haloperidol decanoate. Results of an open-ended multicentric study in chronic psychotic states].

UNLABELLED: An open multicentric study of 196 in-patients was carried out in 9 centres. After an initial stabilization (min. 15 days) with oral haloperidol, patients received haloperidol decanoate IM for at least 24 weeks (or a minimum of 9 injections). RESULTS: - esterification of haloperidol increased the duration of its efficacy (interval between 2 injections: average 4 weeks) without interfering with its therapeutic activity (global appreciation scale, BPRS at each injection and at the end of the treatment); - equivalent quantities of haloperidol injected at a time were 15 to 20 times those administered daily during the initial stabilisation period; - side-effects were not different with haloperidol decanoate as compared to those of the previous period (haloperidol).

Adult↗