A cetoacidose diabética (CAD) é uma das complicações mais graves do diabetes mellitus (DM) em pequenos animais. A CAD é uma emergência médica caracterizada por alterações metabólicas extremas, incluindo hiperglicemia, acidose metabólica, cetonemia, desidratação e perda de eletrólitos. Embora seja um distúrbio comum e de alta mortalidade, os padrões dos distúrbios ácido-base de cães com CAD ainda não foram avaliados objetivamente. Muitas das assunções sobre a CAD em cães são generalizadas com base em dados de pacientes humanos e estudos experimentais em cães. O objetivo do presente estudo foi descrever os distúrbios ácido-base e eletrolíticos de cães com CAD e cetose diabética (CD) e caracterizá-los segundo a freqüência de ocorrência, adequação dos mecanismos de compensação e ocorrência de distúrbios mistos. Foram avaliados 40 cães diabéticos (22 animais recém diagnosticados e 18 cães em tratamento com insulina) atendidos apresentando cetonúria e hiperglicemia (>250 mg/dL). De acordo com critérios clínicos, esses cães foram distribuídos em dois subgrupos: (CAD, n=22 e CD n=18) e foram determinados o pH e a hemogasometria arteriais e eletrólitos plasmáticos (sódio, cloro, potássio, cálcio ionizado) e o magnésio total e o fósforo inorgânico séricos. As alterações do equilíbrio ácido-base foram avaliadas sistematicamente pelo método de Van Slyke-Henderson-Hasselbalch. Os resultados foram comparados com os obtidos a partir de 37 cães clinicamente hígidos. Com relação aos distúrbios ácido-base, a acidose metabólica foi o mais comumente identificado (n = 27). A maior parte dos animais apresentava acidose normoclorêmica. A acidose hiperclorêmica foi observada em sete pacientes. Dos cães com acidose metabólica, 15 apresentavam alcalose respiratória concomitante. A distribuição dos valores de eletrólitos foi diferente entre o grupo de estudo e o controle, com exceção do magnésio. Não houve diferença na distribuição dos valores dos eletrólitos entre os subgrupos, com exceção do potássio plasmático. A hiponatremia e a hipocloremia foram os distúrbios eletrolíticos mais comumente observados nos 40 cães com DM. A hipocalemia ocorreu com maior freqüência no subgrupo CAD e a hipercalemia no subgrupo CD. Os valores do fósforo inorgânico sérico foram semelhantes entre os subgrupos de estudo. A hiperfosfatemia foi comum em ambos os subgrupos e nenhum paciente apresentou hipofosfatemia. A hipermagnesemia foi observada em sete pacientes com CAD e em apenas um com CD. A maior parte dos pacientes tinha hipocalcemia por ocasião do atendimento inicial. Distúrbios ácido-base mistos, principalmente a acidose metabólica normoclorêmica associada a alcalose respiratória são comuns em cães com cetose ou cetoacidose diabética, assim como distúrbios eletrolíticos como hiponatremia, a hipocloremia e hipocalemia e hiperfosfatemia. / Diabetic ketoacidosis (DKA) is one of the most serious complications of diabetes mellitus (DM) in small animals. DKA is a medical emergency characterized by extreme metabolic abnormalities, including hyperglycemia, metabolic acidosis, ketonemia, dehydration, and electrolyte losses. Despite it is a common disorder and with high mortality, the patterns of the acid-base disturbances in dogs with DKA were not evaluated objectively. Many of the assumptions about DKA in dogs are derived from studies in human beings and experimental studies in dogs. The objective of the present study was to describe the acid-base and electrolytic disturbances in dogs with DKA and diabetic ketosis (DK) according to their frequency, adequacy of the compensatory mechanisms e occurrence of mixed disturbances. Forty dogs with DM (22 with new onset diabetes and 18 insulin-treated dogs) with ketonuria and hyperglycemia (> 250 mg/dL) were enrolled. On the basis of clinical criteria, the dogs were assigned to one of two subgroups: (DKA, n=22 e DK n =18). Arterial blood gases and plasma electrolytes (sodium, chloride, potassium and, ionized calcium), and serum total magnesium and inorganic phosphorus were determined in all dogs. The acid base abnormalities were evaluated systematically by the Van Slyke-Henderson-Hasselbalch method and the results compared to those obtained from 37 healthy dogs (control group). Metabolic acidosis was the most common acid-base disorder identified (n = 27) and most of the dogs had normochloremic acidosis. Hyperchloremic acidosis was observed in seven patients. Fifteen of the dogs with metabolic acidosis had coexisting respiratory alkalosis. The distribuition of the electrolytes values was different between the study group and the control group, with the exception of serum magnesium. The distribution of the electrolytes values was similar between the subgroups, with the exception of plasma potassium. Hyponatremia and hypochloremia were the most common observed electrolyte abnormalities showed in dogs with DK or DKA. Hypokalemia occurred more frequently in dogs with DKA and hyperkalemia in dogs with DK. Serum inorganic phosphorus values were similar between the subgroups. Hyperphosphatemia was a common finding and hypophosphatemia was not observed. Hypermagnesemia was detected in seven patients with DKA and in only one with DK. Most of the dogs were hypocalcemic on admission. Mixed acid-base disorders, mainly metabolic normochloremic acidosis with coexisting respiratory alkalosis are common in dogs with diabetic ketosis or ketoacidosis and electrolytic disturbances, mostly hyponatremia, hypochloremia, hypokalemia, and hyperphosphatemia, were also common.

O parálogo 3 do trocador Na+/H+ (NHE3) é essencial para a reabsorção de HCO3- nos túbulos proximais renais e sua expressão e função adaptam-se às diferentes condições ácido-base do organismo. O objetivo desta tese foi avaliar quais as diferenças entre os efeitos da acidose metabólica (AM) e respiratória (AR) sobre a regulação do NHE3 e identificar variáveis responsáveis pelas respostas adaptativas observadas. Em células OKP, a AM foi simulada diminuindo a [HCO3-] do meio de cultura e a AR aumentando a pCO2 ambiente por 24 h. Foram observados os efeitos das acidoses sobre o RNAm-Nhe3, a presença da proteína-NHE3 na membrana celular e a atividade promotora do gene do Nhe3. Concluiu-se que o pH extracelular não é a variável físico-química responsável por estimular a expressão do NHE3, contudo é um importante candidato à variável responsável por regular o tráfego da proteína para a membrana. Além disso, a região de -471 a -153 pb em relação ao sítio de início de transcrição do promotor do gene do Nhe3 contém prováveis reguladores positivos que atuam em resposta à AM. / The Na+/H+ exchanger 3 (NHE3) is essential for HCO3- reabsorption in renal proximal tubules and its expression and function must adapt to acid-base conditions. The goal of the presente study was to evaluate whether there are differences between metabolic (MA) and respiratory acidosis (RA) with regard to NHE3 modulation and to identify variables that may trigger these distinct adaptive responses. In OKP cells, MA was achieved by lowering [HCO3-] in the cell culture medium and RA by increasing pCO2 in the incubator chamber for 24 h. The effects of both acidosis on Nhe3 mRNA levels, cell-surface NHE3 expression and promoter activity were evaluated. In summary, it was concluded that low extracellular pH is not the physical-chemical variable that up-regulates NHE3 expression, however, extracellular pH is a candidate for the variable related to the NHE3 displacement to the apical membrane. Moreover, the Nhe3 gene promoter region spanning from -471 to -153 base pairs upstream from the transcriptional start site contains putative enhancers regulated in response to MA.

Em Medicina Veterinária, os avanços em Neonatologia são escassos quando comparados aos da Medicina Humana. Dentre as possíveis causas para esta situação atual destacam-se as particularidades fisiológicas deste período. Os objetivos do presente estudo foram: estabelecer os valores normais de algumas variáveis laboratoriais de neonatos nascidos de parto eutócico, identificar eventuais alterações metabólicas maternas e dos neonatos nascidos em diferentes condições obstétricas, verificar os efeitos da administração de ocitocina sob variáveis neonatais e maternas e mensurar os níveis de cortisol materno e neonatal como forma de estudar as diferentes situações de estresse no momento do parto. Vinte e nove fêmeas caninas foram alocadas em 3 grupos, de acordo com o tipo de parto: eutocia (grupo 1), distocia corrigida por manobras obstétricas ou cesariana (grupo 2) e indução de contrações uterinas com ocitocina (grupo 3). Cinqüenta e um neonatos foram avaliados por meio do sistema Apgar e temperatura corpórea ao nascimento, 5 minutos e 1 hora após o nascimento, bem como por avaliação hemogasométrica, dosagem de cortisol e glicemia ao nascimento e após 1 hora. A avaliação materna constituiu no controle da pressão arterial, monitorização cardíaca, glicemia e dosagem de cortisol em momentos pontuais no pré, intra e pós-parto. Os neonatos dos distintos grupos apresentaram acidose mista associada à hipóxia ao nascimento, com maior comprometimento metabólico nos filhotes do grupo 3. Após 1 hora, recuperaram-se do componente respiratório, mantendo apenas o quadro de acidose metabólica por maior comprometimento da hipóxia. A avaliação neonatal pelo escore Apgar demonstrou que filhotes do grupo 2 nascem em maior depressão que neonatos dos grupos 1 e 3, porém todos apresentam adequada recuperação após 1 hora. Nas parturientes, a administração de ocitocina favoreceu a elevação da pressão arterial para níveis normais durante o trabalho de parto, bem como o aumento da glicemia. Neonatos nascidos por manobra obstétrica ou cesariana apresentaram maior concentração de cortisol plasmático ao nascimento, em comparação aos grupos 1 e 3. Contudo, todos os neonatos apresentaram redução significativa dos níveis de cortisol após 1 hora do nascimento. Por outro lado, foi possível verificar maior concentração sérica deste hormônio após o término do parto nas fêmeas submetidas à infusão de ocitocina. Em conclusão, a administração de ocitocina é responsável por maiores alterações metabólicas em neonatos; na parturiente, a administração de ocitocina promove alterações na pressão arterial, glicemia e aumento da liberação de cortisol; a manobra obstétrica ou cesariana promove maior estresse neonatal ao nascimento. / Studies accomplishing canine neonatology are scarce in Veterinary Medicine comparing to Human Neonatology due to the particularity of this refered period. The aims of the present study were to establish standard laboratorial values of the canine neonate, identify metabolic changes of bitches and neonates born under different obstetric conditionsl, verify the consequences of dystocia treated medically by oxytocin administration on maternal and neonatal variables and to measure maternal and neonatal cortisol levels on distinc stress situations during parturition. Twenty nine canine females were allocated into 3 groups according to the obstetric conditions: eutocia (group 1; n=10), manipulative obstetric assistance or cesarean section (group 2; n=10) and maternal dystocia treated with oxytocin (group 3; n=9). Fifty one neonates were submitted to a clinical evaluation by Apgar scoring and body temperature measurement immediately after birth, at 5 and 60 minutes postnatal; and hemogasometric evaluation, blood glucose and cortisol assay immediately after birth and 60 minutes postnatal. Maternal noninvasive arterial blood pressure, blood glucose and cardiac monitoring were peformed during the first stage of labor, intra-partum, immediately after the last puppy was born and 1 hour later. Neonates from distinct groups showed mixed acidosis in addition to hypoxemia at birth. Neonates remained under metabolic acidosis even after 1 hour of birth due to a detrimental effect on hypoxia. Comparing the results among groups, puppies from group 2 showed significantly lower Apgar score at birth. However, 1 hour later all neonates showed full recovery. Dams subjected to oxytocin infusion showed an increase in blood pressure, hence switching to a normotension status and also presented higher glucose level during parturition. Manipulative obstetric assistance or cesarean section arised neonatal cortisol levels at birth. However, all neonates exhibited significantly lower cortisol concentration after 1 hour of birth. Bitches of group 3 showed significantly higher cortisol level immediatly after whelping. In conclusion, dystocia treated medically by oxytocin infusion resulted in more intense metabolic alterations compared to neonates born under eutocia; oxytocin administration promotes blood pressure enhance, glucose alterations and increase in maternal stress; manipulative obstetric assistance or cesarean section increased neonatal cortisol release at birth.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Bibliography: leaves 150-158. / by Ramesh Shrikrishna Patil. / Ph.D.

Fluorescent nucleic acid base analogues (FBAs) are an important class of molecule used to study the structure and dynamics of DNA and RNA. These base analogues are molecules with structures that resemble one of the natural bases but which, unlike the natural bases, have high fluorescence quantum yields. 2-Aminopurine (2AP) has long been the most widely used fluorescent base analogue and is one of the few base analogues commercially available. One problem with 2AP is that it undergoes significant quenching when incorporated into DNA: the quantum yield decreases 100 fold from that of the free base, thus becoming too low for use in, for example, single molecule studies. A secondary problem is that the 305 nm absorption peak requires excitation in the UV. A variety of new fluorescent base analogues are being produced, with a view to remedying the deficiencies of 2AP and expanding the current range of use. The first part of this thesis explores the one-photon photophysical properties of several of these novel FBAs. The first of these novel FBAs is the 6-aza-uridine family. These compounds, analogues of uridine, have large Stokes shifts and their absorption and emission spectra are red-shifted in comparison to 2AP; their quantum yields as free bases have been shown to exceed that of 2AP and their environmental sensitivity has been demonstrated. Time-resolved measurements reported in this thesis indicate the presence of multiple emitting species. A density functional theory (DFT) study has been carried out to rationalise these emitting species as rotational isomers. Similar fluorescence lifetime measurements were made on a second class of FBAs, the quadracyclic adenine analogues, qANs; these results also indicated the presence of multiple emitting species. Experimental results show that these FBAs undergo excited-state proton transfer. The final FBA studied in this thesis is pentacyclic adenine, pA. This FBA showed some of the most promising characteristics of all the analogues investigated, such as a high quantum yield in both polar and non-polar solvents. A time-resolved investigation into pA-containing oligonucleotides indicated that in an oligonucleotide pA adopts multiple stacked conformations and its behaviour is highly sequence dependent. Several of these aforementioned fluorescent base analogues have absorption spectra in a region that makes them accessible to two-photon (2P) excitation with a Ti:Sapphire laser. In biological systems, multiphoton excitation has several advantages over one-photon excitation. By avoiding the use of ultraviolet light there is reduced phototoxicity. Out of focus photobleaching and autofluorescence are also minimised which leads to a higher signal-to-background ratio and allows deeper tissue penetration to be achieved. Fluorescent base analogues tend to have small Stokes shifts; this is another problem that can be overcome by using two-photon excitation. To be of potential use in multiphoton microscopy, a FBA must have a high two-photon absorption cross-section and a high two-photon brightness. Previously, the highest two- photon brightness measured for a fluorescent base analogue was less than 2 GM. Amongst the base analogues investigated here, are several that have higher two-photon brightness than ever reported for FBAs; these include pA which is shown to have the highest 2P brightness of a FBA in an oligonucleotide, 1.3 GM, and a member of the 6-azauridine family which as a free base has a 2P brightness of 18 GM. Detection of individual molecules represents the ultimate level of sensitivity and enables details about a molecular system that would otherwise be concealed using conventional ensemble techniques to be revealed. With the improved 2P brightness of the molecules measured in this thesis, it has become feasible to detect single FBA molecules using 2P excitation. To maximise the chance of detection, ultrafast, shaped laser pulses have been used as the excitation source. For the first time, the signal has been high enough and the molecule of interest sufficiently photostable such that 2P fluorescence correlation spectroscopy of a fluorescent base analogue in an oligonucleotide could be measured. In summary, this thesis reports the fluorescence lifetimes and two-photon cross-sections of a series of novel fluorescent base analogues, as well as fluorescence correlation spectroscopy measurements of the most promising candidates.

No presente trabalho focalizou-se a atenção nas propriedades de substâncias húmicas, em particular a fração de ácido húmico (AH), o qual foi obtido de duas fontes, sendo uma comercial e outra isolada de sedimentos do Rio Tietê, coletados no reservatório de Barra Bonita (SP). O isolamento do AH do sedimento foi realizado segundo o procedimento proposto pela Sociedade Internacional de Substâncias Húmicas (S.I.S.H.). Ambas amostras foram caracterizadas em paralelo através de análise elementar, absorção molecular no visível (razão E4/E6) e infravermelho e teores de cinzas. As propriedades ácido-base das amostras foram estudadas por titulação potenciométrica, adotando-se o modelo de distribuição de sítios discretos, empregando-se funções de Gran modificadas para tratamento dos dados. Foi possível caracterizar seis classes de grupos tituláveis em força iônica 0,1 (NaCI), com pKa entre 3 e 10. Constatou-se maior contribuição de grupos carboxílicos (grupos titulados com pKa < 7) do que fenólicos e amínicos em ambas amostras. Os resultados foram comparados com os métodos clássicos do acetato de cálcio e barita, assim como por titulação condutométrica. Estudou-se as propriedades de complexação dos AHs com íons Cu2+,Pb2+, Cd2+ e Zn2+ através de titulação potenciométrica com eletrodo íon-seletivo de membrana sólida para o CU2+ e de amálgama para os demais íons. Constatou-se a seguinte ordem de estabilidade para os complexos formados com ambos AHs: log K AH-Cu > log K AH-Pb > log K AH-Cd aproximadamente igual a log K AH-Zn. Quanto a capacidade de complexação (Cc), observou-se que CcPb > CcCu > CcCd aproximadamente igual a CcZn. / The aim of the present work was to study the humic substances, with emphasis to the humic acid (HA) fraction isolated from sediments of the Tietê River, collected at the Barra Bonita reservoir. The extraction of the humic acid was performed according to the procedure proposed by the International Humic Substances Society (I.H.S.S.). A commercial humic acid from Aldrich was studied in parallel. Both HA samples were characterized by elemental analysis, molecular absorption in the visible (E4/E6 ratio) and infrared regions, and ash contents. The acid-base properties of both humic acids were studied by potentiometric titrations, adopting the discrete site distribuition model and the modified Gran functions for data fitting. Six classes of titratable groups were characterized in 0,1 mol.L-1 (NaCI) ionic medium, with pKa values between 3 and 10. The sum of carboxylic groups (titratable groups with pKa < 7) was greater than the sum of aminic and phenolic groups for both humic acids. These results were compared with those provided by classical methods such as baryta adsorption and calcium acetate, as well as condutometric titration. The complexing properties were studied with regard to Cu2+,Pb2+, Cd2+ and Zn2+, by potentiometric titration with solid membrane copper ion-selective electrode and amalgam electrodes for the other ions. The following stability was observed for both HAs complexes: log KHA-Cu > log KHA-Pb > log KHA-Cd approximately equal to log KHA-Zn. With regard the complexing capacity (Cc),the following order was observed: CcPb > CcCu > CcCd approximately equal to CcZn.

Intestinal HCO3- secretion and the excretion of resultant CaCO3 precipitates have become a recognized characteristic of seawater osmoregulation in teleosts; however, this is the first report of this osmoregulatory strategy outside of teleosts and also includes evidence for its use in green turtles, Chelonia mydas. Furthermore, the effects of feeding on intestinal HCO3- secretion were newly investigated in teleosts. Intestinal base secretion via apical Cl-/HCO3- exchange was found to increase following feeding, at a magnitude sufficient to offset the "alkaline tide" commonly associated with digestion. Intestinal HCO3- secretion in marine teleosts draws HCO3- from both endogenous (via hydration of intracellular CO2) and serosal (blood) sources, of which serosal HCO3- was found to contribute a greater proportion to the elevated postprandial intestinal base secretion measured in gulf toadfish, Opsanus beta. The mechanism by which this serosal HCO3- crosses the basolateral membrane for subsequent secretion into the intestinal lumen was confirmed in toadfish to be a basolateral Na+/HCO3- co-transporter, tfNBCe1. Furthermore, the isolated intestinal tissue was found to have a high metabolic rate in both control and postprandial toadfish, with respect to that of the whole animal, and shows a considerable specific dynamic action (SDA) response to feeding. Overall, this dissertation provides evidence for the widespread use of intestinal HCO3- secretion as a strategy of marine osmoregulation across aquatic taxa, and also for its newly recognized involvement in postprandial acid-base balance.

Acid/base and metal ion adsorption properties have been investigated for a range of chemically modified bleached Kraft fibre materials (pulps). The studies were performed via potentiometric titrations, Flame Atomic Absorbtion (and Emission) Spectroscopy, Inductively Coupled Plasma Optical Emission Spectroscopy and Extended X-ray Absorbtion Fine Structure measurements. As a result of a chemical modification procedure, the total concentration of acidic carboxylate groups in the fibre materials ranged between 43 and 590 μmol/g. The preferable surface potential model for modelling the ionic strength dependent acid/base properties of fibre materials with low charge densities, i.e. unmodified fully bleached Kraft fibre materials, was found to be the Basic Stern Model. For fibre materials with high total charge, ≳100 μmol/g, this model resulted in poor fits to data, and for such materials a number of Constant Capacitance Models, one at each ionic strength, must be recommended. With respect to metal ion adsorption, the results have indicated that the unspecific Donnan theory could correctly model the simultaneous adsorption of several metal ions, i.e. K+, Na+, Mg2+, Ca2+ and Cu2+, provided that the salt concentration in the fibre suspension is low. In suspensions of high salt concentration it was, however, found that this very same model strongly underestimated the adsorption of Ca2+ and Cu2+. Here, the Donnan model had to be complemented by specific ion exchange equilibria. These results were corroborated by spectroscopic evidence of specific interactions between Cu2+-ions and fibres. The spectroscopic indication of a complex formed between two fibre surface carboxylate groups and one Cu2+-ion, agree with the specific ion exchange model. It was therefore concluded that specific metal ionfibre interactions cannot be neglected, especially at high salt concentrations. The interactions occurring between the polycation GaO4Al12(OH)24(H2O)127+ and fibre materials were studied by both adsorption and spectroscopic measurements. These indicate that GaO4Al12(OH)24(H2O)127+ is surprisingly stable in fibre suspensions and that intact GaO4Al12(OH)24(H2O)127+- ions are strongly adsorbed onto the fibres. Also for this ion, specific interactions has to be considered, since the strong adsorption registered was too strong to be explained by Donnan equilibria. In the thesis, the stochiometric composition and an equilibrium constant characterising these interactions is presented.

Goldfish undergo an adaptive morphological change in their gills involving the reversible growth and loss of a mass of cells (interlamellar cell mass, ILCM) in between the lamellae depending on oxygen demand, which can be altered by the environment or metabolic demands of the individual. The ILCM contributes to decreased passive Na+ efflux across the gill. Active uptake is maintained by the re-distribution of the ionocytes expressing Na+-uptake relevant genes (NHEs and H+-ATPase) to the outer edge of the ILCM where they can establish contact with the external environment and/or lamellar epithelium. This adaptation is thought to be partly responsible for the extreme anoxia tolerance demonstrated by goldfish, which they experience on a seasonal basis living in a pond environment. Hypoxia and hypercapnia are frequently encountered in such freshwater environments and as such, the effect of the ILCM on the capacity for acid-base regulation was evaluated. Differences in the time course of acid excretion to the environment without effect on systemic pH regulation were likely the result of the ILCM.

Goldfish undergo an adaptive morphological change in their gills involving the reversible growth and loss of a mass of cells (interlamellar cell mass, ILCM) in between the lamellae depending on oxygen demand, which can be altered by the environment or metabolic demands of the individual. The ILCM contributes to decreased passive Na+ efflux across the gill. Active uptake is maintained by the re-distribution of the ionocytes expressing Na+-uptake relevant genes (NHEs and H+-ATPase) to the outer edge of the ILCM where they can establish contact with the external environment and/or lamellar epithelium. This adaptation is thought to be partly responsible for the extreme anoxia tolerance demonstrated by goldfish, which they experience on a seasonal basis living in a pond environment. Hypoxia and hypercapnia are frequently encountered in such freshwater environments and as such, the effect of the ILCM on the capacity for acid-base regulation was evaluated. Differences in the time course of acid excretion to the environment without effect on systemic pH regulation were likely the result of the ILCM.