Eight healthy males performed two rides to exhaustion at a work load corresponding to 125% Q02 max, one hr after ingesting either NaHCO3 (E) or NaCl (C). Mean + SE pre-exercise blood pH, HCO3 and base excess (BE) values were respectively 7.42 + 0.01, 28.2 + 1.5 mmol/l and 2.02 + 0.1 mmol/l for the E condition, and 7.39 + 0.01, 24.4 + 0.7 mmol/l and -0.4 + 0.7 mmol/l for the C condition (P < 0.05 for all variables). Cycling time to exhaustion (E = 100.66.1; C = 98.6 + 5.7 sec) and total "02 during recovery (E 17.7 + 0.9; C = 17.3 + 0.8 1/30 min) did not differ between treatments. Blood pH, HCO3 and BE were significantly higher while the hydrogen ion to lactate ratio (LH+I/ELAI) was significantly lower in E than in C during recovery. Blood LA levels were also greater in E than in C during the latter part of recovery although peak individual values were not significantly different between trials CE = 14.4 + 0.4; C = 13.3 + 0.0 mmol /1) . In view of the insignificant differences in cycling time, peakLA production was greater in E than in C. Rather it individual LA and total recovery 002, it is not likely that Given this protocol, alkalosis does not help to sustain an appears that LA efflux was enhanced by the NaHCO3 feeding. Additionally, the return of the acid-base status in blood to resting conditions was more rapid during alkalosis does not help to sustain an intense exercise bout. These data suggest, however, that NaHCO3 may be of benefit following repeated work bouts.

Thesis (Ph. D.)--University of Chicago, 1942. / Lithoprinted. Description based on print version record. Includes bibliographical references.

Abstract High-sucrose diet and metabolic acidosis have some similar effects on bone and they both reduce the formation of dentine. This series of experiments was conducted in order to get information about the effects of acidosis and alkalosis on dentine during primary dentinogenesis and also to ascertain if high-sucrose diet affects dentine formation via acidosis. Chronic metabolic acidosis (0.25 mol/L of NH4Cl in drinking water), chronic metabolic alkalosis (0.25 mol/L of NaHCO3 in drinking water) and chronic respiratory alkalosis (atmospheric pressure equivalent to an altitude of 3000 m) were induced in the rats immediately after weaning for 6 and 7 weeks. One subgroup from each of the main groups was fed a high-sucrose (43%) diet and one a standard maintenance diet, each ad libitum. The control groups had the same diets, but normal drinking water and atmospheric pressure. All the rats were injected with tetracycline (to mark the onset of the experiment in dentine) and inoculated orally with Streptococcus sobrinus. The acid-base status was verified by blood gas analysis at the end of the experiments. After sacrifice, fissure caries was scored with Schiff reagent and the areas of dentinal lesions and tetracycline-marked new dentine were measured from sagittally sectioned mandibular molars. The mineral elements (Ca, Mg, F, Na, P and total mineral contents) of the dentine formed before and during the experiment were measured with an electron probe microanalyzer. With the high-sucrose diet, respiratory alkalosis and metabolic acidosis promoted the initiation and progression of caries while metabolic alkalosis slightly retarded it. With the standard diet, all the experimental conditions slowed the rate of dentine formation and metabolic acidosis had the most pronounced effect. The mineral analysis revealed a totally different pattern of mineralization when the rats with metabolic acidosis (increased calcium and total mineral content) were compared to the previously reported rats with a high-sucrose diet (decreased calcium and total mineral content). Besides this, metabolic alkalosis did not correct the effects of the dietary sucrose on dentine formation and blood gas analysis showed no acid-base disturbances in the sucrose diet group. Therefore, a high amount of sucrose in the diet slows the rate of dentine formation and reduces the ability of teeth to resist caries attack by mechanisms different from those of metabolic acidosis. Nevertheless, metabolic acidosis was found to be the most harmful state of disturbance in acid-base balance for the teeth of young rats, especially with a diet containing a high amount of sucrose.

Graduation date: 1995

The aims of this thesis were to: 1) develop a new method for the determination of interstitial pH at rest and during exercise in vivo, 2) systematically explore the effects of different ingestion regimes of 300 mg.kg-1 sodium citrate on blood and urine pH at rest, and 3) to combine the new interstitial pH technique with the findings of the second investigation in an attempt to provide a greater understanding of H+ movement between the extracellular compartments. The purpose of the first study was to develop a method for the continuous measurement of interstitial pH in vastus lateralis was successfully developed using microdialysis and 2,7-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). To avoid the presence of an artificial alkalosis during exercise, it was necessary to add 25 mM HCO3- to the perfusate. The outlet of the probe was cut less than 10 mm from the skin and connected to a stainless steel tube completing the circuit to a microflow-through cuvette (8 fÝl) within a fluorescence spectrophotometer. This prevented the loss of carbon dioxide from the dialysate and any subsequent pH artefact. Interstitial pH was collected from six subjects before, during and after five minutes of knee-extensor exercise at three intensities 30, 50, and 70 W. Mean,,bSEM interstitial pH at rest was 7.38,,b0.02. Exercise reduced interstitial pH in an almost linear fashion. The nadir value for interstitial pH at 30, 50 and 70 W exercise was 7.27, 7.16 and 7.04, respectively. The lowest pH was obtained 1 min after exercise, irrespective of workload, after which the interstitial pH recovered in a nearly exponential manner. The mean half time of interstitial recovery was 5.2 min. The changes in interstitial pH exceeded the changes in venous blood pH. This study demonstrated that interstitial pH can be measured using microdialysis and that it is continuously decreased during muscle activity. The purpose of the second study was to establish an optimal ingestion regime for the ingestion of 300 mg.kg-1 of sodium citrate and maximise the alkalotic effect while minimising any side effects. Increasing the effectiveness of alkali ingestion may lead to further increases in muscle performance. Ingesting 300 mg.kg-1 sodium citrate at a rate of 300 mg.min-1 was identified as the optimal ingestion regime to maximise alkalosis at rest, which occurred 3.5 h post-ingestion. This was determined by monitoring eight human subjects ingesting 300 mg.kg-1 sodium citrate at five different rates, control (no ingestant), bolus, 300, 600 and 900 mg.kg.min-1 on five days separated by at least 48 hours. Sodium citrate was ingested in capsule form with water ad libitum, with the exception of bolus, which was combined with 400 ml less than 25 percent orange juice and consumed in less than 1 min. Arterialised blood (mean 71.3,,b3.5 mmHg) acid-base and electrolyte status was assessed via the withdrawal of ~5 ml of blood every 30 min across an eight hour duration, placed on ice and analysed within five minutes. No alkalotic difference was found between ingestion rates (mean 7.445,,b0.004, 7.438,,b0.004 and 7.442,,b0.004 for 300, 600 and 900 mg.min-1, respectively). All experimental ingestion regimes were associated with elevations in [HCO3-] (29.6, 29.7, 29.8, 29.9 and 26.3 mmol.l-1 for bolus, 300, 600, 900 and control, respectively). The 300 ingestion regime had the greatest impact on [H+], a 0.66 meq.l-1,,e10-8 change. Bolus ingestion (3.93,,b0.08 mmol.l-1) of sodium citrate had no effect on control (4.06,,b0.08 mmol.l-1) blood [K+], however, 300 mg.min-1 decreased blood [K+] (p less than 0.05). There was no effect of sodium citrate on blood [Cl-], but after 2.5 h blood [Cl-] was lower than pre-ingestion values (p less than0.05). All ingestion rates of sodium citrate increased (p less than 0.05) urine pH above control. This is the first study to investigate the effect of varying ingestion rates on acid-base status at rest in humans. The results suggest that ingesting sodium citrate in small doses in quick succession induce a greater blood alkalosis than the commonly practised bolus protocol. Using the interstitial pH technique described above and the optimal ingestion regime (300 mg.min-1) identified above, the final experiment was designed to assess the influence of sodium citrate ingestion on interstitial pH at both rest and during exercise. Five subjects ingested 300 mg.kg-1 sodium citrate at 300 mg.min-1 again in capsule form with water ad libitum. Prior to ingestion, each subject had a cannula placed into their cephalic vein and one microdialysis probe (CMA-60) inserted into their left thigh, orientated along the fibres of vastus lateralus. This probe was used for the measurement of pH as described above. At the end of this period, an exercise protocol required five subjects to perform light exercise (10 W) for 10 min, before starting an intense exercise period (~90-95% leg VO2peak) to exhaustion followed by a 15 min recovery period. Dialysate and blood samples were collected across all periods. Mean,,bSEM interstitial pH for placebo and alkalosis were 7.38,,b0.12 and 7.24,,b0.16, respectively. Sodium citrate ingestion was not associated with an interstitial alkalosis. An exercise induced acidosis was observed in the interstitium during placebo but not during alkalosis (p less than 0.05). Mean,,bSEM venous pH were 7.362,,b0.003 and 7.398,,b0.003 for placebo and alkalosis, respectively. Sodium citrate ingestion was not associated with a venous alkalosis. Sodium citrate ingestion was associated with an increase in mean,,bSEM venous [HCO3-] (placebo 25.5,,b0.2, alkalosis 28.1,,b0.2). This increase in the blood bicarbonate buffer system was not associated with an increase in time to exhaustion (placebo 352,,b71, alkalosis 415,,b171). This was the first study to investigate the effects of sodium citrate ingestion on interstitial pH. The results of this study demonstrated that an interstitial alkalosis does not ensue after alkali ingestion, however, it was associated with the lack of an exercise induced acidosis suggesting an improved pH regulation during exercise.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-15T16:27:12Z No. of bitstreams: 1 PGCA16MA211.pdf: 910415 bytes, checksum: 51ae39dddf70a9c249c0895146f82c99 (MD5) / Made available in DSpace on 2018-03-15T16:27:12Z (GMT). No. of bitstreams: 1 PGCA16MA211.pdf: 910415 bytes, checksum: 51ae39dddf70a9c249c0895146f82c99 (MD5) Previous issue date: 2016-11-11 / Capes / More productive and efficient animals in the feed conversion and who can dribble more stressfull transition period are critical to improving performance in intensive milk production. Crossovers arise as an alternative by the search for healthier and more profitable animals. Blood gas analysis has a great importance on the evaluation of acidbase balance and electrolyte profile, providing essential information for the diagnosis and prognosis of several diseases in domestic animal. Dairy cows are more susceptible to metabolic disorders on the transition period and blood gas analysis provides important information to decision making and prevention of the development of many disorders. The objective was to determinate and compare the blood gas profile, feeding behavior and feed efficiency of Holstein and crossbreeding Holstein x Jersey cows in postpartum. Weekly, blood samples were collected from 24 Holstein and crossbred Holstein x Jersey cows. After blood sampling, a complete blood gas analysis was performed including pH, bicarbonate (HCO3 -), partial pressure of carbon dioxide (pCO2) and ionized calcium throughout the portable clinical analyzer for blood gas analysis, I-STAT using the CG8 + cartridge. The ingestive behavior, dry matter intake and milk production was evaluated. Data were submitted to analysis of variance with repeated measures, using the MIXED procedure of SAS statistical package. There were differences between genetic groups for pH values (P = 0.005), ionized calcium (P = 0.0203), base excess, BE (P = 0.0311), glucose (P = 0.0468) and hematocrit (P = 0.0209). The ionic calcium levels found were below the reference values throughout the evaluation period. However, crossbred cows showed higher levels of ionic calcium when compared to Holstein cows from prepartum period to parturition, being that and important health parameter of dairy cows, which is a positive characteristic feature on the choice for crossbreeding. The blood gas analysis has identified differences between Holstein and crossbred Holstein x Jersey cows in transition period. Crossbred cows Holstein x Jersey and Holstein cows have a similar dry matter intake and feed efficiency. Crossbred Holstein x Jersey cows tended to have higher feed efficiency for milk corrected to 4% fat and higher feed efficiency for fat production of. Crossbred Holstein x Jersey cows spend more time throughout the day feeding when compared to Holstein cows. Ruminations time was similar between Holstein and Holstein x Jersey cows / A busca por animais mais produtivos e eficientes na conversão de alimentos e que conseguem driblar mais os efeitos estressores do período de transição são fundamentais para melhorar o desempenho na produção intensiva de leite. Os cruzamentos surgem como uma alternativa pela busca de animais mais saudáveis e rentáveis. Vacas de leite no período de transição são muito suscetíveis a transtornos metabólicos, sendo que o exame hemogasométrico pode fornecer informações importantes, em nível de rebanho, para a tomada de decisão e prevenção da evolução de muitos distúrbios. O exame hemogasométrico é de grande importância na avaliação do equilíbrio ácido-básico e do perfil eletrolítico, fornecendo informações fundamentais para o diagnóstico e o prognóstico de várias enfermidades de animais domésticos. O objetivo deste trabalho foi determinar e comparar o perfil hemogasométrico, o comportamento ingestivo e a eficiência alimentar de vacas Holandês e Holandês x Jersey no período de transição pré e pós-parto. Coletaram-se semanalmente, amostras de sangue de 24 vacas Holandês e mestiças Holandês x Jersey, entre duas semanas pré e oito semanas pós-parto. Após o parto, as vacas foram alojadas em baias individualmente. Avaliou-se o pH sanguíneo, bicarbonato (HCO3 -), pressão de dióxido de carbono (pCO2) e cálcio ionizado através do analisador clínico portátil de gases sanguíneos, I-STAT utilizando o cartucho CG8+. Avaliou-se também, o comportamento ingestivo, o consumo de matéria seca e a eficiência alimentar das vacas. Os dados foram submetidos à análise de variância com medidas repetidas no tempo, utilizando-se o procedimento MIXED do pacote estatístico SAS. Houve diferença entre grupamentos genéticos nos valores de pH (P = 0,005), cálcio iônico (P = 0,0203), excesso de base, BE (P = 0,0311), glicose (P = 0,0468) e hematócrito (P = 0,0209). Os níveis de cálcio iônico encontraram-se abaixo dos valores de referência ao longo de todo o período de avaliação, mas, as vacas mestiças apresentaram níveis superiores de cálcio iônico quando comparadas às vacas Holandês, do pré-parto ao parto. O exame hemogasométrico permitiu identificar diferenças entre vacas Holandês e mestiças Holandês x Jersey no período de transição. Vacas mestiças Holandês x Jersey apresentam consumo de matéria seca diária e eficiência alimentar similar que as vacas puras Holandês. As vacas mestiças Holandês x Jersey tiveram tendência de maior eficiência alimentar para produção de leite corrigido a 4% de gordura e maior eficiência alimentar para produção de gordura. Vacas mestiças Holandês x Jersey passam mais tempo ao longo do dia se alimentando quando comparadas com as vacas Holandês, sem diferença no tempo de ruminação