Human Neutrophils Couple Nitric Oxide Production and Extracellular Traps Formation in Allergic Asthma.

RATIONALE: Nitric oxide (NO) is elevated in the airways and serum of allergic asthmatic patients, suggesting an important role in asthma. NO production has been widely attributed to the canonical inducible nitric oxide synthase (iNOS). Much effort has been made to inhibit this enzyme with two outcomes: no asthma improvement; and partial NO reduction, suggesting the involvement of an iNOS-independent source. OBJECTIVES: Neutrophils produce NO under inflammatory conditions and their role in asthma has been overlooked. The present study analyzes their possible role as source of NO. METHODS: Our hypothesis was tested in 99 allergic patients with intermittent bronchial asthma and 26 healthy donors. NO production by blood and sputum neutrophils in response to allergens, anti-IgE, and anti-IgE receptors Abs was assessed by Griess, flow cytometry and confocal microscopy. Extracellular traps (ETs) formation, as a possible consequence of NO production, was quantified by western blot and confocal microscopy, and reactive oxygen species by luminol-enhanced chemiluminescence. RESULTS: Among blood and sputum granulocytes from allergic asthmatic patients, only neutrophils, produce NO by an IgE-dependent mechanism. This production is independent of NOS, but dependent on a reaction between L-arginine and reactive oxygen species from NOX2. NO and ETosis are induced in parallel, and NO amplifies ETs formation, which is a key mediator in asthma. CONCLUSIONS: Our findings reveal a novel role of neutrophils as the unique allergen/IgE-dependent NO source in allergic asthma enhancing ETs formation. These results suggest that NO produced by neutrophils needs further consideration in the treatment of allergic asthma.

Associated Factors of Pneumonia in Individuals with Chronic Obstructive Pulmonary Disease (COPD) Apart from the Use of Inhaled Corticosteroids.

Inhaled corticosteroids (ICSs) are widely used in chronic obstructive pulmonary disease (COPD) and in combination with long-acting ß2 agonists (LABAs) to reduce exacerbations and improve patient lung function and quality of life. However, ICSs have been associated with an increased risk of pneumonia in individuals with COPD, although the magnitude of this risk remains unclear. Therefore, it is difficult to make informed clinical decisions that balance the benefits and adverse effects of ICSs in people with COPD. There may be other causes of pneumonia in patients with COPD, and these causes are not always considered in studies on the risks of using ICSs in COPD. We consider it very useful to clarify these aspects in assessing the influence of ICSs on the incidence of pneumonia and their role in the treatment of COPD. This issue has important implications for current practice and the evaluation and management of COPD, since COPD patients may benefit from specific ICS-based treatment strategies. Many of the potential causes of pneumonia in patients with COPD can act synergistically, so they can be included in more than one section.

Regulation and directed inhibition of ECP production by human neutrophils.

Background: Neutrophils are involved in the pathophysiology of allergic asthma, where the Eosinophil Cationic Protein (ECP) is a critical inflammatory mediator. Although ECP production is attributed to eosinophils, we reported that ECP is also present in neutrophils from allergic patients where, in contrast to eosinophils, it is produced in an IgE-dependent manner. Given the key role of ECP in asthma, we investigated the molecular mechanisms involved in ECP production as well as the effects induced by agonists and widely used clinical approaches. We also analyzed the correlation between ECP production and lung function. Methods: Neutrophils from allergic asthmatic patients were challenged with allergens, alone or in combination with cytokines, in the presence of cell-signaling inhibitors and clinical drugs. We analyzed ECP levels by ELISA and confocal microscopy. Lung function was assessed by spirometry. Results: IgE-mediated ECP release is dependent on phosphoinositide 3-kinase, the extracellular signal-regulated kinase (ERK1/2) and the production of reactive oxygen species by NADPH-oxidase. Calcineurin phosphatase and the transcription factor NFAT are also involved. ECP release is enhanced by the cytokines interleukin (IL)-5 and granulocyte macrophage-colony stimulating factor, and inhibited by interferon-γ, IL-10, clinical drugs (formoterol, tiotropium and budesonide) and allergen-specific IT. We also found an inverse correlation between asthma severity and ECP levels. Conclusions: Our results suggest the molecular pathways involved in ECP production and potential therapeutic targets. We also provide a new method to evaluate disease severity in asthmatic patients based on the quantification of in vitro ECP production by peripheral neutrophils.

A Fabricated Force Glove That Measures Hand Forces during Activities of Daily Living.

Understanding hand and wrist forces during activities of daily living (ADLs) are pertinent when modeling prosthetics/orthotics, preventing workplace-related injuries, and understanding movement patterns that make athletes, dancers, and musicians elite. The small size of the wrist, fingers, and numerous joints creates obstacles in accurately measuring these forces. In this study, 14 FlexiForce sensors were sewn into a glove in an attempt to capture forces applied by the fingers. Participants in this study wore the glove and performed grasp and key turn activities. The maximal forces produced in the study were 9 N at the distal middle finger phalanx and 24 N at the distal thumb phalanx, respectively, for the grasp and key turn activities. Results from this study will help in determining the minimal forces of the hand during ADLs so that appropriate actuators may be placed at the appropriate joints in exoskeletons, orthotics, and prosthetics.

Targeted inhibition of allergen-induced histamine production by neutrophils.

Histamine is a critical inflammatory mediator in allergic diseases. We showed in a previous work that neutrophils from allergic patients produce histamine in response to allergens to which the patients were sensitized. Here, we investigate the molecular mechanisms involved in this process using peripheral blood neutrophils. We challenged these cells in vitro with allergens and analyzed histamine release in the culture supernatants. We also explored the effect of common therapeutic drugs that ameliorate allergic symptoms, as well as allergen-specific immunotherapy. Additionally, we examined the expression of histidine decarboxylase and diamine oxidase, critical enzymes in the metabolism of histamine, under allergen challenge. We show that allergen-induced histamine release is dependent on the activation of the phosphoinositide 3-kinase, mitogen-activated protein kinase p38, and extracellular signal-regulated kinase 1/2 signaling pathways. We also found a contribution of the phosphatase calcineurin to lesser extent. Anti-histamines, glucocorticoids, anti-M3-muscarinic receptor antagonists, and mainly ß2 -receptor agonists abolished the allergen-dependent histamine release. Interestingly, allergen-specific immunotherapy canceled the histamine release through the downregulation of histidine decarboxylase expression. Our observations describe novel molecular mechanisms involved in the allergen-dependent histamine release by human neutrophils and provide new targets to inhibit histamine production.

A Wearable Pulse Oximeter With Wireless Communication and Motion Artifact Tailoring for Continuous Use.

Advances in several engineering fields have led to a trend toward miniaturization and portability of wearable biosensing devices, which used to be confined to large tools and clinical settings. Various systems to continuously measure electrophysiological activity through electrical and optical methods are one category of such devices. Being wearable and intended for prolonged use, the amount of noise introduced on sensors by movement remains a challenge and requires further optimization. User movement causes motion artifacts that alter the overall quality of the signals obtained, hence corrupting the resulting measurements. This paper introduces a fully wearable optical biosensing system to continuously measure pulse oximetry and heart rate, utilizing a reflectance-based probe. Furthermore, a novel data-dependent motion artifact tailoring algorithm is implemented to eliminate noisy data due to the motion artifact and measure oxygenation level with high accuracy in real time. By taking advantages of current wireless transmission and signal processing technologies, the developed wearable photoplethysmography device successfully captures the measured signals and sends them wirelessly to a mobile device for signal processing in real time. After applying motion artifact tailoring, evaluating accuracy with a continuous clinical device, the blood oxygenation measurements obtained from our system yielded an accuracy of at least 98%, when compared to a range of 93.6%-96.7% observed before from the same initial data. Additionally, heart rate accuracy above 97% was achieved. Motion artifact tailoring and removal in real time, continuous systems will allow wearable devices to be truly wearable and a reliable electrophysiological monitoring and diagnostics tool for everyday use.

Influencia de la sobrecarga de calcio sobre el metabolismo óseo y mineral en 55 centros de hemodiálisis de Lima / Impact of calcium overload on bone and mineral metabolism at 55 hemodialysis centers in Lima

ANTECEDENTES: Las alteraciones del metabolismo óseo y mineral son complicaciones frecuentes de los pacientes de hemodiálisis que presentan una gran variabilidad geográfica. OBJETIVOS: El objetivo del presente estudio fue evaluar por primera vez dichas alteraciones en pacientes de hemodiálisis de Perú. MÉTODOS: El estudio incluyó 1.551 pacientes de hemodiálisis de 55 centros concertados con el seguro social de salud de Perú, pertenecientes a la ciudad de Lima. De cada paciente se recogieron datos demográficos, comorbilidades, tratamientos y parámetros bioquímicos. Los valores de calcio, fósforo y PTH fueron categorizados según los rangos recomendados en las guías KDOQI y KDIGO. RESULTADOS: La edad media de los pacientes fue de 59,5 ± 15,6, con tiempo medio en hemodiálisis de 58,0 ± 54,2 meses. Todos los pacientes se dializaban con una concentración de calcio en el líquido de diálisis de 3,5 mEq/l y el 68,9% recibían captores de fósforo (98,4% carbonato de calcio). Se observó un alto porcentaje de pacientes con calcio sérico por encima y fósforo sérico por debajo de los rangos recomendados en las guías KDOQI (32,8% y 37,3% respectivamente). Más de la mitad de los pacientes tenían valores de PTH por debajo de los rangos recomendados, tanto en KDOQI como en KDIGO (56,4% y 51,6% respectivamente). CONCLUSIONES: Los pacientes incluidos en el presente estudio se caracterizaron por ser más jóvenes que los de otros estudios y por tener hipofosforemia y PTH suprimida, probablemente debido a una excesiva sobrecarga de calcio a través del líquido de diálisis y el empleo de captores de fósforo con calcio

BACKGROUND: Mineral and bone metabolism disorders are common complications in haemodialysis patients that present significant geographical variability. OBJECTIVES: The objective of this study was to assess these disorders for the first time in haemodialysis patients from Peru. METHODS: The study included 1551 haemodialysis patients from 55 centres affiliated with the Social Health System of Peru in the city of Lima. Demographic data, comorbidities, treatments and biochemical parameters were collected from each patient. Serum calcium, phosphorus and PTH levels were categorised according to the recommended ranges in the KDOQI and KDIGO guidelines. RESULTS: The mean age of the patients was 59.5 ± 15.6 years, with a mean time on haemodialysis of 58.0 ± 54.2 months. All patients were dialysed with a calcium concentration in the dialysis fluid of 3.5 mEq/l and 68.9% of patients were prescribed phosphate-binding agents (98.4% of them calcium carbonate). A high percentage of patients showed serum calcium above, and serum phosphorus below, the recommended ranges in the KDOQI guidelines (32.8% and 37.3%, respectively). More than half of the patients had serum PTH values below the recommended ranges of both the KDOQI and KDIGO guidelines (56.4% and 51.6%, respectively). CONCLUSIONS: Patients included in this study were younger than those from other studies and showed both hypophosphataemia and suppressed PTH, probably due to an excessive calcium overload through dialysis fluid and the use of calcium-containing phosphate binding agents

Bone and mineral metabolism at 55 haemodialysis centres in Lima. / Influencia de la sobrecarga de calcio sobre el metabolismo óseo y mineral en 55 centros de hemodiálisis de Lima.

BACKGROUND: Mineral and bone metabolism disorders are common complications in haemodialysis patients that present significant geographical variability. OBJECTIVES: The objective of this study was to assess these disorders for the first time in haemodialysis patients from Peru. METHODS: The study included 1551 haemodialysis patients from 55 centres affiliated with the Social Health System of Peru in the city of Lima. Demographic data, comorbidities, treatments and biochemical parameters were collected from each patient. Serum calcium, phosphorus and PTH levels were categorised according to the recommended ranges in the KDOQI and KDIGO guidelines. RESULTS: The mean age of the patients was 59.5±15.6 years, with a mean time on haemodialysis of 58.0±54.2 months. All patients were dialysed with a calcium concentration in the dialysis fluid of 3.5 mEq/l and 68.9% of patients were prescribed phosphate-binding agents (98.4% of them calcium carbonate). A high percentage of patients showed serum calcium above, and serum phosphorus below, the recommended ranges in the KDOQI guidelines (32.8% and 37.3%, respectively). More than half of the patients had serum PTH values below the recommended ranges of both the KDOQI and KDIGO guidelines (56.4% and 51.6%, respectively). CONCLUSIONS: Patients included in this study were younger than those from other studies and showed both hypophosphataemia and suppressed PTH, probably due to an excessive calcium overload through dialysis fluid and the use of calcium-containing phosphate binding agents.

Outbreak of Escherichia coli O157:H7 Infections Linked to Aged Raw Milk Gouda Cheese, Canada, 2013.

Between 12 July and 29 September 2013, 29 individuals in five Canadian provinces became ill following infection with the same strain of Escherichia coli O157:H7 as defined by molecular typing results. Five case patients were hospitalized, and one died. Twenty-six case patients (90%) reported eating Gouda cheese originating from a dairy plant in British Columbia. All of the 22 case patients with sufficient product details available reported consuming Gouda cheese made with raw milk; this cheese had been produced between March and July 2013 and was aged for a minimum of 60 days. The outbreak strain was isolated from the implicated Gouda cheese, including one core sample obtained from an intact cheese wheel 83 days after production. The findings indicate that raw milk was the primary source of the E. coli O157:H7, which persisted through production and the minimum 60-day aging period. This outbreak is the third caused by E. coli O157:H7 traced to Gouda cheese made with raw milk in North America. These findings provide further evidence that a 60-day ripening period cannot ensure die-off of pathogens that might be present in raw milk Gouda cheese after production and have triggered an evaluation of processing conditions, physicochemical parameters, and options to mitigate the risk of E. coli O157:H7 infection associated with raw milk Gouda cheese produced in Canada.

Trasplante renal grupo sanguíneo ABO incompatible. Experiencia colaborativa inédita España y Perú / Incompatible ABO blood group renal transplant. Unprecedented collaborative experience between Spain and Peru

La incompatibilidad de grupo sanguíneo ABO y la sensibilización al HLA constituyen grandes barreras a vencer en pro de la óptima utilización de riñones de donante vivo. Describimos en nuestro medio el primer trasplante renal exitoso ABO incompatible en un paciente de 24 años, retrasplantado renal, altamente sensibilizado (PRA: 89%) y sin opción alguna en disponer de donantes cadavéricos ni familiares. Sin embargo, su único donante vivo HLA compatible era de grupo sanguíneo A incompatible con el grupo O del receptor. El paciente requirió de un régimen precondicionante consistente en recambios plasmáticos, rituximab, imunoglobulina y terapia inmunosupresora cuádruple, a fin de reducir los títulos elevados de isoaglutininas anti A de 1:128 a niveles de seguridad de 1:8, para el éxito del trasplante. Este fue realizado en Coordinación con la Unidad de Trasplante Renal del Hospital Clínic de Barcelona España (HCB). La ausencia de rechazo mediado por isoaglutininas muestra el potencial beneficio del protocolo al remover los anticuerpos anti grupo sanguíneo. A los dos años del trasplante, la función renal se mantiene estable con niveles de creatinina 1,5 mg%. Concluimos que el trasplante renal ABO incompatible (ABOi) es opción viable para pacientes cuyo único donante sea grupo sanguíneo incompatible, y entre nosotros representa esperanzadora fuente de órganos.

ABO blood group incompatibility and HLA sensitization are major barriers that need to be overcome in order to make optimum use of kidneys from living donors possible. We report the first successful ABO- incompatible kidney transplant in a 24-year old, highly sensitized (panel reactive antibodies (PRA) 89% kidney retransplantation patient, who lacked any option to get a cadaveric or family donor. However, the patient's sole HLA-compatible living donor had group A blood incompatible with the recipient's O blood group. The < patient required a pre-conditioning regime that consisted of plasma exchange, rituximab, immunoglobulin, and quadruple immunosuppressive therapy in order to reduce high titers of anti-A isoagglutinins from 1:128 to a safe level of 1:8, for successful transplant. This was performed in coordination with the Renal Transplant Unit of Hospital Clinic de Barcelona (HCB), Spain. Absence of rejection mediated by isoagglutinins shows the potential benefit of a protocol consisting in removing antibodies from the anti-blood group. Two yearsafter transplantation, the kidney function remains stable, with creatinine levels of 1.5 mg%. We conclude that an ABO-incompatible kidney transplant is a viable option for patients whose only donor has blood of an incompatible blood group and for us this represents a hope-inspiring source of organs .

Infección del tracto urinario en receptores de trasplante renal / Urinary tract infection in renal transplant recipients

Introducción. La infección del tracto urinario (ITU) es común en receptores de trasplante renal (TR). La frecuencia de ITU depende de factores previos y posteriores al trasplante. Objetivos. Determinar la cronología de aparición de ITU sintomática, los microorganismos causantes y la incidencia de ITU resistente a antibióticos en receptores de TR. Diseño. Estudio retrospectivo. Lugar. Unidad de Trasplante Renal, Hospital Edgardo Rebagliati Martins, EsSalud, Lima, Perú. Participantes. Pacientes sometidos a TR. Intervenciones. Se revisó la historia clínica de 304 pacientes sometidos a TR en el período 2002-2011, con seguimiento de hasta cuatro años por paciente. Se constató 215 episodios de ITU sintomática confirmada mediante urocultivo en 84 receptores. Principales medidas de resultados. Incidencia, cronología, determinación microbiológica/susceptibilidad, resistencia bacteriana, factores de riesgo, estrategias diagnósticas, presencia o no de bacteriemia y manejo terapéutico. Resultados. En 50% de los 84 receptores el episodio inicial ocurrió durante los primeros tres meses, y en 39% se constató más de un episodio de ITU. Las bacterias representaron la etiología más frecuente (94%), siendo la Escherichia coli (77%) el uropatógeno prevalente, con tasa productora betalactamasa espectro extendido (BLEE) en 38%, seguida de Klebsiella pneumonie (11%) con BLEE 65%. En 12% de los 215 episodios de ITU el hemocultivo fue positivo. Entre los factores de riesgo se detectó luego del trasplante 19% receptores con anormalidades anatómicas del tracto urinario. Conclusiones. La ITU ocurrió tempranamente luego del trasplante y la Escherichia coli fue el microorganismo etiológico más frecuente. La resistencia antibiótica estuvo presente en 37% de los 215 episodios de ITU, representando un desafío contínuo a resolver en la práctica clínica.

Introduction. Urinary tract infections (UTI) are common among renal transplant recipients (RTR) and their frequency depends on pre- and post-transplant factors. Objectives. To determine the time of appearance of symptomatic UTI among renal transplant recipients, microorganisms causing the infection, and incidence of UTI resistant to antibiotics. Design. Retrospective study. Setting. Renal Transplant Unit, Hospital Edgardo Rebagliati Martins, EsSalud, Lima, Peru. Participants. Patients who have undergone renal transplantation. Interventions. The clinical records of 304 patients subject to kidney transplantation performed between 2002 and 2011 and followed for up to four years were reviewed. There were 215 urine culture-confirmed UTI episodes in 84 transplant recipients. Main outcome measures. Incidence, chronology, microbiological determination/ susceptibility, bacterial resistance, risk factors, diagnostic strategies, presence or absence of bacteremia, and therapeutic management. Results. In 42 of the 84 recipients, the initial episode occurred during the first three months, and 33 (39%) had more than one UTI episode. Bacteria represented the most common etiology (94%), and Escherichia coli was the most prevalent uropathogen, with an extended-spectrum beta-lactamase (ESBL) production rate of 38%, followed by Klebsiella pneumoniae (11%) with an ESBL of 65%. Blood culture was positive in 25 (12%) of the 215 UTI episodes. In 17 recipients (19%), anatomic anomalies of the urinary tract were detected following the transplant. Conclusions. UTI occurred early following kidney transplantation, and Escherichia coli was the most common microorganism found. Antibiotic resistance was present in 79 (37%) of the 215 UTI episodes, representing a continuous challenge in clinical practice.

Novel tailoring algorithm for abrupt motion artifact removal in photoplethysmogram signals.

Photoplethysmogram (PPG) signals are widely used for wearable electronic devices nowadays. The PPG signal is extremely sensitive to the motion artifacts (MAs) caused by the subject's movement. The detection and removal of such MAs remains a difficult problem. Due to the complicated MA signal waveforms, none of the existing techniques can lead to satisfactory results. In this paper, a new framework to identify and tailor the abrupt MAs in PPG is proposed, which consists of feature extraction, change-point detection, and MA removal. In order to achieve the optimal performance, a data-dependent frame-size determination mechanism is employed. Experiments for the heart-beat-rate-measurement application have been conducted to demonstrate the effectiveness of our proposed method, by a correct detection rate of MAs at 98% and the average heart-beat-rate tracking accuracy above 97%. On the other hand, this new framework maintains the original signal temporal structure unlike the spectrum-based approach, and it can be further applied for the calculation of blood oxygen level (SpO2).

Tuberculosis en receptores de trasplante renal: experiencia en una unidad de trasplante renal de Perú / Tuberculosis in renal transplant recipients: experience in a kidney transplant unit in Peru

Introducción: El trasplante de órganos conlleva riesgo de contraer tuberculosis (TB) a resultas de la necesaria inmunosupresión concurrente. La literatura señala una incidencia de 0,35 por ciento a 15 por ciento. En nuestro medio, carecemos de datos al respecto. Objetivos: Explorar la epidemiolog¡a, cuadro clinico y pronóstico de la TB en receptores de trasplante renal en  rea endémica. Igualmente, efectuar el analisis de casos multidrogorresistentes (MDR). Diseño: Estudio retrospectivo. Institución: Departamento de Nefrologia, Hospital Edgardo Rebagliati Martins, EsSalud, Lima, Perú. Material: Historias clinicas de casos de trasplante renal comprendidos en el periodo 1999-2014. Intervenciones: Se revisó en 619 casos de trasplante renal la instalación de tuberculosis, as¡ como se efectuó el analisis de casos multidrogorresistentes. Principales medidas de resultados: Instalación de tuberculosis y casos multidrogorresistentes. Resultados: La TB se instaló en 22 pacientes (3,5 por ciento), incidencia mayor que la obtenida en la población general del pais (96/100 000/anual). La fiebre (57 por ciento) y la tos crónica (28 por ciento) fueron los sintomas m s comunes. La TB extrapulmonar (50 por ciento) predominó sobre la pulmonar (40 por ciento) y la diseminada (10 por ciento). La ocurrencia de TB fue mayoritariamente después del año (72 por ciento). Siete de los casos (28 por ciento) cursaron con creatinina mayor de 2 mg porcentaje al momento del diagnóstico y tres de ellos retornaron a dialisis. Hubo cuatro casos de TB MDR. Conclusiones: El diagnóstico temprano en base a la sospecha clinica de TB y el tratamiento oportuno mejora el pronóstico en esta población.

Introduction: Organ transplantation carries a risk of contracting tuberculosis (TB) due to the required concurrent immunosuppression. Literature reports an incidence of 0.35 per cent-15 per cent. There is no data on this matter in our region. Objectives: To determine epidemiology, clinical findings and prognosis of TB in renal transplantation recipients in an endemic area. The study also aimed to analyze multidrug-resistant (MDR) cases. Design: Retrospective study. Setting: Department of Nephrology, Hospital Edgardo Rebagliati Martins, EsSalud, Lima, Peru. Material: Clinical charts of renal transplant patients attended during 1999-2014. Interventions: Onset of tuberculosis was determined in 619 cases of renal transplant, as well as analysis of multidrug-resistant cases. Main outcome measures. Installation of tuberculosis and cases of multidrug resistance. Results: TB developed in 22 patients (3.5 per cent), more prevalent that the country general population (96/100 000/year). Fever (57 per cent) and chronic cough (28 per cent) were the most common symptoms. Extrapulmonary TB (50 per cent) predominated over pulmonary (40 per cent) and disseminated TB (10 per cent). TB occurred usually after one year (72 per cent) and on average within the 41st month post transplantation. Seven cases (28 per cent) presented creatinine above 2 mg percentage at diagnosis and three of them returned to dialysis. There were four cases of MDR TB. Conclusions: Early diagnosis based on TB clinical suspicion and timely treatment improves the prognosis in this population of immunosuppressed patients.

Nefropatía asociada a poliomavirus BK en trasplante renal / BK polyomavirus-associated nephropathy in kidney transplant

El objetivo del presente reporte es dar a conocer los dos primeros casos de nefropatía del injerto asociada a poliomavirus BK (NPBK) ocurridos en el Hospital Edgardo Rebagliati Martins, EsSalud, Lima, Perú. El diagnóstico definitivo de la NPBK se corroboró mediante biopsia renal y estudio de microscopia electrónica. En el caso 1, el deterioro funcional renal no se controló a pesar de reducir la inmunosupresión y añadir drogas antivirales (leflunamide y ciprofloxacina), evolucionando a falla renal y su posterior acceso a retrasplante renal. En el caso 2, la alternativa terapéutica se basó en infusión de inmunoglobulina endovenosa asociada a reducción de la inmunosupresión, resultando en moderada mejora histológica y estabilización de la función renal. En ambos injertos renales hubo concomitantemente NPBK y lesiones histológicas compatibles con rechazo agudo celular pendientes de interpretar. En conclusión, la presencia del poliomavirus BK representa serio problema en el riñón trasplantado. La mejor conducta terapéutica se basa en el diagnóstico precoz y subsecuente reducción de la inmunosupresión. Es imprescindible disponer de metodología apropiada que posibilite un diagnóstico preciso. Se utiliza tamizaje de células señuelo o marcadoras (decoy cells) en orina, reacción de cadena polimerasa (PCR), biopsia renal o la microscopia electrónica como método valioso de ayuda en el diagnóstico etiológico viral. Se considera el retrasplante como opción ante la pérdida del injerto por NPBK (caso 1)...

Two documented cases of BK polyomavirus-associated nephropathy (BKVN) seen at Hospital Edgardo Rebagliati Martins, EsSalud, Lima, Peru are reported. Final BKVN diagnosis was confirmed by renal biopsy and electron microscopy study. Case 1: Renal functional deterioration was not controlled despite reduction of immunosuppression and addition of antiviral drugs (leflunomide and ciprofloxacin), evolving to renal failure and subsequent kidney retransplantation. Case 2: The therapeutical management consisted in intravenous immunoglobulin infusion linked to reduction of immunosuppression; this resulted in modest histological improvement and stabilization of renal function. Both renal grafts concomitantly presented BKVN and histological lesions consistent with acute rejection, pending interpretation. In conclusion presence of BK polyomavirus is a serious problem for transplanted kidneys. The best treatment is based on early diagnosis and subsequent reduction of immunosuppression. It is essential to have an appropriate methodology for precise diagnosis. Early electron microscopy is a valuable method for viral etiologic diagnosis. Retransplantation is considered a treatment option when faced with possible BKVN-related graft loss (Case 1)...

Cerebellin 4, a synaptic protein, enhances inhibitory activity and resistance of neurons to amyloid-ß toxicity.

Imbalances between excitatory and inhibitory transmissions in the brain anticipate the neuronal damage and death that occur in the neurodegenerative diseases like Alzheimer's disease (AD). We previously showed that amyloid-ß (Aß), a natural peptide involved in the onset and development of AD, counteracts the neurotrophic activity of the nerve growth factor (NGF) by dampening the γ-aminobutyric acid (GABA)ergic connectivity of cultured hippocampal neurons. Neuronal plasticity is partly controlled by the NGF-promoted expression of the homologue of enhancer-of-split 1 (Hes1), a transcription factor that regulates the formation of GABAergic synapses. We now show that Hes1 controls the expression of cerebellin 4 (Cbln4), a member of a small family of secreted synaptic proteins, and we present the evidence that Cbln4 plays an essential role in the formation and maintenance of inhibitory GABAergic connections. Cbln4 immunoreactivity was found in the hippocampus, mostly in the dendrites and somata of pyramidal neurons. In the CA1, the hippocampal region where the first neurons degenerate in AD, Cbln4 immunoreactivity was associated with GABAergic synapses (detected by vesicular inhibitory amino acid transporter [VGAT] immunostaining), which appear to surround and embrace the somata of CA1 pyramidal neurons (basket cells). Moreover, significant decreases of Hes1, Cbln4, and VGAT immunoreactivities and messenger RNA expression were found in the hippocampus of a mouse model of AD. We also found that either the overexpression of Cbln4 in cultured hippocampal neurons or the application of recombinant Cbln4 to the cultures increased the number of GABAergic varicosities, rescuing neurons from Aß-induced death. In contrast, knockdown of Cbln4 gene in cultured neurons was followed by a large reduction of GABAergic connections. Such an effect was reverted by exogenously added Cbln4. These findings suggest a therapeutic potential for Cbln4 in the treatment of AD.

Selective regulation of axonal growth from developing hippocampal neurons by tumor necrosis factor superfamily member APRIL.

APRIL (A Proliferation-Inducing Ligand, TNFSF13) is a member of the tumor necrosis factor superfamily that regulates lymphocyte survival and activation and has been implicated in tumorigenesis and autoimmune diseases. Here we report the expression and first known activity of APRIL in the nervous system. APRIL and one of its receptors, BCMA (B-Cell Maturation Antigen, TNFRSF17), are expressed by hippocampal pyramidal cells of fetal and postnatal mice. In culture, these neurons secreted APRIL, and function-blocking antibodies to either APRIL or BCMA reduced axonal elongation. Recombinant APRIL enhanced axonal elongation, but did not influence dendrite elongation. The effect of APRIL on axon elongation was inhibited by anti-BCMA and the expression of a signaling-defective BCMA mutant in these neurons, suggesting that the axon growth-promoting effect of APRIL is mediated by BCMA. APRIL promoted phosphorylation and activation of ERK1, ERK2 and Akt and serine phosphorylation and inactivation of GSK-3ß in cultured hippocampal pyramidal cells. Inhibition of MEK1/MEK2 (activators of ERK1/ERK2), PI3-kinase (activator of Akt) or Akt inhibited the axon growth-promoting action of APRIL, as did pharmacological activation of GSK-3ß and the expression of a constitutively active form of GSK-3ß. These findings suggest that APRIL promotes axon elongation by a mechanism that depends both on ERK signaling and PI3-kinase/Akt/GSK-3ß signaling.

Growth differentiation factor 5 is a key physiological regulator of dendrite growth during development.

Dendrite size and morphology are key determinants of the functional properties of neurons. Here, we show that growth differentiation factor 5 (GDF5), a member of the bone morphogenetic protein (BMP) subclass of the transforming growth factor ß superfamily with a well-characterised role in limb morphogenesis, is a key regulator of the growth and elaboration of pyramidal cell dendrites in the developing hippocampus. Pyramidal cells co-express GDF5 and its preferred receptors, BMP receptor 1B and BMP receptor 2, during development. In culture, GDF5 substantially increased dendrite, but not axon, elongation from these neurons by a mechanism that depends on activation of SMADs 1/5/8 and upregulation of the transcription factor HES5. In vivo, the apical and basal dendritic arbours of pyramidal cells throughout the hippocampus were markedly stunted in both homozygous and heterozygous Gdf5 null mutants, indicating that dendrite size and complexity are exquisitely sensitive to the level of endogenous GDF5 synthesis.

Histamine production by human neutrophils.

Histamine is an important mediator in the development of allergic reactions. Only a small subset of human cell types is able to produce histamine. No previous studies have shown that human neutrophils are among them. The present work was undertaken to analyze whether human neutrophils produce histamine, and to determine what agonists are involved in histamine production by human neutrophils. The expression of histidine decarboxylase in human neutrophils was established by quantitative PCR, Western blotting, and flow cytometry analysis. The activity of the enzyme was determined by ELISA, which measured histamine in the culture supernatant of neutrophils stimulated with a set of classical agonists. Human neutrophils are bona fide histamine-producing cells. Neutrophils store ∼0.29 pg/cell and release ∼50% of the histamine content in an antigen-dependent manner and on stimulation with other neutrophil agonists. Basal expression of histidine decarboxylase, the rate-limiting enzyme in histamine production, is higher in neutrophils from patients with allergies than from healthy donors. Our results cannot be ascribed to cell contamination for several reasons. LPS failed to induce histamine release by basophils, whereas it induced histamine release by neutrophils; and we did not detect basophils, monocytes, or lymphocytes in our neutrophil preparations. Eosinophils, albeit detected, were only 0.001-0.004% of the final cell population, and they did not store or release histamine on antigen or LPS stimulation. Antigens to which patients with allergies were sensitized stimulated release of histamine from neutrophils. These observations represent a novel view of neutrophils as possible source of histamine in the allergic diseases.

Increased expression of the homologue of enhancer-of-split 1 protects neurons from beta amyloid neurotoxicity and hints at an alternative role for transforming growth factor beta1 as a neuroprotector.

INTRODUCTION: Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the deposition of ß-amyloid (Aß) in the brain, which produces progressive neuronal loss and dementia. We recently demonstrated that the noxious effects of Aß on cultured hippocampal neurons are in part provoked by the antagonism of nerve growth factor (NGF) signalling, which impairs the activation of nuclear factor κB (NF-κB) by impeding the tyrosine phosphorylation of I-κBα. As a result, the expression of the homologue of Enhancer-of split 1 (Hes1) gene is downregulated and ultimately, gamma-aminobutyric acid (GABA)-ergic connectivity is lost. METHODS: Hes1 activity was promoted in cultured hippocampal neurons by overexpressing a Hes1-encoding plasmid or by upregulating this gene by activating NF-κB through different approaches (overexpressing either the I-κB kinaseß, or p65/RelA/NF-κB). Alternatively neurons were exposed to TGFß1. Dendrite patterning, GABAergic connectivity and cell survival were analyzed by immunofluorescence microscopy. Hes1 expression was determined by real-time PCR. NF-κB activation was measured using the dual-luciferase reporter assay. RESULTS: The expression of Hes1 abolished the effects of Aß on dendritic patterning and GABAergic input, and it prevented the death of the cultured neurons. TGFß1, a known neuroprotector, could counteract the deleterious effects of Aß by inducing NF-κB activation following the serine phosphorylation of I-κBα. Indeed, the number of GABAergic terminals generated by inducing Hes1 expression was doubled. CONCLUSION: Our data define some of the mechanisms involved in Aß-mediated cell death and they point to potential means to counteract this noxious activity.

Identification of the distinctive type i/XhoI+ strain of Epstein-Barr virus in gastric carcinoma in Peru.

AIM: To clarify the reason for the low frequency of Epstein-Barr virus-associated gastric carcinoma (EBVaGC) in Peru, despite the high frequency reported in neighboring countries, the distribution of the distinctive EBV (type i/XhoI+) strain in EBVaGC and a healthy population was examined. MATERIALS AND METHODS: EBV polymorphisms in BamHI W1/I1 and XhoI restriction site of the latent membrane protein 1 gene (LMP1) were examined among 11 EBVaGCs and 172 healthy controls from Peru, and these frequencies were compared with those in a previous study of Chile and Colombia (n=303). RESULTS: The frequency of the distinctive EBV strain in EBVaGCs (55%) was significantly higher than that in controls (7%). Furthermore, the frequency of this EBV type in Peruvian controls was significantly lower than that in controls from Chile and Colombia (27%, p<0.001). CONCLUSION: The low frequency of the distinctive EBV strain among the Peruvian population might be a reason for the lower incidence of EBVaGC in Peru, as compared with neighboring countries.