Concordance between direct and indirect measurements of free 25-OH vitamin D

Pilar Peris1, Xavier Filella2, Ana Monegal1

  • 1Hospital Clínic de Barcelona, IDIBAPS, CIBERehd, Spain.

Related Concept Videos

Role of Skin in Vitamin D Synthesis01:23

Role of Skin in Vitamin D Synthesis

The skin plays a crucial role in the synthesis of vitamin D, a vital nutrient for various physiological processes in the body. Vitamin D is unique because it can be synthesized in the skin through a series of chemical reactions triggered by exposure to ultraviolet B (UVB) radiation from sunlight.
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin...
8.3K
Measurement of Bioavailability: Pharmacodynamic Methods01:20

Measurement of Bioavailability: Pharmacodynamic Methods

Pharmacodynamic methods provide insights into a drug's effects on physiological processes over time and play a crucial role in understanding bioavailability and therapeutic efficacy. These methods can be broadly classified into acute pharmacological and therapeutic response approaches, each with distinct mechanisms and applications.The acute pharmacological response method directly correlates a drug's physiological effects, such as ECG or pupil diameter changes, to its time course in the body.
872
Drug Concentrations: Measurements01:23

Drug Concentrations: Measurements

Drug concentration is the quantity of a drug present in a biological sample. Measuring drug amounts in biological samples allows the clinician to understand how a drug is absorbed, distributed, metabolized, and excreted. Samples can be obtained through invasive or non-invasive methods. Invasive techniques involve surgical or parenteral interventions to gather blood, cerebrospinal fluid, or tissue biopsy. Conversely, non-invasive approaches provide samples like urine, feces, and saliva.
Plasma...
1.2K
Measurement of Bioavailability: Pharmacokinetic Methods01:30

Measurement of Bioavailability: Pharmacokinetic Methods

Pharmacokinetics is a vital branch of pharmacology that examines how drugs are absorbed, distributed, metabolized, and excreted by the body. Two key methodologies in pharmacokinetics are plasma drug concentration studies and urinary drug excretion analyses, both of which provide critical insights into a drug's therapeutic efficacy and bioavailability.Plasma Drug Concentration-Time StudiesPlasma drug concentration-time studies involve analyzing blood samples at specific intervals to quantify...
315
Microbial Growth Measurement: Indirect Methods01:27

Microbial Growth Measurement: Indirect Methods

Estimating microbial growth is essential for understanding population dynamics and environmental adaptations. Indirect methods provide valuable insights by measuring parameters such as turbidity, metabolic activity, and biomass, enabling efficient and reproducible assessments.During exponential growth, microbial cells scatter light proportionally to their biomass, a principle used in turbidity measurements. About one million cells per milliliter produce detectable scattering, which a...
1.6K