Transcriptional activity and splicing factors are preserved during physiological apoptosis.

Apoptosis is the best-known programmed cell death that maintains tissue homeostasis in eukaryotic cells. The morphological characteristics include nuclear and cytoplasmic contraction and cytoplasmic blebbing, its biochemical hallmarks include caspase protease activity and DNA fragmentation. In rat ovaries, cell death is a normal process that occurs throughout the organism's life. Granulosa cells, the more abundant cell type forming the ovarian follicles, are eliminated via different routes of cell death. Most granulosa cells are eliminated through apoptotic cell death. In this work, we analyzed the behavior of nuclear components throughout the apoptotic process and determined how they are regionalized and conserved during follicular atresia in rat ovaries. Apoptosis was detected based on caspase-3 activity and DNA fragmentation using the TUNEL technique. We identified the transcription markers H3ac and RNA Pol II, and splicing factor SC35 by immunodetection. The nucleolar components were analyzed via light microscopy and transmission electron microscopy through immunodetection of the proteins nucleolin and nucleophosmin-1. The nuclear ultrastructure was analyzed using standard contrast and preferential ribonucleoprotein contrast. Our results demonstrate that during the progression of apoptosis, chromatin is remodeled to constitute apoptotic bodies; transcription and spliceosome elements are reorganized along with the nucleolar components. Additionally, the splicing and transcription factors are segregated into specific territories inside the apoptotic bodies, suggesting that transcriptional elements are reorganized during the apoptotic process. Our results indicate that apoptotic bodies not only are compacted, and chromatin degraded but all the nuclear components are progressively reorganized during cell elimination; moreover, the transcriptional components are preserved.

Dolor fantasma en niños y jóvenes amputados adquiridos: prevalencia y características clínicas / Phantom pain in children and teenagers with acquired amputations: prevalence an clinical features

Introducción: El dolor fantasma es una condición frecuente en pacientes amputados lo que genera discapacidad importante. En población adulta se estima una prevalencia entre 49-82 por ciento. Existe escasa evidencia de la incidencia y prevalencia en población de niños y adolescentes. Objetivos: Estimar la incidencia y la prevalencia del dolor fantasma en la población de amputados adquiridos del Instituto Teletón (IT) de Santiago de 10 años y más; caracterizar a esta población y asociar distintos factores clínicos y demográficos con la presencia de este dolor. Pacientes y Métodos: Estudio descriptivo de incidencia y prevalencia basado en la revisión de fichas clínicas para la obtención de datos demográficos, clínicos y evaluación de registro de dolor fantasma. Se aplicó encuesta telefónica a pacientes de 10 años o más, con diagnóstico de una o más amputación/es adquirida/s, que se atiendan o hayan sido atendido en IT Santiago hasta el año 2013. Resultados: La incidencia de dolor fantasma en la población estudiada es de 11 por 100 personas/año y prevalencia de 62 por ciento. Se encontraron asociaciones estadísticamente significativas, entre la presencia de dolor fantasma y el tiempo transcurrido desde la amputación (a mayor tiempo transcurrido, menor dolor) y edad de la amputación (a mayor edad en que se realizó la amputación mayor dolor). Conclusión: El dolor fantasma es un fenómeno frecuente en pacientes amputados adquiridos de 10 años y más atendidos en el IT de Santiago con una prevalencia del 62 por ciento.

Introduction: Phantom pain is a common condition in amputated patients generating significant disability. Prevalence among adult population is estimated at 49-82 percent. There is little evidence of the incidence and prevalence in child and adolescent population. Objectives: To estimate the incidence and prevalence of phantom pain in amputees aged 10 years and older of the Telethon Institute of Santiago; characterize this population and associate different clinical and demographic factors with the presence of phantom pain. Patients and Methods: Study incidence and prevalence based on a review of medical records to obtain demographic and clinical data. In addition a telephone survey was made to patients 10 years or older diagnosed with one or more acquired amputations who are treated or have been treated at Telethon Institute of Santiago until 2013. Results: The incidence of phantom pain in the study population is 11 per 100 persons/year and prevalence is 62 percent. Statistically significant associations were found between the presence of phantom pain variables and time since amputation (the longer the time elapsed, less pain) and age of amputation (the older the age at which major amputation was performed more pain). Conclusion: Phantom pain is a common phenomenon in patients with acquired amputation aged 10 years and older treated at the Telethon Institute of Santiago prevalence being 62 percent.

Effect of the ketamine/xylazine anesthetic on the auditory brainstem response of adult gerbils

The auditory brainstem response (ABR) is a test widely used to assess the integrity of the brain stem. Although it is considered to be an auditory-evoked potential that is influenced by the physical characteristics of the stimulus, such as rate, polarity and type of stimulus, it may also be influenced by the change in several parameters. The use of anesthetics may adversely influence the value of the ABR wave latency. One of the anesthetics used for e ABR assessment, especially in animal research, is the ketamine/xylazine combination. Our objective was to determine the influence of the ketamine/xylazine anesthetic on the ABR latency values in adult gerbils. The ABRs of 12 adult gerbils injected with the anesthetic were collected on three consecutive days, or a total of six collections, namely: pre-collection and A, B, C, D, and E collections. Before each collection the gerbil was injected with a dose of ketamine (100 mg/kg)/xylazine (4 mg/kg). For the capture of the ABR, 2000 click stimuli were used with rarefaction polarity and 13 stimuli per second, 80 dBnHL intensity and in-ear phones. A statistically significant difference was observed in the latency of the V wave in the ABR of gerbils in the C and D collections compared to the pre-, A and E collections, and no difference was observed between the pre-, A, B, and E collections. We conclude that the use of ketamine/xylazine increases the latency of the V wave of the ABR after several doses injected into adult gerbils; thus clinicians should consider the use of this substance in the assessment of ABR.

Effect of the ketamine/xylazine anesthetic on the auditory brainstem response of adult gerbils.

The auditory brainstem response (ABR) is a test widely used to assess the integrity of the brain stem. Although it is considered to be an auditory-evoked potential that is influenced by the physical characteristics of the stimulus, such as rate, polarity and type of stimulus, it may also be influenced by the change in several parameters. The use of anesthetics may adversely influence the value of the ABR wave latency. One of the anesthetics used for e ABR assessment, especially in animal research, is the ketamine/xylazine combination. Our objective was to determine the influence of the ketamine/xylazine anesthetic on the ABR latency values in adult gerbils. The ABRs of 12 adult gerbils injected with the anesthetic were collected on three consecutive days, or a total of six collections, namely: pre-collection and A, B, C, D, and E collections. Before each collection the gerbil was injected with a dose of ketamine (100 mg/kg)/xylazine (4 mg/kg). For the capture of the ABR, 2000 click stimuli were used with rarefaction polarity and 13 stimuli per second, 80 dBnHL intensity and in-ear phones. A statistically significant difference was observed in the latency of the V wave in the ABR of gerbils in the C and D collections compared to the pre-, A and E collections, and no difference was observed between the pre-, A, B, and E collections. We conclude that the use of ketamine/xylazine increases the latency of the V wave of the ABR after several doses injected into adult gerbils; thus clinicians should consider the use of this substance in the assessment of ABR.

Histamine is required during neural stem cell proliferation to increase neuron differentiation.

Histamine in the adult central nervous system (CNS) acts as a neurotransmitter. This amine is one of the first neurotransmitters to appear during development reaching its maximum concentration simultaneously with neuron differentiation peak. This suggests that HA plays an important role in neurogenesis. We have previously shown that HA is able to increase neuronal differentiation of neural stem cells (NSCs) in vitro, by activating the histamine type 1 receptor. However the mechanism(s) by which HA has a neurogenic effect on NSCs has not been explored. Here we explore how HA is able to increase neuron phenotype. Cortex neuroepithelium progenitors were cultured and at passage two treatments with 100 µM HA were given during cell proliferation and differentiation or only during differentiation. Immunocytochemistry was performed on differentiated cultures to detect mature neurons. To explore the expression of certain important transcriptional factors involved on asymmetric cell division and commitment, RT-PCR and qRT-PCR were performed. Results indicate that HA is required during cell proliferation in order to increase neuron differentiation and suggest that this amine increases neuron commitment during the proliferative phase probably by rising prospero1 and neurogenin1 expression.

Unilateral variation in the origin of the inferior alveolar and buccal arteries: a case report / Variación unilateral en el origen de las arterias alveolar inferior y bucal: reporte de un caso

The maxillary artery (MA) is one of the terminal branches of the external carotid artery (ECA) and is located in the infratemporal fossa (IF). Some of the branches in this region are the inferior alveolar artery (IAA) and the buccal artery (BA), both descending branches. Here, we report an unusual unilateral origin of the IAA and the BA from a common trunk directly from the ECA. We conducted a routine dissection of both IF in a 54-year-old hispanic male cadaver. Fixed with Universidad de los Andes® conservative solution and red latex for vascular filling. On each side, the MA is observed superficially located over the lateral pterygoid muscle. On the right side, the IAA and the BA originate from a common trunk from the ECA approximately 5 mm prior to the bifurcation into their terminal branches. On the left side, the IAA originates from the MA that is immediately next to its origin, making a common trunk with the pterygoid branches. Knowing the morphology of the MA and its branches at the IF is important for oral and maxillofacial surgery procedures; and any variation in the origin or course of these arteries may result in the patient's increased morbidity during some invasive procedure in the area.

La arteria maxilar (AM) es una rama terminal de la arteria carótida externa (ACE), y se ubica en la región infratemporal (RI). Algunas de sus ramas en esta región son la arteria alveolar inferior (AAI) y la arteria bucal (AB), ambas ramas descendentes. En este trabajo informamos de un inusual origen unilateral de la AAI y de la AB a partir de un tronco común desde la ACE. Se realizó una disección de rutina de ambas regiones infratemporales en un cadáver de 54 años, sexo masculino, caucásico. Fijado con solución conservadora Universidad de los Andes® y repleción vascular con látex rojo. A cada lado, se observa la AM en ubicación superficial sobre el músculo pterigoideo lateral. Al lado derecho, la AAI y la AB se originan de un tronco común desde la ACE aproximadamente 5 mm antes de la bifurcación en sus ramas terminales. Al lado izquierdo la AAI se origina de la AM inmediato a su origen, formando un tronco común con los ramos pterigoideos. El conocimiento de la morfología de la AM y de sus ramas en la RI es de importancia en procedimientos odontológicos, de cirugía oral y maxilofacial. Por lo que cualquier variación en el origen o trayecto de estas arterias puede predisponer a un paciente a una mayor morbilidad durante algún procedimiento invasivo en la zona.

Tumor odontogénico adenomatoide en maxilar: reporte de un caso y revisiónde la literatura / Adenomatoid odontogenic tumor in maxilla: a report case and review of the literature

El tumor odontogénico adenomatoide es una neoplasia benigna según la nueva clasificación del 2005 sobre tumores odontogénicos. Es una lesión muchas veces de crecimiento lento pero progresivo y no invasivo. Este reporte describe una paciente de 17 años, sexo femenino, con un tumor odontogénico adenomatoide del subtipo folicular en la región maxilar anterior comprometiendo al canino maxilar izquierdo. Además se realiza una revisión para los profesionales de la salud sobre aspectos diagnósticos y manejo según los hallazgos más recientes en esta patología.

Adenomatoid odontogenic tumor is a benign neoplasm in the new classification of odontogenic tumors of 2005. This lesion is often slow growing but progressive and noninvasive. This report describes a 17-year old female patient with an adenomatoid odontogenic tumor follicular subtype in the anterior maxillary region compromising the left maxillary canine. This article also provides a refresher for the health professionals on its diagnosis and management according to recent findings in this pathology.

PPARγ expression is increased in systemic lupus erythematosus patients and represses CD40/CD40L signaling pathway.

Systemic lupus erythematosus (SLE) is a heterogeneous disease involving several immune cell types and pro-inflammatory signals, including the one triggered by binding of CD40L to the receptor CD40. Peroxisome-proliferator activated receptor gamma (PPARγ) is a transcription factor with anti-inflammatory properties. Here we investigated whether CD40 and PPARγ could exert opposite effects in the immune response and the possible implications for SLE. Increased PPARγ mRNA levels were detected by real-time PCR in patients with active SLE, compared to patients with inactive SLE PPARγ/GAPDH mRNA = 2.21 ± 0.49 vs. 0.57 ± 0.14, respectively (p < 0.05) or patients with infectious diseases and healthy subjects (p < 0.05). This finding was independent of the corticosteroid therapy. We further explored these observations in human THP1 and in SLE patient-derived macrophages, where activation of CD40 by CD40L promoted augmented PPARγ gene transcription compared to non-stimulated cells (PPARγ/GAPDH mRNA = 1.14 ± 0.38 vs. 0.14 ± 0.01, respectively; p < 0.05). This phenomenon occurred specifically upon CD40 activation, since lipopolysaccharide treatment did not induce a similar response. In addition, increased activity of PPARγ was also detected after CD40 activation, since higher PPARγ-dependent transcription of CD36 transcription was observed. Furthermore, CD40L-stimulated transcription of CD80 gene was elevated in cells treated with PPARγ-specific small interfering RNA (small interfering RNA, siRNA) compared to cells treated with CD40L alone (CD80/GAPDH mRNA = 0.11 ± 0.04 vs. 0.05 ± 0.02, respectively; p < 0.05), suggesting a regulatory role for PPARγ on the CD40/CD40L pathway. Altogether, our findings outline a novel mechanism through which PPARγ regulates the inflammatory signal initiated by activation of CD40, with important implications for the understanding of immunological mechanisms underlying SLE and the development of new treatment strategies.

Immune cells and oxidative stress in the endotoxin tolerance mouse model

Sepsis is a systemic inflammatory response that can lead to tissue damage and death. In order to increase our understanding of sepsis, experimental models are needed that produce relevant immune and inflammatory responses during a septic event. We describe a lipopolysaccharide tolerance mouse model to characterize the cellular and molecular alterations of immune cells during sepsis. The model presents a typical lipopolysaccharide tolerance pattern in which tolerance is related to decreased production and secretion of cytokines after a subsequent exposure to a lethal dose of lipopolysaccharide. The initial lipopolysaccharide exposure also altered the expression patterns of cytokines and was followed by an 8- and a 1.5-fold increase in the T helper 1 and 2 cell subpopulations. Behavioral data indicate a decrease in spontaneous activity and an increase in body temperature following exposure to lipopolysaccharide. In contrast, tolerant animals maintained production of reactive oxygen species and nitric oxide when terminally challenged by cecal ligation and puncture (CLP). Survival study after CLP showed protection in tolerant compared to naive animals. Spleen mass increased in tolerant animals followed by increases of B lymphocytes and subpopulation Th1 cells. An increase in the number of stem cells was found in spleen and bone marrow. We also showed that administration of spleen or bone marrow cells from tolerant to naive animals transfers the acquired resistance status. In conclusion, lipopolysaccharide tolerance is a natural reprogramming of the immune system that increases the number of immune cells, particularly T helper 1 cells, and does not reduce oxidative stress.

Immune cells and oxidative stress in the endotoxin tolerance mouse model.

Sepsis is a systemic inflammatory response that can lead to tissue damage and death. In order to increase our understanding of sepsis, experimental models are needed that produce relevant immune and inflammatory responses during a septic event. We describe a lipopolysaccharide tolerance mouse model to characterize the cellular and molecular alterations of immune cells during sepsis. The model presents a typical lipopolysaccharide tolerance pattern in which tolerance is related to decreased production and secretion of cytokines after a subsequent exposure to a lethal dose of lipopolysaccharide. The initial lipopolysaccharide exposure also altered the expression patterns of cytokines and was followed by an 8- and a 1.5-fold increase in the T helper 1 and 2 cell subpopulations. Behavioral data indicate a decrease in spontaneous activity and an increase in body temperature following exposure to lipopolysaccharide. In contrast, tolerant animals maintained production of reactive oxygen species and nitric oxide when terminally challenged by cecal ligation and puncture (CLP). Survival study after CLP showed protection in tolerant compared to naive animals. Spleen mass increased in tolerant animals followed by increases of B lymphocytes and subpopulation Th1 cells. An increase in the number of stem cells was found in spleen and bone marrow. We also showed that administration of spleen or bone marrow cells from tolerant to naive animals transfers the acquired resistance status. In conclusion, lipopolysaccharide tolerance is a natural reprogramming of the immune system that increases the number of immune cells, particularly T helper 1 cells, and does not reduce oxidative stress.

Purine nucleotides reduce superoxide production by nitric oxide synthase in a murine sepsis model

Sepsis involves a systemic inflammatory response of multiple endogenous mediators, resulting in many of the injurious and sometimes fatal physiological symptoms of the disease. This systemic activation leads to a compromised vascular response and endothelial dysfunction. Purine nucleotides interact with purinoceptors and initiate a variety of physiological processes that play an important role in maintaining cardiovascular function. The purpose of the present study was to investigate the effects of ATP on vascular function in a lipopolysaccharide (LPS) model of sepsis. LPS induced a significant increase in aortic superoxide production 16 h after injection. Addition of ATP to the organ bath incubation solution reduced superoxide production by the aortas of endotoxemic animals. Reactive Blue, an antagonist of the P2Y receptor, blocked the effect of ATP on superoxide production, and the nonselective P2Y agonist MeSATP inhibited superoxide production. Nitric oxide synthase (NOS) inhibition by L-NAME blocked vascular relaxation and reduced superoxide production in LPS-treated animals. In the presence of L-NAME there was no ATP effect on superoxide production. A vascular reactivity study showed that ATP increased maximal relaxation in LPS-treated animals compared to controls. The presence of ATP induced increases in Akt and endothelial NOS phosphorylated proteins in the aorta of septic animals. ATP reduces superoxide release resulting in an improved vasorelaxant response. Sepsis may uncouple NOS to produce superoxide. We showed that ATP through Akt pathway phosphorylated endothelial NOS and “re-couples” NOS function.

Purine nucleotides reduce superoxide production by nitric oxide synthase in a murine sepsis model.

Sepsis involves a systemic inflammatory response of multiple endogenous mediators, resulting in many of the injurious and sometimes fatal physiological symptoms of the disease. This systemic activation leads to a compromised vascular response and endothelial dysfunction. Purine nucleotides interact with purinoceptors and initiate a variety of physiological processes that play an important role in maintaining cardiovascular function. The purpose of the present study was to investigate the effects of ATP on vascular function in a lipopolysaccharide (LPS) model of sepsis. LPS induced a significant increase in aortic superoxide production 16 h after injection. Addition of ATP to the organ bath incubation solution reduced superoxide production by the aortas of endotoxemic animals. Reactive Blue, an antagonist of the P2Y receptor, blocked the effect of ATP on superoxide production, and the nonselective P2Y agonist MeSATP inhibited superoxide production. Nitric oxide synthase (NOS) inhibition by L-NAME blocked vascular relaxation and reduced superoxide production in LPS-treated animals. In the presence of L-NAME there was no ATP effect on superoxide production. A vascular reactivity study showed that ATP increased maximal relaxation in LPS-treated animals compared to controls. The presence of ATP induced increases in Akt and endothelial NOS phosphorylated proteins in the aorta of septic animals. ATP reduces superoxide release resulting in an improved vasorelaxant response. Sepsis may uncouple NOS to produce superoxide. We showed that ATP through Akt pathway phosphorylated endothelial NOS and "re-couples" NOS function.

Treatment of hemorrhagic shock with hypertonic saline solution modulates the inflammatory response to live bacteria in lungs

Shock and resuscitation render patients more susceptible to acute lung injury due to an exacerbated immune response to subsequent inflammatory stimuli. To study the role of innate immunity in this situation, we investigated acute lung injury in an experimental model of ischemia-reperfusion (I-R) followed by an early challenge with live bacteria. Conscious rats (N = 8 in each group) were submitted to controlled hemorrhage and resuscitated with isotonic saline (SS, 0.9 percent NaCl) or hypertonic saline (HS, 7.5 percent NaCl) solution, followed by intratracheal or intraperitoneal inoculation of Escherichia coli. After infection, toll-like receptor (TLR) 2 and 4 mRNA expression was monitored by RT-PCR in infected tissues. Plasma levels of tumor necrosis factor α and interleukins 6 and 10 were determined by ELISA. All animals showed similar hemodynamic variables, with mean arterial pressure decreasing to nearly 40 mmHg after bleeding. HS or SS used as resuscitation fluid yielded equal hemodynamic results. Intratracheal E. coli inoculation per se induced a marked neutrophil infiltration in septa and inside the alveoli, while intraperitoneal inoculation-associated neutrophils and edema were restricted to the interseptal space. Previous I-R enhanced lung neutrophil infiltration upon bacterial challenge when SS was used as reperfusion fluid, whereas neutrophil influx was unchanged in HS-treated animals. No difference in TLR expression or cytokine secretion was detected between groups receiving HS or SS. We conclude that HS is effective in reducing the early inflammatory response to infection after I-R, and that this phenomenon is achieved by modulation of factors other than expression of innate immunity components.

Treatment of hemorrhagic shock with hypertonic saline solution modulates the inflammatory response to live bacteria in lungs.

Shock and resuscitation render patients more susceptible to acute lung injury due to an exacerbated immune response to subsequent inflammatory stimuli. To study the role of innate immunity in this situation, we investigated acute lung injury in an experimental model of ischemia-reperfusion (I-R) followed by an early challenge with live bacteria. Conscious rats (N = 8 in each group) were submitted to controlled hemorrhage and resuscitated with isotonic saline (SS, 0.9% NaCl) or hypertonic saline (HS, 7.5% NaCl) solution, followed by intratracheal or intraperitoneal inoculation of Escherichia coli. After infection, toll-like receptor (TLR) 2 and 4 mRNA expression was monitored by RT-PCR in infected tissues. Plasma levels of tumor necrosis factor alpha and interleukins 6 and 10 were determined by ELISA. All animals showed similar hemodynamic variables, with mean arterial pressure decreasing to nearly 40 mmHg after bleeding. HS or SS used as resuscitation fluid yielded equal hemodynamic results. Intratracheal E. coli inoculation per se induced a marked neutrophil infiltration in septa and inside the alveoli, while intraperitoneal inoculation-associated neutrophils and edema were restricted to the interseptal space. Previous I-R enhanced lung neutrophil infiltration upon bacterial challenge when SS was used as reperfusion fluid, whereas neutrophil influx was unchanged in HS-treated animals. No difference in TLR expression or cytokine secretion was detected between groups receiving HS or SS. We conclude that HS is effective in reducing the early inflammatory response to infection after I-R, and that this phenomenon is achieved by modulation of factors other than expression of innate immunity components.

Progesterone increases dopamine neurone number in differentiating mouse embryonic stem cells.

Progesterone participates in the regulation of several functions in mammals, including brain differentiation and dopaminergic transmission, but the role of progesterone in dopaminergic cell differentiation is unknown. We investigated the effects of progesterone on dopaminergic differentiation of embryonic stem cells using a five-stage protocol. Cells were incubated with different progesterone concentrations during the proliferation (stage 4) or differentiation (stage 5) phases. Progesterone added at 1, 10 and 100 nm during stage 4 increased the number of dopamine neurones at stage 5 by 72%, 80% and 62%, respectively, compared to the control group. The administration of progesterone at stage 5 did not induce significant changes in the number of dopamine neurones. These actions were not mediated by the activation of intracellular progesterone receptors because RU 486 did not block the positive effects of progesterone on differentiation to dopaminergic neurones. The results obtained suggest that progesterone should prove useful with respect to producing higher proportions of dopamine neurones from embryonic stem cells in the treatment of Parkinson's disease.

The role of the vagus nerve in hypertonic resuscitation of hemorrhagic shocked dogs.

Previous studies have suggested a critical role for the vagi during the hypertonic resuscitation of hemorrhagic shocked dogs. Vagal blockade prevented the full hemodynamic and metabolic recovery and increased mortality. This interpretation, however, was challenged on the grounds that the blockade also abolished critical compensatory mechanisms and therefore the animals would die regardless of treatment. To test this hypothesis, 29 dogs were bled (46.0 +/- 6.2 ml/kg, enough to reduce the mean arterial pressure to 40 mmHg) and held hypotensive for 45 min. After 40 min, vagal activity was blocked in a reversible manner (0 masculine C/15 min) and animals were resuscitated with 7.5% NaCl (4 ml/kg), 0.9% NaCl (32 ml/kg), or the total volume of shed blood. In the vagal blocked isotonic saline group, 9 of 9 dogs, and in the vagal blocked replaced blood group, 11 of 11 dogs survived, with full hemodynamic and metabolic recovery. However, in the hypertonic vagal blocked group, 8 of 9 dogs died within 96 h. Survival of shocked dogs which received hypertonic saline solution was dependent on vagal integrity, while animals which received isotonic solution or blood did not need this neural component. Therefore, we conclude that hypertonic resuscitation is dependent on a neural component and not only on the transient plasma volume expansion or direct effects of hyperosmolarity on vascular reactivity or changes in myocardial contraction observed immediately after the beginning of infusion.

The role of the vagus nerve in hypertonic resuscitation of hemorrhagic shocked dogs

Previous studies have suggested a critical role for the vagi during the hypertonic resuscitation of hemorrhagic shocked dogs. Vagal blockade prevented the full hemodynamic and metabolic recovery and increased mortality. This interpretation, however, was challenged on the grounds that the blockade also abolished critical compensatory mechanisms and therefore the animals would die regardless of treatment. To test this hypothesis, 29 dogs were bled (46.0 ± 6.2 ml/kg, enough to reduce the mean arterial pressure to 40 mmHg) and held hypotensive for 45 min. After 40 min, vagal activity was blocked in a reversible manner (0ºC/15 min) and animals were resuscitated with 7.5 percent NaCl (4 ml/kg), 0.9 percent NaCl (32 ml/kg), or the total volume of shed blood. In the vagal blocked isotonic saline group, 9 of 9 dogs, and in the vagal blocked replaced blood group, 11 of 11 dogs survived, with full hemodynamic and metabolic recovery. However, in the hypertonic vagal blocked group, 8 of 9 dogs died within 96 h. Survival of shocked dogs which received hypertonic saline solution was dependent on vagal integrity, while animals which received isotonic solution or blood did not need this neural component. Therefore, we conclude that hypertonic resuscitation is dependent on a neural component and not only on the transient plasma volume expansion or direct effects of hyperosmolarity on vascular reactivity or changes in myocardial contraction observed immediately after the beginning of infusion.

Enhanced expression of Fc alpha receptor I on blood phagocytes of patients with gram-negative bacteremia is associated with tyrosine phosphorylation of the FcR-gamma subunit.

Sepsis caused by gram-negative bacteria is a common finding having high incidence and mortality. Fc alpha RI (CD89), a receptor for immunoglobulin A (IgA), has been shown to mediate bacterial phagocytosis, which might play a role in the pathogenesis of sepsis. In this study the expression and function of Fc alpha RI were analyzed on blood monocytes and neutrophils of patients with bacteremia. We found a marked increased in expression of the alpha- and gamma-subunits of the Fc alpha RI on both types of cells in patients with gram-negative bacteremia, but not in patients with gram-positive bacteremia. This increase was independent of serum IgA levels. Fc alpha RI M(r) was lower on cells from gram-negative patients than on cells from controls (50-65 kDa versus 55-75 kDa), despite a similar 32-kDa backbone, indicating altered glycosylation. Increased levels of Fc alpha RI on blood phagocytes correlated with enhanced serum IL-6 levels, but not with IFN gamma or TNF-alpha. FcR-gamma chain associated with Fc alpha RI was phosphorylated in patients neutrophils, indicating functional engagement of this receptor during gram-negative sepsis. Increased expression and activation of Fc alpha RI-gamma 2 complexes following gram-negative infections suggests its involvement in host defense against bacteria.

Refeeding procedures after 43 days of total fasting.

Refeeding syndrome encompasses fluid and electrolyte imbalances and metabolic, intestinal, and cardiorespiratory derangements associated with appreciable morbidity and mortality. Although refeeding syndrome has been well documented in concentration-camp subjects, and more recently during parenteral therapy of critically ill patients, little is known about the importance of refeeding syndrome during recovery from a hunger strike. Thus, we studied the response to a four-step dietary replenishment routine in eight hunger strikers who refused food for 43 d. In this retrospective, observational study, we assessed the safety and efficacy of the refeeding procedure and analyzed the clinical and nutritional course of the cohort during both starvation and refeeding, mainly on the basis of clinical as well as a few biochemical determinations. During starvation, average weight loss was about 18% and, with the exception of occasional oral vitamins and electrolytes, the subjects consumed only water. Available body-composition and biochemical profiles showed no clinically significant changes during starvation, but one-half of the group displayed spontaneous diarrhea at some time before refeeding. Stepwise nutritional replenishment lasted for 9 d, after which all patients tolerated a full, unrestricted diet. Only one episode of diarrhea occurred during this phase, and both clinical and biochemical indexes confirmed a favorable clinical course, without any manifestation of refeeding syndrome. In conclusion, we observed the following: 1) Hypophosphatemia and other micronutrient imbalances did not occur, nor was macronutrient intolerance detected. 2) Despite some episodes of diarrhea, nutritional replenishment was not associated with significant enteral dysfunction. 3) There was some fluid retention, but this was mild. 4) Acute-phase markers were abnormally elevated during the refeeding phase, without associated sepsis or inflammation.

Impact of BAL in the management of pneumonia with treatment failure: positivity of BAL culture under antibiotic therapy.

BACKGROUND: Pneumonia is responsible for 50% of antibiotics prescribed in ICUs. Treatment failure, ie, absence of improvement or clinical deterioration under antibiotic therapy, presents a dilemma to physicians. BAL is an invasive method validated for etiologic diagnosis in pneumonia. STUDY OBJECTIVE: To evaluate in ICU patients the impact of BAL in the etiologic diagnosis, treatment, and outcome of pneumonia with treatment failure. DESIGN: Prospective clinical study. SETTING: Nonsurgical, medical ICU of a university hospital in Brazil. PATIENTS AND PARTICIPANTS: Sixty-two episodes of pneumonia treated for at least 72 h without clinical improvement in 53 patients hospitalized for diverse clinical emergencies. Mean duration of hospitalization was 14.2 days. Mean duration of previous antibiotic therapy was 11.4 days. INTERVENTIONS: Bronchoscopy and BAL were performed in each episode. BAL fluid was cultivated for aerobic and anaerobic bacteria; the cutoff considered positive was 10(4) cfu/mL; 10(3) cfu/mL was also analyzed if under treatment. Pneumocystis carinii, fungi, Legionella spp, and Mycobacterium spp were also researched. MEASUREMENTS AND RESULTS: Fifty-eight of 62 BAL were performed under antibiotics. The results showed positivity in 45 of 62 (72.6%); 42 of the 45 positive episodes (93.3%) had > 10(4) cfu/mL. The three cases with between 10(3) and 10(4) cfu/mL were considered positive and were treated according to BAL cultures. The main agents were Acinetobacter baumannii (37.1%), Pseudomonas aeruginosa (17.7%), and methicillin-resistant Staphylococcus aureus (MRSA; 16.1%); 46.7% of the episodes (21 of 45) were polymicrobial. BAL results directed a change of therapy in 34 episodes (54.8%). Overall mortality was 43.5%. There was no difference in mortality among positives, negatives, and patients who changed therapy guided by BAL culture. CONCLUSIONS: (1) BAL fluid examination was positive in 45 of 62 episodes (72.6%), with 58 of 62 BAL performed under antibiotics. This suggests that BAL may be a sensitive diagnostic method for treatment failures of clinically diagnosed pneumonias, even if performed under antibiotics; (2) the main pathogens in our study were A baumannii, P aeruginosa, and MRSA, and approximately 45% of infections were polymicrobial; (3) BAL culture results directed a change of therapy in 75.6% of positive episodes (34 of 45) and in 54.8% of all episodes of treatment failure (34 of 62); and (4) there was no difference in mortality among positives, negatives, and patients who changed therapy guided by BAL culture.