Biocompatibility analysis and chemical characterization of Mn-doped hydroxyapatite.

The present work studies the effect of Mn doping on the crystalline structure of the Hap synthesized by the hydrothermal method at 200 °C for 24 h, from Ca(OH)2 and (NH4)2HPO4, incorporating MnCl2 to 0.1, 0.5, 1.0, 1.5 and 2.0 %wt of Mn concentrations. Samples were characterized by the X-Ray Diffraction technique, which revealed the diffraction peaks that corresponded to the hexagonal and monoclinic phase of the Hap; it was observed that the average size of crystallite decreased from 23.67 to 22.69 nm as the concentration of Mn increased. TEM shows that in all samples, there are two distributions of particle sizes; one corresponds to nanorods with several tens of nanometers in length, and the other in which the diameter and length are very close. FTIR analysis revealed absorption bands corresponding to the PO4-3 and OH- groups characteristic of the Hap. It was possible to establish a substitution mechanism between the Mn and the ions of Ca+2 of the Hap. From the Alamar blue test, a cell viability of 86.88% ± 5 corresponding to the sample of Hap at 1.5 %wt Mn was obtained, considered non-cytotoxic according to ISO 10993-5. It also evaluated and demonstrated the good osteoinductive properties of the materials, which were verified by histology and immunofluorescence expression of osteogenic markers. Adhesion, viability, biocompatibility and osteoinductive properties, make these materials candidates for future applications in bone tissue engineering with likely uses in regenerative medicine.

[Dream content in different sleep disorders: sleep apnoea and hypopnoea syndrome, primary insomnia, idiopathic REM sleep behaviour disorder and narcolepsy type 1]. / Contenido onírico en diferentes trastornos del sueño: síndrome de apnea e hipopnea del sueño, insomnio primario, trastorno de la conducta del sueño REM idiopático y narcolepsia de tipo 1.

AIM: The aim of this study is to determine whether there are any differences in the dream content in different sleep disorders and to describe their characteristics. PATIENTS AND METHODS: We studied four sleep disorders: sleep apnoea and hypopnoea syndrome (SAHS), primary insomnia (PI), idiopathic REM sleep behaviour disorder (IRBD) and narcolepsy type I. Each patient was asked to keep a dream diary for two weeks. The content of the diaries was transcribed and analysed for length, mental content, complexity and threat. The results were compared to establish differences. RESULTS: Eighty-nine patients were studied: 23 with SAHS without continuous positive airway pressure (CPAP) who had the highest number of dreams involving threats (32.5%); 19 with SAHS treated with CPAP who had the highest number of dreams involving objects (64.8%), descriptive elements (38%) and higher complexity (9.5%); 22 with primary insomnia who had the highest number of dreams with threatening events in the social sphere (57.7%); 12 with IRBD who had the highest number of dreams with failures (14%) and lower complexity (71.7%); and 13 with narcolepsy type I who had the highest number of dreams related to activities (84.3%) and threats to life (41.4%) These differences were statistically significant (p <0.05). CONCLUSIONS: Different sleep disorders are associated with different dream contents, which would be translating different underlying neurological processes. These findings should be replicated in studies that analyse more patients and add a control group without sleep disorders.

TITLE: Contenido onírico en diferentes trastornos del sueño: síndrome de apnea e hipopnea del sueño, insomnio primario, trastorno de la conducta del sueño REM idiopático y narcolepsia de tipo 1.Objetivo. Determinar si existen diferencias en el contenido onírico en diferentes trastornos del sueño y describir sus características. Pacientes y métodos. Estudiamos cuatro trastornos del sueño: síndrome de apnea e hipopnea del sueño (SAHS), insomnio primario (IP), trastorno de conducta del sueño REM idiopático (TCSRI) y narcolepsia de tipo 1. Se solicitó a cada paciente que llenara un diario de sus sueños durante dos semanas. El contenido de los diarios fue transcrito y analizado en longitud, contenido mental, complejidad y amenaza. Los resultados se compararon para establecer diferencias. Resultados. Se estudió a 89 pacientes: 23 con SAHS sin presión positiva continua de la vía aérea (CPAP) que tuvieron la mayor cantidad de sueños con participación en amenazas (32,5%); 19 con SAHS tratados con CPAP que tuvieron la mayor cantidad de sueños con objetos (64,8%), elementos descriptivos (38%) y de más alta complejidad (9,5%); 22 con insomnio primario con la mayor cantidad de sueños con eventos amenazantes al ámbito social (57,7%); 12 con TCSRI que tuvieron en sus sueños la más alta cantidad de fracasos (14%) y menor complejidad (71,7%), y 13 con narcolepsia de tipo 1 que tuvieron la mayor cantidad de sueños relacionados con actividades (84,3%) y amenazas hacia la vida (41,4 %). Estas diferencias fueron estadísticamente significativas (p menor de 0,05). Conclusiones. Los distintos trastornos del sueño sí se asocian a contenidos oníricos diferentes que traducirían distintos procesos neurológicos subyacentes. Estos hallazgos deberían replicarse en estudios que analicen más pacientes y añadan un grupo control sin trastornos del sueño.

Contenido onírico en diferentes trastornos del sueño: síndrome de apnea e hipopnea del sueño, insomnio primario, trastorno de la conducta del sueño REM idiopático y narcolepsia de tipo 1 / Dream content in different sleep disorders: sleep apnoea and hypopnoea syndrome, primary insomnia, idiopathic REM sleep behaviour disorder and narcolepsy type 1

Objetivo: Determinar si existen diferencias en el contenido onírico en diferentes trastornos del sueño y describir sus características. Pacientes y métodos: Estudiamos cuatro trastornos del sueño: síndrome de apnea e hipopnea del sueño (SAHS), insomnio primario (IP), trastorno de conducta del sueño REM idiopático (TCSRI) y narcolepsia de tipo 1. Se solicitó a cada paciente que llenara un diario de sus sueños durante dos semanas. El contenido de los diarios fue transcrito y analizado en longitud, contenido mental, complejidad y amenaza. Los resultados se compararon para establecer diferencias. Resultados: Se estudió a 89 pacientes: 23 con SAHS sin presión positiva continua de la vía aérea (CPAP) que tuvieron la mayor cantidad de sueños con participación en amenazas (32,5%); 19 con SAHS tratados con CPAP que tuvieron la mayor cantidad de sueños con objetos (64,8%), elementos descriptivos (38%) y de más alta complejidad (9,5%); 22 con insomnio primario con la mayor cantidad de sueños con eventos amenazantes al ámbito social (57,7%); 12 con TCSRI que tuvieron en sus sueños la más alta cantidad de fracasos (14%) y menor complejidad (71,7%), y 13 con narcolepsia de tipo 1 que tuvieron la mayor cantidad de sueños relacionados con actividades (84,3%) y amenazas hacia la vida (41,4 %). Estas diferencias fueron estadísticamente significativas (p < 0,05). Conclusiones: Los distintos trastornos del sueño sí se asocian a contenidos oníricos diferentes que traducirían distintos procesos neurológicos subyacentes. Estos hallazgos deberían replicarse en estudios que analicen más pacientes y añadan un grupo control sin trastornos del sueño.(AU)

Aim: The aim of this study is to determine whether there are any differences in the dream content in different sleep disorders and to describe their characteristics. Patients and methods: We studied four sleep disorders: sleep apnoea and hypopnoea syndrome (SAHS), primary insomnia (PI), idiopathic REM sleep behaviour disorder (IRBD) and narcolepsy type I. Each patient was asked to keep a dream diary for two weeks. The content of the diaries was transcribed and analysed for length, mental content, complexity and threat. The results were compared to establish differences. Results: Eighty-nine patients were studied: 23 with SAHS without continuous positive airway pressure (CPAP) who had the highest number of dreams involving threats (32.5%); 19 with SAHS treated with CPAP who had the highest number of dreams involving objects (64.8%), descriptive elements (38%) and higher complexity (9.5%); 22 with primary insomnia who had the highest number of dreams with threatening events in the social sphere (57.7%); 12 with IRBD who had the highest number of dreams with failures (14%) and lower complexity (71.7%); and 13 with narcolepsy type I who had the highest number of dreams related to activities (84.3%) and threats to life (41.4%) These differences were statistically significant (p <0.05). Conclusions: Different sleep disorders are associated with different dream contents, which would be translating different underlying neurological processes. These findings should be replicated in studies that analyse more patients and add a control group without sleep disorders.(AU)

Wet chemical synthesis of nanocrystalline hydroxyapatite flakes: effect of pH and sintering temperature on structural and morphological properties.

Wet chemical synthesis of hydroxyapatite (HAp) nanostructures was carried out with different solution pH values (9, 10 and 11) and sintering temperatures (300°C, 500°C, 700°C and 900°C). The effects of pH and sintering temperature on the structural and morphological properties of nanocrystalline HAp powders were presented. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were performed to obtain the crystalline structure, chemical composition, morphology and particle size of the HAp powders. The TEM analysis is used in order to observe the rod- and flake-like HAp structures. XRD confirms the presence of both HAp hexagonal and monetite phases, although the monetite phase was less abundant in the resultant powders. Increase in pH reduced the monetite phase and enhanced Ca/P ratio from 1.7 to 1.83. Additionally, an increment in sintering temperature increased the crystallite size from 20 to 56 nm. The SEM analysis revealed the formation of semi-spherical and flake-like HAp structures with preferential flake morphology. An increase in pH and sintering temperature resulted in the growth and coalescence of crystals resulting in a porous capsular morphology. The FTIR analysis confirmed the reduction of carbonate stretching modes with an increase in pH and H-O-H antisymmetric stretching mode is eliminated for powders sintered at 900°C confirming the formation of stable and porous HAp powders.

Alternativas de analgesia: interacciones entre fármacos y receptores / Analgesic alternatives: interactions between drugs and receptors

No obstante los adelantos en el conocimiento y tratamiento del dolor agudo y del dolor crónico, esta entidad continúa siendo un azote para la humanidad. Se ha considerado que más de 1’500,000’000,000 de seres humanos sufren de dolor crónicomoderado a severo, lo que significa un elevado costo económico y de salud, aun en los países más desarrollados. Por siglos la humanidad ha utilizado remedios para aliviar este sufrimiento y aunque el uso de opioides y de analgésicos antiinflamatoriosno esteroideos transformó el manejo racional del dolor, sus efectos secundarios son una restricción que limita su uso y eficacia terapéutica. El conocimiento de novedosos nociceptores y de sus ligandos revolucionó el conocimiento del dolor, facilitando tanto su prevención como su tratamiento. El uso de fármacos con acción analgésica en diversos receptores específicos de las múltiples y complejas vías dolorosas se fundamenta en el conocimiento de los mecanismos de interacción molecular involucrados en diversos nociceptores como por ejemplo los canales de sodio y potasio, los receptores purinérgicos, los receptores NMDA, los receptorescannabinoides, entre otros muchos. El redescubrimiento de las características analgésicas de antiguos fármacos y el desarrollo de nuevas moléculas con efectos antinociceptivos específicos ha revolucionado el manejo del dolor, creando el concepto de analgesiadirigida al órgano blanco (at-site pain targets). En esta breve revisión se discuten algunos de los mecanismos de acción analgésica de antiguos y de nuevos medicamentos que podemos utilizar en las personas con dolor agudo postoperatorio, con dolor crónicono oncológico y en dolor secundario al cáncer.

Despite major advances in the understanding and treatment of acute and chronic pain, this entity continues to be a plague to mankind. It was considered that more than 1’500,000’000,000 human beings suffer from moderate to severe chronic pain, which means a high health and economic costs, even in the most developed countries. For centuries mankind has used remedies to relieve pain suffering and although the use of opioids and nonsteroidal anti-inflamma tory drugs revolutionized the management of pain, their side effects are a restriction limiting its use and therapeutic efficacy. The knowledge of novel nociceptors and their ligands revolutionized our understanding of pain, facilitating its prevention and treatment. The proper use of analgesic and co-adyuvant drugs with selective actions on specific receptors of the multiple and complex pain pathways is based on the understanding of the pain mechanisms involved in molecular interaction on nociceptor receptors such as sodium and potassium membrane channels, purinergic, NMDA, and cannabinoid receptors, among many others. The rediscovery of the ancient analgesic properties of drugs and development of new molecules with specific antinociceptive effects has revolutionized pain management, creating the concept of analgesia addressed to the target organ (at-site pain targets). In this brief review we discuss some of the mechanisms of analgesic action of old and new drugs that can be used in people with acute postoperative pain, chronic noncancer pain and pain secondary to cancer.

Biosorption of Cr(III) and Fe(III) in single and binary systems onto pretreated orange peel.

Trivalent chromium and iron are the products of the traditional reduction of hexavalent chromium by ferrous salts in industrial wastewater. Although there have been a few studies of Cr(III) adsorption, none have considered the effect of Fe(III) on Cr(III) adsorption in a binary system representing expected products of hexavalent chromium in industrial wastewater. The biosorption of Cr(III) and Fe(III) ions onto pretreated ground orange peel in single and binary systems was studied in batch experiments using a variety of techniques. The kinetic results showed a rapid rate of biosorption of Cr(III) and Fe(III) in single and binary systems and mutual interference effects in the competitive binary Cr(III)-Fe(III) system. Second order kinetic models showed the best fit for all systems. The behavior of competitive Cr(III)-Fe(III) biosorption were successfully described by the multicomponent Langmuir model, obtaining maximum capacities for Cr(III) and Fe(III) of 9.43 and 18.19 mg/g respectively. SEM/EDS results confirmed that the metals adsorb on the surface and FTIR identified the hydroxyl groups on the carboxylic acids as the active binding sites.

Characterization of hydroxyapatite by electron microscopy.

The obtention of hydroxyapatite (HAp) is reported using brushite (CaHPO4.2H2O) and the skeleton of a starfish (Mellita eduardobarrosoi sp. nov.), primarily composed of magnesian calcite ((Ca,Mg)CO3) as precursors. Stoichiometric amounts of both were reacted under hydrothermal conditions: a pressure of 5.8 MPa and a temperature of 200 degrees C for 2, 4, 6, 8, 10, and 20 h of reaction times. The samples obtained were characterized by means of scanning electron microscopy, X-ray diffraction, infrared spectroscopy, and transmission electron microscopy. Two defined populations of HAp fibers were found: A bundle of fibers 75 mum in length and 1-13 mum in diameter, and a second bundle of fibers 5 mum in length and less than 0.5 mum in diameter. Furthermore, an increase in HAp formation and a Ca/P ratio as a function of reaction time were observed. The growth mechanism of HAp is also discussed.

TEM and molecular simulation studies on the hydroxylapatite structure with Si and Mg impurities.

Transmission electron microscopy (TEM) and molecular simulation studies of traces of chemical elements such as Mg, Si, and OH in the hydroxylapatite (CaHAP) crystal structure obtained from the sand dollar were carried out. Two different types of CaHAP crystal morphologies in the samples synthesized by the hydrothermal method used were observed. Reflections with regular intensity in the experimental electron diffraction patterns obtained from these morphologies were observed. However, when these results were compared with a simulated electron diffraction pattern (which was obtained using the crystalline structure proposed for the hydroxylapatite) some forbidden reflections in the experimental pattern were observed. Then, in order to reproduce the experimental patterns Si and Mg atoms in the crystalline lattice were introduced. These elements in the elemental chemical analysis carried out by X-ray energy dispersive spectroscopy (EDS) in the typical CaHAP morphologies were detected. The positions of these atoms in the asymmetric unit were obtained using molecular simulation and during the relaxation process, the structure did not show changes in the lattice parameters. Subsequently, the crystalline structure was reproduced and matched the electron diffraction patterns simulated resulting in the experimental electron diffraction pattern. Experimental and simulated X-ray diffraction spectra were also matched.

Psychometric properties of a Spanish version of the McGill Pain Questionnaire in several Spanish-speaking countries.

OBJECTIVE: Versions of the McGill Pain Questionnaire are available in a several languages and are used in clinical studies and sociocultural or ethnic comparisons of pain issues. However, there is a lack of studies that compare the validity and reliability of the instrument in the countries where it is used. The current study investigates the psychometric properties of a Spanish version of the McGill Pain Questionnaire in five Spanish-speaking countries. DESIGN: The authors conducted a multicenter and transnational study with one investigator in each center. Patients were evaluated once with a Spanish version of the McGill Pain Questionnaire, a visual analog scale, and a verbal rating scale. SETTING: The study was performed in pain clinics and acute pain units of four Latin American countries (Argentina, Costa Rica, Mexico, and Panama) and Spain. PATIENTS: The study included 205 patients (84 with acute pain, 121 with chronic pain) from Latin America. Their data were compared with those of 282 Spanish patients. INTERVENTIONS: The McGill Pain Questionnaire, visual analog scale, and verbal rating scale were administered once to all patients. The McGill Pain Questionnaire was administered again to patients from Latin America countries to ascertain descriptor comprehension. OUTCOME MEASURES: Demographic data, McGill Pain Questionnaire parameters, and visual analog scale and a verbal rating scale scores were obtained from patients with chronic and acute pain. Psychometric properties of the Spanish version of the McGill Pain Questionnaire were established for each country by calculating the ordinal consistency by means of rank-scale correlation (Spearman test), intercategory correlation, and interparameter correlation (Pearson test). Concurrent validity was also calculated by comparing scores from the visual analog scale (Pearson test) and verbal rating scale (Spearman test) with questionnaire parameters (qualitative-to-quantitative comparisons). RESULTS: The Spanish version of the McGill Pain Questionnaire maintained a high internal validity when tested in different countries. Ordinal consistency, intercategory, interparameter, and qualitative-to-quantitative parameter correlations were similar in all countries. Few descriptors were considered to be inappropriate or difficult to understand. CONCLUSIONS: The psychometric properties of the Spanish version of the McGill Pain Questionnaire assessed in different Latin-American countries suggest that the questionnaire may be used to evaluate Spanish-speaking patients. The validity of this test should be extended with reliability studies to further establish its usefulness in the evaluation of pain.

A mutant streptokinase lacking the C-terminal 42 amino acids is less reactive with preexisting antibodies in patient sera.

Streptokinase (SK) is an efficacious thrombolytic drug for the treatment of myocardial infarction. Because of its immunogenicity, patients receiving SK therapy develop high anti-SK antibody (Ab) titers, which might provoke severe allergic reactions and neutralize SK activity. In this report we studied the reactivity of a synthetic 42-residue peptide resembling SKC-2 C-terminus with patient sera. SKC-2(373-414) peptide was recognized by 39 and 64% of patients, before and after SKC-2 therapy, respectively. An SKC-2 deletion mutant (mut-C42), lacking the same 42 C-terminal residues, was constructed and expressed in Escherichia coli. Recognition of mut-C42 by preexisting Abs from patient sera was 51 and 68% of reactivity to SKC-2, as assessed by direct binding and competition assays, respectively. For most of the patients, mut-C42-neutralizing activity titer (NAT) significantly decreased with respect to SKC-2-NAT. This study opens the possibility of producing a less immunogenic variant of SK, which could constitute a preferred alternative for thrombolytic therapy.

Identification and activity of cytosol creatine phosphokinase enzymes in normal and diseased skin.

Phosphocreatine molecules (PCR) in skin regenerate adenosine triphosphate and help cutaneous tissue survive ischemia associated with skin flaps, grafts, and hair transplantation procedures. In addition, PCR concentration in psoriasis is elevated many times above normal, indicating either overproduction of PCR by mitochondrial creatine phosphokinase (CPK) enzymes or a defect in cytosol CPK enzymatic activity. Skin CPK isoenzymes, before this study, have not been identified. Herein, for the first time, cytosol CPK enzymatic activity was measured in normal and psoriatic, involved and uninvolved skin, skin tumors, and mouse skin and keratinocyte cell cultures. Creatine phosphokinase MM is the major isoenzyme in normal, uninvolved psoriatic and mouse skin. Total CPK enzymatic activity was increased in psoriasis and skin tumors. These data clearly indicate that increased PCR concentration in a psoriatic skin is not a result of decreased cytosol CPK enzymatic activity.

The effects of video advertising on physician recruitment to a family practice residency program.

BACKGROUND: The number of medical students entering family practice residencies has been decreasing in recent years. In an effort to increase this number, many family practice residencies send videos describing their programs to prospective applicants. This study was designed to evaluate the effects of video advertising on resident recruitment. METHODS: In the fall of 1992, a short promotional video was produced to highlight many aspects of the University of Maryland Family Practice Residency Program. The video was sent to half of all persons who applied to the program. RESULTS: Of the 248 inquiries, 120 (48%) received the video. Of these, 35 (29%) completed the application compared with 69 (54%) who received routine materials only. Applicants who did not receive the video were 2.86 times more likely (95% confidence interval 1.6-5.0) to apply to our program (P < 0.0001). None of the applicants who received the video matched with the program (P < 0.005). CONCLUSION: Residency recruitment videos may have a negative impact on residency recruitment.