[Pathologies of the immigrant child in the Intensive Care Unit. Update]. / Patologías del niño inmigrante en la Unidad de Cuidados Intensivos. Actualización.

It is increasingly common to provide medical care in the Intensive Care Unit (ICU) for immigrant children and adolescents as well as those born in Chile with parents in such condition. Currently, this has caused that the health team has to face diverse infrequent pathologies in our country and/ or diagnostic problems derive from the poor knowledge of genetic conditions of this population, some resulting from their health conditions. This review addresses several aspects of hematological, infectious, parasitic, respiratory, and cardiovascular pathologies, all relevant topics to know during their stay in the ICU. It is a duty of the health team to be updated on pathologies of low prevalence in our country, some of them very little known until a decade ago, but which are currently increasingly present in the ICUs of the Chilean public health system.

Cryopreservation on a cryo-plate of Arundina graminifolia protocorms, dehydrated with silica gel and drying beads.

BACKGROUND: There are various methods for the cryopreservation of plant material, with each biological specimen potentially requiring protocol optimization to maximize success. OBJECTIVE: The aim of this study is to compare droplet-vitrification, encapsulation-dehydration, and the cryo-plate method for cryopreservation of protocorms of the orchid Arundina graminifolia, using silica gel and drying beads as the desiccation materials. MATERIALS AND METHODS: The cryo-plate method included preculture of protocorms, developed from seeds, placed on aluminium cryo-plates and embedded in alginate gel. Cryo-plates were surface dried using sterile filter paper, placed in Petri dishes containing 50 g silica gel or 30 g drying beads in a laminar air-flow cabinet. Specimens on cryo-plates were dehydrated to 25 % moisture content, placed into 2 mL cryotubes and plunged directly into liquid nitrogen for 1 d. RESULTS: For cryopreservation, the cryo-plate method, involving dehydration with 30 g drying beads gave the highest regrowth (77 %), followed by the encapsulation-dehydration method with 30 g drying beads (64 % regrowth) and the droplet-vitrification method, following exposure to PVS2 solution for 20 min (33 % regrowth). CONCLUSIONS: Regrowth of cryopreserved protocorms using the cryo-plate method was rapid with the highest survival and regrowth.

Osteocalcin, under-carboxylated osteocalcin and osteopontin are not associated with gestational diabetes mellitus but are inversely associated with leptin in non-diabetic women.

OBJECTIVE: To measure serum osteocalcin (OC), under-carboxylated osteocalcin (ucOC), osteopontin (OPN), and leptin in pregnant women with gestational diabetes mellitus (GDM) and in healthy pregnant women during pregnancy and after birth and relate these markers to glucose metabolism. METHODS: This was a prospective study including 60 women with GDM and 60 subjects with normal gestation who were evaluated at gestational week 30 and 6 weeks postpartum. Serum OC, ucOC, OPN, leptin, insulin and insulin resistance were evaluated during the study. RESULTS: Bone biomarkers and leptin were similar between GDM and normal pregnancy. After delivery, OC, ucOC and OPN increased in both groups, while leptin decreased only in healthy controls. Bone markers did not correlate with insulin and insulin resistance in the two groups, but leptin was positively correlated with insulin and insulin resistance and negatively correlated with bone biomarkers only in healthy women. Furthermore, the women who developed diabetes postpartum had lower levels of OC than women with normal glucose tolerance. CONCLUSION: GDM is not associated with OC, ucOC, OPN, and leptin and does not correlate with insulin resistance. At postpartum, women who develop diabetes have lower osteocalcin concentrations. Leptin correlates with insulin resistance and bone biomarkers in non-diabetic women.

Three-dimensional image reconstruction of insect flight muscle. I. The rigor myac layer.

We have obtained detailed three-dimensional images of in situ cross-bridge structure in insect flight muscle by electron microscopy of multiple tilt views of single filament layers in ultrathin sections, supplemented with data from thick sections. In this report, we describe the images obtained of the myac layer, a 25-nm longitudinal section containing a single layer of alternating myosin and actin filaments. The reconstruction reveals averaged rigor cross-bridges that clearly separate into two classes constituting lead and rear chevrons within each 38.7-nm axial repeat. These two classes differ in tilt angle, size and shape, density, and slew. This new reconstruction confirms our earlier interpretation of the lead bridge as a two-headed cross-bridge and the rear bridge as a single-headed cross-bridge. The importance of complementing tilt series with additional projections outside the goniometer tilt range is demonstrated by comparison with our earlier myac layer reconstruction. Incorporation of this additional data reveals new details of rigor cross-bridge structure in situ which include clear delineation of (a) a triangular shape for the lead bridge, (b) a smaller size for the rear bridge, and (c) density continuity across the thin filament in the lead bridge. Within actin's regular 38.7-nm helical repeat, local twist variations in the thin filament that correlate with the two cross-bridge classes persist in this new reconstruction. These observations show that in situ rigor cross-bridges are not uniform, and suggest three different myosin head conformations in rigor.

Three-dimensional image reconstruction of insect flight muscle. II. The rigor actin layer.

The averaged structure of rigor cross-bridges in insect flight muscle is further revealed by three-dimensional reconstruction from 25-nm sections containing a single layer of thin filaments. These exhibit two thin filament orientations that differ by 60 degrees from each other and from myac layer filaments. Data from multiple tilt views (to +/- 60 degrees) was supplemented by data from thick sections (equivalent to 90 degrees tilts). In combination with the reconstruction from the myac layer (Taylor et al., 1989), the entire unit cell is reconstructed, giving the most complete view of in situ cross-bridges yet obtained. All our reconstructions show two classes of averaged rigor cross-bridges. Lead bridges have a triangular shape with leading edge angled at approximately 45 degrees and trailing edge angled at approximately 90 degrees to the filament axis. We propose that the lead bridge contains two myosin heads of differing conformation bound along one strand of F-actin. The lead bridge is associated with a region of the thin filament that is apparently untwisted. We suggest that the untwisting may reflect the distribution of strain between myosin and actin resulting from two-headed, single filament binding in the lead bridge. Rear bridges are oriented at approximately 90 degrees to the filament axis, and are smaller and more cylindrical, suggesting that they consist of single myosin heads. The rear bridge is associated with a region of apparently normal thin filament twist. We propose that differing myosin head angles and conformations consistently observed in rigor embody different stages of the power stroke which have been trapped by a temporal sequence of rigor cross-bridge formation under the constraints of the intact filament lattice.

Allergen-sensitization increases mast-cell expression of the exocytotic proteins SNAP-23 and syntaxin 4, which are involved in histamine secretion.

BACKGROUND: Activation of mast cells (MCs) via aggregation of immunoglobulin E (IgE) bound to its high affinity receptor (FcepsilonRI) results in release of inflammatory mediators from secretory granules. Histamine is one of the critical biological mediators released in the allergic response. Synaptosomal-associated protein of 23 kDa (SNAP-23) and syntaxin 4 are plasma membrane proteins that have been associated with exocytosis in MCs. Studies with monoclonal IgEs indicate that binding of IgE to FcepsilonRI induces molecular and biological changes in OBJECTIVES: The aim of this study was to investigate changes in the expression of SNAP-23 and syntaxin 4 by MCs following rat sensitization with ovalbumin (OVA). In addition, we assessed whether these proteins were involved in histamine secretion. METHODS: SNAP-23 and syntaxin 4 expression was analyzed by Western blot using MCs from control and sensitized animals. Successful sensitization was confirmed based on the passive cutaneous anaphylaxis reaction. To test the role of these exocytotic proteins in histamine secretion, permeabilized MCs were incubated with SNAP-23 and syntaxin 4 antibodies. RESULTS: Expression of SNAP-23 and syntaxin 4 was significantly higher in MCs from OVA-sensitized rats than in cells from control animals. In addition, incubation of permabilized cells with antibodies to SNAP-23 and syntaxin 4 led to a marked reduction of histamine secretion in stimulated cells. CONCLUSIONS: Sensitization with OVA increases the expression of SNAP-23 and syntaxin 4 in MCs. Furthermore, our data suggest that these exocytotic proteins participate in histamine secretion.

NF-κB as a Therapeutic Target in Inflammatory-Associated Bone Diseases.

Inflammation is a defensive mechanism for pathogen clearance and maintaining tissue homeostasis. In the skeletal system, inflammation is closely associated with many bone disorders including fractures, nonunions, periprosthetic osteolysis (bone loss around orthopedic implants), and osteoporosis. Acute inflammation is a critical step for proper bone-healing and bone-remodeling processes. On the other hand, chronic inflammation with excessive proinflammatory cytokines disrupts the balance of skeletal homeostasis involving osteoblastic (bone formation) and osteoclastic (bone resorption) activities. NF-κB is a transcriptional factor that regulates the inflammatory response and bone-remodeling processes in both bone-forming and bone-resorption cells. In vitro and in vivo evidences suggest that NF-κB is an important potential therapeutic target for inflammation-associated bone disorders by modulating inflammation and bone-remodeling process simultaneously. The challenges of NF-κB-targeting therapy in bone disorders include: (1) the complexity of canonical and noncanonical NF-κB pathways; (2) the fundamental roles of NF-κB-mediated signaling for bone regeneration at earlier phases of tissue damage and acute inflammation; and (3) the potential toxic effects on nontargeted cells such as lymphocytes. Recent developments of novel inhibitors with differential approaches to modulate NF-κB activity, and the controlled release (local) or bone-targeting drug delivery (systemic) strategies, have largely increased the translational application of NF-κB therapy in bone disorders. Taken together, temporal modulation of NF-κB pathways with the combination of recent advanced bone-targeting drug delivery techniques is a highly translational strategy to reestablish homeostasis in the skeletal system.

Relationships among Bone Quality, Implant Osseointegration, and Wnt Signaling.

A variety of clinical classification schemes have been proposed as a means to identify sites in the oral cavity where implant osseointegration is likely to be successful. Most schemes are based on structural characteristics of the bone, for example, the relative proportion of densely compact, homogenous (type I) bone versus more trabeculated, cancellous (type III) bone. None of these schemes, however, consider potential biological characteristics of the bone. Here, we employed multiscale analyses to identify and characterize type I and type III bones in murine jaws. We then combined these analytical tools with in vivo models of osteotomy healing and implant osseointegration to determine if one type of bone healed faster and supported osseointegration better than another. Collectively, these studies revealed a strong positive correlation between bone remodeling rates, mitotic activity, and osteotomy site healing in type III bone and high endogenous Wnt signaling. This positive correlation was strengthened by observations showing that the osteoid matrix that is responsible for implant osseointegration originates from Wnt-responsive cells and their progeny. The potential application of this knowledge to clinical practice is discussed, along with a theory unifying the role that biology and mechanics play in implant osseointegration.

The obese child in the Intensive Care Unit. Update. / El niño obeso en la Unidad de Cuidados Intensivos. Puesta al día.

Given that childhood obesity is an epidemic, the frequency of critically-ill patients who are overweight or obese seen at intensive care units has increased rapidly. Adipose tissue is an endocrine organ that secretes a number of protein hormones, including leptin, which stands out because it regulates adipose tissue mass. The presence of arterial hypertension, metabolic syndrome, diabetes mellitus, respiratory disease and chronic kidney disease may become apparent and complicate the course of obese pediatric patients in the Intensive Care Unit. Obesity management is complex and should involve patients, their families and the medical community. It should be coordinated with comprehensive government health policies and implemented in conjunction with a change in cultural context.

Actualmente, la obesidad infantil constituye una epidemia. La frecuencia de pacientes críticos con sobrepeso u obesidad ha aumentado rápidamente en las unidades de cuidados intensivos. El tejido adiposo es un órgano endocrino que secreta varias hormonas proteicas, entre las que se destaca la leptina, la cual es reguladora de su masa. La presencia de hipertensión arterial, síndrome metabólico, diabetes mellitus, enfermedades respiratorias y enfermedad renal crónica se puede manifestar en el paciente pediátrico obeso durante su estadía en la Unidad de Cuidados Intensivos y complicar su evolución. El tratamiento de la obesidad es complejo y debe involucrar al paciente, a su familia y a la comunidad médica. Debe realizarse en coordinación con políticas sanitarias gubernamentales integrales y en conjunto con un cambio de marco cultural.

Effect of Ovariohysterectomy at the Time of Tumor Removal in Dogs with Mammary Carcinomas: A Randomized Controlled Trial.

BACKGROUND: Ovarian hormones play crucial roles in mammary carcinogenesis. However, whether ovarian ablation by ovariohysterectomy (OHE) improves the prognosis in dogs with mammary carcinomas is unclear. OBJECTIVES: Determine if OHE at the time of mastectomy improves the prognosis in dogs with mammary carcinomas and evaluate if hormonal factors influence the effect of OHE. ANIMALS: Sixty intact dogs with mammary carcinomas. METHODS: Dogs were randomly assigned in a 1:1 ratio to undergo OHE (n = 31) or not (n = 29) at the time of tumor removal. Peri-surgical serum estradiol (E2) and progesterone concentrations were measured, tumor diagnosis was confirmed histologically, and tumor estrogen and progesterone receptor status was immunohistochemically determined. The dogs were monitored for recurrence and metastases every 3-4 months for at least 2 years. Uni- and multivariable survival analyses were performed with relapse and all-cause death as endpoints in addition to univariable subgroup analyses. RESULTS: Overall, OHE did not significantly decrease hazard of relapse (hazard ratio [HR], 0.64; P = .18) or all-cause death (HR, 0.87; P = .64) in univariable analyses. In multivariable analysis OHE did not significantly influence the hazard of relapse (HR, 0.54; P = .12), but an interaction effect was identified between ER status and E2 (P = .037). Subgroup analysis identified decreased hazard of relapse in the OHE group compared to the non-OHE group in the subsets of dogs with increased E2 (HR, 0.22; P = .012) or grade 2 tumors (HR, 0.26; P = .02). CONCLUSION: Dogs with grade 2, ER-positive tumors, or with increased peri-surgical serum E2 concentration represent a subset of dogs with mammary carcinomas likely to benefit from OHE.

Inhibition of osteolysis and increase of bone formation after local administration of siRNA-targeting RANK in a polyethylene particle-induced osteolysis model.

Receptor activator of nuclear factor kappa-B (RANK) and RANK-ligand are relevant targets for the treatment of polyethylene particle-induced osteolysis. This study assessed the local administration of siRNA, targeting both human RANK and mouse Rank transcripts in a mouse model. Four groups of mice were implanted with polyethylene (PE) particles in the calvaria and treated locally with 2.5, 5 and 10 µg of RANK siRNA or a control siRNA delivered by the cationic liposome DMAPAP/DOPE. The tissues were harvested at day 9 after surgery and evaluated by micro-computed tomography, tartrate-resistant acid phosphatase (TRAP) immunohistochemistry for macrophages and osteoblasts, and gene relative expression of inflammatory and osteolytic markers. 10 µg of RANK siRNA exerted a protective effect against PE particle-induced osteolysis, decreasing the bone loss and the osteoclastogenesis, demonstrated by the significant increase in the bone volume (P<0.001) and by the reduction in both the number of TRAP(+) cells and osteoclast activity (P<0.01). A bone anabolic effect demonstrated by the formation of new trabecular bone was confirmed by the increased immunopositive staining for osteoblast-specific proteins. In addition, 5 and 10 µg of RANK siRNA downregulated the expression of pro-inflammatory cytokines (P<0.01) without depletion of macrophages. Our findings show that RANK siRNA delivered locally by a synthetic vector may be an effective approach for reducing osteolysis and may even stimulate bone formation in aseptic loosening of prosthetic implants.

Patologías del niño inmigrante en la Unidad de Cuidados Intensivos: actualización / Pathologies of the immigrant child in the Intensive Care Unit: update

Resumen: Cada vez es más frecuente la atención médica en la Unidad de Cuidados Intensivos (UCI) de niños o adolescentes inmigrantes como también de aquellos nacidos en nuestro país con padres en tal condición. Esto ha ocasionado, en la actualidad, que el equipo de salud se deba enfrentar con problemas diagnósticos derivados del escaso conocimiento de condiciones genéticas propias de esta población y/o el desarrollo de diversas patologías infrecuentes en nuestro país, algunas resultantes de su condi ción sanitaria. En esta revisión se abordan diversos aspectos de la patología hematológica, infecciosa, parasitaria, respiratoria y cardiovascular, todos tópicos relevantes de conocer durante su estadía en la UCI. Es un deber del equipo de salud actualizarse sobre patologías de baja prevalencia en nuestro país, algunas de ellas muy poco conocidas hasta hace una década, pero que, actualmente, están cada vez más presentes en las UCI del sistema de salud público chileno.

Abstract: It is increasingly common to provide medical care in the Intensive Care Unit (ICU) for immigrant children and adolescents as well as those born in Chile with parents in such condition. Currently, this has caused that the health team has to face diverse infrequent pathologies in our country and/ or diagnostic problems derive from the poor knowledge of genetic conditions of this population, some resulting from their health conditions. This review addresses several aspects of hematological, infectious, parasitic, respiratory, and cardiovascular pathologies, all relevant topics to know during their stay in the ICU. It is a duty of the health team to be updated on pathologies of low prevalence in our country, some of them very little known until a decade ago, but which are currently increasingly present in the ICUs of the Chilean public health system.

Chromosome analysis of cryopreserved cells.

We describe a technique for freezing and thawing human leukemic cells for cytogenetic studies. We studied 64 harvests on 26 cryopreserved samples from 20 individuals. Chromosome quality was best in the samples from patients with myeloid disturbances. Successful chromosome studies of approximately 50% of the samples were accomplished. Cryopreservation of leukemic cells is not a substitute for fresh material because the method produces relatively few metaphases and mediocre chromosome spreading and banding. However, when rigid and appropriate research objectives are applied, chromosome analysis of cryopreserved leukemic cells can be a viable alternative to analysis of fresh cells.

Temperature directly affects the rate of irradiation-induced mass loss from phosphatidylcholine multilayers.

We monitored the mass thickness of egg yolk phosphatidylcholine multilayers at several temperatures during electron irradiation. The rate of irradiation-induced mass loss was reduced substantially when this specimen was cooled to liquid nitrogen temperature from room temperature. Additional cooling to liquid helium temperature caused an additional reduction of mass-loss rate. The characteristic doses D(1/e), which are the slopes of the logarithm of the differential mass thickness against dose, were approximately 7 x 10(3) e/nm2 at 290 K, 8 x 10(4) e/nm2 at 130 K, and 1.4 x 10(5) e/nm2 at less than 10 K. The fractions of the original mass thickness that remained after arbitrarily high doses were about 69% at 290 K, 72% at 130 K, and 77% at less than 10 K.

Hypogastric carotid bypass for Takayasu's disease.

Two cases of Takayasu's disease are presented which were successfully resolved by a Dacron graft from the right hypogastric artery to the right internal carotid artery. We recommend this bypass procedure of connecting the hypogastric artery to one of the aortic branches. Medical treatment with antibiotics, steroids and anti-coagulants has not been satisfactory.

Sedation and analgesia in children undergoing invasive procedures.

INTRODUCTION: As a result of the increased number of both diagnostic and therapeutic procedures in pediatric outpatients, sedation and analgesia have gained relevance in this context. OBJECTIVE: To characterize the type of sedation and analgesia used by pediatric sedation teams in procedures done outside the operating room, as well as its safety and outcome. POPULATION AND METHODS: All procedures performed in 1 month to 5 year old patients under intravenous sedation with midazolam, ketamine, propofol or lidocaine were analyzed over a 14-month period. The Ramsay sedation scale and the CHEOPS pain scale were used to determine the response to the sedation and analgesia administered. RESULTS: A total of 186 procedures were analyzed. The results of the evaluation of response to sedation and analgesia indicated that an adequate deep sedation was obtained in 98% of cases, and that an adequate analgesia was achieved in 92% of patients. Around 12% of the procedures were associated with adverse events, all related to the airways, and none was serious. The only statistically significant endpoint associated with adverse events were procedures which involved airway interventions, i.e., fibrobronchoscopy, upper gastrointestinal endoscopy or transesophageal echocardiogram, with an OR of 6.27 (95% CI: 1.28-30.63; p = 0.023). CONCLUSIONS: In this group of patients, intravenous outpatient sedation and analgesia administered by a specialized team were safe and effective.

Sedation and analgesia in children undergoing invasive procedures / Sedación y analgesia para procedimientos invasivos en los niños

Introduction. As a result of the increased number of both diagnostic and therapeutic procedures in pediatric outpatients, sedation and analgesia have gained relevance in this context. Objective. To characterize the type of sedation and analgesia used by pediatric sedation teams in procedures done outside the operating room, as well as its safety and outcome. Population and Methods. All procedures performed in 1 month to 5 year old patients under intravenous sedation with midazolam, ketamine, propofol or lidocaine were analyzed over a 14-month period. The Ramsay sedation scale and the CHEOPS pain scale were used to determine the response to the sedation and analgesia administered. Results. A total of 186 procedures were analyzed. The results of the evaluation of response to sedation and analgesia indicated that an adequate deep sedation was obtained in 98% of cases, and that an adequate analgesia was achieved in 92% of patients. Around 12% of the procedures were associated with adverse events, all related to the airways, and none was serious. The only statistically significant endpoint associated with adverse events were procedures which involved airway interventions, i.e., fibrobronchoscopy, upper gastrointestinal endoscopy or transesophageal echocardiogram, with an OR of 6.27 (95% CI: 1.28-30.63; p = 0.023). Conclusions. In this group of patients, intravenous outpatient sedation and analgesia administered by a specialized team were safe and effective.

Introducción. Producto del aumento de los procedimientos pediátricos, tanto diagnósticos como terapéuticos fuera del quirófano, la sedación y analgesia en este contexto ha cobrado importancia. Objetivo. Caracterizar el tipo de sedoanalgesia utilizada por un equipo de sedación pediátrico en procedimientos fuera del quirófano, así como sus resultados y su seguridad. Pacientes y métodos. Se analizaron todos los procedimientos realizados bajo sedación intravenosa con midazolam, ketamina, propofol o lidocaína, en pacientes de entre 1 mes y 5 años, en un período de 14 meses. Para determinar la respuesta a la sedoanalgesia administrada, se aplicó la escala de sedación de Ramsay y la escala de dolor de CHEOPS. Resultados. Se analizaron 186 procedimientos. Al evaluar la respuesta a la sedoanalgesia, se obtuvo una sedación profunda adecuada en un 98% de los casos y una analgesia adecuada en un 92% de los pacientes. Un 12% de los procedimientos se asociaron a efectos adversos, todos relacionados con la vía aérea, ninguno grave. La única variable vinculada de forma estadísticamente significativa a la ocurrencia de eventos adversos fue el procedimiento con intervención de la vía aérea, es decir, fibrobroncoscopia, endoscopia digestiva alta o ecocardiograma transesofágico, con un OR de 6,27 (IC 95% 1,28 a 30,63; p= 0,023). Conclusiones. En este grupo de pacientes la sedación y analgesia intravenosa para procedimientos fuera del quirófano, otorgada por un equipo especializado, resultó segura y eficaz.