[Microbiological characterization and antimicrobial susceptibility pattern of infections associated with febrile neutropenia in pediatric hemato-oncological patients.] / Caracterización microbiológica y de susceptibilidad antimicrobiana de las infecciones asociadas a neutropenia febril en pacientes hemato-oncológicos pediátricos.

INTRODUCTION: Febrile neutropenia (FN) is the most frequent hemato-oncological emergency, with high morbidi ty and mortality in pediatrics. The objective of the study was the microbiological characterization and antimicrobial susceptibility of infections associated with FN in pediatric hemato-oncological patients. PATIENTS AND METHOD: Retrospective cohort study with patients aged between 1 month and 18 years, with onco-hematological pathology according to ICD-10 codes, hospitalized in a tertiary healthcare center in Bucaramanga, Colombia. Based on the medical records of the period 2013-2017, the episodes of FN were identified, and the isolated microorganisms and their susceptibility pattern were described. Biochemical identification and antimicrobial susceptibility testing were performed with the Dade Behring Microscan« automated system. The resistant microorganism classification was performed based on the Minimum Inhibitory Concentration (MIC) and the interpretation of the laboratory according to the cut-off points of the Clinical and Laboratory Standards Institute recommendations. RESULTS: Of 130 patients, 14.7% of the cultures obtained were positive. Bloods tream infection was observed in 17.5% of the episodes. The isolated microorganisms were mainly Gram-negative bacteria (75.8%). Enterobacteriaceae (EB) were the most frequent, led by Klebsiella pneumoniae, Escherichia coli, followed by Pseudomonas aeruginosa and coagulase-negative Staphylo cocci. Of the EBs, 40.5% showed resistance to Piperacillin/Tazobactam, 33.3% to Cefepime, and 8.2% to Meropenem. According to the antimicrobial resistance pattern, it was observed that 16.4% of the positive EB cultures had an extended-spectrum beta-lactamase pattern and 5% a pattern suggestive of carbapenemases. All Gram-positive cocci were sensitive to Vancomycin. CONCLUSION: In the studied patients, the predominant pathogenic microorganisms were Gram-negative ones with resistance in dices similar to those of developing countries.

Inhibition of cytotoxicity of Shiga toxin of Escherichia coli O157:H7 on vero cells by Prosopis alba Griseb (Fabaceae) and Ziziphus mistol Griseb (Rhamnaceae) extracts.

The capacity of Prosopis alba Griseb. and Ziziphus mistol Griseb. fruit extracts to inhibit the toxic action of Shiga toxin (Stx) was investigated. Purification of Stx from Escherichia coli O157:H7 was performed by saline precipitation and affinity chromatography using a column with globotriaosylceramide, while the fruits were subjected to ethanolic or aqueous extractions. The protective action of both fruits was determined by pre-, co-, and postincubation of one 50% cytotoxic dose per ml of Stx with different concentrations of ethanolic and aqueous extracts in confluent monolayers of Vero cells for 72 h at 37°C (5% CO2). The inhibition of the cytotoxic effect of Stx by fruit extracts was determined by the neutral red vital staining technique. The extraction of the polyphenols and flavonoids was effective, and more polyphenols per milligram of dissolved solids were obtained from P. alba than from Z. mistol. However, there were more flavonoids in Z. mistol than in P. alba. Components of both fruits increased the viability of cells treated with Stx when the extracts were preincubated with Stx for 1 h before being applied to the cell cultures, with the ethanolic extract of P. alba showing 95% cell viability at a concentration of 2.45 mg/ml. The extracts were less effective in protecting cells when Stx, extracts, and cells were coincubated together without a previous incubation of Stx; only the concentrations of 19.46 mg/ml for the P. alba aqueous extract and 3.75 mg/ml for the Z. mistol ethanolic extract resulted in the inhibition of cytotoxicity, with 52 and 56% cell viability occurring, respectively. Investigation into this difference in the protection of cells indicated that the protein molecule of Stx suffered degradation to advanced oxidative protein products during preincubation with extracts, principally with P. alba, which exhibited a greater amount of nonflavonoid polyphenols than Z. mistol. The prooxidant action on Stx favored the cells and enhanced the protective action of both fruits.

Mechanisms underlying state dependent surface-evoked response patterns.

Cortical evoked response potentials (ERPs) display a rich set of waveforms that are both context and state dependent. However, the mechanisms that underlie state dependent ERP patterns are unclear. Determining those mechanisms through analysis of single trial ERP waveform signatures may provide insight into the regulation of cortical column state and the roles that sleep plays in cortical function. We implanted rats with electroencephalogram (EEG) and electromyogram (EMG) electrodes to record ERPs and to assess sleep/wake states continuously during 1-2 s random auditory clicks. Individual cortical auditory ERPs were sorted into one of eight behavioral states, and fell into three categories based on amplitude and latency characteristics. ERPs within waking and rapid eye movement (REM) sleep were predominantly low amplitude and short latency. Approximately 50% of ERPs during light quiet sleep (quiet sleep 1 and quiet sleep 2) exhibited low amplitude, short latency responses, and the remaining ERPs had high amplitude, long latency responses. This distribution was characteristic of EEG fluctuations during low frequency delta waves. Significantly more individual ERPs showed very low amplitudes during deep quiet sleep (quiet sleep 3 and quiet sleep 4), resulting in a lower average ERP. These results support the hypothesis that evoked response amplitudes and waveform patterns follow specific EEG patterns. Since evoked response characteristics distribute differently across states, they could aid our understanding of sleep mechanisms through state-related and local neural signaling.

Tumor necrosis factor alpha: activity dependent expression and promotion of cortical column sleep in rats.

Cortical surface evoked potentials (SEPs) are larger during sleep and characterize a sleep-like state in cortical columns. Since tumor necrosis factor alpha (TNF) may be involved in sleep regulation and is produced as a consequence of waking activity, we tested the hypothesis that direct application of TNF to the cortex will induce a sleep-like state within cortical columns and enhance SEP amplitudes. We found that microinjection of TNF onto the surface of the rat somatosensory cortex enhanced whisker stimulation-induced SEP amplitude relative to a control heat-inactivated TNF microinjection. We also determined if whisker stimulation enhanced endogenous TNF expression. TNF immunoreactivity (IR) was visualized after 2 h of deflection of a single whisker on each side. The number of TNF-IR cells increased in layers II-IV of the activated somatosensory barrel column. In two separate studies, unilateral deflection of multiple whiskers for 2 h increased the number of TNF-IR cells in layers II-V in columns that also exhibited enhanced cellular ongogene (Fos-IR). TNF-IR also colocalized with NeuN-IR suggesting that TNF expression was in neurons. Collectively these data are consistent with the hypotheses that TNF is produced in response to neural activity and in turn enhances the probability of a local sleep-like state as determined by increases in SEP amplitudes.

Morgagni hernia: repair with a mesh using laparoscopic surgery.

The aim of this study is to present two patients diagnosed with diaphragmatic Morgagni hernia and treated by repairing the hernia defect with a mesh by laparoscopic surgery. We describe the placement of a double-layer mesh anchored with helicoidal staples to repair the hernia defect using laparoscopic surgery. Laparoscopic surgery allows repair of these defects whilst avoiding the disadvantages of a major laparotomy or a thoracotomy. The existence of double-layer meshes that can be placed in contact with the abdominal viscera allows the defect to be closed safely and without tension.

Induction of rapid eye movement sleep by neurotrophin-3 and its co-localization with choline acetyltransferase in mesopontine neurons.

Because neurotrophin-3 (NT-3), a neurotrophic factor closely related to nerve growth factor, is capable of modulating neuronal activity [Yamuy et al., Neuroscience 95 (2000a) 1089-1100], we sought to examine if the microinjection of NT-3 into the nucleus reticularis pontis oralis (NPO) of chronically prepared cats also induced changes in behavior. In contrast to vehicle administration, NT-3 injection induced, with a mean latency of 4.7 min, long-duration episodes (mean, 21.6 min) of a state that was polygraphically indistinguishable from naturally occurring REM sleep. If NT-3 plays a physiologic role in the generation of REM sleep, then an endogenous source for this neurotrophin that is capable of controlling the activity of NPO neurons should exist. We therefore determined whether cholinergic neurons in the latero-dorsal and pedunculo-pontine tegmental (LDT and PPT) nuclei, which are involved in the initiation of REM sleep and project to the NPO, contained NT-3. Most, if not all, of the LDT-PPT cholinergic neurons exhibited NT-3 immunoreactivity. A portion (10%) of the NT-3+ neurons in the LDT-PPT were not cholinergic. The present data indicate that NT-3 rapidly modulates the activity of NPO neurons involved in REM sleep and that cholinergic neurons in the LDT and PPT contain NT-3. Taken together, these results support the hypothesis that NT-3 may be involved in the control of naturally occurring REM sleep.

Delivery of multiple epitopes by recombinant detoxified adenylate cyclase of Bordetella pertussis induces protective antiviral immunity.

CyaA, the adenylate cyclase toxin from Bordetella pertussis, can deliver its N-terminal catalytic domain into the cytosol of a large number of eukaryotic cells and particularly into professional antigen-presenting cells. We have previously identified within the primary structure of CyaA several permissive sites at which insertion of peptides does not alter the ability of the toxin to enter cells. This property has been exploited to design recombinant CyaA toxoids capable of delivering major histocompatibility complex (MHC) class I-restricted CD8(+) T-cell epitopes into antigen-presenting cells and to induce specific CD8(+) cytotoxic T-lymphocyte (CTL) responses in vivo. Here we have explored the capacity of the CyaA vector carrying several different CD8(+) T-cell epitopes to prime multiple CTL responses. The model vaccine consisted of a polyepitope made of three CTL epitopes from lymphocytic choriomeningitis virus (LCMV), the V3 region of human immunodeficiency virus gp120, and chicken ovalbumin, inserted at three different sites of the catalytic domain of genetically detoxified CyaA. Each of these epitopes was processed on delivery by CyaA and presented in vitro to specific T-cell hybridomas. Immunization of mice by CyaA toxoids carrying the polyepitope lead to the induction of specific CTL responses for each of the three epitopes, as well as to protection against a lethal viral challenge. Moreover, mice primed against the vector by mock CyaA or a recombinant toxoid were still able to develop strong CTL responses after subsequent immunization with a recombinant CyaA carrying a foreign CD8(+) CTL epitope. These results highlight the potency of the adenylate cyclase vector for induction of protective CTL responses with multiple specificity and/or broad MHC restriction.

Dosis letal 50 de lorazepam en raton (Mus musculus) Albino, cepa suizo-icr / Letal dose 50 (LD50) of lorazepam in albino mice (Mus musculus), swiss ICR strain

Objetivo: Como un primer paso para estudiar la toxicidad conjunta de mezclas de escopolamina y benzodiacepinas (nueva burundanga) se determinó la dosis letal 50 (DL50) del lorazepam en ratones (Mus musculus) albinos, cepa suizo ICR. Método: Se utilizaron 60 ratones machos adultos, asignados aleatoriamente a cinco grupos experimentales y uno de control. La dosis de lorazepam administrada por vía intraperitoneal a cada grupo fue: 10 mg/kg al grupo I, 20 mg/kg al grupo II, 40 mg/kg al grupo III, 80 mg/kg al grupo IV, y 160 mg/kg al grupo V. Al grupo de control se le administró solamente la solución vehículo. Se registró la mortalidad durante 15 días después de la administración y se realizó necropsia de los animales muertos durante el ensayo y de los supervivientes al final del mismo. Los datos fueron procesados mediante análisis de probit y estimación de la función de supervivencia. Resultados: La DL50 estimada fue 90.71 mg/kg, con intervalo de confianza del 95 por ciento entre 65,02 y 150,13 mg/kg. La mortalidad se produjo durante los primeros seis días después de la administración de dosis superiores a los 80 mg/kg, siendo mayor en las primeras 48 horas. Conclusiones: La DL50 de lorazepam estimada en nuestro estudio es aproximadamente el doble de la reportada, lo cual sugiere una mayor resistencia de la cepa utilizada en este experimento. El período crítico para la intoxicaciones por lorazepam abarca las primeras 48 horas

mAb against hen egg-white lysozyme regulate its presentation to CD4(+) T cells.

Specific antibodies increase antigen uptake and presentation by antigen-presenting cells via the B cell receptor in B cells or FcgammaR in dendritic cells. To determine whether the interaction between antibody and antigen could influence the set of peptides presented by MHC II molecules, we analyzed the presentation of different CD4(+) T cell epitopes of hen egg-white lysozyme (HEL) after the capture of immune complexes formed between HEL and seven different specific mAb. The 103-117 T cell epitope (I-E(d)) was specifically and selectively up-regulated by the D1.3 and F9.13.7 mAb that binds to proximal loops in the native structure of HEL. Furthermore, Ii-independent T cell epitopes exposed on the HEL surface (116-129 and 34-45, I-A(k) restricted) which require a mild processing involving the recycling of MHC II molecules were selectively up-regulated by mAb that overlap those T cell epitopes (D1.3 and D44.1). However, F10.6.6, somatically derived from the same germ line genes as D44.1 and exhibiting an higher affinity for HEL, was without effect on the presentation of the 34-45 epitope. An Ii-dependent T cell epitope buried into the tertiary structure of HEL (45-61, I-A(k) restricted) and requiring the neosynthesis of MHC II was up-regulated by high-affinity mAb recognizing epitopes located at the N- or C-terminus of the T cell epitope. These results strongly suggest that (i) the spatial relationship linking the T cell epitope and the B cell epitope recognized by the mAb, (ii) the intrinsic processing requirements of the T cell epitope, and (iii) the antibody affinity influences the presentation of a given T cell epitope.

Pancreatitis associated with pleural-mediastinal pseudocyst, panniculitis and polyarthritis.

We describe two patients with pancreatitis. One patient had acute pancreatitis of biliary origin and presented with small joint polyarthritis and panniculitis lesions. The other patient was originally hospitalised for dyspnoea with bilateral pleural effusion, and subsequently developed migratory polyarthritis. During his hospital stay he developed panniculitis lesions and a monoclonal IgG disorder of unknown significance. Very few patients with pancreatitis develop polyarthritis and panniculitis. The appearance of pseudocysts in the pleural and mediastinal cavity in the course of pancreatitis is an infrequent complication.