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Al-Kaleel A, Al-Gialani L. Sourcebook update: RBC hemolysis studies using a simple modified blood film technique. ADVANCES IN PHYSIOLOGY EDUCATION 2024; 48:427-429. [PMID: 38545643 DOI: 10.1152/advan.00033.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/14/2024] [Accepted: 03/24/2024] [Indexed: 05/01/2024]
Abstract
Water movement across the cell membrane is crucial, with red blood cells (RBCs) experiencing the flow of water in both directions at a rate of approximately 100 times their volume per second. This process typically results in no net water flow due to an equal balance of water movement in opposite directions, a phenomenon known as osmosis, driven by water potential or impermeant solute concentration. Understanding osmosis is essential for both physiology and medical practice, yet its complexity may not be effectively conveyed to the students through traditional teaching methods. This study presents a novel approach to observing the osmotic effect on RBCs using a simple, modified blood film technique. Aimed at enhancing educational understanding of cellular behavior in different osmotic environments, this method provides a practical hands-on learning experience. By applying various osmotic solutions to prepared blood films and observing the resultant morphological changes in RBCs under a microscope, this technique allows for direct visualization of osmosis in action.NEW & NOTEWORTHY This study presents an innovative teaching approach for understanding osmosis and its effects on red blood cells. Using a simple, modified blood film technique, students can visually observe and engage with the dynamic process of osmosis. This hands-on method enhances learning, making complex physiological concepts accessible and practical. Ideal for resource-limited settings, it bridges theoretical knowledge and practical application, transforming physiology education.
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Affiliation(s)
- Ali Al-Kaleel
- Faculty of Medicine, Cyprus International University, Nicosia, Cyprus
| | - Lubna Al-Gialani
- Faculty of Medicine, Cyprus International University, Nicosia, Cyprus
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2
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Kumar D, Gayen A, Chandra M. Membrane Permeability Dominates over Electrostatic Interactions in Dictating Drug Transport in Osmotically Shocked Escherichia coli. J Phys Chem B 2024; 128:4911-4921. [PMID: 38736363 DOI: 10.1021/acs.jpcb.3c08426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
To combat surging multidrug-resistant Gram-negative bacterial infections, better strategies to improve the efficacy of existing drugs are critical. Because the dual membrane cell envelope is the first line of defense for these bacteria, it is crucial to understand the permeation properties of the drugs through it. Our recent study shows that isosmotic conditions prevent drug permeation inside Gram-negative bacteria, Escherichia coli, while hypoosmotic stress enhances the process. Here, we unravel the reason behind such differential drug penetration. Specifically, we dissect the roles of electrostatic screening and low membrane permeability in the penetration failure of drugs under osmotically balanced conditions. We compare the transport of a quaternary ammonium compound malachite green in the presence of an electrolyte (NaCl) and a wide variety of commonly used organic osmolytes, e.g., sucrose, proline, glycerol, sorbitol, and urea. These osmolytes of different membrane permeability (i.e., nonpermeable sucrose and NaCl, freely permeable urea and glycerol, and partially permeable proline and sorbitol) clarify the role of osmotic stress in cell envelope permeability. The results showcase that under balanced osmotic conditions, drug molecules fail to penetrate inside E. coli cells because of low membrane permeabilities and not because of electrostatic screening imposed by the osmolytes. Contribution of the electrostatic interactions, however, cannot be completely overruled as at osmotically imbalanced conditions, drug transport across the bacterial subcellular compartments is found to be dependent on the osmolytes used.
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Affiliation(s)
- Deepak Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Anindita Gayen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Manabendra Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
- Center of Excellence: Tropical and Infectious Diseases, Gangwal School of Medical Sciences and Technology, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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Skarlovnik T, Lamut A, Hostnik G, Gole B, Bren U. Osmolality and Tonicity of Isotonic Beverages. Foods 2024; 13:1483. [PMID: 38790783 PMCID: PMC11120308 DOI: 10.3390/foods13101483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/02/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
This study aimed to measure and compare the osmolality and tonicity of isotonic beverages that can be bought on the Slovenian market. The main goal was to examine how good is the agreement between the measured osmolalities of the beverages and the requirements for isotonic beverages set up by EFSA. Osmolalities were measured with an osmometer using the freezing point depression method. Afterwards, two complementary methods for the observation of tonicity were developed. Erythrocytes were exposed to standard NaCl solutions of different osmolalities to observe their influence on the volume and shape of cells following the turbidity of the solution and the morphology of erythrocytes. These two methods enabled us to determine whether standard solutions were hypo-, iso-, or hypertonic. In this way, we found that the osmolality of 12 out of the 18 investigated isotonic beverages was in the range of 270-330 mOsm/kg, as required by EFSA. However, six samples did not meet this criterion and should therefore not have the label "isotonic" or be described as such. The measurements of turbidity of solutions indicated that most isotonic beverages exhibit a lower tonicity than standard NaCl solutions of identical osmolality. However, examination of the erythrocytes in isotonic beverages showed that the measurements were additionally complicated by the low pH values of these beverages. Finally, by demonstrating how different components of isotonic beverages pass through the erythrocyte membranes, we found that even isoosmolal beverages are often not isotonic, as the concentration of actively transported sugars in these beverages is relatively high.
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Affiliation(s)
- Tjaša Skarlovnik
- Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia; (T.S.); (G.H.)
| | - Andraž Lamut
- Meditop d.o.o., Ulica Vita Kraigherja 5, SI-2000 Maribor, Slovenia;
- Institute for Environmental Protection and Sensors, d.o.o., Beloruska ulica 7, SI-2000 Maribor, Slovenia
| | - Gregor Hostnik
- Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia; (T.S.); (G.H.)
| | - Boris Gole
- Faculty of Medicine, University of Maribor, Taborska ulica 8, SI-2000 Maribor, Slovenia;
| | - Urban Bren
- Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia; (T.S.); (G.H.)
- Institute for Environmental Protection and Sensors, d.o.o., Beloruska ulica 7, SI-2000 Maribor, Slovenia
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, SI-6000 Koper, Slovenia
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Dmitrieva NI, Boehm M, Yancey PH, Enhörning S. Long-term health outcomes associated with hydration status. Nat Rev Nephrol 2024; 20:275-294. [PMID: 38409366 DOI: 10.1038/s41581-024-00817-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2024] [Indexed: 02/28/2024]
Abstract
Body water balance is determined by fundamental homeostatic mechanisms that maintain stable volume, osmolality and the composition of extracellular and intracellular fluids. Water balance is maintained by multiple mechanisms that continuously match water losses through urine, the skin, the gastrointestinal tract and respiration with water gains achieved through drinking, eating and metabolic water production. Hydration status is determined by the state of the water balance. Underhydration occurs when a decrease in body water availability, due to high losses or low gains, stimulates adaptive responses within the water balance network that are aimed at decreasing losses and increasing gains. This stimulation is also accompanied by cardiovascular adjustments. Epidemiological and experimental studies have linked markers of low fluid intake and underhydration - such as increased plasma concentration of vasopressin and sodium, as well as elevated urine osmolality - with an increased risk of new-onset chronic diseases, accelerated aging and premature mortality, suggesting that persistent activation of adaptive responses may be detrimental to long-term health outcomes. The causative nature of these associations is currently being tested in interventional trials. Understanding of the physiological responses to underhydration may help to identify possible mechanisms that underlie potential adverse, long-term effects of underhydration and inform future research to develop preventative and treatment approaches to the optimization of hydration status.
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Affiliation(s)
- Natalia I Dmitrieva
- Laboratory of Cardiovascular Regenerative Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, Maryland, USA.
| | - Manfred Boehm
- Laboratory of Cardiovascular Regenerative Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, Maryland, USA
| | - Paul H Yancey
- Biology Department, Whitman College, Walla Walla, Washington, USA
| | - Sofia Enhörning
- Perinatal and Cardiovascular Epidemiology, Lund University Diabetes Centre, Department of Clinical Sciences in Malmö, Lund University, Malmö, Sweden
- Department of Internal Medicine, Skåne University Hospital, Malmö, Sweden
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Rodríguez-Dueñas WR, Bernal Muñóz HA, Rodríguez Burbano DC. A hands-on activity to teach the osmosis phenomenon. ADVANCES IN PHYSIOLOGY EDUCATION 2022; 46:251-258. [PMID: 35085036 DOI: 10.1152/advan.00186.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
This study proposes a hands-on activity as an experimental alternative method to teach biomedical engineering students the osmosis phenomenon. The students were guided along a learning path that involved their participation in the design and construction of a test device used to measure osmotic flow rate. Thereafter, an experiment was conducted with the test device. The students analyzed the obtained experimental values, which provided them with evidence of the functionality of the device. In addition, they were provided with the opportunity to suggest improvements and to propose alternatives to expand the use of the device to test other transport phenomena such as diffusion. Moreover, a student perception survey was conducted, and the results showed that this proposed plan allows for a better understanding of the phenomenon and stimulates the curiosity of students, improving the receptiveness, key in the learning process of the students.
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Krump L, Sayers RG, Kennedy E, O'Mahony J, Sayers GP. Evaluation of the optimal strong ion difference concentration of an oral electrolyte and buffering solution for the treatment of neonatal calf diarrhea. J Vet Med Sci 2021; 83:1715-1721. [PMID: 34544938 PMCID: PMC8636875 DOI: 10.1292/jvms.21-0391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
An observational study was conducted to comparatively assess the efficacy of three different oral rehydration and buffering solutions, differentiated by their strong ion difference (SID)
concentration, for treatment of neonatal calves with naturally acquired diarrhea. The SID concentrations tested were 100 mM, 170 mM and 230 mM for treatments SID100,
SID170 and SID230, respectively. Clinical assessment and blood gas analysis were completed for 18 diarrheic calves once pre- and twice post- (6 and 24 hr after) oral
administration with one of the three treatments. A repeated measure mixed model approach was used to analyze (a) the within-group efficacy of each treatment over time and (b) the
between-group comparison at each timepoint. SID230 treatment resulted in a significant increase in blood pH, HCO3−, BE, SID and Na+ at 6 and 24 hr
after treatment, and a significant decrease in AG and K+ by 24 hr after treatment. There were no significant changes in any of the blood gas parameters after treatment with
SID100 and SID170. SID230 treatment also resulted in blood gas parameter changes that were significantly different to the other two groups. These results
suggest that the optimum SID concentration for the treatment of calves with diarrhea is likely to be higher than current recommendations.
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Affiliation(s)
- Lea Krump
- Department of Biological and Pharmaceutical Sciences, Munster Technological University, Tralee, Co. Kerry, V92 CX88, Ireland
| | - Ríona G Sayers
- Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland
| | - Emer Kennedy
- Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland
| | - Jim O'Mahony
- Department of Biological Sciences, Munster Technological University, Cork, Co. Cork, T12 P928, Ireland
| | - Gearóid P Sayers
- Department of Biological and Pharmaceutical Sciences, Munster Technological University, Tralee, Co. Kerry, V92 CX88, Ireland
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Montrezor LH. The Physiological Court. MEDICAL SCIENCE EDUCATOR 2021; 31:155-160. [PMID: 34457875 PMCID: PMC8368945 DOI: 10.1007/s40670-020-01158-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/05/2020] [Indexed: 06/13/2023]
Abstract
Research has been important to prove that student achievement can improve when active methodologies are properly implemented, either in isolation or integrated with lectures. Here, active methodology was organized according to a student-centered collaborative design that involved group debate, described as a Physiological Court. The purpose of this work was to evaluate the performance and perception of medical students after integrating short lectures with collaborative work and debate. The activity was carried out with students (n = 50) from the 2nd year of medical school. The activity performed was related to the hypothalamus-pituitary-thyroid and hypothalamus-pituitary-adrenal axes. The students were instructed to prepare a study material on the proposed themes to be used on the day of the debate. At the activity day, the 2 students' groups (n = 25) were organized in the classroom so that they were face-to-face. Five days after, the students answered the cognitive monitoring test (CMT) which consists of 5 multiple choice questions (MCQ). Students also answered a question about their perception of the activities performed. Ninety-two percent of students showed a positive perception of the activities performed. After completion of the physiological court, 83 ± 4% of students achieved grades above 7.0 on CMT. The percentage of incorrect answers was 5 ± 1.3% in CMT. The association of 40-min lectures with active methodologies was positive for the perception and the performance of students in the second years of medical school related to the physiology of the endocrine systems.
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Affiliation(s)
- Luís Henrique Montrezor
- Department of Biological Science and Health – Biotechnology and Medicine, University of Araraquara – UNIARA, Rua Carlos Gomes, 1217, Araraquara, SP 14801-340 Brazil
- Medicinal Chemistry and Regenerative Medicine Group – QUIMMERA – UNIARA, Araraquara, SP Brazil
- Undergraduate Education Committee – Brazilian Society of Physiology (SBFis), São Paulo, Brazil
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Chow RS. Terms, Definitions, Nomenclature, and Routes of Fluid Administration. Front Vet Sci 2021; 7:591218. [PMID: 33521077 PMCID: PMC7844884 DOI: 10.3389/fvets.2020.591218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/02/2020] [Indexed: 12/14/2022] Open
Abstract
Fluid therapy is administered to veterinary patients in order to improve hemodynamics, replace deficits, and maintain hydration. The gradual expansion of medical knowledge and research in this field has led to a proliferation of terms related to fluid products, fluid delivery and body fluid distribution. Consistency in the use of terminology enables precise and effective communication in clinical and research settings. This article provides an alphabetical glossary of important terms and common definitions in the human and veterinary literature. It also summarizes the common routes of fluid administration in small and large animal species.
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Affiliation(s)
- Rosalind S Chow
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MI, United States
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Abstract
Dehydration of cells by acute hyperosmotic stress has profound effects upon cell structure and function. Interphase chromatin and mitotic chromosomes collapse ("congelation"). HL-60/S4 cells remain ~100% viable for, at least, 1 hour, exhibiting shrinkage to ~2/3 their original volume, when placed in 300mM sucrose in tissue culture medium. Fixed cells were imaged by immunostaining confocal and STED microscopy. At a "global" structural level (μm), mitotic chromosomes congeal into a residual gel with apparent (phase) separations of Ki67, CTCF, SMC2, RAD21, H1 histones and HMG proteins. At an "intermediate" level (sub-μm), radial distribution analysis of STED images revealed a most probable peak DNA density separation of ~0.16 μm, essentially unchanged by hyperosmotic stress. At a "local" structural level (~1-2 nm), in vivo crosslinking revealed essentially unchanged crosslinked products between H1, HMG and inner histones. Hyperosmotic cellular stress is discussed in terms of concepts of mitotic chromosome structure and liquid-liquid phase separation.
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Affiliation(s)
- Ada L Olins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, Portland, ME, USA
| | - Travis J Gould
- Department of Physics & Astronomy, Bates College, Lewiston, ME,USA
| | - Logan Boyd
- Department of Physics & Astronomy, Bates College, Lewiston, ME,USA
| | - Bettina Sarg
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Donald E Olins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, Portland, ME, USA
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The Role of Water Homeostasis in Muscle Function and Frailty: A Review. Nutrients 2019; 11:nu11081857. [PMID: 31405072 PMCID: PMC6723611 DOI: 10.3390/nu11081857] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 07/31/2019] [Accepted: 08/07/2019] [Indexed: 02/07/2023] Open
Abstract
Water, the main component of the body, is distributed in the extracellular and intracellular compartments. Water exchange between these compartments is mainly governed by osmotic pressure. Extracellular water osmolarity must remain within very narrow limits to be compatible with life. Older adults lose the thirst sensation and the ability to concentrate urine, and this favours increased extracellular osmolarity (hyperosmotic stress). This situation, in turn, leads to cell dehydration, which has severe consequences for the intracellular protein structure and function and, ultimately, results in cell damage. Moreover, the fact that water determines cell volume may act as a metabolic signal, with cell swelling acting as an anabolic signal and cell shrinkage acting as a catabolic signal. Ageing also leads to a progressive loss in muscle mass and strength. Muscle strength is the main determinant of functional capacity, and, in elderly people, depends more on muscle quality than on muscle quantity (or muscle mass). Intracellular water content in lean mass has been related to muscle strength, functional capacity, and frailty risk, and has been proposed as an indicator of muscle quality and cell hydration. This review aims to assess the role of hyperosmotic stress and cell dehydration on muscle function and frailty.
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