Why phylogenetic signal of traits is important in ecosystems: uniformity of a plant trait increases soil fauna, but only in a phylogenetically uniform vegetation.

Phylogenetically closely related plant species often share similar trait states (phylogenetic signal), but local assembly may favor dissimilar relatives and thereby decouple the diversity of a trait from the diversity of phylogenetic lineages. Associated fauna might either benefit from plant trait diversity, because it provides them complementary resources, or suffer from it due to dilution of preferred resources. We hence hypothesize that decoupling of trait and phylogenetic diversity weakens the relationship between the plant-trait diversity and the abundance and diversity of associated fauna. Studying permanent meadows, we tested for combined effects of plant phylogenetic diversity and diversity of two functional traits (specific leaf area, leaf dry matter content) on major groups of soil fauna (earthworms, mites, springtails, nematodes). We found that only in phylogenetically uniform plant communities, was uniformity in the functional traits associated with (i) high abundance in springtails, and (ii) high abundance of the sub-group that feeds more directly on plant material (in springtails and mites) or those that are more prone to disturbance (in nematodes), and (iii) high diversity in all three groups tested (springtails, earthworms, nematodes). Our results suggest that soil fauna profits from the resource concentration in local plant communities that are uniform in both functional traits and phylogenetic lineages. Soil fauna would hence benefit from co-occurrence of closely related plants that have conserved the same trait values, rather than of distantly related plants that have converged in traits. This might result in faster decomposition and a positive feedback between trait conservatism and ecosystem functioning.

Clinical and molecular characterization of patients with cancer of unknown primary in the modern era.

BACKGROUND: On the basis of historical data, patients with cancer of unknown primary (CUP) are generally assumed to have a dismal prognosis with overall survival of less than 1 year. Treatment is typically cytotoxic chemotherapy guided by histologic features and the pattern of metastatic spread. The purpose of this study was to provide a clinical and pathologic description of patients with CUP in the modern era, to define the frequency of clinically actionable molecular alterations in this population, to determine how molecular testing can alter therapeutic decisions, and to investigate novel uses of next-generation sequencing in the evaluation and treatment of patients with CUP. PATIENTS AND METHODS: Under Institutional Review Board approval, we identified all CUP patients evaluated at our institution over a recent 2-year period. We documented demographic information, clinical outcomes, pathologic evaluations, next-generation sequencing of available tumor tissue, use of targeted therapies, and clinical trial enrollment. RESULTS: We identified 333 patients with a diagnosis of CUP evaluated at our institution from 1 January 2014 through 30 June 2016. Of these patients, 150 had targeted next-generation sequencing carried out on available tissue. Median overall survival in this cohort was 13 months. Forty-five of 150 (30%) patients had potentially targetable genomic alterations identified by tumor molecular profiling, and 15 of 150 (10%) received targeted therapies. Dominant mutation signatures were identified in 21 of 150 (14%), largely implicating exogenous mutagen exposures such as ultraviolet radiation and tobacco. CONCLUSIONS: Patients with CUP represent a heterogeneous population, harboring a variety of potentially targetable alterations. Next-generation sequencing may provide an opportunity for CUP patients to benefit from novel personalized therapies.

Prognostic value of PTEN loss in men with conservatively managed localised prostate cancer.

BACKGROUND: The natural history of prostate cancer is highly variable and difficult to predict. We report on the prognostic value of phosphatase and tensin homologue (PTEN) loss in a cohort of 675 men with conservatively managed prostate cancer diagnosed by transurethral resection of the prostate. METHODS: The PTEN status was assayed by immunohistochemistry (PTEN IHC) and fluorescent in situ hybridisation (PTEN FISH). The primary end point was death from prostate cancer. RESULTS: The PTEN IHC loss was observed in 18% cases. This was significantly associated with prostate cancer death in univariate analysis (hazard ratio (HR)=3.51; 95% CI 2.60-4.73; P=3.1 × 10(-14)). It was highly predictive of prostate cancer death in the 50% of patients with a low risk score based on Gleason score, PSA, Ki-67 and extent of disease (HR=7.4; 95% CI 2.2-24.6; P=0.012) ), but had no prognostic value in the higher risk patients. The PTEN FISH loss was only weakly associated with PTEN IHC loss (κ=0.5). Both PTEN FISH loss and amplification were univariately predictive of death from prostate cancer, but this was not maintained in the multivariate analyses. CONCLUSION: In low-risk patients, PTEN IHC loss adds prognostic value to Gleason score, PSA, Ki-67 and extent of disease.

Cloning and expression of ethylene receptor ERS1 at various developmental and ripening stages of mango fruit.

Ethylene induces characteristic ripening reactions in climacteric fruits through its binding to histidine-kinase (HK) receptors, activating the expression of ripening genes. Ethylene receptors have been found in Arabidopsis thaliana (Brassicaceae) and some fruits; number and expression patterns differ among species. In mango, only ethylene receptor ETR1 was known. We cloned ERS1 cDNA from mango, and evaluated the expression of Mi-ERS1 and Mi-ETR1 by qPCR in developmental and ripening stages of this fruit. The Mi-ERS1 coding sequence is 1890 bp long and encodes 629 amino acids, similar to ERS1 from other fruits. Also, the amino acid sequence of ERS1 C-terminal HK domain shows the cognate fold after molecular modeling. Mi-ERS1 expression levels increased as mangoes ripened, showing the highest levels at the climacteric stage, while Mi-ETR1 levels did not change during development and ripening. We conclude that the patterns of expression of Mi-ERS1 and Mi-ETR1 differ in mango fruit.

Massive digestive bleeding as a result of gastric heterotopy: a case report. / Sangrado digestivo masivo por heterotopia gástrica. Reporte de un caso.

INTRODUCTION: Gastric heterotopy is a rare entity in the pediatric population. It occurs in the gastrointestinal tract, leading to digestive bleeding. CLINICAL CASE: This is the case of a 10-year-old boy with gastric tissue in the proximal jejunum, which caused two massive digestive bleeding episodes. Diagnostic techniques included endoscopic capsule, enteroscopy, and biopsy. The patient was scheduled for laparotomy and resection. After one year of follow-up, he remained asymptomatic. DISCUSSION: Gastric heterotopy approach represents a diagnostic challenge. Owing to how rare it is, there is no global consensus in terms of treatment. However, surgery is the definitive therapy. In this case, decision was made not to perform intestinal resection and anastomosis, but resection of the compromised intestinal wall. No malignity was reported in the literature reviewed.

INTRODUCCION: La heterotopia gástrica es una entidad infrecuente en la población pediátrica. Se presenta en el tracto gastrointestinal llevando a cuadros clínicos de sangrado digestivo. CASO CLINICO: Se reporta el caso de un escolar de 10 años, el cual presentó tejido gástrico en el yeyuno proximal, originando sangrado digestivo masivo en dos ocasiones. La secuencia de apoyos diagnósticos requirió cápsula endoscópica, enteroscopia y biopsia. Fue llevado a laparotomía y resección de la lesión. En el seguimiento al año se mantuvo asintomático. DISCUSION: Su abordaje genera un reto diagnóstico. Debido a su infrecuente presentación no hay un consenso global para el tratamiento, sin embargo, la intervención quirúrgica es la terapia definitiva. En este caso no se hizo resección intestinal y anastomosis sino resección de la pared intestinal comprometida. No se reportó malignidad en la literatura revisada.

Seropositivity for Trypanosoma cruzi and Leishmania mexicana in dogs from a metropolitan region of Central Mexico.

Trypanosoma cruzi and Leishmania mexicana are parasites of humans and other mammals, causing American Trypanosomiasis and Cutaneous Leishmaniasis, respectively. Domestic dogs are considered key hosts for these parasites in the domicile and peridomicile cycles of transmission, due to their abundance and contact with human population. In Mexico, there are few studies that involve the study of infection with these parasites in dogs, and have only been carried out mainly in the endemic areas for these diseases. In the state of Querétaro (Mexico), infections with both parasites have been reported for dogs only from rural areas, with no records for the metropolitan zone. We analyzed the seropositivity to T. cruzi and L. mexicana in dogs from localities within of the metropolitan zone of Querétaro City in order to determine if these animals are exposed to these parasites and thus, could be an important part of the transmission cycle of these trypanosomatids in a densely populated urban region within the state of Querétaro, Mexico. Serum samples were collected from 303 dogs housed in the Animal Control centers of the municipalities of Querétaro and El Marques, analyzed by indirect ELISA and Western Blot using as an antigen the Iron Superoxide Dismutase (FeSODe) of the parasites. From the total serum samples, we detected 10.2% of seropositivity for T. cruzi and 2.9% for L. mexicana. Our results represent the first evidence of infection with T. cruzi in domestic dogs from the Metropolitan Zone of Querétaro, and the first record for L. mexicana in Central Mexico. Ongoing investigations seek to confirm the circulation of these parasites in the area to evaluate the risk associated to the human population.

La sucralosa promueve la polarización a macrófagos proinflamatorios M1

RESUMEN La sucralosa es un edulcorante no calórico de amplio consumo a nivel mundial, es considerado como un aditivo seguro, debido a que es eliminado en periodos cortos de tiempo. Recientemente se evidenció su bioacumulación en tejido adiposo, donde se encuentran inmersos macrófagos, células del sistema inmune involucradas en el desarrollo de la inflamación sistémica de bajo grado. A la fecha, no se cuenta con suficiente información para demostrar si los edulcorantes potencian los procesos inflamatorios alterando la función de células presentes en tejido y/o contribuyen en el desarrollo de patologías metabólicas. Por lo anterior, en nuestro trabajo se evaluó el efecto de la sucralosa en la viabilidad de los macrófagos diferenciados de la línea celular monocítica THP-1, por azul de tripán y ensayos de MTT, así como su efecto en la polarización M1/M2 por PCR según la expresión de IRF4, IRF5, STAT1, STAT6, perfil de expresión de IL-6, IL-12, TNF-α, TGF-β, IL-10 y SOCS3 por qPCR, y la cuantificación de la quimiocina IP-10 por ELISA. Los resultados indicaron que la sucralosa no tiene efectos citotóxicos, pero disminuye el número de células viables metabólicamente activas determinadas por MTT de manera dependiente de la concentración. La sucralosa incrementa la concentración de la quimiocina IP-10 y la expresión génica del factor de transcripción IRF5 y disminuye la expresión de IRF4 y STAT6, favoreciendo la polarización hacia poblaciones M1. La bioacumulación de sucralosa en tejido adiposo, y su interacción con macrófagos, podría inducir su polarización a M1.

ABSTRACT Sucralose is a non-nutritive sweetener widely consumed worldwide; it is considered a safe additive because it is eliminated quickly. Recently its bioaccumulation in adipose tissue was evidenced, where macrophages, cells of the immune system involved in developing low-grade systemic inflammation, are found. To date, there is a paucity of information regarding whether sweeteners potentiate inflammatory processes by altering the function of cells present in tissue and/or contribute to the development of metabolic pathologies. We evaluate the effect of sucralose on the viability of differentiated macrophages of the monocytic cell line THP-1, by trypan blue and MTT assays, respectively, as well as its effect on M1/ M2 by PCR according to the expression of IRF4, IRF5, STAT1, STAT6, expression profile of IL6, IL-12, TNF-α, TGF-β, IL-10 and SOCS3 by qPCR, and the quantification of the chemokine IP-10 by ELISE. The results indicated that sucralose has no cytotoxic effects but decreases the number of metabolically active viable cells determined by MTT of macrophages in a concentration-dependent manner. Sucralose increased the concentration of the chemokine IP-10 and the gene expression of the transcription factors IRF5 and decreased the expression of IRF4 and STAT 6 gene expression, favoring polarization towards M1 populations. The bioaccumulation of sucralose in adipose tissue, and its interaction with macrophages, could induce its polarization to M1.

Increased Young's modulus and hardness of Col1a2oim dentin.

Mice harboring the Col1a2(oim) mutation (oim) express dentinogenesis imperfecta. To determine the effect of Col1a2 genotype on tissue mechanical properties, we compared Young's modulus and hardness of dentin in the 3 Col1a2 genotypes. Upper incisors were tested by nanoindentation. Genotype had a significant effect on Young's modulus, but there was not a simple mutant allele dosage relationship. The effect of genotype on hardness did not reach significance. Hardness and Young's modulus were greater near the dento-enamel junction than near the pulp chamber. Greater hardness and Young's modulus values near the dento-enamel junction reflected continued mineralization of the dentin following its initial synthesis. Analysis showed the mechanical data to be consistent with Fourier transform infrared and backscattered electron microscopy studies that revealed increased mineralization in oim bone. Analysis of the data suggests that clinical fragility of teeth in oim mice is not due to deficiencies of hardness or Young's modulus, but may be due to defects in post-yield behavior or resistance to fatigue damage.

Increased expression of hypoxia inducible factor-1alpha in rat and human prostate cancer.

Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that regulates genes involved in adaptation to hypoxia. Expression of HIF-1alpha was evaluated in rat and human prostate cancer cell lines. Increased expression of HIF-1alpha mRNA in rat prostate cancer cell lines and hypoxia-induced expression of HIF-1alpha protein in human prostate cancer cell lines are associated with increased cell growth rates and metastatic potential. HIF-1alpha mRNA was undetectable in the normal rat ventral prostate by Northern blot hybridization. HIF-1alpha protein expression and HIF-1 DNA binding activity were detected in normoxic PC-3 cells. Human prostate cancer cells plated at low density manifested higher functional HIF-1alpha expression than cells plated at high density independent of O2 tension. HIF-1alpha may become dysregulated in prostate cancer and thus drive the transcription of hypoxia-adaptive genes involved in tumor progression. This is also the first evidence that human cancer cells can express functional HIF-1alpha protein under normoxic conditions.

Evaluación del impacto de la pandemia COVID-19 en el diagnóstico y tratamiento de pacientes con cáncer de mama tratadas en Clínica Alemana de Santiago / Evaluation of the impact of the COVID-19 pandemic in the diagnosis and treatment of breats cancer patients at Clínica Alemana de Santiago

Resumen Introducción: Debido a la pandemia COVID-19 se ha visto un retraso en diagnósticos de en-fermedades oncológicas, cambio de tratamientos y aumento en mortalidad. Objetivo: Evaluar efectos de la pandemia en pacientes de Clínica Alemana de Santiago con diagnóstico reciente de cáncer de mama, comparadas con igual periodo año 2019. Materiales y Método: Estudio cuantitativo, retrospectivo, tipo descriptivo. Período 1 de abril - 31 de julio de 2020 comparado con igual periodo de año 2019. Revisión de nuestra base de datos, comparando motivo de consulta, estadio y tratamiento. Análisis estadístico con programa STATA, test T student y test exacto de Fisher. Consideramos significativo p < 0,05. Resultados: Total 156 pacientes, 70 (44,87%) consultaron en periodo señalado año 2020 versus 86 (55,13%) en 2019 (p = 0,1). Edad promedio 55 años versus 58 (p = 0,38). Consulta por nódulo palpable de mama, 25 versus 29 (p = 0,86). Hubo diferencias en pacientes que consultaron por antece-dentes familiares de cáncer de mama, 0 versus 6 (p = 0,033), y en pacientes con antecedente personal de cáncer de mama, 0 versus 6 (p = 0,033). Consulta por control imagenológico fue 39 versus 53 (p = 0,5). En época de pandemia hubo más tumores Her 2, 11 versus 2 (p = 0,006). Por estadios, no hubo diferencia. Por tratamiento indicado, cirugía fue de 49 pacientes versus 71 (p = 0,85). Hormonoterapia neoadyuvante 7 versus 1 (p = 0,058). Conclusiones: En periodo de pandemia hubo menor consulta por cáncer de mama. La mayoría por control imagenológico y lesiones palpables, sin diferencia en estos grupos entre ambos periodos. Hubo menos cirugías y más tratamientos con hormonoterapia neoadyuvante.

Introduction: Due to SARS-CoV-2 pandemic there has been a delay in oncological diagnosis and treatments potentially increasing mortality. Aim: To evaluate the effects of the pandemic in patients treated in Clinica Alemana with recent diagnosis of breast cancer, comparing the reason of consultation, stage and treatment to a similar time frame in 2019. Materials and Method: This is a retrospective, descriptive and quantitative study. Analyzing patients registry from April 1st to July 31st, 2020 compared with same time frame of 2019. Retrospective analysis of our database searching for reason of consultation, stage and treatment. Data analysis using STATA, T student test and Fisher exact test, considering significant a p < 0.05. Results: N156, 70 (44.87%) consultations in the 2020-time frame versus 86 (55.13%) in 2019 (p = 0.1). Mean age 55 years versus 58 (p = 0.38). Palpable tumor 25 versus 29 (p = 0.86). There was a difference in patients consulting due to personal breast oncological background, 0 versus 6 (p = 0.033) or familiar breast oncological background 0 versus 6 (p = 0.033). Breast images control 39 versus 53 (p = 0.5). In Pandemic more Her 2 tumors were diagnosed 11 versus 2 (p = 0.006). No differences in stages were observed. Upfront surgical treatment in 49 versus 71 patients (p = 0.85) and neoadjuvant hormonal treatment 7 versus 1 (p = 0.058). Conclusion: In the pandemic time frame there were less consultations due to breast cancer. The majority of the patients came because of a palpable tumor or breast image control without a significant difference compared with a similar time frame in previous year. There were less surgeries and more neoadjuvant hormonal treatments.

Primeras cirujanas de Chile / First female surgeons of Chile

Resumen En el año 2020 las cirujanas chilenas se reunieron en torno a la necesidad de trabajar para solucionar varios problemas que aquejan a la labor quirúrgica de la mujer en nuestro país, desde la formación de pregrado en adelante. Algunos de estos problemas son la poca visibilidad de la mujer en cirugía y la falta de reconocimiento de las cirujanas líderes y referentes del pasado y actuales. El objetivo de esta investigación fue indagar quienes habían sido las primeras cirujanas de Chile. La búsqueda fue difícil, ya que la información en la internet es escasa, por lo que se recurrió a entrevistas a discípulos y a algunas de las primeras cirujanas tanto en su especialidad o región del país. La cronología muestra lo reciente que ha sido la llegada de cirujanas a algunas regiones o la escasa representatividad de cirujanas en algunas subespecialidades. Esto se puede entender por barreras legales y culturales que han tenido que enfrentar las mujeres desde el ingreso a la carrera de medicina hasta el poder desarrollar la especialidad en cirugía a lo largo de la historia de este país.

In 2020, Chilean women surgeons gathered to discuss different problems affecting the development of a career in surgery. Through the history of the medicine and surgery in Chile, there have been several legal and cultural barriers that have kept women out of this specialty. One of this problem is the lack of knowledge of who were the first female surgeons and the lack of awareness of that there are women that can be leaders as well as male surgeons. So, generations of medical students and residents continue thinking that surgery might be a man's job. The purpose of this investigation is to reveal who went and are the first women surgeon in this country, not only in their time but also in their specialty, so we all know that there were and there still are pioneers among us.

Visibilizando a las cirujanas en Chile / Making female surgeons visible in Chile

Resumen Introducción: La cirugía ha sido tradicionalmente considerada una especialidad masculina. Se desconoce si el aumento en el número de médicas en las últimas décadas ha producido un aumento significativo en el número de cirujanas. Objetivo: Analizar y visibilizar la participación actual e histórica de las mujeres en Medicina y en Cirugía General en Chile. Materiales y Método: Estudio retrospectivo de la cohorte de médicas/os y cirujanas/os egresados de escuelas de medicina chilenas desde el año 1970, complementado con estudio de corte transversal para conocer la información actual de las cirujanas y residentes. Las fuentes de datos fueron los Registros de la Superintendencia de Salud, CONACEM y el Catastro de la Asociación de Cirujanas. Resultados: Ha existido un aumento sostenido de médicas egresadas sobrepasando a sus pares masculinos a partir de 2018. Las cirujanas representan el 15% del total de cirujanas y cirujanos, y este número se ha duplicado por década a partir de los años 70. Actualmente, 33% de los residentes en formación son de género femenino. Las áreas más comunes de desarrollo son cirugía general (35%), y dentro de las subespecialidades: mama, plástica y cabeza y cuello. Conclusión: Las mujeres siguen siendo minoría en cirugía; sin embargo, se ha producido un aumento progresivo y se espera siga la misma tendencia. Es necesario visibilizar la importancia de las cirujanas para que sirvan como modelo a nuevas generaciones de estudiantes y así poder aumentar la representación femenina en la especialidad.

Introduction: Surgery traditionally has been considered a male discipline. It is unknown if the increase in the number of female doctors in the last decades has increased the number of female surgeons. Aim: Is to analyze and make visible the historical and current participation of women in Medicine and Surgery in Chile. Materials and Method: Retrospective cohort study of all medical doctors and surgeons graduated from chilean Universities since 1970 to date, and cross-sectional study to know current information of female surgeons and residents. Source of data were the Registries of Health Superintendence, CONACEM and the Registry of the Female Surgeon Association. Results: There has been a steady increase in the number of graduated female doctors in Chile, surpassing male doctors since 2018. Female surgeons are 15% of all surgeons, and the number has duplicated every decade since 1970s. Currently, 33% of the residents are female. Main area of developing is general surgery (35%), and within subspecialties: Breast, Plastics, and Head and Neck. Conclusions: Women are still underrepresented in Surgery: however, there has been a steady increase and that trend is expected to continue. It is necessary to make visible the importance of female surgeons to be able to increase female representation.

Further characterization of ATP-initiated calcification by matrix vesicles isolated from rachitic rat cartilage. Membrane perturbation by detergents and deposition of calcium pyrophosphate by rachitic matrix vesicles.

Although membrane associated enzymes such as ATPase, alkaline phosphatase, and NTP pyrophosphohydrolase in matrix vesicles (MVs) may underlie the mechanisms of ATP-promoted calcification, prior to the current investigation, the role of the MV membrane in calcification had not been addressed. In this study, various perturbations were introduced to the MV membrane in in vitro calcification systems to determine ideal conditions for ATP-initiated calcification by MVs isolated from rachitic rat epiphyseal cartilage. Membrane integrity appears to be required, since the rupture of the vesicular membrane by vigorously mixing with 10% butanol abolished calcification. In contrast, a mild treatment of MVs with low concentrations (e.g., 0.01%, which is much below the critical concentration for micelle formation) of either neutral Triton X-100 or anionic deoxycholate stimulated calcification by >2-fold, without inducing obvious changes in vesicular appearance. Fourier transform infrared spectroscopic studies were done to identify the mineral phase formed in these experiments. For the first time, rachitic MVs were shown to induce the formation of a calcium pyrophosphate dihydrate-like phase after their exposure to calcifying medium with 1 mM ATP. The integration of spectral areas indicated that calcification was enhanced by Triton X-100. The detergent effect was reversible and appeared to be not mediated through activation of ATPase, alkaline phosphatase, or ATP pyrophosphohydrolase. In contrast to neutral Triton X-100 and anionic deoxycholate, cationic cetyltrimethylammonium bromide inhibited both ATPase activity (I50=10 microM) and ATP-initiated calcification. These observations suggest that membrane perturbations can affect calcification and that the presence of NTP-pyrophosphohydrolase in MVs may play a role in the deposition of CaPPi in rachitic cartilage.

Fourier transform infrared imaging spectroscopy analysis of collagenase-induced cartilage degradation.

Collagenase treatment of cartilage serves as an in vitro model of the pathological collagen degradation that occurs in the disease osteoarthritis (OA). Fourier transform infrared imaging spectroscopic (FT-IRIS) analysis of collagenase-treated cartilage is performed to elucidate the molecular origin of the spectral changes previously found at the articular surface of human OA cartilage. Bovine cartilage explants are treated with 0.1% collagenase for 0, 15, or 30 min. In situ collagen cleavage is assessed using immunofluorescent staining with an antibody specific for broken type II collagen. The FT-IRIS analysis of the control and treated specimens mirrors the differences previously found between normal and OA cartilage using an infrared fiber optic probe (IFOP). With collagenase treatment, the amide II/1338 cm(-1) area ratio increases while the 1238 cm(-1)/1227 cm(-1) peak ratio decreases. In addition, polarized FT-IRIS demonstrates a more random orientation of the collagen fibrils that correlate spatially with the immunofluorescent-determined regions of broken type II collagen. We can therefore conclude that the spectral changes observed in the collagenase-treated cartilage, and similarly in OA cartilage, arise from changes in collagen structure. These findings support the use of mid-infrared spectral analysis, in particular the minimally invasive IFOP, as potential techniques for the diagnosis and management of degenerative joint diseases such as osteoarthritis.

The material basis for reduced mechanical properties in oim mice bones.

Osteogenesis imperfecta (OI), a heritable disease caused by molecular defects in type I collagen, is characterized by skeletal deformities and brittle bones. The heterozygous and homozygous oim mice (oim/+ and oim/oim) exhibit mild and severe OI phenotypes, respectively, serving as controlled animal models of this disease. In the current study, bone geometry, mechanics, and material properties of 1-year-old mice were evaluated to determine factors that influence the severity of phenotype in OI. The oim/oim mice exhibited significantly smaller body size, femur length, and moment of area compared with oim/+ and wild-type (+/+) controls. The oim/oim femur mechanical properties of failure torque and stiffness were 40% and 30%, respectively, of the +/+ values, and 53% and 36% of the oim/+ values. Collagen content was reduced by 20% in the oim/oim compared with +/+ bone and tended to be intermediate to these values for the oim/+. Mineral content was not significantly different between the oim/oim and +/+ bones. However, the oim/oim ash content was significantly reduced compared with that of the oim/+. Mineral carbonate content was reduced by 23% in the oim/oim bone compared with controls. Mineral crystallinity was reduced in the oim/oim and oim/+ bone compared with controls. Overall, for the majority of parameters examined (geometrical, mechanical, and material), the oim/+ values were intermediate to those of the oim/oim and +/+, a finding that parallels the phenotypes of the mice. This provides evidence that specific material properties, such as mineral crystallinity and collagen content, are indicative and possibly predictive of bone fragility in this mouse model, and by analogy in human OI.

Calcitonin alters bone quality in beagle dogs.

Because of its antiresorptive properties, calcitonin is widely used to prevent and treat osteoporosis. A stimulatory effect of calcitonin on osteoblasts has also been reported; however, a recent histologic study points to a negative effect of calcitonin on mineralization of cancellous bone. The present experiment was performed to determine whether the observed histological signs of alterations in mineralization are also observed in cortical bone and whether this results in changes in mechanical properties, mineral densities, or mineral properties of canine bone. Sixteen female adult beagle dogs were randomly allocated to receive either human calcitonin at a dose of 0.25 mg/dog (50 IU, n = 8) or vehicle (mannitol, n = 8) every other day for 16 weeks. At the end of the study, the dogs were euthanized. Both tibiae, L1 and L5 vertebrae, and iliac crest bone samples were excised and defleshed. Torsional mechanical properties of tibial diaphyses and compressive strengths of vertebrae were measured. Bone mineral densities (BMD) of tibiae and vertebrae were measured by using dual-energy X-ray absorptiometry. Ultrastructural mineral characteristics of iliac crest bone were determined by gravimetry and Fourier transform infrared spectroscopy (FTIR). Bone histomorphometry was performed in the cortical envelope of the iliac crest. Tibiae from dogs treated with calcitonin withstood significantly less maximum torque until failure, required less torsional energy to reach the maximum torque, and had less torsional stiffness than the tibiae from dogs treated with vehicle (p < 0.05). Cancellous cores of vertebrae from calcitonin-treated dogs withstood less compressive mechanical loading than did vertebral cores from vehicle-treated animals (p < 0.05). Dogs treated with calcitonin had less BMD of both tibiae and vertebrae than vehicle-treated animals (p < 0.05). Bones from calcitonin-treated dogs had significantly less ash content, which correlated with the lower phosphate-to-amide I (detected by FTIR) and greater carbonate-to-phosphate ratios than did bones from vehicle-treated dogs (p < 0.05). Calcitonin-treated dogs exhibited a decrease in bone formation and mineralization rates and an increase in mineralization lag time. These results point to a negative effect of calcitonin on bone quality. These findings are intriguing and call for further studies addressing whether the observed abnormalities are transient or permanent.

Effect of abnormal mineralization on the mechanical behavior of X-linked hypophosphatemic mice femora.

The Hyp mouse is an established animal model of X-linked hypophosphatemia, one of the most common genetic forms of metabolic bone disease in humans. This study describes the first determination of whole bone mechanical behavior in the heterozygous male and female Hyp mouse. Femora from 12-week-old mice were tested in torsion. The contribution of structural and material properties to mechanical behavior was determined by geometrical evaluation prior to testing and by analysis of the diaphyseal mineral after testing. The male and female Hyp femora were found to undergo significantly more angular deformation at failure than the same sex normal femora (82.49 +/- 24.37 vs. 22.63 +/- 8.02 rad/m [corrected] for the females and 128.90 +/- 37.05 vs. 22.79 +/- 7.24 rad/m [corrected] for the males) and to have a significantly lower structural stiffness (0.373 +/- 0.130 x 10(-3) vs. 1.33 +/- 0.380 x 10(-3) [corrected] [N-m/(rad/m)] for the females and 0.167 +/- 0.104 x 10(-3) vs. 1.60 +/- 0.502 x 10(-3) [corrected] [N-m/(rad/m)] for the males). The male Hyp femora had a significantly lower failure torque than male normal femora (1.58 +/- 0.62 x 10(-2) vs. 3.44 +/- 1.57 x 10(-2) N-m). Because the polar movement of inertia, a geometrical property that affects torsional behavior, was not significantly different between the Hyp femora and the same sex normals, differences in mechanical behavior were attributed to material properties.(ABSTRACT TRUNCATED AT 250 WORDS)

Complementary information on bone ultrastructure from scanning small angle X-ray scattering and Fourier-transform infrared microspectroscopy.

Scanning small angle X-ray scattering (scanning SAXS) and Fourier-transform infrared microspectroscopy (FT-IRM) have previously been utilized independently to characterize the structural properties of bone in an anatomical position-resolved fashion. Whereas SAXS provides a direct measure of the physical characteristics of apatitic crystals, FT-IRM assesses structure of both mineral and organic matrix at the molecular level. In the present study both methods were applied to examine the same developing bone tissue from the L-4 vertebra of a 14-month-old (accidental death). A 200-microm-thick section was processed for examination by scanning electron microscopy and SAXS. Spectra were collected at 200 microm spatial resolution at specific locations in cortical and cancellous bone. Parameters determined included total SAXS intensity, crystal thickness (T), and degree and direction of predominant crystal orientation. For FT-IRM analysis, a section 4 microm thick was cut longitudinally from the top of the sample. Spectra of regions 100 x 100 microm2 were acquired from the same locations as the SAXS spectra. Integrated areas of the phosphate nu(1,3) collagen amide I, and carbonate nu2 absorbances, were calculated to obtain mineral: matrix and carbonate:mineral ratios. The relative quantities of types A, B, and labile carbonate (substituted for apatite hydroxyl, phosphate, and surface positions, respectively) were also evaluated. Polarized FT-IRM data were collected to determine molecular orientation of the apatite and collagen components. The results of this study show that the information obtained from the two techniques is complementary. Both SAXS and FT-IRM data revealed that the crystals were significantly larger in the cancellous region compared with the cortical region, that mineralization was greater in the cortex, and that the crystals were oriented to a larger degree in the cancellous compared with the cortical bone. The scanning SAXS measure of crystal thickness was significantly correlated to the FT-IRM measures of crystallinity, type A carbonate substitution, and crystal orientation. In conclusion, it was found that the combined use of SAXS and FT-IRM provides valuable, unique information on structural changes in bone at both the microstructural and ultrastructural level. Although each method can be used individually, the combination of techniques provides additional insights into the mechanism of bone crystal maturation.

Isolation of calcifiable vesicles from human atherosclerotic aortas.

Advanced mineralization can cause brittleness of aortic walls with decreased elasticity thereby causing the wall to rupture. Although the precise mechanisms of dystrophic calcification remain unknown, morphological evidence reveals the presence of mineral-associated vesicles in the lesions and defective bioprosthetic valves. In an attempt to demonstrate the calcifiability of the vesicles, small segments of human atherosclerotic aortas with calcified lesions were removed at autopsy and then digested in a crude collagenase solution to release vesicles. A differential centrifugation was then used to isolate calcifiable vesicles, which was precipitated at 300,000 x g for 20 min. An exposure of the vesicles to a calcifying medium containing physiologic levels of Ca2+, Pi, and 1 mM ATP caused Ca deposition in a vesicle protein-concentration dependent manner. The calcifiability of the vesicles was further demonstrated by electron microscopy. Fourier transform spectroscopic analysis of the deposited mineral revealed the presence of a hydroxyapatite phase, closely resembling the native form of mineral in atherosclerotic plaques. In addition, calcifiable vesicles were enriched in ATP-hydrolyzing enzymes including Mg2+ or Ca2+-ATPase and NTP pyrophosphohydrolase that may be involved in normal and pathological calcification. Triton X-100 at 0.01% abolished 80% of both ATPase activity and ATP-initiated calcification. A comparison of vesicles isolated from non-atherosclerotic and atherosclerotic aortas indicated that atherosclerotic vesicles tended to have higher calcifiability. These observations suggest that the calcifiable vesicles play a part in dystrophic calcification of aortas in atherosclerosis.