Biomedical subjects

L Nadal

Publications and source records attributed to L Nadal.

7 recordsLinked to original sources

PubMed2004

Antifungal activity of actinomycetes from Cuban soils.

This study reports on the capacity of actinomycete strains isolated from Cuban soils to produce antifungal agents. The antimicrobial activities were determined by susceptibility disk assay methods. We isolated 563 different actinomycetes and 286 produced compounds with antifungal activity. Our screening method indicated the presence of many possible polyene macrolide antibiotics and the important antifungal activity in the soils rich in minerals.

Actinobacteria↗

PubMed1999

Mitochondrial creatine kinase functional development in post-natal rat skeletal muscle. A combined polarographic/31P NMR study.

Mitochondrial creatine kinase (Mi-CK) function in viable mitochondria from developing rat skeletal muscle was assessed both by polarographic measurements of creatine-induced respiration and 31P NMR spectroscopy measurements of phosphocreatine (PCr) synthesis. Creatine-induced respiration was observed in very young rats and increased by 50% to 35 days of age. PCr synthesis was present in 7 day old animals and increased by 300% reaching levels measured in 35 day and adult muscle. Unlike reports showing Mi-CK enzymatic activities but no mitochondrial function in several situations, a concomitant progression of enzymatic activity and mitochondrial function was evidenced during the developmental stages of skeletal muscle Mi-CK in altricious animals. These results correlated with the progressive pattern of muscle differentiation during development of motricity in such animals. The observation that Mi-CK is functional in skeletal muscle mitochondria very early after birth, strongly favors the notion that adaptations in skeletal muscle of Mi-CK knock-out mice occur early.

Animals↗

PubMed1998

Quantification of plasma lipoprotein fractions by wavelet transform time-domain data processing of the proton nuclear magnetic resonance methylene spectral region.

Quantitative analysis of lipoprotein major fractions, LDL, VLDL and HDL, is of great interest for medical purposes, for instance in liver or heart diseases, diet management or cancer. The presently available biochemical methods require time consuming ultracentrifugation. A potentially automated method is proposed, using time domain quantification by Wavelet Transform (WT-NMR) method. The aim of the present study was to evaluate, on a preliminary series of nine human plasmas, the potential interest of WT-NMR in the quantification of both NMR-visible lipids and total lipoprotein fractions. The correlation coefficients between low and intermediate density (LDL+IDL), very low density (VLDL) and high density (HDL) lipoprotein visible lipid quantifications, obtained on nine human plasmas with WT-NMR and standard biochemical methods, were 0.79, 0.84 and 0.92, respectively. For the total lipoprotein assay, i.e. including an estimation of non NMR-visible protein and free cholesterol, the correlation between WT-NMR and the biochemistry were 0.87 for LDL+IDL, 0.81 for VLDL and 0.88 for HDL.

Blood Proteins↗

PubMed1997

Proton and phosphorus nuclear magnetic resonance spectroscopy of human brain tumor extracts with automatic data classification: a preliminary study.

High-resolution one-dimensional proton and phosphorus and two dimensional COSY proton Magnetic Resonance Spectroscopy were used to investigate the lipid and carbohydrate metabolism of human brain tumors. Sixteen meningioma (MG) (benign tumors) and ten glioblastoma (GB) (malignant tumors) samples from brain surgery were treated for dual extraction of lipidic and aqueous phases before NMR processing. A highly significant variation of the 1H metabolite spectral pattern was observed between benign and malignant tumors. Double extraction method combined with both 1H and 31P NMR in vitro analyses provided a large set of biochemical information which may be statistically analyzed to elucidate tumor-specific biochemical pathways and to improve interpretation of in vivo spectra.

Brain Neoplasms↗

PubMed1996

Phosphocreatine synthesis by isolated rat skeletal muscle mitochondria is not dependent upon external ADP: a 31P NMR study.

Phosphocreatine synthesis by mitochondria isolated from rat skeletal muscle was determined in presence of inorganic phosphate, creatine, and either ATP or ADP, using 31P NMR spectroscopy in a new protocol maintaining mitochondria for several hours in a well-coupled state. Maximal velocity of phosphocreatine synthesis was identical with 0.4 mM of ADP or 0.5 mM ATP at a rate of 0.063 mM/min. External ATP and ADP were always present in the spectra, demonstrating that in skeletal muscle cells as in heart muscle cells, mitochondrial creatine kinase coupled to translocase has a very strong amplifying effect on oxidative phosphorylation and converts external inorganic phosphate and creatine into phosphocreatine without net adenine nucleotide consumption. Therefore, adenine nucleotides can be considered as cofactors rather than regulators of mitochondria metabolism. This is in agreement with the "phosphocreatine-circuit" theory.

Adenosine Diphosphate↗

PubMed1975

Do elephants ever forget?

Three adult female elephants (Elephas maximus) were tested on a light-dark discrimination problem with an 8-yr intertrial interval. The first subject took only 6 min to reach criterion and made only two errors, suggesting remarkable retention. The other two subjects were found to have visual anomalies that would have gone undetected without this research.

Animals↗

PubMedDate not supplied

Proton nuclear magnetic resonance spectroscopy of plasma lipoprotein: technical problems and potential interest in cancer disease.

This paper reviews several methods presently available for analysing lipoprotein NMR spectra. Two main steps can be distinguished: NMR signal processing and data analysis. Time domain (wavelet transform) and frequency domain (curve fitting) signal processing methods are compared. Statistical methods of data analysis (Ascending Hierarchical Classification, Correspondence Analysis and Principal Component Analysis) have been tested on simulated NMR data of plasma lipoprotein with different numbers of sampling points and different noise levels. These few examples clearly attest that the NMR approach to complex "mixture" (such as body fluids) analysis is emerging from its infancy. New interest in plasma lipoprotein analysis in cancer biology is finally discussed in the light of previous clinical and experimental results and of understanding of lipid metabolism in cancer.

Humans↗