Positive SARS-CoV-2 RT-qPCR of a nasal swab spot after 30 days of conservation on filter paper at room temperature

We tested the use of nasal swabs spotted onto filter paper (Whatman 3M) for the molecular diagnosis of SARS-CoV-2 infection. Spots of a positive nasal swab in conservation medium (B.1.177 strain, 21Ct) were still positive (duo E-gene/IP4) after 10, 20, and 30 days of conservation at room temperature, with Ct values of 28, 27, and 26, respectively. Direct spotting of the swab at bedside (omicron strain) still gave a positive result after 10 days in two RT-qPCR systems: 33.7 Ct using duo E-gene/IP4, and 34.8 using a specific Omicron system. Spotting of a dilution range of media spiked with the Delta (strain 2021/FR/0610, lineage B 1.617.2) and Omicron strains (strain UVE/SARS-CoV-2/2021/FR/1514) showed a threshold of 0.04 TCID₅₀ after 10 days of conservation. We show, for the first time, that this simple and low-cost conservation method can be used to store samples for RT-qPCR against SARS-CoV-2 for up to at least 1 month.     

Pharmacokinetics of high-dose methotrexate in adult osteogenic sarcoma

The pharmacokinetics of 222 infusions of high-dose methotrexate (MTX) with leucovorin rescue were studied in 22 adults with osteosarcoma. To reduce the variability of plasma concentration, we individualized dose regimens using a Bayesian method to reach a concentration of 10^–3 M MTX at the end of an 8-h infusion. The mean concentration observed at the end of the infusion was 1016±143 mol/l. The mean dose delivered was 13.2±2 g/m². The clearance was 49.1±11.7 ml min^–1 m^–2. The decay of the plasma concentration of MTX after completion of the infusion followed a two-compartment model with at _1/2 of 2.66±0.82 h and at _1/2 of 15.69±8.63 h. The volume of distribution was 0.32±0.08 l/kg. As compared with previously published data, the interindividual and intraindividual variations in the concentration at the end of the infusion were reduced, with values of 14% and 5.9%–21%, respectively, being obtained. Severe toxicities were avoided, and there were only 3 hematologic and 8 digestive grade 3 side effects and no grade 4 complication. Thet _1/2 and the MTX plasma concentrations at 23 and 47 h were correlated with renal toxicity (P<0.001). However, no correlation was found between the pharmacokinetic parameters and other signs of toxicity. There was no significant difference in pharmacokinetics between the toxic and nontoxic groups. In the same manner, the parameters of the group of patients sensitive to MTX were not statistically significantly different from those of the group of nonsensitive patients.     

Dietary docosahexaenoic acid-enriched phospholipids normalize urinary melatonin excretion in adult (n-3) polyunsaturated fatty acid-deficient rats.

Melatonin (MEL) plays an essential role in physiologic functions associated with darkness. We examined the effects of docosahexaenoic acid (DHA)-enriched phospholipids from pig brains (BPL) or hen eggs (EPL), as sources of DHA, on lipid FA composition of pineal membranes and daytime and nighttime concentrations of 6-sulfatoxymelatonin (aMT6) in adult male control and (n-3)-deficient rats fed BPL and EPL diets for 5 wk. In two experiments, at 3 wk of age, rats were divided into subgroups and fed semipurified diets containing either peanut oil [(n-3)-deficient group] or peanut plus rapeseed oil (control group) and two dietary formulas containing either 3.5 g/100 g diet of BPL (Experiment 1) or 5.0 g/100 g diet of EPL (Experiment 2). BPL and EPL diets provided approximately 200 mg of DHA/100 g diet. During the daytime, aMT6 concentrations were not significantly different among groups. Conversely, the (n-3)-deficient rats had significantly lower nighttime aMT6 concentrations than the control rats. BPL and EPL did not affect urinary nighttime aMT6 concentration in the control group, whereas (n-3)-deficient + BPL or EPL groups exhibited significantly higher nighttime aMT6 concentrations than the (n-3)-deficient group (76 and 110%, respectively). The level of DHA was significantly higher in the pineal glands of control rats than in (n-3)-deficient rats. In rats fed EPL and BPL, the level of DHA reached a plateau, between 10 and 11 mg/100 mg total fatty acids in control + BPL or EPL and (n-3)-deficient + BPL or EPL groups. These findings suggest that new DHA-enriched formulas may be used as an efficient alternative source of (n-3) polyunsaturated fatty acids to normalize MEL secretion.     

Oxidant stress: the role of nutrients in cell-lipoprotein interactions

Oxidant stress is increasingly becoming an important hypothesis to explain the genesis of several pathologies, including cancer, atherosclerosis and also ageing. Beside a few rare genetic defects, dietary factors are thought to play a key role in the regulation of the production of reactive oxygenated species. An imbalance between nutrients, and in particular those involved in antioxidant status, could explain the onset of an enhanced production of free radicals. We will briefly review information concerning oxidation of lipids and lipoproteins which lead to atherothrombosis. We also present new findings supporting a role for blood platelets in generating oxidant species. New data are also described concerning the role of oxygenated derivatives of cholesterol, oxysterols, in cellular cholesterol efflux and NO production. Also, new developments relating to the influence of direct effects of free radicals on cellular cholesterol homeostasis are presented. Finally, the in vitro effects of butyrate, a natural short-chain fatty acid produced by bacterial fermentation, in the protection against free radical-mediated cytotoxicity are discussed. These data provide information on the mechanisms of dietary antioxidants in preventing oxidant stress.     

Laboratory data in healthy volunteers: reference values, reference changes, screening and laboratory adverse event limits in Phase I clinical trials

Objective: Laboratory data are key evaluation procedures for Phase I clinical pharmacology for two reasons. Firstly, laboratory data are used within the screening process to exclude subjects with asymptomatic diseases, which could result in increased danger to themselves or confuse interpretation of the study results. Secondly, during study implementation, safety evaluation and in particular maximum tolerated dose determination have to be done by a case-by-case analysis, sometimes using laboratory adverse events (LAEs). Thus, relevant limits are needed to discriminate between a usual common variation and a significant abnormality, which is considered to be a LAE. This report presents laboratory data distribution, reference values and reference changes and, based on previously published new methods, suggests inclusion limits at screening and laboratory adverse event limits for analysis during study implementation. Subjects and methods: Nine hundred and twenty-seven young healthy male volunteers were recruited in one centre (Association de Recherche Thérapeutique). A standard screening process was carried out. Protocols were approved by the local ethics committee. Blood sampling was performed in the same conditions. Reference values (at screening and at baseline) were determined by a non-parametric procedure selecting 2.5% and 97.5% of the distribution of data. Reference changes were also defined as the 2.5–97.5% interval of distribution of the variations between the end of treatment and baseline. Inclusion limit and LAE limit methods of determination used had been specified in previous articles. Results: Detailed results of laboratory data distribution, reference values at screening and at baseline, reference changes, inclusion limits and LAE limits are presented in tables with number of subjects, mean, median, standard deviation, minimal and maximal values and the 2.5–97.5% interval for each laboratory parameter. Conclusion: The key aims of this paper are to provide clinical pharmacologists with data, reference values or changes obtained in the real conditions of Phase I study implementation, and to propose relevant limits, either for screening as inclusion limits, or during studies as LAE limits. Thus, these data, reference values and specific limits improve the capacity to screen healthy volunteers and to analyse LAEs during Phase I studies. Received: 30 July 1998 / Accepted in revised form: 25 November 1998     

Quantitation of adriamycin in plasma and urine: comparative study of radioimmunoassay and high-performance liquid chromatography methods

The response of tumours to adriamycin, and the cardiotoxicity of the drug, may be related to its pharmacokinetics and plasma levels. Rapid and sensitive methods of adriamycin determination in plasma and urine samples are thus needed. A comparative study shows that high-performance liquid chromatography with fluorimetric detection is a reliable and specific method, but it is relatively slow and sometimes lacks sensitivity. A commercially-available radioimmunoassay kit is convenient, but there is a cross reaction with the major metabolise adriamycinol and unless the assay is combined with an extraction step, it gives erroneously high results.     

Adriamycin: a possible indirect radiosensitizer of hypoxic tumor cells.

Multicellular spheroids grown in vitro provide a convenient model of nodular tumors for experimental tumor therapy studies. Adriamycin was found to inactivate cells grown as spheroids less efficiently than single cells, presumably due to enhanced cellular resistance analogous to the increased radioresistance observed when these cells are grown in close contact. Spheroid growth was retarded by a minimally toxic (0.005 mug/ml) chronic level of adriamycin; irradiation and exposure to that drug concentration were not found to be synergistic. Large adriamycin concentrations (0.5 mug/ml) present during radiation exposure produced a marked "radiosensitization," presumably due to the drug-inhibitng cellular oxygen consumption and thus permitting reoxygenation of the previously hypoxic spheroid cells.