Biomedical subjects

M Guillaumont

Publications and source records attributed to M Guillaumont.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Stability of fat-soluble vitamins A (retinol palmitate), E (tocopherol acetate), and K1 (phylloquinone) in total parenteral nutrition at home.

Our purpose was to extend previous studies of the stability of vitamins A (retinol palmitate), E (tocopherol acetate), and K1 (phylloquinone) to total parenteral nutrition at-home (TPNH) admixtures. First, stability over 20 days was tested. Experimental conditions included presence or absence of lipids, presence or absence of trace elements, and storage in a glass bottle or in a single or multi-layer plastic bag (ethylene vinyl acetate, polyvinyl chloride, Stedim 5, and Stedim 6). The 20-day storage studies were conducted at 4 degrees C or at ambient air temperature. The second part of the study consisted of exposing to natural light TPNH admixtures with or without lipids, but with trace elements, in the same containers (except polyvinyl chloride). Finally, a clinical situation of TPNH was simulated with a TPNH admixture prepared 11 days before the test in a Stedim 6 plastic bag and stored at 4 degrees C in total darkness. For vitamins A, E, and K1, we observed good stability for 20 days; the final concentrations ranged from 75% to 100% of initial concentrations whatever the conditions studied. It appears that there is no significant difference of action between all containers and that the presence or absence of lipids and trace elements in admixtures stored at 4 degrees C or ambient temperature makes no difference. With exposure to sunlight, vitamin losses were 100% at 3 hours for vitamin A and 50% for vitamin K1; vitamin E concentrations were unchanged after 12 hours of experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Diterpenes↗

PubMedDate not supplied

Is vitamin K1 supplementation necessary in long-term parenteral nutrition?

BACKGROUND: I.v. lipid emulsions contain vitamin K in substantial quantities and in 1989, we therfore stopped supplying vitamin K1 to patients receiving home parenteral nutrition (HPN). METHODS: Nine patients (group I) receiving HPN before 1989 (10 mg i.v. vitamin K1 supplementation weekly until 1989, which was discontinued thereafter) and six patients with an initial low plasma vitamin K1 concentration (related to their malabsorption) (group II) receiving HPN after 1989 were studied. Prothrombin time (PT), plasma vitamin K1 concentration, and vitamin K1, content in lipid emulsions were measured throughout the period of HPN. RESULTS: All lipid emulsions, except for Eurolip 20% and Clinoleic 20% (Baxter SA, Maurepas, France) contained vitamin K1, with concentration ranges from 179 +/- 39 to 353 +/- 78 ng/L. Group I patients had an initial high plasma vitamin K1 concentration due to the vitamin K1 supplementation. After this supplementation was discontinued, plasma vitamin K1 decreased and remained in normal ranges with a normal PT. Throughout the HPN period after 1989, patients received 255 +/- 104 micrograms of vitamin K1 weekly through lipid emulsions. The PT and plasma vitamin K1 concentrations in group II patients were restored by lipid emulsions, which contained 418 +/- 143 micrograms/wk of vitamin K1. CONCLUSIONS: In patients receiving i.v. lipids (except for Eurolip and Clinoleic), a normal vitamin K1 status can be maintained during long-term HPN without vitamin K1 supplementation. However, vitamin K supplementation cannot be abandoned until the vitamin K content of emulsions is standardized by manufacturers. A weekly supply of 250 to 400 micrograms of vitamin K1 is enough to maintain and even restore a normal vitamin K1 status in HPN.

Adult↗

PubMedDate not supplied

Population pharmacokinetics of cisplatin in patients with advanced ovarian cancer during intraperitoneal hyperthermia chemotherapy.

The objective of this study was to determine the pharmacokinetic profile of total platinum administered by hyperthermic peritoneal perfusion (HPP) in 16 patients with ovarian cancer. The patients had a performance status of lIIalpha/b/c on the FIGO scale. They received 60, 80 or 100 mg of cisplatin. The percent of cisplatin remaining in the body after the peritoneum was emptied averaged 65% (41.7-85.4%). The average ratio between peritoneal drug concentrations and plasma concentrations was 73. A Bayesian estimation of individual phamacokinetic parameters was carried out using the non-linear mixed-effect modeling approach as implemented in the NONMEM computer program. A two-compartment model with an additional peritoneal cavity compartment was used to fit the data. Large interindividual variability of the pharmacokinetic parameters occurred The maximum platinum concentration in plasma was reached between 1 and 1.5 hours after the beginning of administration; it ranged from 0.37 to 1.7 microg/ml (1.9 to 8.72 microM). The elimination half-life was 80 hours (48-152 hours and the area under the plasma concentration time curve normalized to a 100 mg cisplatin dose was 79 mg/liter x hours. The simultaneous fit of perfusate and plasma concentrations allowed us to estimate the percent of cisplatin that reached the systemic circulation at about 20%. At time infinity, the urinary cisplatin recovery accounted for only 20% of the administered dose. The results in this study showed that a high proportion of the cisplatin dose was absorbed by target tumor cells. In spite of the advanced disease of patients at the time of HPP, 37.5% of them were still alive three years after HPP (ie., 3-6 years after cancer diagnosis) and 12.5%, 7 years after HPP (i.e., 8 years after cancer diagnosis).

Adult↗