Oxygen Measurement
Lara Wijayasiri, Kate McCombe, Paul Hatton, David Bogod in The Primary FRCA Structured Oral Examination Study Guide 1, 2017
Haldane apparatus: This is utilised as an instrument for estimating the proportion of oxygen in expired gases.It consists of a burette containing a volume of gas.The gas is then exposed to a solution of pyrogallol (a powerful reducing agent able to absorb oxygen).The volume of the remaining gas is then measured.The reduction in gas volume indicates the quantity of oxygen absorbed by the pyrogallol.This system can also be used to measure CO2, but here potassium hydroxide solution is used instead of pyrogallol.
Controlled and Reproducible Fixation of the Lung for Correlated Studies
Joan Gil in Models of Lung Disease, 2020
The most important prerequisite is that the instillation pressure with respect to the level of the supine lung should be defined and generally in the order of 20 cm of water. In small rodents, this is best met by vertically attaching a ruler to the table with a 20 cm mark aligned with the level of the fixative contained inside a burette. As the fluid flows into the lung, the pressure can be kept constant either by lowering the operating table, if it is mounted on top of a laboratory jack, or by raising the burette so that the 20 cm mark and the fluid level are flush. The fluid is allowed to pour until it spontaneously stops. After several seconds, the airway is clamped to prevent loss of fluid and the lung is dissected from the chest and immersed in a beaker containing the same fixative used to fill the air spaces. Care must be taken to insure that the lungs in the beaker are well covered with fixative: they will sink spontaneously only in the rare cases when no air was trapped inside. The lungs can be turned around inside the fluid with the apex facing the bottom or a lead weight (from a fishing outfit) can be attached to the tracheal ligature to make them sink. The lungs should be allowed to fix for at least 1-2 h; alternatively, they can remain in the fixative without harm over the weekend. To prevent lipid extraction, the beaker should be stored in a refrigerator.
Chloramphenicol and Thiamphenicol
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
The chloramphenicol sodium succinate ester is used for parenteral administration. It is a highly water-soluble preparation that can be easily administered by either the intramuscular or the intravenous route. This ester has no antibacterial activity, but after administration it is converted to active chloramphenicol. For intramuscular administration, the contents of a 1.2-g vial may be dissolved in as little as 2.0 ml of water for injection, resulting in a 40% solution. For intermittent intravenous injections, it is recommended that a more dilute 10% solution be used, and that the dose be slowly injected intravenously over 1 minute. Rapid intravenous injection of a more concentrated solution is not dangerous, but the patient may experience an intensely bitter taste lasting a few minutes, and concentrated solutions may also cause thrombophlebitis. The duration of the infusion is an important factor in determining the percentage of the succinate that is excreted in the urine before it has been converted to active chloramphenicol. To make valid comparisons of chloramphenicol serum levels, the rate of infusion from the burette should be standardized. For adults, the contents of the burette are commonly infused over a period of 30 minutes.
Gastroretentive bilayer film for sustained release of atorvastatin calcium and immediate release of amlodipine besylate: pharmaceutical, pharmacokinetic evaluation, and IVIVC
Published in Pharmaceutical Development and Technology, 2020
Amit Porwal, Harinath Dwivedi, Kamla Pathak
Modified Rosette Rice Test apparatus was used to perform in vitro drug release study (Gohel et al. 2004; Singh and Pathak 2016). The modified beaker was filled with 70 ml of phosphate buffer, pH 4.5 with 0.02% w/v Tween 80 into which the films were placed as shown in Figure 1. A pH of 4.5 was selected which represents the midvalue of fed state pH ranging from 2.5 to 6.5. The test was performed at 37 ± 0.5 °C and 75 rpm. From a burette, fresh dissolution medium was added at a flow rate of 2 ml/min. A 5 ml of sample was withdrawn at 0, 5, 10, 15, 20, and 25 min and filtered. To maintain the sink condition, an equal volume of fresh media was replaced immediately after withdrawing test sample into the beaker. The samples were diluted suitably and analyzed spectrophotometrically (UV 6300 Double beam Spectrophotometer) at 225 nm. All experiments were performed in triplicate.
Prior exposure to nutritive and artificial sweeteners differentially alters the magnitude and persistence of sucrose-conditioned flavor preferences in BALB/c and C57BL/6 inbred mouse strains
Published in Nutritional Neuroscience, 2019
Sam LaMagna, Kerstin Olsson, Deena Warshaw, Gabriela Fazilov, Ben Iskhakov, Agata Buras, Richard J. Bodnar
At 4 weeks of age, the mice were individually housed in plastic cages (30 × 20 × 15 cm3) with stainless steel tops throughout the study and received burettes of sucrose (10%, 5 M, 5 F of each strain), saccharin (0.2%, 5 M, 5 F of each strain) or water (5 M, 5 F of each strain) solutions in their cages in addition to pre-weighed chow and water continuously for 4 weeks. The burettes were made by retrofitting a leur slip tip syringe (100 ml, 1 ml gradations), silicone sealant, a rubber cork, and a straight sipper tube (63 mm in length, 8 mm in width, Lab Products, Seaford, DE). The burette was built by removing and drilling a hole into the tip of the syringe, inserting the cork and sipper tube into the hole, and securing them with the sealant that also prevented leaking. The burette was firmly secured to the stainless steel top of the cage by a taut metal spring (100 mm) with clips at each end that affixed to the cage top (e.g.14,15,25). Body weights were measured before exposure, and at the end of each of the 4 weeks of adolescent exposure to the solutions. Burette, chow, and water intakes were measured twice each week, and weekly intakes were calculated. Because the animals were housed in their home cages with bedding to minimize stress, spillage of uneaten chow could not be assessed.
Quantification of corneal transparency in post‐mortem human corneas using laser scatter image analysis
Published in Clinical and Experimental Optometry, 2019
Aarwin Joshua Richard, Jeyanth Suresh Rose, Sanita Korah, Mahima Keziah, Shalin Arambhan, A Arthi, Sm Jaisakthi, V Vijayarajan
The modified artificial anterior chamber with the corneal button was then held in a horizontal position using a burette clamp which was fixed over a lab stand at a fixed distance from the projection screen. The laser source (Class III Helium‐Neon Laser, 632 nm, of 2.5 mW) was placed 30 cm away from the modified artificial anterior chamber maintainer such that the laser light passed through the back of the modified artificial anterior chamber, through the centre of the cornea and the image was projected onto the screen. A camera of 16 megapixels with the standardised setting was mounted on the tripod stand. This was then introduced in between the laser source and the modified artificial anterior chamber in such a way that it did not block the laser light. The camera was adjusted so that the image of the laser fell in the central grid of the camera (Figure 1). Three consecutive images were captured for each cornea to check for consistency. The time taken to mount the cornea in the modified anterior chamber and capture the laser image was less than 10 minutes.
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