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Methods and Equipment for Quality Control of Radiopharmaceuticals
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Rolf Zijlma, Danique Giesen, Yvette Kruiter, Philip H. Elsinga, Gert Luurtsema
It is important that a radiopharmaceutical used for i.v. injection must be physiological neutral. Therefore, the injection solution must be isotone. This means that the ion concentration is similar to that in plasma. To check the osmolality, a dedicated osmometer is needed.
Intracellular Double Labeling of Substantia Nigra and Pedunculopontine Neurons in in vitro Slice Preparation
Published in Avital Schurr, Benjamin M. Rigor, BRAIN SLICES in BASIC and CLINICAL RESEARCH, 2020
The superfusing Krebs-Ringer’s solution is composed as follows (mM): NaCl 124.0; KCl1.8; MgSO41.3; CaCl2 2.4; KH2PO41.24; NaHCO, 26.0; and D-glucose 10.0. The pH of the Krebs-Ringer’s solution is maintained at 7.3 to 7.4 by bubbling a gas mixture of 95% O2-5% CO2 through the perfusate. The osmolarity of the Krebs-Ringer’s solution is checked prior to an experiment with an osmometer and adjusted to 305 ± 5 mOsm. Glass pipettes filled with 3 M potassium acetate or biocytin (Sigma) in 0.05 M Tris buffer and 0.5 M KCl (pH 7.0 to 7.4) are used for recording.
Liposomes
Published in Danilo D. Lasic, LIPOSOMES in GENE DELIVERY, 2019
Surface potential is measured via ζ-potential. Particles migrate in an electric field, and their movement is detected either by the naked eye through a microscope or by laser (Doppler effect). Results are qualitatively very useful, but more for quality control than quantitative data on the structure of the complexes. Osmolality is normally checked by vapor pressure osmometer and pH with a standard pH meter.
Diurnal variations of tear film osmolarity on the ocular surface
Published in Clinical and Experimental Optometry, 2023
Hugo Pena-Verdeal, Carlos Garcia-Resua, Jacobo Garcia-Queiruga, Belen Sabucedo-Villamarin, Eva Yebra-Pimentel, Maria Jesus Giraldez
Another commonly used method of osmometry is to analyse diurnal variations in osmolarity based on the freezing point depression principle34−38,49,50; examples include the Clifton Osmometer (Clifton Technical Physics, Hartford, NY),22,63,64 the Advanced Tear Osmometer (Advanced Instruments Inc., Norwood, MA),65,66 the Fiske 210 osmometer (Advanced Instruments Inc., Norwood, MA)67,68 or the Multi-OSMETTE 2430 osmometers (Precision Systems, Inc., Natick, MA, USA)46,50 (Table 1). Except for the Advanced Tear Osmometer65,66 (no longer available on the European market) used in the study of Dalton et al.,38 none of those osmometers are specific to tear film osmolarity clinical assessment (all were regular laboratory osmometers).34,35,37,46
Diagnostic tests in dry eye
Published in Expert Review of Ophthalmology, 2019
Amy Kloosterboer, Harrison Isaac Dermer, Anat Galor
A hallmark of DE is increased tear osmolarity, and it is believed to be one of the central mechanisms of the disease [1,42]. Hyperosmolarity is a global indicator of DE, regardless of etiology[1]. Hyperosmolarity can occur in many situations including in the setting of decreased tear production, meibomian gland dysfunction, and exposure. As such, this test cannot distinguish between DE sub-types[42]. The TearLab osmometer non-invasively measures tear osmolarity after the chip collects a 50 nL sample of tears. This test must be performed prior to administration of ocular anesthetic and other types of tests. The osmometer is a handheld device with a single-use microchip at the tip that measures the electrical impedance of the tear fluid sample. To collect the sample, the osmometer’s tip is placed on the inferior lateral meniscus of the tear film, and the microchip passively absorbs the fluid (Figure 6(a)). After a few seconds, the osmometer will display the osmolarity measurement (Figure 6(b)). This procedure should be carried out in both eyes with the higher number obtained used as the determinant value. A reading of 308 mOsms/L or greater in either eye or a difference of greater the 8 mOsms/L between eyes indicates tear osmolarity disruption[43]. It is important to note that due to tear film instability, the values obtained with this test can be variable[44]. As with other clinical tests, the severity of symptoms may not correlate to tear osmolarity values. Therefore, this test should be used in conjunction with the overall clinical presentation to diagnose DE.
Assessing the impact of inadequate hydration on isotope-GFR measurement
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2019
Tania Telford, David F. Keane, Ashley E. Garner, Michael L. Waller, Andrew F. Scarsbrook, Mark C. Barnfield
Analysis of urine and serum allows for the measurement of a number of biochemical markers (sodium, creatinine, urea, osmolality) which are associated with fluid status [7,12–14]. Sodium, creatinine (enzymatic) and urea were measured on a Siemens Advia 2400 analyser (Siemens Healthcare Ltd, Surrey, UK). Osmolality was measured by freezing point depression on an Advanced Instruments 2020 osmometer (Vitech Scientific Ltd, West Sussex, UK). Serum creatinine was also used to calculate an estimate of GFR (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, which is generally accepted to be most accurate in subjects with a GFR above 60 ml/min/1.73 m2 [15]. On the day of each GFR test, a urine sample was taken from the second voiding of the day, as it was felt that the first one may occur before the participants have had their breakfast on the day of their per-guideline measurement, with the result that any differences between their urine samples might not be evident.