Atomic Force Microscopy of Protein Shells: Virus Capsids and Beyond.

In Atomic Force Microscopy (AFM) the probe is a nanometric tip located at the end of a microcantilever which palpates the specimen under study as a blind person uses a white cane. In this way AFM allows obtaining nanometric resolution images of individual protein shells, such as viruses, in liquid milieu. Beyond imaging, AFM also enables the manipulation of single protein cages, and the characterization a variety physicochemical properties able of inducing any measurable mechanical perturbation to the microcantilever that holds the tip. In this chapter we start revising some recipes for adsorbing protein shells on surfaces. Then we describe several AFM approaches to study individual protein cages, ranging from imaging to spectroscopic methodologies devoted to extracting physical information, such as mechanical and electrostatic properties.

The presence of precursors of benign pre-B lymphoblasts (hematogones) in the bone marrow of a paediatric patient with cytomegalovirus infection.

Hematogones are normal B-lymphoid precursors that multiply in the bone marrow of small children and of adults with ferropenic anaemia, neuroblastoma or idiopathic thrombocytopenic purpura. They are not normally found in peripheral blood, and the immunophenotype is virtually indistinguishable from that of B lymphoblasts. We discuss the case of a 3-month infant with an active cytomegalovirus infection, with hepatitis and pancytopenia associated with 13% hematogones in the bone marrow.

Melatonin increases following convulsive seizures may be related to its anticonvulsant properties at physiological concentrations.

Melatonin ( N-acetyl-5-methoxytryptamine, aMT) is an indoleamine produced by several organs and tissues including the pineal gland. Melatonin (aMT) modulates the activity of the brain, mainly acting on both GABA and glutamate receptors. Previous studies have shown the participation of melatonin in the control of convulsive crises, suggesting that aMT concentration increases during seizures, and that patients with seizures of diverse origins show an alteration of the aMT rhythm. However, what is not known is the duration of the aMT response to seizures, and whether aMT changes during seizures could be a marker of the disease. For this reason, the serum levels of aMT in 54 children with a convulsive crisis, febrile and epileptic, were analyzed during the crisis, as well as at 1 h and 24 hours after the seizure. The results show that aMT significantly increases during the seizure (Day group, 75.64+/-45.91 and Night group, 90.69+/-51.85 pg/mL), with normal values being recovered 1 h later (Day group, 26.33+/-10.15 and Night group, 27.78+/-7.82 pg/mL) and maintained for up to 24 hours, when the circadian variation of aMT returns to the normal acrophase. Due to the interindividual variation of aMT levels among healthy people, a single determination of the indoleamine concentration is not a suitable marker of the existence of a convulsive crisis unless the circadian profile of aMT secretion in the patient is known. The results obtained also support the view that the stimulation of aMT production by the convulsive crisis may participate in the response of the organism against the seizures.

Consideraciones sobre el manejo clínico de la diarrea aguda y la deshidratación en pediatría / Management of acute diarrhoea in Pediatrics

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[Familial study of factor XI deficiency. Presurgical prophylactic treatment with desmopressin plus antifibrinolytics]. / Estudio familiar de déficit de factor XI. Tratamiento profiláctico prequirúrgico con desmopresina y antifibrinolíticos.

Factor XI deficiency is a rare inherited coagulation disorder. It rarely produces spontaneous bleeding although patients with this disorder are at risk for hemorrhagic complications after trauma or surgery. Because there is no clear correlation between the tendency to bleed and the severity of the disease itself, predicting hemorrhagic complications after surgery in patients with mild disease is difficult. This hereditary deficiency is characterized by prolongation of activated partial thromboplastin time with normal prothrombin time, and the demonstration of selective plasma factor XI deficit. Currently available products in the therapeutic arsenal are transfusion of fresh-frozen plasma, virus-inactivated factor XI concentrates, desmopressin (DDAVP) and antifibrinolytic drugs, whether alone or in combination. We describe a family with two affected children, in which the deficiency was identified as an autosomal recessive trait. Of the two patients, one required prophylactic treatment with desmopressin and tranexamic acid before surgery; the treatment was successful and no related complications were observed. The long-term outcome of individuals with this disease seems to be good with continuous follow up and early control of hemorrhagic episodes. Prophylactic therapy is not required, except when surgery is anticipated.

Estudio familiar de déficit de factor XI. Tratamiento profiláctico prequirúrgico con desmopresina y antifibrinolíticos / Familial study of factor xi deficiency. presurgical prophylactic treatment with desmopressin plus antifibrinolytics

La deficiencia de factor XI es una coagulopatía hereditaria poco frecuente, caracterizada por presentar raramente sintomatología hemorrágica espontánea, aunque sí existe el riesgo de complicaciones hemorrágicas graves inducidas por un traumatismo o cirugía. No se puede establecer una correlación clara entre los niveles de factor XI y la tendencia hemorrágica, por lo que es difícil predecir las posibles complicaciones hemorrágicas posquirúrgicas en pacientes con déficit leve. Este déficit se caracteriza por presentar un tiempo de tromboplastina parcial activado (TTPA) alargado, con un tiempo de protrombina (TP) normal, y la demostración mediante estudio con plasma deficiente de un déficit selectivo de factor XI. Las posibilidades terapéuticas y profilácticas en esta enfermedad incluyen: transfusión de plasma fresco congelado, concentrado de factor XI sometido a procesos de inactivación viral, fármacos antifibrinolíticos y desmopresina, ya sea como terapia única o combinada. Se describe una familia con los 2 hijos afectados en el que se demuestra una herencia autosómica recesiva del déficit. De los 2 casos, uno ha requerido tratamiento profiláctico prequirúrgico con desmopresina (DDAVP) y ácido tranexámico, con buena respuesta a éste, sin que presentara complicaciones asociadas al mismo. La evolución a largo plazo de este proceso parece ser buena, con un adecuado seguimiento y un control precoz de los episodios hemorrágicos. No es necesario realizar ningún tratamiento profiláctico, salvo en caso de cirugía (AU)

[Continuous treatment with colony stimulating factors (G-CSF) for neutropenia associated with type Ib glycogenosis]. / Tratamiento continuo con factores estimulantes de colonias (G-CSF) de la neutropenia asociada a la glucogenosis tipo Ib.

In the last few years, granulocyte colony stimulating factors (G-CSF), or hematopoietic growth factors, have created new possibilities for treating severe neutropenias, with high clinical efficacy and minimal adverse effects. Moreover, due to genetic recombinant techniques, the therapeutic use of these glycoproteins is increasing. We report the case of a 4-year-old girl who was diagnosed with glycogenosis IB at the age of 7 months. From the age of 2 years, she presented severe established neutropenia secondary to the main disease. Subcutaneus G-CSF therapy was started. The patient has shown no serious infections, has maintained normal growth and development, and has not required hospitalization. Adverse effects have been minimal. The therapeutic efficacy demonstrated by this case justifies the continuous use of G-CSF, although the lack of long-term perspectives should not be forgotten.

Tratamiento continuo con factores estimulantes de colonias (G-CSF) de la neutropenia asociada a la glucogenosis tipo Ib / Treatment with granulocyte colony stimulating factors for neutropenia in glycogenosis ib

En los últimos años, los factores estimulantes de colonias (CSF) o de crecimiento hemopoyético han abierto una vía para el tratamiento de las neutropenias graves, con alta eficacia clínica y efectos secundarios irrelevantes. Además, su uso se ha generalizado gracias a la síntesis mediante técnicas de recombinación genética. Se expone el caso clínico de una niña de 4 años, diagnosticada de glucogenosis Ib desde los 7 meses de vida. Desde hace 2 años presenta neutropenia grave establecida, derivada de la enfermedad principal. Se inició tratamiento con CSF de granulocitos (G-CSF) subcutáneo: la paciente no ha presentado infecciones de importancia, ha mantenido un crecimiento y desarrollo adecuados y no ha precisado hospitalización. Los efectos adversos han sido mínimos, hasta el momento. La eficacia terapéutica en este caso justifica el uso de G-CSF de manera continua, pero no debe olvidarse la falta de perspectiva temporal de dicho tratamiento (AU)

Evaluación de la eficacia antipirética y seguridad de dos formulaciones pediátricas de ibuprofeno / Evaluation of the antipyretic safety and accuracy of two pediatric ibuprofen formulations

OBJETIVO: Comparar la eficacia y evaluar la bioequivalencia clínica de dos presentaciones de ibuprofeno para niños, suspensión y gránulos efervescentes, en el tratamiento de la fiebre. MÉTODOS: Ensayo clínico abierto, de distribución aleatoria y multicéntrico. Se administró a niños con pesos superiores a 25kg, que acudieron con temperatura axilar superior a38º C a servicios de urgencias hospitalarios, una dosis de ibuprofeno en suspensión de 7 mg/kg, o una dosis de gránulos efervescentes con la siguiente posología: 200 mg en niños con pesos entre 25 y 40 kg, o 400 mg si pesaban entre 35 y 40 kg y tenían una temperatura axilar superior a 39 ºC, así como en los niños de más de 40 kg. Se tomó la temperatura axilar antes del tratamiento y a los 30, 60, 90, 120, 180 y 240 min, y se registraron posibles efectos adversos. RESULTADOS: Se incluyeron 103 pacientes, 51 recibieron gránulos y 52 suspensión. La temperatura media se redujo en los dos grupos a lo largo del estudio (p < 0,005), sin diferencias entre ellos. Las diferencias medias de temperatura en cada momento del estudio se situó dentro del intervalo de bioequivalencia (60,5ºC). En un caso se alcanzó una temperatura axilar de 35,9 ºC, siendo el único acontecimiento adverso ocurrido. CONCLUSIÓN: Ambas formulaciones se mostraron eficaces en la reducción de la temperatura y pueden considerarse bioequivalentes clínicamente (AU)

El uso de factores de crecimiento hematopoyéticos, ¿es seguro a largo plazo? / Is the long-term use of hematopoietic growth factors safe?

Los factores de crecimiento hematopoyéticos (G-CSF) son fármacos de reciente adquisición en nuestro arsenal terapéutico; su descubrimiento y posterior síntesis mediante técnicas de recombinación genética ha abierto una posibilidad de tratamiento en diversas situaciones clínicas en las que las opciones terapéuticas eran como mínimo limitadas. El tratamiento con G-CSF es generalmente bien tolerado, y sus escasos efectos secundarios, así como su facilidad de administración, son los responsables de su amplia utilización. Describimos el caso de una paciente de 16 años diagnosticada de neutropenia cíclica a los 9, tratada desde entonces con G-CSF por vía subcutánea mediante autoadministración. Después de un seguimiento de 66 meses, la paciente no ha padecido efectos secundarios relevantes, su calidad de vida es buena y únicamente ha necesitado antibioticoterapia en 2 ocasiones durante estos 7 años. Por tanto, la utilidad clínica del tratamiento con G-CSF, medida en términos de calidad de vida, es evidente, ya que permite el desarrollo de la actividad habitual para su edad, sin complicaciones infecciosas ni consultas médicas continuas (AU)

Utility of high doses of melatonin as adjunctive anticonvulsant therapy in a child with severe myoclonic epilepsy: two years' experience.

Recent data indicate that melatonin inhibits brain glutamate receptors and nitric oxide production, thus suggesting that it may exert a neuroprotective and antiexcitotoxic effect. Melatonin has been seen to prevent seizures in several animal models and to decrease epileptic manifestations in humans. The lack of response to conventional anticonvulsants in an epileptic child led us to use melatonin in this case. A female child who began to have convulsive seizures at the age of 1.5 months and was diagnosed as having severe myoclonic epilepsy was unsuccessfully treated with different combinations of anticonvulsants, including valproic acid, phenobarbital, clonazepam, vigabatrin, lamotrigin, and clobazam. Melatonin was thus added to the treatment. Imaging studies (CT, SPECT, and MNR), EEG recordings, blood biochemical, and hematological analyses, including measures of the circadian rhythm of melatonin, were made. The child was initially treated with various anticonvulsants. Severe neurological and psychomotor deterioration combined with increased seizure activity showed a lack of response to the treatment. At the age of 29 mon the patient was in a pre-comatose stage at which time melatonin was added to treatment. After 1 month of melatonin plus phenobarbital therapy and for a year thereafter, the child's seizures were under control. On reducing the melatonin dose after this time, however, seizures resumed and the patient's condition was re-stabilized after restoring melatonin. Prior to our attempts to reduce melatonin, all analyses, including EEG recordings and SPECT, were normal. As far as the results of neurological examination are concerned, only mild hypotony without focalization remained. Changes in the therapeutic schedules during the second year of melatonin treatment, including the withdrawal of phenobarbital, did not result in the same degree of seizure control, although progressively the child became satisfactorily controlled. At the present moment the child continues to have mild hypotony and shows attention disorder and irritability. Melatonin has proven to be useful as adjunctive therapy in the clinical control of this case of severe infantile myoclonic epilepsy. The results suggest that melatonin may have a useful role in mechanisms of neuroprotection and also indicate its use in other cases of untreatable epilepsy. Further studies using more patients and placebo-treatment would be beneficial in understanding the potential use of melatonin as a co-therapy in some cases of seizures.

[The effect of melatonin as anti-convulsant and neuron protector]. / Efeto de la melatonina como anticonvulsivante y protector neuronal.

INTRODUCTION: Melatonin is the principal hormone secreted by the pineal gland. In human beings the pineal gland is found on the posterior aspect of the midbrain. Melatonin is synthesized from tryptophan following a circadian rhythm, with low levels during the day and high levels during the night. It regulates many biological processes in relation to the cycles of light and darkness. DEVELOPMENT: Its first known function was that of inducing sleep. In experimental animals its effect as a depressor of the central nervous system and its anti-convulsive action have been shown. Few studies have been done in human beings, although there is some evidence of its beneficial effect in epileptic patients, improving both the frequency of the crises and the EEG tracing. In our experience we gave melatonin to a girl with severe myoclonic epilepsy which did not respond to usual treatment, obtaining improvement in both the number of crises daily and in psycho-motor development. Several possible modes of action have been described for melatonin; increase in Gabaergic transmission at a cerebral level, where GABA is the main inhibitory neurotransmitter; interaction with benzodiazepinic cerebral receptors; it may owe its effect to the activity of its metabolites, particularly kinurenic and kinurenic acid; it may induce hormone changes in the organism. Recent studies show the marked anti-oxidant activity of melatonin. Its considerable capacity to accept free radicles resulting from biological processes has been shown and it thus acts as a cell protector. CONCLUSIONS: It seems reasonable to assume that melatonin has anticonvulsant and neuroprotector properties. Further study may define its pharmacological usefulness in these disorders.