(Osm) A unit of osmotic pressure used in physical chemistry, cell biology, and medicine.
Definition: 1 osmole is the osmotic pressure of a one molar solution (that is, a solution with a concentration of one mole per liter of solvent) of a substance that does not dissociate.
If chemical solutions are separated by a semipermeable membrane (a membrane that resists the passage of dissolved substances but permits the passage of the solvent, usually water), then the solvent will diffuse across the membrane to equalize the concentrations. This process is called osmosis.
Solutions with higher concentrations of dissolved substances are said to have higher osmotic pressure than solutions having lower concentrations; thus the solvent moves from an area of low osmotic pressure to an area of higher osmotic pressure.
Osmotic pressure depends on the total number of dissolved particles, so for a substance that dissociates into two ions, such as ordinary salt (sodium chloride), a one molar solution has an osmotic pressure of 2 osmoles. In practice, most measurements are in milliosmoles (mOsm). Typical values range from 20 mOsm for fresh water through 290 mOsm for typical human blood plasma to 1010 mOsm for salt water from the open ocean.

See also Part Per Million, and Mole.

[This entry is marked for removal.]

'POINT Biomedical was a privately held pharmaceutical company, founded in 1996 to pursue technologies related to imaging and drug delivery. POINT's core technology was based upon an ultrasonically responsive two-layer, biodegradable microsphere or BiSphere™. One of the most important features of this technology is the ability to noninvasively trigger the BiSpheres™ to release their contents at sites within the body using externally generated pulses of ultrasound. From this basic platform, POINT was developing a pipeline of products that leverage the unique properties of the BiSphere™ technology in the areas of imaging and therapeutics. POINT has initially focused development of this platform on the assessment of tissue specific blood flow. The lead product, CARDIOsphere®, is a pharmaceutical agent that will enable cardiologists to perform myocardial perfusion imaging studies in the office setting using ultrasound rather than more expensive and cumbersome nuclear medicine (or radioisotope) techniques.'
'According to BioSpace, Tom Feldman, ex-CEO of Point BioMedical, the company's lead investor, Vendanta Capital has chosen not to follow through with the second half of its $50 million private equity financing. Point BioMedical has withdrawn the new drug application for its molecular imaging agent CARDIOsphere and is liquidating its assets to avoid a formal bankruptcy proceeding in 2008.'

Different stages of testing drugs in humans for example ultrasound contrast agents, from first application in humans through limited and broad clinical tests, to postmarketing studies. Preclinical trials are the testing in animals.

See also Drug Development and Approval Process USA, Food and Drug Administration, and European Medicines Agency.

(PACS) A system used to communicate and archive medical imaging data, mostly images and associated textural data generated in a radiology department, and disseminated throughout the hospital. A PACS is usually based on the DICOM (Digital Imaging and Communications in Medicine) standard.

The main components in the PACS are: acquisition devices where the images are acquired;
Acquisition devices, which acquire their data in direct digital format, like a MRI system, are most easily integrated into a PACS.
Short term archives need to have rapid access, such as provided by a RAID (redundant array of independent disks), whereas long term archives need not have such rapid access and can be consigned, e.g. to optical disks or a magnetic.
High speed networks are necessary for rapid transmission of imaging data from the short term archive to the diagnostic workstations. Optical fibre, ATM (asynchronous transfer mode), fast or switched Ethernet, are examples of high speed transmission networks, whereas demographic textural data may be transmitted along conventional Ethernet.
Sophisticated software is a major element in any hospital-wide PACS. The software concepts include: preloading or prefetching of historical images pertinent to current examinations, worklists and folders to subdivide the vast mass of data acquired in a PACS in a form, which is easy and practical to access, default display protocols whereby images are automatically displayed on workstation monitors in a prearranged clinically logical order and format, and protocols radiologists can rapidly report worklists of undictated examinations, using a minimum of computer manipulation.

Ultrasound technology has evolved significantly, providing sonographers with a wide range of ultrasound machines. As technology has advanced, portable ultrasound equipment, including handheld ultrasound systems, have emerged in the field of medical imaging. However, these devices may have limited imaging capabilities and reduced image quality compared to larger systems.
Types of ultrasound systems compiled according to their portability:

In summary, pros and cons of portable ultrasound machines:

See also Ultrasound Accessories and Supplies, Environmental Protection, Sonographer, Ultrasound Technology and Equipment Preparation.