Amniotic membrane stimulates cell migration by modulating transforming growth factor-ß signalling.

Keratinocyte migration is a mandatory aspect of wound healing. We have previously shown that amniotic membrane (AM) applied to chronic wounds assists healing through a process resulting in the overexpression of c-Jun at the wound's leading edge. We have also demonstrated that AM modifies the genetic programme induced by transforming growth factor-ß (TGF-ß) in chronic wounds. Here we used a scratch assay of mink lung epithelial cells (Mv1Lu) and a spontaneously immortalized human keratinocyte cell line (HaCaT) cells to examine the influence of AM application on the underlying signalling during scratch closure. AM application induced c-Jun phosphorylation at the leading edge of scratch wounds in a process dependent on MAPK and JNK signalling. Strikingly, when the TGF-ß-dependent Smad-activation inhibitor SB431542 was used together with AM, migration improvement was partially restrained, whereas the addition of TGF-ß had a synergistic effect on the AM-induced cell migration. Moreover, antagonizing TGF-ß with specific antibodies in both cell lines or knocking out TGF-ß receptors in Mv1Lu cells had similar effects on cell migration as using SB431542. Furthermore, we found that AM was able to attenuate TGF-ß-Smad signalling specifically at the migrating edge; AM treatment abated Smad2 and Smad3 nuclear localization in response to TGF-ß in a process dependent on mitogen-activated protein kinase kinase 1 (MEK1) activation but independent of EGF receptor or JNK activation. The involvement of Smad signalling on AM effects on HaCaT keratinocytes was further corroborated by overexpression of either Smad2 or Smad3 and the use of Smad phosphorylation-specific inhibitors, revealing a differential influence on AM-induced migration for each Smad. Thus, AM TGF-ß-Smad signalling abating is essential for optimal cell migration and wound closure.

Amniotic Membrane Modifies the Genetic Program Induced by TGFß, Stimulating Keratinocyte Proliferation and Migration in Chronic Wounds.

BACKGROUND: Post-traumatic large-surface or deep wounds often cannot progress to reepithelialisation because they become irresponsive in the inflammatory stage, so intervention is necessary to provide the final sealing epidermis. Previously we have shown that Amniotic Membrane (AM) induced a robust epithelialisation in deep traumatic wounds. METHODS AND FINDINGS: To better understand this phenomenon, we used keratinocytes to investigate the effect of AM on chronic wounds. Using keratinocytes, we saw that AM treatment is able to exert an attenuating effect upon Smad2 and Smad3 TGFß-induced phosphorylation while triggering the activation of several MAPK signalling pathways, including ERK and JNK1, 2. This also has a consequence for TGFß-induced regulation on cell cycle control key players CDK1A (p21) and CDK2B (p15). The study of a wider set of TGFß regulated genes showed that the effect of AM was not wide but very concrete for some genes. TGFß exerted a powerful cell cycle arrest; the presence of AM however prevented TGFß-induced cell cycle arrest. Moreover, AM induced a powerful cell migration response that correlates well with the expression of c-Jun protein at the border of the healing assay. Consistently, the treatment with AM of human chronic wounds induced a robust expression of c-Jun at the wound border. CONCLUSIONS: The effect of AM on the modulation of TGFß responses in keratinocytes that favours proliferation together with AM-induced keratinocyte migration is the perfect match that allows chronic wounds to move on from their non-healing state and progress into epithelialization. Our results may explain why the application of AM on chronic wounds is able to promote epithelialisation.

Mesenchymal dental stem cells in regenerative dentistry

In the last decade, tissue engineering is a field that has been suffering an enormous expansion in the regenerative medicine and dentistry. The use of cells as mesenchymal dental stem cells of easy access for dentist and oral surgeon, immunosuppressive properties, high proliferation and capacity to differentiate into odontoblasts, cementoblasts, osteoblasts and other cells implicated in the teeth, suppose a good perspective of future in the clinical dentistry. However, is necessary advance in the known of growth factors and signalling molecules implicated in tooth development and regeneration of different structures of teeth. Furthermore, these cells need a fabulous scaffold that facility their integration, differentiation, matrix synthesis and promote multiple specific interactions between cells. In this review, we give a brief description of tooth development and anatomy, definition and classification of stem cells, with special attention of mesenchymal stem cells, commonly used in the cellular therapy for their trasdifferentiation ability, non ethical problems and acceptable results in preliminary clinical trials. In terms of tissue engineering, we provide an overview of different types of mesenchymal stem cells that have been isolated from teeth, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHEDs), periodontal ligament stem cells (PDLSCs), dental follicle progenitor stem cells (DFPCs), and stem cells from apical papilla (SCAPs), growth factors implicated in regeneration teeth and types of scaffolds for dental tissue regeneration (AU)

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Mesenchymal dental stem cells in regenerative dentistry.

In the last decade, tissue engineering is a field that has been suffering an enormous expansion in the regenerative medicine and dentistry. The use of cells as mesenchymal dental stem cells of easy access for dentist and oral surgeon, immunosuppressive properties, high proliferation and capacity to differentiate into odontoblasts, cementoblasts, osteoblasts and other cells implicated in the teeth, suppose a good perspective of future in the clinical dentistry. However, is necessary advance in the known of growth factors and signalling molecules implicated in tooth development and regeneration of different structures of teeth. Furthermore, these cells need a fabulous scaffold that facility their integration, differentiation, matrix synthesis and promote multiple specific interactions between cells. In this review, we give a brief description of tooth development and anatomy, definition and classification of stem cells, with special attention of mesenchymal stem cells, commonly used in the cellular therapy for their trasdifferentiation ability, non ethical problems and acceptable results in preliminary clinical trials. In terms of tissue engineering, we provide an overview of different types of mesenchymal stem cells that have been isolated from teeth, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHEDs), periodontal ligament stem cells (PDLSCs), dental follicle progenitor stem cells (DFPCs), and stem cells from apical papilla (SCAPs), growth factors implicated in regeneration teeth and types of scaffolds for dental tissue regeneration.

An automatic wash method for dimethyl sulfoxide removal in autologous hematopoietic stem cell transplantation decreases the adverse effects related to infusion.

BACKGROUND: Products cryopreserved with dimethyl sulfoxide (DMSO) in stem cell transplant (SCT) often cause many adverse effects during their infusion (major cardiovascular events, dyspnea … even death). These are especially frequent in pediatric patients. We tested if a fully automated and closed wash procedure (Sepax S-100, Biosafe) allowed us to maintain the absolute CD34+ cell number, cell viability, and engraftment potential, decreasing the untoward reactions. STUDY DESIGN AND METHODS: Forty-six washes of DMSO cryopreserved peripheral blood hematopoietic progenitor (HP) apheresis were studied. Blood aliquots were taken both after thawing and after washing to assess the total nucleated and CD34+ cell counts, as well as cell viability. The washed products were infused in 26 autologous SCTs (ASCTs). Results were compared with the 53 previous SCTs performed without DMSO removal. RESULTS: After washing there were no significant differences between the pre- and postwashing CD34+ cell counts (p=0.08) or viability (p=0.68). No significant differences were observed between washed and nonwashed infusions in relation to the day of the neutrophil (p=0.46) and platelet (p=0.26) engraftment. One adverse event, abdominal pain, occurred during the washed cells infusions. When compared with the 14 untoward reactions that took place during the nonwashed HP infusions, significance was reached (p=0.00043). CONCLUSIONS: The automatic method described is effective in terms of CD34+ cell recovery and viability in ASCT. Moreover, Sepax decreased significantly the untoward reactions during the infusion.

Large-volume-apheresis facilitates autologous transplantation of hematopoietic progenitors in poor mobilizer patients.

Given that pre-apheresis CD34(+) cell count (PA-CD34) predicts the apheresis' yield, a minimum of 5 to 20 PA-CD34/microl is required in many institutions to initiate cell collection. The aim of this study was to clarify whether large-volume-apheresis (LVA) could facilitate progenitor cell transplantation in patients with low PA-CD34. Apheresis was initiated in 226 patients, disregarding PA-CD34, at days: +5 in G-CSF, +10 in cyclophosphamide+G-CSF, and +15 to +20 in other chemotherapy+G-CSF mobilization, when leucocytes >2.5 x 10(9)/L. Four times the blood volume was processed. Patients were grouped according to their PA-CD34: >or=10/microl (group-A, n = 143); <10/microl but >or=5/microl (group-B, n = 40) and <5/microl (group-C, n = 43). No differences were found in diagnoses, gender, age, previous treatments or mobilization regimen between groups. Enough CD34(+) cells (>1.9 x 10(6)/kg) were obtained in 31 patients (72%) from group-C, although in this group two mobilizations were needed in 20 patients (46.5%), compared to 5 (3.5%) and 1 (2.5%) in groups A and B, respectively (P < 0.01). Evenly three apheresis or more were required in 28 patients (65.1%) from group-C, compared to 8 (5.6%) and 6 (15.0%) in groups A and B, respectively (P < 0.01). In conclusion LVA can facilitate autologous transplantation in poor-mobilizer-patients, low PA-CD34 should not be an inflexible exclusion factor.

Leucemia mieloide aguda: evaluacion clínico terapéutica en niños del Hospital Universitario de Caracas: (período 1995-2004) / Acute myeloid leukemia: clinical-therapeutic evaluation in children Hospital Universitario of Caracas: (period 1995-2004)

Identificar las características clínico- hematológicas y la evolución terapéutica de niños con leucemia mieloide aguda, no promielocitica de novo, en el Servicio de Hematología del HUC entre 1995-2004. Estudio cliníco-epidemilógico descriptivo y retrospectivo a través de la revisión de historias clínicas de pacientes menores 18 años, tratados según el Protocolo P94 o el Protocolo modificado (PM), con sustitución de Idarubicina por Daunorubicina. Las características clínicas más frecuentes fueron fiebre, astenia, disnea, adenomegalias, palidez y hepatomegalia. La mayoría se presentó con anemia, leucocitosis y trombocitopenia. La incidencia de infiltración del SNC fue 5 por ciento. Cinco pacientes recibieron el P49 y 15 el PM. El P94 produjo 80 por ciento de remisión completa (RC) y el PM 73 por ciento (diferencia no significativa). La Sobrevida Libre de Eventos (SLEv), Sobrevida libre de enfermedad (SLE) y Sobrevida Total (ST) a los 26 meses de seguimiento fue 33.3 por ciento, 50 por ciento y 37,5 por ciento respectivamente para el P94 y de 14,3 por ciento, 20 por ciento y 18,7 por ciento para el PM (diferencias no significativas). Los resultados son levemente superiores a los obtenidos en el HUC con el PN80 y el P86, e inferiores a los obtenidos por grupos internacionales.

To identify clinical–hematological features and treatment results of 20 children with Acute Myeloid Leukemia, non promyelocytic diagnosed and treated in The Hematology Service of Caracas University Hospital between 1995-2004. The study is of a retrospective, descriptive and clinical-epidemiologic type. Data was obtained by chart review of patients <18years old treated by P94 regimen or Modified (MP) in which Idarubicin was changed by Daunorubicin. Relevant clinical features were fever, fatigue, dispnea, lymph node enlargement, pallor and hepatomegaly. Most patients presented anemia, leukocytosis and thrombocytopenia. Central nervous system infiltration was present in 1 patient (5%). Five received P94 and 15 received MP. P94 produced 80% and MP 73% complete remissions (non statiscal difference). The Event Free Survival (EFS), Disease Free Survival (DFS) and Total Survival (TS) at 26 monts with P94 were 33.3%, 50% y 37,5% and with the Modified Protocol 14.3%, 20% y 18,7% (non statistical difference). Results are slightly better than previously obtained at The University Hospital with PN80 and P86, but lower than those obtained by international groups.

Alteraciones funcionales y morfológicas de la glándula tiroides en pacientes con enfermedad de hodgkin tratados con radioterapia y quimioterapia / Alteration functionals and morphologic of the gland thyroid in patients with disease of hodgkin treaty with radiotherapy and chemotherapy

Determinar la frecuencia de disfunción tiroidea, patología tiroidea autoinmune y enfermedad nodular en pacientes tratados con radioterapia y quimioterapia por enfermedad de Hodgkin, estableciendo correlación con los cambios al ecosonograma tiroideo en dichos pacientes. Se evaluaron 25 pacientes tratados por enfermedad de Hodgkin entre 1985 y 1986; 21 recibieron radioterapia y quimioterapia y dos quimioterapia. La región tiroidea fue irradiada en 22 pacientes. El intervalo de tiempo medio entre tratamiento y la evaluación due 66 meses. Se determinó TSH, T41, anticuerpos antimicrosomales y ecosonograma tiroideo en cada paciente, comparándose con 25 controles. 8 (32 por ciento) pacientes presentaron Hipotiroidismo subclínico, 2 (8 por ciento) Hipotiroidismo Evidente, 3 (12 por ciento) Enf. Nodular y 3(12 por ciento) Tiroiditis de Hashimoto. El volumen tiroideo por ultrasonografía mostró reducción significativa en comparación con los controles. El ecopatron heterogéneo se observó en 7(70 por ciento) de pacientes con hipotiroidismo. La elevación frecuencia de patologías tiroideas en estos pacientes hace necesario evaluación periódica y prolongada, incorporando el ecosonograma como herramienta útil en el diagnóstico precoz de estas alteraciones

Malaria inducida en Venezuela, un problema recurrente: reporte de dos casos por transfusión de derivados sanguíneos / Induced malaria in Venezuela, an recurrent problem: report of 2 cases from transfution of derivates sanguineous

Se comunica la ocurrencia de dos casos de infección malárica inducida por transfusión de componentes sanguíneos, derivados de un mismo donante asintomático. Uno de ellos correspondió a una paciente con púrpura trombocitopénica inmune, quien recibió una transfusión de concentrado plaquetario infectante y desarrolló una infección mixta severa por P. falciparum y P. vivax. El otro paciente adquirió una infección por P. falciparum, luego de recibir una unidad de concentrado de glóbulos rojos. Se discuten los diversos aspectos clínicos, epidemiológicos y diagnósticos del problema; igualmente, se revisa la literatura nacional al respecto