ABSTRACT
Biomineralization is the process by which diverse organisms have the capacity to create heterogeneous accumulations, derived from organic and inorganic compounds that induce the process of mineral formation. An example of this can be seen an extrapallial protein (EP) of Mytilus californianus, which is responsible for carrying out the biomineralization process. In order to determine their ability to perform the biomineralization process, EP protein was absorbed and mixed in chitosan scaffolds which were tested in simulated physiological fluid. The materials were analyzed by FTIR spectroscopy, field emission scanning electron microscopy-energy-dispersive electron X-ray spectroscopy andX-ray diffraction. Results confirmed that the EP protein stimulates the rapid growth of biological apatite on the chitosan scaffolds. The mixing method favored more the apatite growth as well as the formation of second nucleation sites than the immersion method.
ABSTRACT
Resumen El presente artículo es una amplia revisión bibliográfica de algunos de los polímeros naturales más utilizados en la fabricación de apósitos para curación de heridas cutáneas y regeneración de piel en los últimos años. Asimismo, se presenta un análisis descriptivo de los polímeros de origen natural más estudiados en la ingeniería de tejidos, remarcando sus propiedades físicas, químicas y biológicas. Encontrando que las investigaciones más recientes se han centrado en la exploración de apósitos a partir de biopolímeros como una alternativa a los materiales sintéticos derivados del petróleo, debido a las propiedades que poseen, como una mayor biodegradabilidad, biocompatibilidad y sostenibilidad por ser obtenidos naturalmente. Sin embargo, aún no existe un apósito ideal que pueda ser aplicado de manera eficiente en todos los tipos de heridas; por lo que los investigadores se han enfocado en el desarrollo y la optimización de apósitos que satisfagan la mayoría de las necesidades para una etapa en particular de la herida.
Abstract This review includes the bio-polymers most used in recent years for the manufacturing of materials used as dressings in cutaneous wound healing and skin regeneration. Also, the natural polymers most studied in tissue engineering are mentioned, highlighting their physical, chemical and biological properties for skin regeneration and wound healing. Through an extensive review of the clinical and research uses different types of natural polymers were compared, as well as the results of chemical and biological tests carried out during experimental research performed internationally.
ABSTRACT
The pulmonary surfactant is a lipoproteic complex that serves to lower surface tension at the air-liquid interface in the pulmonary alveoli. Approximately 2 to 4% of the pulmonary surfactant is constituted by the protein A (SP-A). The objective of the study was to determine the effects that maternal protein calorie malnutrition has on the fetal pulmonary growth and the production of SP-A messenger RNA in fetal rats. MATERIALS AND METHODS: Pregnant Sprague Dawley rats were divided into two groups, which received a diet with either 8% or 21% of proteins from gestational day 1 until the day 20. In this last day 11 fetuses were extracted by caesarean section and their lungs were removed to quantify the mRNA of the SP-A. First the mRNA was boosted using the technique of reverse transcriptase and polimerase chain reaction (RT-PCR) and then its concentration was determined by means of fluorodensitometry. RESULTS: There was a reduction in body weight and in wet lung weights of malnourished fetuses in comparison with the normal fetuses (5.03 +/- 0.20 g vs. 4.32 +/- 0.32 g, p < 0.05 and 79.0 +/- 3.8 mg vs. 146.0 +/- 3.4 mg, p < 0.05, respectively). The densitometric analysis of the SP-A mRNA concentration demonstrated a reduction of 32% in the malnourished fetuses (0.52 +/- 0.11 vs. 0.77 +/- 0.07, p < 0.05) compared with the normal fetuses. CONCLUSIONS: The maternal protein calorie malnutrition affected the pulmonary development and the synthesis of the SP-A mRNA. These data suggest that a defect occurrs at pre-transcriptional level that results in a diminution of the concentration of mRNA of SP-A in the neumocytes type II
Subject(s)
Animals , Female , Pregnancy , Rats , Pregnancy Complications , Protein-Energy Malnutrition , Pulmonary Surfactant-Associated Protein A/genetics , Lung/embryology , RNA, Messenger/analysis , Pulmonary Surfactants/chemistry , Rats, Sprague-DawleyABSTRACT
UNLABELLED: The pulmonary surfactant is a lipoproteic complex that serves to lower surface tension at the air-liquid interface in the pulmonary alveoli. Approximately 2 to 4% of the pulmonary surfactant is constituted by the protein A (SP-A). The objective of the study was to determine the effects that maternal protein calorie malnutrition has on the fetal pulmonary growth and the production of SP-A messenger RNA in fetal rats. MATERIALS AND METHODS: Pregnant Sprague Dawley rats were divided into two groups, which received a diet with either 8% or 21% of proteins from gestational day 1 until the day 20. In this last day 11 fetuses were extracted by caesarean section and their lungs were removed to quantify the mRNA of the SP-A. First the mRNA was boosted using the technique of reverse transcriptase and polimerase chain reaction (RT-PCR) and then its concentration was determined by means of fluorodensitometry. RESULTS: There was a reduction in body weight and in wet lung weights of malnourished fetuses in comparison with the normal fetuses (5.03 +/- 0.20 g vs. 4.32 +/- 0.32 g, p < 0.05 and 79.0 +/- 3.8 mg vs. 146.0 +/- 3.4 mg, p < 0.05, respectively). The densitometric analysis of the SP-A mRNA concentration demonstrated a reduction of 32% in the malnourished fetuses (0.52 +/- 0.11 vs. 0.77 +/- 0.07, p < 0.05) compared with the normal fetuses. CONCLUSIONS: The maternal protein calorie malnutrition affected the pulmonary development and the synthesis of the SP-A mRNA. These data suggest that a defect occurrs at pre-transcriptional level that results in a diminution of the concentration of mRNA of SP-A in the neumocytes type II.