Einleitung: Die Kationen-Anionen Bilanz (DCAB) des Futters modifiziert den Säure-Basen Status von Tieren und findet Anwendung in der Prävention von Milchfieber bei Kühen, MMA bei Sauen und Urolithiasis bei Haustieren. Durch die Veränderung des Kationen-Anionen-Verhältnisses in Futterrationen können biologische Prozesse beeinflusst werden, der Stickstoffmetabolismus. Ziel der Untersuchung: Die vorliegende Studie befasst sich mit der Frage, ob eine kaliumbedingte Variation der DCAB des Futters für wachsende Schweine einen Einfluss auf bestimmte Parameter des Säure-Basen-Haushaltes und möglicherweise auch auf die Stickstoffbilanz hat. Materialien und Methoden: Dem Versuch standen insgesamt 38 männlich kastrierte Mastschweine (Dreirassen-Kreuzung von Pietrain x Deutsches Edelschwein x Deutsche Landrasse) mit einem Einstallungsalter von ca. 12 Wochen und einer Lebendmasse von 17,3 kg bis 30,3 kg zur Verfügung. In randomisierter Reihenfolge erfolgte die Zuteilung der Schweine zu den acht Versuchsfuttern; Rohproteingehalt von 140 g kg-1 Futter und 200 g kg-1 Futter, sowie je 4 g, 10 g, 14 g oder 20 g Kalium kg-1 Futter. Die Versuchsfutter wiesen eine konstante Konzentration an Natrium und Chlorid auf. Die Hauptfutterkomponenten waren Mais und Weizen. Die beiden Rohproteingehalte wurden durch unterschiedliche Sojaextraktionsschrot- und Maisklebermengen gewonnen. Über Kaliumhydrogencarbonat (KHCO3) und Kaliumchlorid (KCl) resultierte die Einstellung der genannten Kaliumkonzentrationen sowie der vier DCAB-Stufen von -125 mEq kg-1, 66 mEq kg-1, 168 mEq kg-1, und 342 mEq kg-1 Futter. In einer Adaptionsphase von 15 Tagen gewöhnten sich die Scheine an das Versuchsfutter und die Umgebung. Die Einstallung erfolgte in Einzelboxen und die Versuchstiere erhielten Wasser ad libitum. Während der anschießenden zwei Bilanzphasen von je fünf Tagen wurden die Schweine in Bilanzkäfigen gehalten. Zwischen den beiden Bilanzphasen kam es zu einer fünftägigen Pause ohne Änderung der Fütterung. In der Bilanzzeit wurden der gesamte Harn und Kot der Tiere gesammelt sowie der dazugehörige pH-Wert kontinuierlich bestimmt. Harn- und Kotaliquots wurden für Stickstoff- und Elektrolytanalysen einbehalten. Jede fünftägige Bilanz endete mit der Gewinnung einer Blutprobe von jedem Schwein aus der Vena jugulares zur Bestimmung von Kalium, Natrium, Chlorid, pH-Wert, Hydrogencarbonat, Basenüberschuss und Aminosäuren. Ergebnisse: Kalium hat einen Einfluss auf den Harn pH-Wert. Analog zur steigenden Kaliumaufnahme (DCAB↑) wurden die Harn pH-Werte basischer (-125 mEq kg-1 Futter = Ø 5,93; 342 mEq kg-1 Futter = Ø 8,37). Die Blut pH-Werte, die im Durchschnitt bei 7,21 lagen, wie auch die Hydrogencarbonat- und Basenüberschusskonzentration, reagierten aufgrund der renalen Kompensation nicht wesentlich auf die unterschiedlichen DCAB im Futter. Die dazugehörigen Kot pH-Werte waren bei -125 mEq kg-1 Futter und 66 mEq kg-1 Futter um 0,16 höher als bei den anderen beiden DCAB-Stufen. Die Stickstoffaufnahme variierte zwischen 0,90 g kg-1KM d-1 und 1,22 g kg-1KM d-1 aufgrund der beiden Rohproteingehalte (14 und 20 %) in den Versuchsrationen. Eine Senkung der DCAB im Futter bewirkte eine Verbesserung der Stickstoffverdaulichkeit von 86,1 % auf 89,9 % (p<0,05). Hingegen zeigten die Diäten mit der kaliumärmsten Konzentration die höchsten renalen Stickstoffexkretionen von 442 mg kg-1KM d-1 gegenüber den anderen drei Kaliumkonzentrationen (345 mg kg-1KM d-1). In Folge dessen ergibt sich eine Stickstoffretentionssteigerung mit zunehmender DCAB im Futter. Jedoch wurde bei 66 mEq kg-1 Futter (Kalium 10 g kg-1 Futter) die höchste Stickstoffretention von 643 mg kg-1KM d-1 festgestellt. Die Untersuchung der Blutproben ergab keine Beeinflussung der Summe aller Aminosäuren, die bei ø 44,66 mg dl-1 lag. Die Summe der essentiellen Aminosäuren war bei einer DCAB von 66 mEq kg-1 Futter im Blut geringer als bei den übrigen Variationen. Einige Parameter der Elektrolytbilanzen waren zwischen den Futtervariationen verschieden: Bei dem Versuchsfutter mit einer DCAB von -125 mEq kg-1 Futter (Kalium 4 g kg-1 Futter) schieden die Schweine Na: 2,83 mg kg-1KM d-1 und Cl: 1,54 mg kg-1KM d 1 weniger mit dem Kot und Na: 7,05 mg kg-1KM d-1 weniger mit dem Harn aus gegenüber den weiteren Versuchsgruppen. Die renale Chloridexkretion zeigte keine Variabilität. Die renale, als auch die fäkale Kaliumausscheidung nahm analog zur DCAB des Futters zu (DCAB im Futter: -125 mEq kg-1; 66 mEq kg-1; 168 mEq kg-1; 342 mEq kg-1; K-Abgabe in mg kg-1KM d-1, renal: 74,0; 273,3; 431,1; 609,1; fäkal: 24,5; 31,2; 32,6; 44,0). In der Gesamtheit betrachtet ergibt sich für die Natrium- und Chloridretention keine richtungsweisende Beeinflussung im Zusammenhang mit der DCAB der Versuchsrationen. Die Kaliumretention hingegen stieg von 66,5 mg kg-1KM d-1 (-125 mEq kg-1 Futter) auf 167,0 mg kg-1KM d-1 (342 mEq kg-1 Futter) an, was nicht von den Kaliumkonzentrationen im Blut wiedergegeben wurde. Entsprechendes gilt für die Natrium- und Chloridkonzentrationen im Blut. Schlussfolgerungen: In der Alkalisierung des Harns zeigt sich, dass der DCAB des Futters Einfluss auf den Säure-Basen Status nimmt. Der systemische pH-Wert blieb aufgrund der Puffersysteme des Organismuses weitestgehend unberührt. Durch die KHCO3-Zulagen wurde das intragastrale bzw. das intestinale pH-Milieu verändert, was sich in der schlechteren Verdaulichkeit von Stickstoff bei höherer DCAB wiederspiegelt. Die Stickstoffretention steht in keinem Zusammenhang mit der Stickstoffverdaulichkeit. Mit dem DCAB von 66 mEq kg-1 Futter bzw. K: 10 g kg-1 Futter wurde die beste Retention für Stickstoff beobachtet. Die täglichen Gewichtszunahmen und die Futterverwertungen der Versuchsschweine konnten dies allerdings nicht reflektieren. Anzumerken sei, dass für einen eindeutigen Effekt auf die tägliche Zunahme eine längere Beobachtungsphase notwendig wäre (Sprung der täglichen Zunahmen von 520 g für -125 mEq kg-1 Futter auf das Niveau von 692 g für 66 mEq kg-1 Futter und mehr). Eine Empfehlung in Anlehnung an diese Studie wäre ein DCAB-Wert um die 66 mEq kg-1 Futter. Wird dieser Wert erhöht sinkt die Stickstoffverdaulichkeit auf der anderen Seite verschlechtert sich die Stickstoffretention bei Verringerung der DCAB. / Initiation: The dietary cation-anion balance (DCAB) of the feed modifies the acid-base balance and is used in the prevention of milk fever in cows, MMA in sows and urolithiasis in pets. The modification of the cation-anion ratio in diets can take an impact on biological processes inducting nitrogen metabolism. Objectives of investigations: This study objectively clarifies, whether potassium-based variation of the DCAB of the food has an influence on certain parameters of the nitrogen balance and the acid-base balance. Materials and Methods: The trial covered a total of 38 male castrated pigs (three racial crossing Pietrain x Large White x German Landrace) with a housing-age of approximately 12 weeks and a live weight of 17.3 kg to 30.3 kg. In randomized order, the pigs were allocated to the eight experimental feed: crude protein content of 140 g per kg feed and 200 g per kg feed, as well as 4, 10, 14 or 20 g of potassium per kg feed. The sodium and chloride concentrations in the feed were kept constant. The main food components were corn and wheat. The two crude protein levels were determined by various soybean meal and corn gluten quantities. Potassium hydrogen carbonate (KHCO3) and potassium chloride (KCl) were used to establish the four DCAB levels of -125 mEq kg-1, 66 mEq kg-1, 168 mEq kg-1, and 342 mEq kg-1 feed. In an adaptation period of 15 days pigs were accustomed to food and environment. They were kept in individual pens and were given water ad libitum. During the following two trial phases of five days each, the pigs were kept in balance cages. Between the two trial periods, there was a break of five days (no diet change). During the trial period all urine and excrement of the animals was collected, and the respective pH-value was continuously measured. Aliquots of urine and faeces were used in nitrogen and electrolyte analyses. At the end of each five-day record a blood sample from the jugular vein was taken from each pig for determination of potassium, sodium, chloride, pH-value, hydrogen carbonate, base excess, and amino acids. Results: Potassium has a significant influence on renal pH values. Analogous to increasing potassium intake (DCAB ↑), the urine pH value turned more basic (-125 mEq kg-1 feed = 5.93; 342 mEq kg-1 feed = 8.37). The blood pH levels, which averaged at 7.21, as well as the hydrogen carbonate concentration and base excess concentration, did not respond to the different DCAB in the feed because of the renal compensation. The associated feces pH values at -125 mEq kg-1 feed and 66 mEq kg-1 feed were higher by 0.16 than at the other two DCAB levels. The nitrogen intake varied between 0.90 g kg-1BM d-1 and 1.22 g kg-1BM d-1, based on both crude proteins (14 % and 20 %) in the experimental feeds. A reduction of DCAB in the feed resulted in an improvement of the nitrogen digestibility from 86.1 % to 89.9 % (< 0.05). However, diets with the lowest concentration of potassium showed the highest renal nitrogen excretions of 442 mg kg-1BM d-1 compared to the other three concentrations of potassium (345 mg kg-1BM d-1). As a consequence, nitrogen retention increases with increasing DCAB in the feed. However, the highest nitrogen retention of 643 mg kg-1KM d-1 was found with a 66 mEq kg-1 diet (potassium 10 g kg-1 feed). The examination of blood samples revealed no influence on the sum of the amino acids, which was 44.66 mg dl-1. The sum of the essential amino acids was reduced at a DCAB of 66 mEq kg-1 in blood, similar to the other variations. Some parameters of the electrolyte balances were different between the feed variations: In the experimental diet with a DCAB of -125 mEq kg-1 diet (potassium 4 g kg-1 feed), the pigs eliminated Na: 2.83 mg kg- 1BM d-1 and Cl: 1.54 mg kg– 1BM d-1 less in the feces and Na: 7.05 mg kg- 1KM d-1 less in the urine with respect to the other experimental groups. Renal chloride excretion showed no variability. The renal and fecal excretion of potassium increased proportionally to the DCAB of the feed (DCAB in the feed: -125 mEq kg-1, 66 mEq kg-1, 168 mEq kg-1; 342 mEq kg-1; K output in mg kg- 1BM d-1, renal: 74.0; 273.3; 431.1; 609.1; fecal: 24.5; 31.2; 32.6; 44.0). When viewed against the totality of results for the sodium and chloride retention, there were no trend-setting influences in connection with the DCAB of the experimental diets. The potassium retention, however, increased from 66.5 mg kg- 1BM d-1 (-125 mEq kg-1 feed) to 167.0 mg kg- 1BM d-1 (342 mEq kg -1 feed), which was not reproduced from the potassium concentrations in the blood. The same applied to the sodium and chloride concentrations in the blood. Conclusions: The alkalization of the urine shows that the DCAB of the feed influences the acid-base status. The systemic pH remained largely unaffected due to the buffer systems of the organism. The intragastric, respectively the intestinal, pH medium was changed by the addition of potassium hydrogen carbonate, which is reflected in the poorer digestibility of nitrogen at higher DCAB. The nitrogen retention is not related to the nitrogen digestibility. The best retention of nitrogen was observed with the DCAB of 66 mEq kg-1 feed (K: 10 g kg-1 feed). The daily weight gain and feed utilizations of the pigs certainly could not reflect this. It should be noted, however, that a longer observation period would be necessary for a clear effect on daily gain (jump of the daily weight gain from 520 g of -125 mEq kg-1 feed to the level of 692 g for 66 mEq kg-1 feed and more). A recommendation based on this study would be a DCAB value of 66 mEq kg-1 feed. If this value increases, the nitrogen digestibility decreases; on the other hand, the nitrogen retention deteriorated with reducing DCAB.

Yue Gar-Lee Grace. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 113-120). / Abstracts in English and Chinese. / Abstract (English version) --- p.i / Abstract (Chinese version) --- p.iii / Acknowledgements --- p.v / Table of contents --- p.vi / List of figures --- p.x / List of tables --- p.xiii / List of abbreviations --- p.xiv / Chapter Chapter I: --- Introduction --- p.1 / Chapter 1.1. --- Transepithelial electrolyte transport in colon --- p.1 / Chapter 1.1.1. --- Intestinal fluid secretion --- p.1 / Chapter 1.1.2. --- Cellular mechanism of chloride secretion --- p.3 / Chapter 1.2. --- Biological activities of flavonoids --- p.6 / Chapter 1.2.1. --- Classification and general activities of flavonoids --- p.6 / Chapter 1.2.2. --- Bioavailability and pharmacokinetic properties of flavonoids --- p.8 / Chapter 1.3. --- "What is Scutellariae radix""?" --- p.9 / Chapter 1.3.1. --- Usage in Traditional Chinese Medicine --- p.9 / Chapter 1.3.2. --- Relationship with Coptidis rhizoma --- p.9 / Chapter 1.4. --- Effect of flavonoids on gastrointestinal activities --- p.12 / Chapter 1.4.1. --- Genistein and quercetin --- p.12 / Chapter 1.4.2. --- Baicalein --- p.12 / Chapter 1.5. --- Possible intracellular signaling pathway involved in the secretory response by Scutellariae radix (SR) in T84 cells --- p.14 / Chapter 1.5.1. --- Human colonic T84 cell --- p.14 / Chapter 1.5.2. --- Intracellular signaling pathway --- p.14 / Chapter 1.6. --- Aim of study --- p.17 / Chapter Chapter II : --- Methods and Materials --- p.18 / Chapter II.1. --- Culture technique of the T84 cells --- p.18 / Chapter II.2. --- Simultaneous measurement of short-circuit current (Isc) and intracellular calcium ([Ca2+]i) --- p.21 / Chapter II.2.1. --- Experimental setup --- p.21 / Chapter II.2.2. --- Preparation of the permeable supports --- p.23 / Chapter II.2.3. --- Cell seeding --- p.27 / Chapter II.2.4. --- Dye loading --- p.27 / Chapter II.2.5. --- Simultaneous measurement of Isc and [Ca2+]i- --- p.30 / Chapter II.3. --- Conventional short-circuit current (Isc) measurement --- p.34 / Chapter II.3.1. --- Experimental setup --- p.34 / Chapter II.3.2. --- Preparation of the permeable supports --- p.36 / Chapter II.3.3. --- Cell seeding --- p.36 / Chapter II.3.4. --- Measurement --- p.38 / Chapter II.4. --- Measurement of cAMP --- p.39 / Chapter II.5. --- Solutions and chemicals --- p.40 / Chapter II.6. --- Statistical analysis --- p.42 / Chapter Chapter III : --- Results --- p.43 / Chapter III. 1. --- Effects of baicalein and its interaction with calcium and cAMP-dependent secretagogues --- p.43 / Chapter III. 1.1. --- Effects of baicalein on baseline Isc and [Ca2+]i --- p.43 / Chapter III. 1.2. --- Ionic basis of baicalein-evoked Isc --- p.43 / Chapter III. 1.3. --- Effect of baicalein on carbachol-evoked Isc --- p.47 / Chapter III. 1.4. --- "Effect of baicalein on Isc stimulated by another calcium mobilizing agonist, histamine" --- p.58 / Chapter III. 1.5. --- Effect of carbachol on Isc response stimulated by baicalein --- p.61 / Chapter III. 1.6. --- Chronic effect of baicalein on carbachol-evoked increase in Isc --- p.63 / Chapter III.1.7. --- Interaction of baicalein with forskolin --- p.65 / Chapter III.2. --- Effects of baicalein on cAMP generation in T84 cells --- p.69 / Chapter III.2.1. --- Effects of baicalein on cAMP production --- p.69 / Chapter III.2.2 --- Effects of baicalein on forskolin-induced cAMP production --- p.70 / Chapter III.3. --- Effects of Scutellariae radix extract on ion transport activities in T84 cells --- p.73 / Chapter III.3.1. --- Effects of Scutellariae radix extract (SRE) on baseline Isc --- p.73 / Chapter III.3.2. --- Ionic basis of SRE-evoked Isc --- p.77 / Chapter III.3.3. --- Effects of adenylate cyclase inhibitor and PKA inhibitor --- p.77 / Chapter III.3.4. --- PKC modulation --- p.86 / Chapter III.3.5. --- Involvement of intracellular calcium --- p.86 / Chapter III.3.6. --- Involvement of cAMP --- p.94 / Chapter Chapter IV : --- Discussion --- p.98 / Chapter IV. 1. --- Effects of baicalein on ion transport in human colonic T84 cells --- p.98 / Chapter IV. 1.1. --- Roles of baicalein in chloride secretion in intestinal epithelial cells --- p.98 / Chapter IV. 1.2. --- Potentiation effect of baicalein on calcium-mediated chloride secretion --- p.100 / Chapter IV. 1.3. --- Potentiation effect of carbachol on baicalein-stimulated chloride secretion --- p.102 / Chapter IV. 1.4. --- Interaction between baicalein and forskolin --- p.104 / Chapter IV.2. --- Effects of Scutellariae radix extract on ion transport in human colonic T84 cells --- p.107 / Chapter IV.2.1 --- Characteristcs of Isc induced by Scutellariae radix extract --- p.107 / Chapter IV.2.2. --- Possible signaling mechanism involved in Isc induced by Scutellariae radix extract --- p.108 / Chapter IV.3. --- Comparison of the effects on ion transport in human colonic T84 cells produced by baicalein and Scutellariae radix extract --- p.110 / Chapter IV.3.1. --- Properties of baicalein- and Scutellariae radix extract- induced Isc response --- p.110 / Chapter IV.3.2. --- Summary --- p.111 / Chapter Chapter V : --- References --- p.113 / Publications --- p.120

South African forestry workers are predisposed to dehydration due to the heavy physical activity they perform in impermeable regulation safety clothing in hot and often humid environments where the availability of a variety of suitable fluids at reasonable temperatures is limited. As dehydration reduces both physical and mental capacity the potential consequences include decreased productivity and an increased risk for injury. The aim of this cross sectional observational study was to determine the prevalence and severity of dehydration in rural forestry workers in both winter (minimum and maximum daily temperatures 3-22°C) and autumn (minimum and maximum daily temperatures 14-27°C). The convenience sample included 103 workers in autumn (Nelspruit, n=64 males, n=39 females, mean age 37.32 years, mean BMI 22.3 kg/m2) and 79 in winter (Richmond, n=68 males, n=11 females, mean age 25.85 years, mean BMI 22.2 kg/m2). The sample included chainsaw operators, chainsaw operator assistants, debarkers and stackers. The risk of heat illness was moderate in Nelspruit (average daily temperature 21.1°C 67% rh) and low in Richmond (average daily temperature 17.0°C 39% rh). The prevalence of dehydration was determined by urine specific gravity (USG) measurements. Percent loss of body weight in the course of the shift was used to determine the severity of dehydration. In Nelspruit 43% (n=43) and in Richmond 47% (n=37) of the forestry workers arrived at work dehydrated (USG>1.020 g/ml). Pre break this had increased to 49% (n=49) in Nelspruit and 55% (n=33) in Richmond. By the end of shift the number of dehydrated forestry workers had significantly increased to 64% (n=64, p≤0.001) in Nelspruit and 63% (n=42, p=0.043) in Richmond. A minimum of 21% (n=2) in Nelspruit and 23% (n=15) in Richmond of the forestry workers had lost more than 2% of their body weight which could significantly decrease work capacity and work output as well as mental and cognitive ability. Dehydration was not related to season (winter/autumn), gender or job category. In Nelspruit 23% (n=23) and in Richmond 13% (n=10) arrived at work overhydrated (USG<1.013 g/ml). Pre break this had decreased to 14% (n=14) in Nelspruit and 10% (n=6) in Richmond. By the end of shift 4% (n=4) in Nelspruit and 2% (n=1) in Richmond had remained overhydrated and without correcting for fluid and food intake, 5% (n=5) had gained over 2% of their body weight in Nelspruit while none had gained weight in Richmond. Overhydration was not related to season (winter/autumn), gender or job category. Physical symptoms at the end of shift included tiredness (24%), toothache (13%) and headaches (10%) although these did not correlate to end of shift USG readings (p=0.221). The fluid requirements for male workers (n=8) who did not eat or drink across the shift was 439 ml per hour. The contractors were unaware of how much fluid should be supplied to workers and how much fluid they actually supplied. The only fluid provided by the contractors was water at the ambient air temperature which was the main source of fluid for the majority. Some forestry workers brought a limited variety of other fluids including amahewu, tea and cold drinks to work. At least 40% of the work force investigated, started their shift already compromised to work to capacity (USG>1.020 g/ml). The prevalence of dehydration had increased by the break emphasizing the need to begin drinking early on in the shift. The majority of forestry workers were dehydrated at the end of the shift. A significant proportion was dehydrated to the extent (>2%) that both work capacity and mental ability would be significantly compromised. A select group of forestry workers were drinking excessive amounts of fluid and were therefore susceptible to potentially fatal dilutional hyponatremia especially as water was the primary source of fluid. Dehydration in both autumn and winter was identified as being a significant but preventable risk. As a consequence of overhydration, a small group of forestry workers may be susceptible to dilutional hyponatremia. Fluid intake guidelines for males of 450 ml per hour appeared to be safe and were within the recommendations of the American College of Sports Medicine. Fluid guidelines for females need investigation. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Teaching topics related to handling water and electrolytes are always a challenge for the medical educator. Faced with the complex area is essential to the physical presence of a teacher in the classroom, or can the student educate themselves with the aid of e-Learning? For the purpose of responding to this question, 62 volunteer undergraduate medical students in the State of Sergipe, Brazil, without prior experience in the specific approach of clinical and therapeutic aspects related to electrolyte balance, were submitted, after random assignment in cascade in accordance with their year of entry to the University and the learning method adopted at the institution (conventional or active methodology), a longitudinal analytical experimental study. The students were randomly assigned to two groups (classroom and distance) receiving lessons for the management of water and electrolytes. Evaluative evidence, with the same content, were applied to the two groupings, at two distinct times: for assessment of prior knowledge (pre-test) and assimilated knowledge (post-test). This defined the gain of learning as well as the difference between the averages of the pre-test and post-test. The data were submitted to descriptive and inferential analysis and significance level for rejection of the null hypothesis which was 0.05. On the basis of the evaluations were calculated measures of central tendency, dispersion and confidence interval. Gains in learning were evaluated using the paired t-test. The groups were compared by means of Student´s t test for independent samples. The statistical analysis showed no significant difference in the learning gain in the comparison between the groups (p= 0.58), indicating that the distance education is as good as the classroom in teaching Hydroelectrolytic Balance and its disorders. / Lecionar tópicos relativos ao manuseio de água e eletrólitos é sempre um desafio para o educador médico. Confrontados com área tão complexa é indispensável à presença física de um professor em sala de aula, ou o aluno pode, com auxílio de e-Learning, instruir-se sozinho? Com o propósito de responder a esta pergunta, 62 alunos voluntários da graduação médica do Estado de Sergipe, Brasil, sem experiência prévia na abordagem específica de aspectos clínicos e terapêuticos relacionados ao equilíbrio hidroeletrolítico, foram submetidos, após alocação randômica em cascata em conformidade com o seu ano de entrada da Universidade e o método de aprendizagem adotado na instituição (convencional ou metodologia ativa), a um estudo longitudinal analítico experimental. Os alunos foram alocados em dois grupos (presencial e a distância) para receberem aulas referentes ao gerenciamento de agua e eletrólitos. Provas avaliativas, com o mesmo teor, foram aplicadas, para os dois grupamentos, em dois momentos distintos: para avaliação de conhecimentos prévios (pré-teste) e conhecimentos assimilados (pós-teste). Definiu-se o ganho de aprendizagem como a diferença entre as médias do pré-teste e do pós-teste. Os dados obtidos foram submetidos à análise descritiva e inferencial e o nível de significância para rejeição da hipótese de nulidade foi de 0,05. Com base nas avaliações foram calculados medidas de tendência central, dispersão e intervalo de confiança. Ganhos de aprendizagem foram avaliados com o teste t pareado. Os grupos foram comparados entre si por meio do teste t de Student para amostras independentes. A análise estatística não mostrou diferença significativa no ganho de aprendizagem no comparativo entre os grupos (p=0,58), indicando que a educação à distância é tão boa quanto à presencial no ensino do Equilíbrio Hidroeletrolíticos e seus distúrbios.