1,721,093 research outputs found
Vitamin D: From measurement problems to clinical implications
No full textLa vitamina D svolge un ruolo cruciale nel metabolismo fosfo-calcico, e molti altri importanti effetti protettivi su diversi distretti ed organi si sono evidenziati negli ultimi anni, tanto da farla considerare un vero e proprio ormone. La sua azione si svolge tramite una serie di metaboliti che vengono attivati attraverso vari passaggi. È molto importante quindi poterne misurare i livelli. La scelta dei valori di riferimento non può essere effettuata considerando un campione della cosiddetta popolazione “normale”, perché gli stati carenziali sono molto diffusi. La determinazione della vitamina D, però, presenta diverse problematiche, legate sia alla scelta del metabolita da valutare, sia al sistema con cui viene trasportata in circolo. Infatti il metabolita più rappresentativo dello stato vitaminico, la 25(OH) vitamina D, circola strettamente legato ad una proteina di trasporto (VDBP), che ne ostacola il dosaggio. Si sono sviluppati, alla luce della sempre maggior importanza che il suo ruolo sembra rivestire, molti metodi di misurazione, sia indiretti (immunochimici) che diretti (HPLC, spettrometria di massa MS). I metodi indiretti presentano il grande vantaggio della possibilità dell’automazione, ma tendono in generale a sottostimare, mentre i metodi diretti sono più accurati, ma soggetti a maggiori interferenze. La valutazione clinica del paziente non può prescindere dalla conoscenza di queste problematiche, anche se molto si sta facendo per ridurre le differenze tra metodi e giungere ad una loro standardizzazione, che permetterà di ridurre la variabilità e quindi l’incertezza del dato.Vitamin D plays a crucial role in phospho-calcic metabolism, and in recent years many other important
protective effects have been highlighted, so it could be considered a true hormone. Its action is due to a
series of metabolites that are activated through various steps. It is very important therefore to measure
levels of this vitamin. The choice of the reference values cannot be done by taking a sample of the socalled
“normal” population, because deficiency states are very prevalent. The determination of vitamin
D, however, presents difficulties, related both to the choice of the metabolite to be evaluated, and to
the system by which it is transported into the circulation. In fact, the most representative metabolite
of vitamin status, 25 (OH) vitamin D, circulates tightly bound to a carrier protein (VDBP), which hinders
the assay. In light of the increasing importance of vitamin D many methods of measurement, both
indirect (immunochemical) and direct (HPLC, mass spectrometry-MS) have been developed. Indirect
methods have the advantage of automation, but generally tend to underestimate, while direct methods
are more accurate, but subject to greater interference. The correct clinical evaluation of a patient cannot
ignore these issues, although much is being done to reduce the differences between methods and
come to a standardization
Improvement of Quality of Life With Supervised Exercise Training in Subjects With Type 2 Diabetes Mellitus
No full text[No abstract available
Biomarkers in emergency medicine
Get PDFResearchers navigate the ocean of biomarkers searching for proper targets and optimal utilization of them. Emergency medicine builds up the front line to maximize the utility of clinically validated biomarkers and is the cutting edge field to test the applicability of promising biomarkers emerging from thorough translational researches. The role of biomarkers in clinical decision making would be of greater significance for identification, risk stratification, monitoring, and prognostication of the patients in the critical- and acute-care settings. No doubt basic research to explore novel biomarkers in relation to the pathogenesis
is as important as its clinical counterpart. This special issue includes five selected research papers that cover a variety of biomarker- and disease-related topics
The methionine analog S-methylthiocysteine stimulates neutral amino acid transport by isolated brain microvessels
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Effects of different modes of exercise training on glucose control and risk factors for complications in type 2 diabetic patients: a meta-analysis: response to Snowling and Hopkins
No full textOPIOID PEPTIDE TRANSPORT MODULATION IN ISOLATED BOVINE BRAIN MICROVESSELS
No full textS. MARINELLA - S. SEVERA, ROM
Effect of ammonia on amino acid uptake by brain microvessels
No full textNH4+ ions, at a concentration (0.25 mM) similar to that found in the plasma of patients with hepatic encaphalopathy, cause, in vitro, a significant stimulation of the uptake by brain microvessels of large neutral amino acids, without any effect on the uptake of α-methylaminoisobutyric acid, glutamic acid, or lysine. Such a stimulation occurs essentially through an increase of the maximal transport capacity (V(max)) of the saturable component. It is apparently mediated by the intracellular formation of glutamine, which is then exchanged, through the L-system of transport, for large neutral amino acids such as leucine, phenylalanine, or tyrosine. At higher concentrations (≥0.5 mM), NH4+ ions cause also a decrease of carrier affinity for neutral amino acids, which counteracts the stimulatory effect on their uptake
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