Biomedical subjects
Publications and source records attributed to R Bourdon.
The authors describe the nicotine quantification in milk by GC - MS. In order to obtain a good chromatographic separation, the nicotine is previously separated by steam distillation. Quinoleine is used as internal standard. CV is lower than 5 per cent.
Fifty-eight patients on intermittent haemodialysis underwent parathyroidectomy because of severe secondary hyperparathyroidism. Mean individual parathyroid gland weight was 689 +/- 62 (SEM) mg. Mean total gland weight per patient was between two and three grams. Increasing nodule formation within hyperplastic glands appeared to develop with increasing time of duration of hyperparathyroidism. Patients with chronic pyelonephritis had a higher gland weight than those with chronic glomerulonephritis. A direct relationship was found between gland weight and circulating immunoreactive parathyroid hormone, but an inverse relationship between gland weight and plasma aluminium concentration. The higher the parathyroid gland aluminium, the higher was the bone aluminium concentration.
Explore the source record for details and available documents.
Ten chronic hemodialysis patients with severe aluminium (Al) intoxication developed a microcytic anemia despite oral iron supplementation. Their microcytosis was reversible after deionization of the dialysis water. Ten age and sex matched hemodialysis patients who were not Al intoxicated but who had a comparable treatment schedule and time on dialysis had no such microcytosis. In order to investigate a possible direct role of Al we intoxicated uremic rats by daily (6/7 days a week) intraperitoneal injections of 30 nmoles/day of aluminium. After 3 months, the Al-intoxicated uremic rats had a significantly lower hematocrit (34.7%), hemoglobin (12.0 g/dl), and MCV (52.5 fl) than the control, vehicle-injected uremic animals (37.4%, 13.1 g/dl and 60.4 fl., respectively). The reticulocyte counts of the intoxicated rats were increased. Serum iron and transferrin iron binding capacity were unchanged. Thus aluminium intoxication of the uremic organism leads to a microcytic anemia possibly by interfering directly with normal hemoglobin synthesis.
Incubation for 48 hours of C6 glioma cell cultures with 10(-4)M tricyclic antidepressant desipramine gave rise to a quantitative increase of total lipids and to qualitative modifications of glycosphinegolipids involving detection by thin-layer chromatography of spots migrating according to cerebroside and sulfatide and presence of an abnormal ganglioside pattern. These lipid modifications were associated with the appearance of stereospecific binding of opiates (dihydromorphine) with a dissociation constant of 30-60 nM. These results favor an important role of lipids in opioid receptor function.
Eighteen patients received morphine 0.2 mg kg-1 in 0.9% saline i.m. (n = 6), extradurally (n = 6), or in a 10% dextrose solution intrathecally (n = 6) for pain relief operation. Plasma unmetabolized morphine was isolated by extraction using liquid-solid chromatography and measured by radioimmunoassay. Conjugated morphine was calculated from the difference between total immunoreactive morphine and unmetabolized morphine. Initial vascular absorption was significantly less in the intrathecal group than in the i.m. and extradural groups. This accounts for persistence of plasma unmetabolized morphine at 24 h and for more prolonged analgesia in the intrathecal group. Prolonged analgesia observed following extradural and intrathecal administration was caused by a small quantity of unmetabolized morphine. Extradural and i.m. groups showed the same pharmacokinetic patterns although extradural analgesia is much more prolonged. Morphine glucuronide appeared later in blood in the intrathecal group than in the two other groups.
To understand the mechanism of the lysosomal lipid storage induced by perhexiline maleate, we performed simultaneous lipid analysis and lysosomal enzymes determinations. Human fibroblasts were cultured for 5 days in the presence of perhexiline maleate at a concentration of 2 micrograms/ml of culture medium. Lipid analysis showed that those non toxic levels determined the same changes as seen with higher concentrations of the drug (Hauw et al. 1980) i. e. increase of cholesterol and of all major phospholipids. Qualitative phospholipid pattern was not markedly changed. Lysosomal enzymes activities were not modified with the exception of sphingomyelinase which was reduced to 12% of its normal level.
It has been suggested that in uremic bone, aluminum interferes with normal mineralization. Aluminum content and aluminum localization were studied in iliac crest biopsies of two groups of patients on regular hemodialysis; one group had histologic osteomalacia, and little or no bone resorption (group 1); the other, osteitis fibrosa and no mineralization defect (group 2). Group 1 patients had significantly higher plasma aluminum concentrations than those of group 2. No difference was found in bone aluminum content, which was above normal in both groups. In the bone samples of the osteomalacic subjects, aluminum was mainly localized at the limit between osteoid and calcified tissue, the site where the bone mineral is normally first deposited. Osteomalacia could not be related to hypocalcemia or to phosphate depletion. Active vitamin D derivatives (25-hydroxycholecalciferol and 1alpha-hydroxycholecalciferol) failed to prevent or to improve the bone disease. In the bone samples of group 2 subjects, aluminum could not be localized by the methods used, except in the two cases with greatly elevated bone aluminum, where it was mainly localized on cement lines. In group 2 subjects, immunoreactive parathyroid hormone plasma concentration, osteoclast surface, and marrow fibrosis were significantly higher than they were in group 1 subjects. It is concluded that in bone from uremic patients on regular dialysis, aluminum can induce a particular form of osteomalacia, resistant to the vitamin D active derivatives. The bone disease is only observed in the absence of severe secondary hyperparathyroidism. This suggests that parathyroid hormone may be involved in the development of the aluminum-induced mineralization defect.
Plasma morphine concentration was measured in eight patients who received morphine 0.02 mg kg-1 intrathecally. The concentration was less than 0.5 ng ml-1 at 2 min and 10 min, 2 +/- 1 ng ml-1 at 30 min, 3 +/- 2 ng ml-1 at 1 h, 6 +/- 4 ng ml-1 at 3 h, 5 +/- 3 ng ml-1 at 12 h, 0.8 +/- 0.2 ng ml-1 at 24 h and less than 0.5 ng ml-1 at 36 h. The small plasma morphine concentrations we observed after intrathecal administration of morphine indicated that analgesia is a result of an action of morphine on opiate receptors, either spinal or cerebral.
Seventeen patients received morphine 0.2 mgkg-1 in a 10% dextrose solution i.m. (n = 5), extradurally (n = 6) and intrathecally (n = 6) for pain after operation. Morphine was measured in plasma by radioimmunoassay. Plasma immunoreactive morphine concentration was significantly less after intrathecal administration after i.m. and extradural administration (P less than 0.05) at 2, 10, 15 and 30 min. We conclude that morphine given extradurally has a greater initial rate of vascular absorption than morphine given intrathecally and is similar to that observed after i.m. administration.
Tricyclic antidepressants (imipramine and desipramine) gave rise to an important decrease of sphingomyelinase activity in murine neuroblastoma and human fibroblast cell cultures. It occurred within 1 to 2 hours at a final concentration of 1 or 2 X 10(-5) M in cell culture medium. Other lysosomal enzymes such as acid lipase, arylsulfatases A and B and hexosaminidases were not modified. Low level of sphingomyelinase activity may be related to the amphiphilic characteristics of the drugs: iminodibenzyle which has the same tricyclic core but is devoid of the side chain necessary for amphiphilic properties had no effect. As iminodibenzyle has no therapeutic action, amphiphilic may be requisite to antidepressant properties of tricyclic drugs.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A hemodialyzed woman with radiologically and histologically proven osteomalacia presents a spontaneous fracture that is associated with aluminium intoxication. The hyperalbuminemia (16,6 mumol/1) was not caused by the aluminium contained in the dialysate fluid but by oral ingestion of aluminium gel in a patient presenting hyperabsorption of this metal. Increased absorption could be demonstrated by oral administration of aluminium hydroxide (2 x 12 g A1 (OH)3 spread over 48 hrs) whereas the same test failed to reveal hyperabsorption in two other hemodialyzed patients. The precise mechanism of increased absorption of aluminium is not known. It is concluded that increased digestive absorption of aluminium should be investigated in patients with kidney failure treated with aluminium gel and presenting high blood levels of this metal.
Explore the source record for details and available documents.
A molecule sensitive to light, to variations in temperature and pH, guanoxabenz hydrochloride cannot be estimated in biological fluids according to classical technics. The authors propose an analytical method based, during the extraction phase, on the formation of a copper complex extractable in organic medium and in the true phase of measurement, on the transformation, by hydrochloric acid hydrolysis in dichloro-2-6-benzaldehyde, estimated by gas phase chromatography with detection by capture of electrons. The sensitivity and the specificity of the technic authorise its use in pharmacokinetic studies in man.
Explore the source record for details and available documents.
Experimental intoxications of pigs were performed. It seems to be confirmed that bismuth crosses the blood-brain barrier. An organic derivative, trivinyl-bismuth, is more active than the inorganic salt of bismuth. In the brain, bismuth is preferentially found in synaptosomes. Bismuth is found in brain lipids of control pigs at very low levels. In intoxicated pigs, the level of bismuth is increased mainly in cerebellum and then in thalamus. Bismuth is partly associated to lipids. There is not a correlation between the level of bismuth in blood and in brain lipids. However, in the trivinyl intoxicated pig, a high level of blood bismuth is concomittant to a high level of brain lipid bismuth. The high content of this metal in cerebellum lipid extract may be of functional significance.