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.

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.

Das Ziel dieser Arbeit war es, den Einfluss unterschiedlich zusammengesetzter Tränken auf den Säuren-Basen-Haushalt bei Kälbern mit experimentell induzierter metabolischer Azidose zu untersuchen. Bei gesunden Kälbern konnte nachgewiesen werden, dass die Fütterung von milchbasierten ORL mit einer [SID3] ≥92 mmol/l eine Erhöhung der Plasma-[SID3] zur Folge hat (BACHMANN et al. 2009b) und damit eine alkalische Wirkung auf den SBS. Zu prüfen galt die Hypothese, ob es bei Kälbern mit experimentell induzierter metabolischer Azidose zu einem stärkeren alkalisierenden Effekt nach Gabe einer Tränke mit einer hohen [SID3] kommt. Bessere alkalisierende Eigenschaften einer Tränke könnten potentiell genutzt werden, um den Genesungsprozess von Kälbern mit metabolischer Azidose zu beschleunigen. Material und Methoden Zur Verfügung standen zwölf Kälber der Rasse Holstein-Friesian im Alter von weniger als vier Lebenswochen. Unter Verwendung von in der Literatur beschriebenen Induktionsprotokollen konnte per Infusion bei jeweils sechs Tieren eine manifeste hyperchlorämische Azidose und bei weiteren sechs Kälbern eine D-/L-Laktatazidose ausgelöst werden. Die Tiere wurden im Anschluss mit Milchaustauscher, wasser- oder milchaustauscher-basierter oraler Rehydratationslösung getränkt bzw. blieben im nüchternen Zustand. Zur Bestimmung von Stewart-Parametern des Säuren-Basen-Haushaltes im Plasma wurden nach einem festgelegten zeitlichen Schema vor und nach Induktion sowie vor und nach der Tränkegabe venöse Blutproben entnommen. Ergebnisse Bedingt durch die Einleitungsprotokolle war die Interpretation der Messergebnisse durch den starken Anstieg des Plasmavolumens bedeutend erschwert. Die eingesetzten Induktionsprotokolle sind nicht für Untersuchungen des Säuren-Basen-Haushaltes bei Kälbern nach unterschiedlicher Fütterung geeignet. Aus diesem Grund kann die aufgestellte Hypothese, dass die Verabreichung von milchaustauscher-basierter ORL zu einer besseren alkalischen Wirkung bei Kälbern mit metabolischer Azidose führt, anhand der vorliegenden Ergebnisse weder abgelehnt noch bestätigt werden. Einige Untersuchungsergebnisse zeigten positive Effekte auf Parameter des SBS bei Kälbern, denen eine Tränke verabreicht wurde, im Vergleich zu nüchternen Tieren. Diese Parameter waren die Plasma-D-Laktatkonzentration, die Strong Ion Difference [SID3] und [SID4] und ionisiertes Calcium [Ca2+]. Die Effekte waren nicht auf eine bestimmte der drei eingesetzten Tränkevarianten zurückzuführen. Weiterhin konnte gezeigt werden, dass ein quadratischer Zusammenhang zwischen der berechneten Variable Strong Ion Gap [SIGAlb/TP] und den gemessenen D-/L-Laktatkonzentrationen im Plasma besteht. Dies könnte zukünftig genutzt werden, um Faktoren zu etablieren, welche die Ableitung der Plasma-D-/L-Laktatkonzentration bei durchfallkranken Kälbern mit ZNS-Symptomatik aus gängigen Parametern ermöglicht, ohne die Laktatkonzentration direkt messen zu müssen. Schlussfolgerungen Für zukünftige Untersuchungen dieser Art wäre ein Induktionsprotokoll wünschenswert, das sowohl eine metabolische Azidose bei gleichzeitiger Dehydratation der Kälber vereint und so die metabolischen Bedingungen durchfallkranker Kälber simuliert. Die Gabe von ORL als direkte Einmischung in Milch bzw. MAT wird kritisch betrachtet. Ein negativer Effekt bei der Gabe von MAT-basierter ORL konnte bei diesen Untersuchungen auf keinen der bestimmten Parameter des SBS im Vergleich zu den anderen Tränkezusammensetzungen festgestellt werden. Klinische Nebenwirkungen Bei dieser Untersuchung traten nach der mehrfachen Infusion von D-/L-Laktat unerwartete Nebenwirkungen auf. Die Verabreichung führte zu starken Irritationen der Vena jugularis externa und zu Ödembildungen. Erhöhte D-Laktatkonzentrationen werden beim Menschen und verschiedenen Tierarten als Marker für traumatische Prozesse, Ischämie, Diabetes, gastrointestinale und neurologische Störungen diskutiert. Die weitere gezielte Untersuchung des Einflusses der wiederholten oder anhaltenden Einwirkung von D-Laktat auf Epithelzellen könnte nach den vorliegenden Untersuchungsergebnissen einen weiteren Anhaltspunkt für die Aufklärung der genauen pathologischen Mechanismen des D-Laktates bieten.

Silicone polymers and network-materials have proven extremely useful in a variety of applications owing to their superb properties when compared to carbon-based polymers. Polysiloxanes containing functional groups other than simple alkyl moieties have allowed for further manipulations of pendant groups along the polymer backbone leading to a greater range of possible chemical transformations, as well as changes in physical/interfacial properties. One aspect of functional polymers that has yet to be explored with respect to primarily silicone-based systems is that of stimuli-responsive materials. In order for this unique application to work, silicones must be functionalized with a group or groups that can influence the polymer’s properties based on that group’s response to specific external stimuli. Boronic acids represent one such group, wherein the most common stimuli used to affect changes in ionization state and solubility are pH and diol-binding. Boronic acids are also capable of forming weak hydrogen-bonded dimers with other boronic acids, and dynamic covalent bonds with Lewis bases. It is proposed that the covalent attachment of boronic acids and their derivatives onto silicones could lead to stimuli-responsive silicone materials. Herein, the synthesis of silicone-boronic acids and their protected boronic esters is described. The simple two-step method involving boronic acid protection followed by hydrosilylation has led to a variety of molecules differing in molecular weight and three-dimensional geometry through the use of commercially available hydride-functional silicones. Initial results regarding saccharide binding selectivity and the impacts on silicone solubility are provided. The unique interfacial behaviour of silicone-boronic esters and their propensity to form self-assembled, crosslinked films at an air/water interface are also reported. Using several different diol protecting groups and a variety of aqueous sub-phases, the mechanism for changes in physical properties as well as crosslinking were revealed. Finally, the production of new thermoplastic silicone elastomers from silicone-boronic esters and amine-containing molecules is discussed. The Lewis acid/Lewis base complexation that occurs between nitrogen and boron can provide enough strength to produce robust, yet recyclable, silicone elastomers without the use of catalyst or solvent. Elastomers can be easily dissolved and reformed through the introduction and removal of a mono-functional Lewis base. The impact of crosslink density, controlled by the quantities and molecular weights of each polymer component used, on physical characteristics is reported. / Thesis / Doctor of Philosophy (PhD)

No description available.

Este trabajo presenta un catálogo de técnicas y patrones de diseño aplicados actualmente en bases de datos NoSQL. El enfoque propuesto consiste en una presentación del estado del arte de las bases de datos NoSQL, una exposición de los conceptos claves relacionados y una posterior exhibición de un conjunto de técnicas y patrones de diseño orientados a la escalabilidad y alta disponibilidad. Para tal fin, • Se describen brevemente las características principales de los bases de datos NoSQL, cuales son los factores que motivaron su aparición, sus diferencias con sus pares relacionales, se presenta el teorema CAP y se contrasta las propiedades ACID contra las BASE. • Se introducen las problemáticas que motivan las técnicas y patrones de diseño a describir. • Se presentan técnicas y patrones de diseños que solucionen las problemáticas. • Finalmente, se concluye con un análisis integrador, y se indican otros temas de investigación pertinentes.

The current generation of Glass Ionomer Cements (GICs) have many advantageous properties over other dental restorative materials but lack the compressive strength of these other materials. The aim of this project is to increase the compressive strength of conventional Glass Poly-Vinyl-Phosphonate cement by inclusion of reactive sub-micron filler particles. The setting characteristics, chemical reactivity and cement strength have been found using oscillating rheology, infrared spectrometry, nuclear magnetic spectrometry, transmission electron microscopy, potentiometer analysis, laser diffractometry and mechanical analysis. The addition of sub-micron filler particles in direct weight by weight replacement of aluminosilicate glass of a control material has increased the ultimate compressive strength of the new cement from 206MPa (control) to 250MPa after 365 days of aging. The strength of the new filler enhanced cements were comparable with the control material after 3 hours. The setting chemistry of the filler enhanced cements follows the same order as the control cement but at a decelerated rate. Theoretical modelling found that a large volume of sub-micron filler could fit into interstitial spacing in formed cement however the alteration of the aluminosilicate glass to polyelectrolyte ratio has been found to drastically alter the cement setting time. The use of cubic and polyhedral shaped filler particles as supposed to spherical particles may increase the cement strength further as greater packing densities are achieved. The formulation of a Glass Ionomer Cement with increased compressive strength may find use as a posterior restorative or as a better material for restoration of lesions and cavity liners.

Der Schwarzkäfer Zophobas rugipes lebt in Höhlen im Dung von Fledermäusen. Die Puppen entwickeln sich in dieser Guanoschicht innerhalb von 9 - 12 Tagen. Sie zeigen während der gesamten Entwicklung den für ruhende Insekten typischen diskontinuierlichen Gasaustausch. Die Umgebungsluft im Guano kann durch Zersetzungsprozesse und Luftabschluss wenig Sauerstoff und viel Kohlendioxid enthalten. Die Puppen müssen daher in der Lage sein, externe Hypoxie oder Hyperkapnie zu tolerieren. Da die Stoffwechselrate zu Beginn und zum Ende des Puppenstadiums relativ hoch ist, ändern sich zusätzlich die internen Anforderungen an den Atemgastransport. Ungünstige Lebensbedingungen und sich im Laufe der Entwicklung ändernde Stoffwechselraten erfordern eine respiratorische und metabolische Anpassung der Puppen. Die vorliegende Arbeit untersucht, welchen Einfluss metabolisch gebildetes und atmosphärisches Kohlendioxid auf den Säure-Basen-Haushalt der Puppen von Zophobas rugipes hat. Untersuchungen des Wassergehalts der Puppen zeigte während der gesamten Entwicklung konstante Werte um 60 %. Die Volumina von HL und Gewebe änderten sich durch Histolyse, Histogenese und Resorption von Exuvialflüssigkeit. Die HL zeigte das für omnivore Insekten charakteristische Ionenmuster mit einem [Na+]-[K+]-Verhältnis von 2,4. [Mg2+] in der HL betrug zu Beginn der Entwicklung 83 meq/l. [Mg2+] und [Cl-] in der HL fielen im Laufe der Entwicklung ab. Protein- und Aminosäurekonzentrationen änderten sich uneinheitlich. Die Nettoladung der Aminosäuren war während des gesamten Puppenstadiums positiv. Von den proteinogenen Aminosäuren fehlten in der HL Aspartat und Methionin. Prolin diente als Energielieferant. Phenyalanin und Tyrosin wurden zu Beginn des Entwicklung bei der Sklerotisierung metabolisiert und später wieder angereichert. Tryptophan wurde zunächst angereichert und zum Ende der Entwicklung zum Aufbau von Ommochromen verwendet. CO2-Kapazitanz und Puffereigenschaften der Kompartimente änderten sich während der gesamten Entwicklung nicht. Die hohe CO2-Kapazitanz der HL spiegelte sich in einer hohen Bikarbonatkonzentration wider. Der in vitro bestimmte Nichtbikarbonatpufferwert (betaNB) betrug 17,0 meq/(l*pH) in der HL und 59,3 meq/(l*pH) im Gewebe. Änderungen des Stoffwechsels während der Entwicklung wurden respiratorisch und nicht durch Anpassung von CO2-Kapazitanz oder betaNB kompensiert. Messung von atmungsabhängigen Änderungen des pH-Werts in der HL erfolgte durch Implantation von pH-Mikro-Glaselektroden an 26 Puppen. Der pH-Wert der HL in vivo betrug 6,65 - 7,11. Die Implantation von pH-Elektroden verursachte eine Erhöhung der Stoffwechselrate und eine Verkürzung der Zyklusdauer. Während der Öffnungsperioden stieg der pH-Wert um etwa 0,01 Einheiten je 100 nmol/g CO2 an. Die Verletzung durch die Implantation verursachte eine metabolische Azidose. Diese Azidose wurde durch den Verlust von Bikarbonat, das als CO2 abgeatmet wurde, respiratorisch kompensiert. Gleichzeitig sank der PCO2 in der HL auf Werte unter 25,8 Torr (3,4 kPa). Eine experimentell induzierte Hyperkapnie wurde metabolisch kompensiert. Als Folge stieg der betaNB der HL auf 37,7 meq/(l*pH). Je höher der in der HL gemessene pH-Wert, desto kürzer waren Zyklusdauer und Dauer der Öffnungsperiode. Dieser Zusammenhang gab Hinweise auf eine Atemregulation durch Wahrnehmung von pH-Wert-Änderungen. / The tenebrionid beetle Zophobas rugipes inhabits caves, living in the dung of bats. The pupal stages develop in 9 to 12 days under a layer of guano. Gas exchange is cyclic and discontinuous during entire pupal development. During development, the atmosphere in the dung may become hypoxic and hypercapnic, extreme environmental conditions to be tolerated by the pupae. Since metabolic rate is relatively high in the beginning and the end of the pupal stage, the pupae have to cope with varying internal respiratory conditions. Extreme environmental conditions and varying metabolic rates have to be compensated by respiratory and metabolic adaptations. This study deals with the effects of metabolic and atmospheric carbon-dioxide on the acid-base-status of pupae of Zophobas rugipes, preceded by an investigation of volume, water-content, and soluble components of haemolmyph and tissue, respectively. Water content of the pupae was rather constant around 60 % during the entire pupal stage. Volumes of haemolymph and tissue changed by histolysis, histogenesis and resorption of exuvial fluid. The ratio between [Na+] and [K+] in the haemolymph (2,4) was typical for omnivorous insects. [Mg2+] in the haemolymph was high in the beginning (83 meq/l), but decreased similar to the pattern for [Cl-] during pupal development. Protein concentration and amino acid concentrations varied irregularly. The sum of amino acid charge was positive. Aspartate and Methionine were not detected in the haemolymph. Proline was used as an energy source. Phenylalanine and Tyrosine were metabolised for sclerotisation in the beginning of the pupal stage and were accumulated during the rest of the development. Tryptophane was accumulated in the beginning of pupal development and was then used as a source for ommochromes. CO2-capacitance and non-bicarbonate buffer-value (betaNB) of haemolymph and tissue did not change during pupal development. They were independent of the changes in concentration of the examined ingredients. The high value of CO2-capacitance was related to a high [HCO3-]. betaNB in vitro was 17,0 meq/(l*pH) in the haemolymph and 59,3 meq/(l*pH) in the tissue. Metabolic changes were compensated by respiratory adjustments rather than by adaptation of CO2-capacitance or betaNB. Respiratory changes in haemolymph-pH were recorded by implantation of pH-micro-glas-electrodes in 26 pupae. Haemolymph-pH in vivo was found to be 6,65 - 7,11. Electrode implantation caused an increase of metabolic rate and diminished the duration of the respiratory cycle. Haemolymph-pH increased during the opening periods with about 0,01 units per 100 nmol/g CO2. Injuring the pupae by implantation of electrodes resulted in a development of metabolic acidosis. This was compensated by buffering action of bicarbonate and expiration of CO2. As a consequence, PCO2 decreased to values lower than 25,8 Torr (3,4 kPa). During elevated atmospheric PCO2, the resulting respiratory acidosis was compensated metabolically. As a consequence, betaNB increased to a value of 37,7 meq/(l*pH). The higher pH in the haemolymph, the shorter was the duration of the respiratory cycle and the opening period. This coincidence is possibly an expression of regulation of respiration by perception of changes in pH.

A acidose metabólica causa perda de mineral ósseo e a estimulação mecânica causa remodelamento ósseo adaptativo. A reabsorção óssea que caracteriza essas mudanças ósseas depende da acidificação extracelular pela secreção vetorial de H+ pelos osteoclastos. A H+-ATPase vacuolar em paralelo com o trocador Cl-/H+ (CLC7) são os mecanismos conhecidos envolvidos na reabsorção óssea, entretanto, os osteoclastos também expressam canais para H+ dependentes a voltagem. Este trabalho foi realizado para avaliar a contribuição dos canais para H+ na função celular visando à compreensão de seu relacionamento com a H+-ATPase vacuolar e o CLC7 (1); analisar se o fluxo de fluido extracelular modifica a secreção de H+ (2) e avaliar a diferenciação dos osteoclastos in vitro sob acidose metabólica devido à redução do HCO3- (3). Osteoclastos de ratos Wistar foram obtidos diretamente dos animais ou foram diferenciados in vitro (com M-CSF e RANKL) e semeados sobre vidro, plástico ou substratos mineralizados em <font face=\"Symbol\">&#945;-MEM + 10% SFB, em pH 7,4 ou 6,9, e então mantidos em incubadora com 5% CO2, a 37<font face=\"Symbol\">&#176;C. A diferenciação celular foi avaliada pela contagem de células TRAP-positivas ou de núcleos marcados por DAPI. A secreção de H+ foi avaliada por epifluorescência, utilizando-se BCECF-AM, sensível a pH. Os registros do pH intracelular foram feitos na vigência de soluções tamponadas por HEPES, na ausência de CO2/HCO3- (pH 7,4, 300 mOsm/L H2O, a 37<font face=\"Symbol\">&#176;C), na presença ou ausência de perfusão contínua de fluido extracelular a uma velocidade de 5 ml/min. Na ausência de perfusão, os osteoclastos exibiram variações cíclicas do pHi (acidificação e alcalinização espontâneas), com período de 12 a 45 minutos (n = 35) e amplitude de 0,12 a 1,43 unidades de pHi. As oscilações não foram abolidas por concanamicina (100 mM) (n = 3), por NPPB (100 <font face=\"Symbol\">mM) (n = 3), na ausência de Na+ extracelular (n = 5) ou na ausência de Cl- extracelular (n = 3). O fluxo de fluido aboliu as oscilações e a ausência de Cl- extracelular modificou significativamente seu padrão. Na ausência de perfusão, a secreção de H+ após acidificação intracelular induzida foi abolida por Zn2+ (100 <font face=\"Symbol\">mM) (n = 5). Além disso, na presença de perfusão, a secreção de H+ após acidificação intracelular induzida foi abolida por NPPB (n = 4) e não foi abolida por bafilomicina (200 nm) (n = 3). A acidose metabólica não modifica o número de osteoclastos diferenciados in vitro, entretanto, o tratamento das culturas com Zn2+ causou redução do numero de células mononucleares e aumento relativo do número de osteoclastos multinucleados em relação ao controle tanto em pH 7,4 quanto em pH 6,9. / Metabolic acidosis can cause a loss of bone mineral and the mechanic stimulation can cause adaptative bone remodeling. The bone resorption characteristic of these bone changes aforementioned depends on the extracellular acidification by osteoclastmediated proton secretion. The H+ secretion by vacuolar H+-ATPase together with Clsecretion through a Cl-/H+ exchanger (CLC7) are the known mechanisms involved in the bone resorption; however, osteoclasts also express voltage-gated proton channels. The proposed aims of these work were to evaluate the contribution of proton channels in the osteoclast function for better understanding its relation with vacuolar H+-ATPase and CLC7 (1); to analyze whether the flow of extracellular fluid modifies the H+ secretion or not (2); and to analyse the osteoclast differentiation in vitro under metabolic acidosis due to HCO3- reduction (3). Osteoclasts were freshly isolated or generated from bone marrow precursor cells (using M-CSF and RANK- L) from of Wistar rats. The cells were placed on glass coverslips, plastic coverslips, or on mineralized substrate in <font face=\"Symbol\">&#945;-MEM + 10% FBS, pH 7.4 or 6.9, and then maintained in a 5% CO2 incubator at 37<font face=\"Symbol\">&#176;C. The differentiation was analyzed by counting of TRAP-stained cells or DAPIstained nuclei. The H+ secretion was analysed by epifluorescence, using the pHsensitive dye BCECF-AM. The intracellular pH record was done using a standard HEPES-buffered solution free of CO2/HCO3- (pH 7.4, 300 mOsm/L H2O, at 37<font face=\"Symbol\">&#176;C), with or without continuous perfusion of extracellular fluid at a rate of 5 ml/min. In the absence of perfusion, the osteoclasts exhibit cyclic pHi variations (spontaneous acidification and alkalinization), with a period of 12 to 45 minutes (n = 35) and amplitude difference between maximal and minimal pHi of 0.12 to 1.43 units pHi. These oscillations were not abolished in the presence of oncanamycin (100 mM) (n = 3), NPPB (100 <font face=\"Symbol\">mM) (n = 3), in the absence of Na+ (n = 5) or in the absence of Cl- (n = 3) in the extracellular solution. The fluid flow itself abolished the pH oscillations and the absence of extracellular Cl- modifies significantly these patterns. In the absence of perfusion, the H+ secretion after induced intracellular acidification was abolished by Zn2+ (100 <font face=\"Symbol\">mM) (n = 5). In addition, in the presence of perfusion, the H+ secretion after induced intracellular acidification was abolished by NPPB (n = 4) and was not abolished by bafilomycin (200 nm) (n = 3). Metabolic acidosis does not modify the number of osteoclasts differentiated in vitro, however, when the cell culture was treated with Zn2+, there was a significant reduction in the number of mononuclear cells and a relative increase in the number of multinucleated osteoclasts compared to control, both in pH 7.4 and pH 6.9 medium.

Justificativa e Objetivos: Acidose é uma desordem muito frequente em pacientes cirúrgicos. Neste cenário, permanecem incertas as implicações clínicas da acidose e características de cada tipo. Portanto, é relevante tentar elucidar o papel de cada tipo de acidose no prognóstico de pacientes cirúrgicos de alto risco. Método: Trata-se de estudo multicêntrico observacional prospectivo, realizado em três diferentes hospitais. Os pacientes que necessitassem no pós-operatório de cuidados intensivos foram incluídos no estudo consecutivamente. Pacientes com baixa expectativa de vida (câncer sem perspectiva de tratamento), pacientes com insuficiência hepática (child B ou C), insuficiência renal (Clearence de creatinina < 50 mL/min ou hemodiálise prévia), diagnóstico de diabetes previamente foram excluídos. Os pacientes classificados na admissão da UTI quanto ao tipo de acidose que desenvolviam no pós-operatório imediato foram acompanhados até 30 dias e alta hospitalar. Tal classificação avaliou acidose metabólica, pela quantificação da diferença de base menor que -4 mmol/L, anion gap corrigido pela albumina (AG) e lactato aumentados, quando maiores que 12 e 2 mmo/L, respectivamente. Então, os pacientes foram classificados como acidose metabólica hiperlactatemica, aumentado e normal (hipercloremica) anion gap corrigido pela albumina. Resultados: O total de 618 pacientes foram incluídos durante dois anos. A incidência de acidose metabólica foi 59,1% na UTI, porém 148 (23,9%) apresentaram hipercloremica, 131 (21,2%) revelaram hiperlactatemia, 86 (13,9%) AG aumentado e em 253 (40,9%) não ocorreu acidose metabólica. Dentre todas as cirurgias, pacientes de cirurgia gastrointestinal foram associados a maiores porcentagens de acidose metabólica 46,2% versus 19,8% sem acidose, P < 0,05. Interessantemente, acidose com hipercloremia apresentou mais altos valores de cloro na admissão da UTI 115,0 ± 5,7 meq/L (P < 0,05) e receberam maiores quantidades de solução fisiológica 0,9% no intraoperatório 3000,0 (2000,0 - 4000,0) mL (P < 0,05). Entretanto, apesar dos pacientes não apresentarem diferenças entre escores de gravidade (SAPS 3, SOFA e ASA), idade e tempo cirúrgicos, ocorreram diferenças em relação a complicações e mortalidade no pós-operatório quando os pacientes mantinham acidose após 12 horas de pós-operatório. Pacientes com lactato e AG aumentados no pós-operatório imediato apresentaram maiores complicações, seguido dos pacientes com hipercloremia, e os sem acidose, respectivamente 68,8%; 68,6%; 65,8% e 59,3%, P = 0,03. Cardiovascular e renal disfunções foram as principais complicações e o grupo hiperlactatemia mostrou maior incidência em comparação aos outros grupos. O mesmo foi verificado em relação à mortalidade hospitalar e em 30 dias de seguimento os grupos hiperlactatemia, AG aumentado, hipercloremicos e sem acidose foram respectivamente 30,1% (HR 1,61, IC 95% 1,02 - 2,53); 24,3% (HR 1,37, IC 95% 0,76 - 2,46); 18,4% (HR 1,55, IC 95% 0,90 - 2,67) e 10,3%, Log-Rank = 0,03. Conclusão: A incidência de acidose metabólica em pacientes cirúrgicos de alto risco no pós-operatório é elevada, principalmente a do tipo hipercloremia. Pacientes cirúrgicos que desenvolvem acidose metabólica, dependendo das características, apresentam piores prognósticos em relação aos pacientes sem acidose, além disso, este estudo demonstra que diferentes etiologias de acidose metabólica estão associadas com diferentes taxas de mortalidade e morbidade no pós-operatório / Background: Acidosis is a very frequent disorder in surgical patients. In this patient set there remains uncertainty the clinic implications from acidosis and characteristics postoperatively. Therefore, it is very important to evaluate the role of each acidosis type in outcome for high-risk surgical patients. Methods: Multicenter prospective observational study was performed in three different hospitals. The patients who needed postoperative ICU were involved in the study consecutively. Patients with low life expectancy (cancer without treatment), hepatic failure, renal failure, and diabetic diagnosis were excluded. The patients were followed until 30 days and hospital discharge. On ICU admission, immediately postoperative period, the patients were classified to each type of acidosis. The classification evaluated metabolic acidosis as base excess < -4 mmol/L and high albumin-corrected anion gap (AG) and hyperlactatemia, both > 12 and > 2 mmol/L, respectively. So, the metabolic acidosis classification patients were related to hyperlactatemic, high and normal (hyperchloremic) albumin-corrected anion gap. Results: The study enrolled 618 patients during 2 years. Overall, the acidosis incidence was 59.1% on ICU admission, 148 (23.9%) hyperchloremic, 131 (21.2%) hyperlactatemia, 86 (13.9%) a high anion gap and in 253 (40.9%) there was no metabolic acidosis. The hyperchloremic group presented the highest chlorine level, 115.0 ± 5.7 meq/L (P < 0.05) and highest administration of 0.9% physiologic solution intraoperatively, 3000,0 (2000,0 - 4000,0) mL (P < 0.05). However, in spite of patients didn\'t present difference in profile demographic and score prognostic, those who remain after 12 hours with acidosis, depend on groups classification in postoperatively showed greater ICU complications, respectively, hyperlactatemia group 68.8%; high anion gap 68.6%; hyperchloremic 65.8% and no acidosis 59.3%, P = 0.03. Cardiovascular and renal dysfunctions were the main complications and hyperlactatemia group showed the highest in all of them. The same was verified in related to 30 days follow-up and hospital mortality rate respectively 30.1% (HR 1.61, IC 95% 1.02 - 2.53) hyperlactatemic; 24.3% (HR 1.55, IC 95% 0.90 - 2.67) high anion gap; 18.4% (HR 1.37, IC 95% 0.76 - 2.46) hyperchloremic and 10.3% no acidosis group, Log-Rank = 0.03. Conclusions: Metabolic acidosis in surgical patients is a very important complication postoperatively, mainly hyperchloremic. Patients who developed metabolic acidosis postoperatively depend on group classification presented worst outcomes compared to no acidosis patients; this result showed that different kinds of acidosis represented different outcomes postoperatively