ABSTRACT
Maintaining normal pH levels in the body fluids is essential for homeostasis and represents one of the most tightly regulated physiological processes among vertebrates. Fish are generally ammoniotelic and inhabit diverse aquatic environments that present many respiratory, acidifying, alkalinizing, ionic and osmotic stressors to which they are able to adapt. They have evolved flexible strategies for the regulation of acid-base equivalents (H+, NH4 +, OH- and HCO3 -), ammonia and phosphate to cope with these stressors. The gills are the main regulatory organ, while the kidneys play an important, often overlooked accessory role in acid-base regulation. Here we outline the kidneys role in regulation of acid-base equivalents and two of the key 'urinary buffers', ammonia and phosphate, by integrating known aspects of renal physiology with recent advances in the molecular and cellular physiology of membrane transport systems in the teleost kidneys. The renal transporters (NHE3, NBC1, AE1, SLC26A6) and enzymes (V-type H+ATPase, CAc, CA IV, ammoniagenic enzymes) involved in H+ secretion, bicarbonate reabsorption, and the net excretion of acidic and basic equivalents, ammonia, and inorganic phosphate are addressed. The role of sodium-phosphate cotransporter (Slc34a2b) and rhesus (Rh) glycoproteins (ammonia channels) in conjunction with apical V-type H+ ATPase and NHE3 exchangers in these processes are also explored. Nephrocalcinosis is an inflammation-like disorder due to the precipitation of calcareous material in the kidneys, and is listed as one of the most prevalent pathologies in land-based production of salmonids in recirculating aquaculture systems. The causative links underlying the pathogenesis and etiology of nephrocalcinosis in teleosts is speculative at best, but acid-base perturbation is probably a central pathophysiological cause. Relevant risk factors associated with nephrocalcinosis are hypercapnia and hyperoxia in the culture water. These raise internal CO2 levels in the fish, triggering complex branchial and renal acid-base compensations which may promote formation of kidney stones. However, increased salt loads through the rearing water and the feed may increase the prevalence of nephrocalcinosis. An increased understanding of the kidneys role in acid-base and ion regulation and how this relates to renal diseases such as nephrocalcinosis will have applied relevance for the biologist and aquaculturist alike.
ABSTRACT
Tityus serrulatus is the most venomous scorpion in Brazil. Little is known about the effects of maternal exposure to venom and serum therapy on fetal development. The effect of moderate doses of venom (4mg/kg s.c.) on the second (GD2) or tenth (GD10) day of pregnancy in pregnant rats and their offspring was investigated, as well as the effect of serum therapy (2 doses of 0.2ml i.p.). The females were evaluated for their weight gain, reproductive and dietary parameters. GD2 and GD10 females exposed to the venom showed an increase in water intake, indicating physiological changes in these females, due to the direct or indirect action of the venom on their bodies. In the pups, their weights and respective organs (placenta, kidneys, liver, heart and lungs), number of live or dead pups and visceral and skeletal abnormalities on the 21st gestational day were observed. Pups of females exposed to the venom in GD2 showed a decrease in the weight of the placentas in relation to the groups that were not exposed, while in GD10 there was a decrease in the weight of the pups and their organs in relation to the groups that were not exposed, indicating that the exposure to T. serrulatus venom results in alterations in the development of rat pups during the gestational period. The group poisoned and treated with serum showed no changes, indicating that the serum was somehow able to neutralize the effects caused by the venom. In addition, the group treated both in GD2 and in GD10 with serum alone showed almost no change, except for an increase in the heart weight of pups in GD2. All these data show advantages of serum therapy during pregnancy, nullifying the deleterious effects of exposure to venom during the prenatal period.
Tityus serrulatus é o escorpião mais peçonhento do Brasil. Pouco se sabe dos efeitos da exposição materna à peçonha e à soroterapia no desenvolvimento fetal. Investigou-se o efeito de doses moderadas da peçonha (4mg/kg s.c.) no segundo (GD2) ou décimo (GD10) dia da gestação em ratas prenhes e seus filhotes, bem como o efeito do tratamento soroterápico (2 doses de 0,2ml i.p.). As fêmeas foram avaliadas quanto a seu ganho de massa, parâmetros reprodutivos e dieta. Fêmeas de GD2 e GD10 expostas à peçonha apresentaram aumento na ingestão de água, indicando alterações fisiológicas destas fêmeas, devido à ação direta ou indireta da peçonha em seus organismos. Nos filhotes foram observados suas massas e respectivos órgãos (placenta, rins, fígado, coração e pulmão), número de filhotes vivos ou mortos e anomalias viscerais e esqueléticas no dia 21 gestacional. Filhotes de fêmeas expostas à peçonha em GD2 apresentaram diminuição na massa das placentas em relação aos grupos que não foram expostos, enquanto em GD10 observou-se diminuição da massa dos filhotes e de seus órgãos em relação aos grupos que não foram expostos, indicando que a exposição à peçonha de T. serrulatus resulta em alterações no desenvolvimento de filhotes de ratas no período gestacional. O grupo envenenado e tratado com soro não apresentou mudanças significativas, indicando que o soro de certa forma foi capaz de neutralizar os efeitos causados pela peçonha. Além disso, tanto em GD2 quanto em GD10 o grupo tratado somente com o soro não apresentou quase nenhuma alteração, salvo aumento da massa do coração de filhotes em GD2. Todos estes dados indicam vantagens do tratamento soroterápico, podendo anular os efeitos deletérios da exposição à peçonha no período pré-natal.
ABSTRACT
BACKGROUND: Various complications after ventriculoperitoneal (VP) shunt surgery have been reported, but peroral extrusion of peritoneal catheter is an extremely rare complication, and only 20 cases have been reported since 1987. The pathophysiology still remains unclear and the management is challenging. CASE DESCRIPTION: A 5-year-old boy presented with a catheter coming out of his mouth. The boy had a posterior fossa tumor surgery and had VP shunt insertion 1 year earlier. Clinical signs and imaging studies showed that the distal end of the catheter had perforated the gaster and migrated upward and extruded through the mouth. Emergency removal of the shunt and proper treatment were done and he made uneventful recovery. CONCLUSION: Peroral extrusion of VP shunt is extremely rare. Clinicians should be aware of this complication. With early diagnosis and proper management, the prognosis for good recovery is excellent, with only two deaths being reported in the literature. Complication of shunt extrusion is difficult to avoid, but knowing the risk factors, pathophysiology and proper management will decrease the morbidity and mortality of such cases.
ABSTRACT
Delirium is a complex syndrome caused most often by secondary neuronal dysfuncions due to systemic disorders. Because of the central nervous system manifestations of the general disease processes that are getting through the blood-brain barrier, the vigilance of attention flucutates and, therefore, the integration of incoming stimuli fails - resulting in inadequate behavioral answers. Delirium is one of the most common and serious complications of diseases, particularly in the elderly and patients in critical state. It cannot be traced back to a single etiologic process; one should consider all those pathophysiologic mechanisms that are interacting with one another simultaneously impairing the integrated functioning of the brain. Despite the high prevalence rate of delirium and the marked adverse effects on the outcome of the underlying disorders, management and therapy are basically lacking professional guidelines. The syndrome is a threatening state, requiring increased clinical attention and often intensive care. Beside evidence based therapeutic methods, conscious, targeted screening of the known risk factors and measures against them when they present themselves may exert remarkable influence on the prevention of delirium, which is also an exceptionally important aspect of the care of patients in critical state.
