RESUMEN
Bacteria within the Paenibacillus genus are known to secrete a diverse array of enzymes capable of breaking down plant cell wall polysaccharides. We studied the extracellular xylanolytic activity of Paenibacillus xylanivorans and examined the complete range of secreted proteins when grown on carbohydrate-based carbon sources of increasing complexity, including wheat bran, sugar cane straw, beechwood xylan and sucrose, as control. Our data showed that the relative abundances of secreted proteins varied depending on the carbon source used. Extracellular enzymatic extracts from wheat bran (WB) or sugar cane straw (SCR) cultures had the highest xylanolytic activity, coincidently with the largest representation of carbohydrate active enzymes (CAZymes). Scaling-up to a benchtop bioreactor using WB resulted in a significant enhancement in productivity and in the overall volumetric extracellular xylanase activity, that was further concentrated by freeze-drying. The enzymatic extract was efficient in the deconstruction of xylans from different sources as well as sugar cane straw pretreated by alkali extrusion (SCRe), resulting in xylobiose and xylose, as primary products. The overall yield of xylose released from SCRe was improved by supplementing the enzymatic extract with a recombinant GH43 ß-xylosidase (EcXyl43) and a GH62 α-L-arabinofuranosidase (CsAbf62A), two activities that were under-represented. Overall, we showed that the extracellular enzymatic extract from P. xylanivorans, supplemented with specific enzymatic activities, is an effective approach for targeting xylan within lignocellulosic biomass.
Asunto(s)
Proteínas Bacterianas , Paenibacillus , Saccharum , Xilanos , Xilosa , Xilosidasas , Xilanos/metabolismo , Paenibacillus/metabolismo , Paenibacillus/enzimología , Proteínas Bacterianas/metabolismo , Saccharum/metabolismo , Saccharum/química , Xilosidasas/metabolismo , Xilosa/metabolismo , Reactores Biológicos/microbiología , Fibras de la Dieta/metabolismo , Endo-1,4-beta Xilanasas/metabolismo , Disacáridos/metabolismo , Glicósido Hidrolasas/metabolismoRESUMEN
Valorization of the hemicellulose fraction of plant biomass is crucial for the sustainability of lignocellulosic biorefineries. The Cellulomonas genus comprises Gram-positive Actinobacteria that degrade cellulose and other polysaccharides by secreting a complex array of enzymes. In this work, we studied the specificity and synergy of two enzymes, CsXyn10A and CsAbf62A, which were identified as highly abundant in the extracellular proteome of Cellulomonas sp. B6 when grown on wheat bran. To explore their potential for bioprocessing, the recombinant enzymes were expressed and their activities were thoroughly characterized. rCsXyn10A is a GH10 endo-xylanase (EC 3.2.1.8), active across a broad pH range (5 to 9), at temperatures up to 55 °C. rCsAbf62A is an α-L-arabinofuranosidase (ABF) (EC 3.2.1.55) that specifically removes α-1,2 and α-1,3-L-arabinosyl substituents from arabino-xylo-oligosaccharides (AXOS), xylan, and arabinan backbones, but it cannot act on double-substituted residues. It also has activity on pNPA. No differences were observed regarding activity when CsAbf62A was expressed with its appended CBM13 module or only the catalytic domain. The amount of xylobiose released from either wheat arabinoxylan or arabino-xylo-oligosaccharides increased significantly when rCsXyn10A was supplemented with rCsAbf62A, indicating that the removal of arabinosyl residues by rCsAbf62A improved rCsXyn10A accessibility to ß-1,4-xylose linkages, but no synergism was observed in the deconstruction of wheat bran. These results contribute to designing tailor-made, substrate-specific, enzymatic cocktails for xylan valorization. KEY POINTS: ⢠rCsAbf62A removes α-1,2 and α-1,3-L-arabinosyl substituents from arabino-xylo-oligosaccharides, xylan, and arabinan backbones. ⢠The appended CBM13 of rCsAbf62A did not affect the specific activity of the enzyme. ⢠Supplementation of rCsXyn10A with rCsAbf62A improves the degradation of AXOS and xylan.
Asunto(s)
Cellulomonas , Xilanos , Cellulomonas/genética , Cellulomonas/metabolismo , Fibras de la Dieta , Endo-1,4-beta Xilanasas/metabolismo , Glicósido Hidrolasas/metabolismo , Hidrólisis , Oligosacáridos/metabolismo , Especificidad por Sustrato , Xilanos/metabolismoRESUMEN
A general and efficient method for the deconjugative α-alkylation of α,ß-unsaturated aldehydes promoted by a synergistic effect between tBuOK and NaH, which considerably increases the reaction rate under mild conditions, is reported. The ß,γ-unsaturated aldehyde, resulting from the α-alkylation, is transformed in high yield into the corresponding allyl acetate via a lead(IV) acetate-mediated oxidative fragmentation. This strategy could be used for the construction of the carbon skeleton of a wide variety of alkyl or arylterpenoids.
Asunto(s)
Aldehídos , Terpenos , Alquilación , Oxidación-Reducción , EstereoisomerismoRESUMEN
<b>Introduction:</b> Giant groin hernia is an unusual disease nowadays and its management can be a challenge for surgeons. The application of botulinum toxin A as a preoperative therapy could decrease the thickness of the lateral wall muscles, increase their length and increase the volume of the abdominal cavity facilitating the surgical repair. Morbidity and mortality due to high intra-abdominal pressure would decrease, allowing a minimal tension closure after reduction of the herniated viscera. <br><b>Case report:</b> We present the repair of two cases of massive inguinal hernia with loss of domain using preoperative abdominal wall injection of botulinum toxin.
Asunto(s)
Toxinas Botulínicas Tipo A/administración & dosificación , Hernia Inguinal/cirugía , Herniorrafia/métodos , Fármacos Neuromusculares/administración & dosificación , Pared Abdominal/cirugía , Anciano , Ingle/cirugía , Hernia Inguinal/tratamiento farmacológico , Humanos , Masculino , Dolor Postoperatorio/prevención & controlRESUMEN
Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) have become serious infections in humans and ruminants. S. aureus strains are showing rapid changes to develop resistance in traditional antibiotic-containing systems. In the continuous fierce fight against the emergent multi-drug resistant bacterial strains, straightforward and scalable synthetic procedures to produce new active molecules are in demand. Analysis of molecular properties points to degraded limonoids as promising candidates. In this article, we report a simple synthetic approach to obtain degraded limonoid analogs as scaffolds for new antibacterial molecules. The minimum inhibitory concentrations against S. aureus were evaluated for the stereoisomer mixtures by the broth microdilution method. Analysis of results showed that the acetylated derivatives were the most active of them all.
RESUMEN
Nannochloropsis gaditana is a non-flagellated microalgae that has been widely used for different purposes, mostly related with the industrial production of biofuels or aquiculture. However, in order to increase the economic viability of the obtained microalgae biomass from a production plant coupled to a coal power plant, a proteomic approach was initiated by using fresh and atomized microalgae samples, as the main used commercial forms. Above 51,000 high quality spectra were obtained per sample in the MS/MS analysis of whole proteome of N. gaditana, yielding above 7,500 peptides, leading the identification of 1,950 proteins, from the N. gaditana protein database, where 655 proteins were presented in all the replicates. The identified proteins were categorized according to gene ontology classification by molecular function and biological process. In this study, it has been described the first proteomic analysis of the microalgae N. gaditana under industrial conditions containing an important number of identified proteins. A significative presence of proteins with a potential role in different agri-food and biomedical applications was detected and studied being the core of future N. gaditana research to expand the current biotechnological applications of this microalga. SIGNIFICANCE OF THE STUDY: Three quarters of the planet earth correspond to seas and oceans, however its potential biotechnological use is still unknown. We described the first proteomic description of the microalgae N. gaditana under industrial conditions. Following the spirit of the EU initiatives of blue growth and the statements of circular economy, CO2 waste from a coal plant power has been transformed in a resource for microalgae biomass production, common product presentations were evaluated by proteomic, and its potential use of identified proteins in Agri-food and Biomedicine has been revealed.
Asunto(s)
Bases de Datos de Proteínas , Microalgas/crecimiento & desarrollo , Péptidos/metabolismo , Proteoma/metabolismo , Proteómica , Estramenopilos/crecimiento & desarrolloRESUMEN
Insights into the evolution of plant cell walls have important implications for comprehending these diverse and abundant biological structures. In order to understand the evolving structure-function relationships of the plant cell wall, it is imperative to trace the origin of its different components. The present study is focused on plant 1,4-ß-xylan, tracing its evolutionary origin by genome and transcriptome mining followed by phylogenetic analysis, utilizing a large selection of plants and algae. It substantiates the findings by heterologous expression and biochemical characterization of a charophyte alga xylan synthase. Of the 12 known gene classes involved in 1,4-ß-xylan formation, XYS1/IRX10 in plants, IRX7, IRX8, IRX9, IRX14 and GUX occurred for the first time in charophyte algae. An XYS1/IRX10 ortholog from Klebsormidium flaccidum, designated K. flaccidumXYLAN SYNTHASE-1 (KfXYS1), possesses 1,4-ß-xylan synthase activity, and 1,4-ß-xylan occurs in the K. flaccidum cell wall. These data suggest that plant 1,4-ß-xylan originated in charophytes and shed light on the origin of one of the key cell wall innovations to occur in charophyte algae, facilitating terrestrialization and emergence of polysaccharide-based plant cell walls.
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Pared Celular/metabolismo , Carofíceas/enzimología , Pentosiltransferasa/metabolismo , Células Vegetales/metabolismo , Secuencias de Aminoácidos , Vías Biosintéticas , Carofíceas/genética , Evolución Molecular , Células HEK293 , Humanos , Pentosiltransferasa/química , FilogeniaRESUMEN
Two new macrocyclic diterpenes, 2-epi-latazienone (4) and 15ß-acetoxy-7ß-nicotinoyloxy-3ß,8α-di-(2-methylpropanoyloxy)-4αH,9αH,l1αH-lathyra- 5E,12E-dien-14-one (5), and three known lathyrane-type diterpenes (1-3) were isolated from Euphorbia laurifolia latex. Their structures were determined on the basis of a detailed analysis of their 1D and 2D NMR spectroscopic and mass spectral data.
Asunto(s)
Diterpenos/química , Euphorbia/química , Látex/química , Extractos Vegetales/química , Estructura MolecularRESUMEN
A method has been developed for the conversion of primary, secondary, and tertiary alcohols, and phenol, into the corresponding esters at room temperature. The method uses a titanium(III) species generated from a substoichiometric amount of titanocene dichloride together with manganese(0) as a reductant, as well as methylene diiodide. It involves a transesterification from an ethyl ester, or a reaction with an acyl chloride. A radical mechanism is proposed for these transformations.
RESUMEN
The reaction of excess TMSCl and LiCCl2 Br at low temperature is a technically simple high yield route to TMSCCl2 Br. The latter is a stable source of the dichlorobromomethide carbanion, which undergoes 1,4-addition with cyclic nitroalkenes and (E)-fumarates leading to dichlorocyclopropanes after bromide expulsion. For nitrostyrenes the reaction arrests at the 1,4-addition product. Low temperature NMR spectroscopy studies and DFT calculations suggest the formation of an "ate" species [(nitronate)SiFMe3 ](-) which, upon boil-off of TMSF at 10-20 °C, yields the cyclopropane. DFT calculations also support the experimental differences between fluoride and acetate as promotors.
RESUMEN
Solvent-free desymmetrisation of meso-dialdehyde 1 with chiral 1-phenylethan-1-ol, led to preparation of 4-silyloxy-6-alkyloxytetrahydro-2H-pyran-2-one (+)-3a with a 96:4 dr Deprotected lactone (+)-19a and the related racemic lactones 16a-18a present a lactone moiety resembling the natural substrate of HMG-CoA reductase and their antifungal properties have been evaluated against the phytopathogenic fungi Botrytis cinerea and Colletotrichum gloeosporioides. These compounds were selectively active against B. cinerea, while inactive against C. gloeosporioides.
Asunto(s)
Botrytis/efectos de los fármacos , Colletotrichum/efectos de los fármacos , Fungicidas Industriales/síntesis química , Glutaral/análogos & derivados , Piranos/síntesis química , Aldehídos/química , Botrytis/crecimiento & desarrollo , Botrytis/aislamiento & purificación , Colletotrichum/crecimiento & desarrollo , Colletotrichum/aislamiento & purificación , Recuento de Colonia Microbiana , Fungicidas Industriales/farmacología , Glutaral/química , Hidroximetilglutaril-CoA-Reductasas NADP-Dependientes/química , Lactonas/química , Imitación Molecular , Alcohol Feniletílico/química , Enfermedades de las Plantas/microbiología , Piranos/farmacología , Estereoisomerismo , Relación Estructura-Actividad , Vitis/microbiologíaRESUMEN
The biological activities of aristolane, aromadendrane, ent-1,10-secoaromadendrane, 2,3-secoaromadendrane, ent-5,10-cycloaromadendrane, bicyclogermacrene, lepidozane, and maaliane terpenoids which contain the gem-dimethylcyclopropyl unit are described. Particular attention is given to their anti-viral, anti-microbial and cytotoxic activities. In the main text there are 119 references covering the literature from 1963-2014. The ESI contains tables listing 332 of these terpenoids, their occurrence and biological activity together with the related references.
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Productos Biológicos , Sesquiterpenos , Productos Biológicos/química , Productos Biológicos/farmacología , Humanos , Estructura Molecular , Sesquiterpenos/química , Sesquiterpenos/farmacologíaRESUMEN
The structure 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide (1) was assigned to a metabolite of Botrytis cinerea, but the spectra of several synthetic analogues had significant differences from that of 1. Examination of the constituents of a B. cinerea mutant that overproduces polyketides gave sufficient quantities of 1, now named cinbotolide, for chemical transformations. These led to a revised γ-butyrolactone structure for the metabolite. This structure has been confirmed by an asymmetric total synthesis, which also established its absolute configuration.
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4-Butirolactona/química , Macrólidos/química , Policétidos/química , Espectroscopía de Resonancia Magnética , Estructura Molecular , Policétidos/síntesis química , EstereoisomerismoRESUMEN
Covering: 1973 to 2013. The biological activities of tigliane, lathyrane, ingenane, casbane, jatropholane and premyrsinane diterpenoids which contain the gem-dimethylcyclopropyl unit are described. Particular attention is given to their anti-viral, anti-microbial and cytotoxic activities. In the main text there are 132 references. The electronic supplementary information contains tables listing 424 of these diterpenoids, their occurrence and biological activity together with the references.
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Productos Biológicos , Ciclopropanos , Diterpenos , Proteína Quinasa C/antagonistas & inhibidores , Animales , Productos Biológicos/química , Productos Biológicos/aislamiento & purificación , Productos Biológicos/farmacología , Ciclopropanos/química , Ciclopropanos/aislamiento & purificación , Ciclopropanos/farmacología , Diterpenos/química , Diterpenos/aislamiento & purificación , Diterpenos/farmacología , Humanos , Ratones , Estructura MolecularRESUMEN
Visual symptoms are common among the nonmotor symptoms in Parkinson's disease. The aims of this study were to assess the diagnostic accuracy and relationship of retinal morphologic and functional changes with motor and non-motor symptoms disturbances in Parkinson's disease. Thirty patients with Parkinson's disease, with a median Hoehn-Yahr stage of 2 (1-4), were compared to 30 age- and gender-matched controls. Retinal thinning and function were measured using optical coherence tomography (OCT), visual evoked potentials (VEP), and pattern electroretinography. Motor impairment and motor laterality were measured using the Short Parkinson's Evaluation Scale/Scales for Outcomes in Parkinson's disease, and non-motor symptoms severity using the nonmotor symptoms questionnaire. Only pattern electroretinography, P50 and N95 amplitudes, were lower in patients with Parkinson's disease, compared to controls (p = 0.01, respectively). Age, disease duration, levodopa dose, motor, and non-motor impairment were not significantly associated with retinal thinning and functional changes. The patients vs. controls area under the curve of OCT, VEP, and pattern electroretinography receiver-operating-characteristic curves were<0.50. In conclusion, morphologic and functional retina changes are not significantly correlated with motor and non-motor symptoms impairment severity, and do not discriminate between Parkinson's disease and controls.
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Actividad Motora/fisiología , Enfermedad de Parkinson/patología , Retina/patología , Retina/fisiopatología , Trastornos de la Visión/etiología , Anciano , Estudios de Casos y Controles , Estudios Transversales , Electrorretinografía , Potenciales Evocados Visuales/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/complicaciones , Curva ROC , Tomografía de Coherencia ÓpticaRESUMEN
OBJECTIVE: Baseline bone health in postmenopausal women is poorly characterized in prospective series of early breast cancer (EBC) patients candidates to aromatase inhibitor (AI) therapy. Our objective is to comprehensively evaluate bone health in a prospective clinical cohort of patients recruited prior to adjuvant AI therapy, with the aim of establishing potential AI impact on bone loss and fractures. METHODS: From January 2006 to April 2010, we consecutively included 343 women with EBC who were about to start adjuvant AI therapy. Participants were assessed at baseline (before AI initiation) and at 3 months, with annual assessments thereafter. Bone mineral density (BMD), spine X-ray, bone metabolism (vitamin D [25(OH)D], bone turnover markers [BTM]), arthralgia and quality of life are measured. RESULTS: Mean age was 61.9 years; 197 (57.4%) had been previously treated with tamoxifen; 145 (42.3%) were taking exemestane, 187 (54.5%) letrozole, and 11 (3.2%) anastrozole. Analysis of baseline data shows only 59 women (17.7%) had normal BMD; 200 (60.1%) had osteopenia and 74 (22.2%) had osteoporosis; 39 women (11.4%) had a prevalent fracture, 293 (89.1%) had 25(OH)D insufficiency (<30 ng/ml), and 61 (18.5%) severe deficiency (<10 ng/ml). Low 25(OH)D concentrations were associated with lower BMD and 233 (67.9%) participants had some degree of arthralgia. CONCLUSIONS: Low bone mass, prevalent fractures and vitamin D insufficiency were highly prevalent among candidates to adjuvant AI for EBC. Therefore, it is crucial to assess BMD, prevalent fractures and 25(OH)D concentrations before starting AI therapy and during follow-up.
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Inhibidores de la Aromatasa/efectos adversos , Huesos/efectos de los fármacos , Huesos/metabolismo , Neoplasias de la Mama/tratamiento farmacológico , Anciano , Inhibidores de la Aromatasa/farmacología , Inhibidores de la Aromatasa/uso terapéutico , Densidad Ósea , Remodelación Ósea/efectos de los fármacos , Remodelación Ósea/fisiología , Resorción Ósea/inducido químicamente , Resorción Ósea/prevención & control , Femenino , Fracturas Espontáneas/inducido químicamente , Fracturas Espontáneas/prevención & control , Humanos , Persona de Mediana Edad , Estudios Prospectivos , Calidad de VidaRESUMEN
INTRODUCTION: Bariatric surgery is the most effective option for the treatment of patients with a high risk of complications due to their obesity. However, it brings about a series of changes in calcium and vitamin D metabolism and an increase in resorption which lead to a loss of bone mass. AIM: The objective of this study is to compare sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) as regards loss of bone mass using bone densitometry and bone remodelling markers. PATIENTS AND METHODS: Fifteen women with morbid obesity were included, 8 by SG and 7 by RYGB, with a mean age of 47.8+/-9 and mean body mass index 43.3+/-3.4. Bone mass measurements were made on the lumbar spine, femur and distal radius, and the bone remodelling markers N-telopeptide (NTx) and bone alkaline phosphatase (BALP), as well as vitamin D levels before and 12 months after surgery. RESULTS: A significant bone mass loss was observed was observed with SG and RYGB, in the lumbar spine and hip, whilst no differences were observed in the radial. The percentage bone mass loss was less in the column and femur after SG than with RYGB, although it did not reach statistical significance, 4.6%+/-4.4 (mean+/-SD) and 6.3%+/-5.4 (mean+/-SD), respectively. At 12 months the Ntx increased for both types of surgery, and the BAP was only increased for SG. CONCLUSION: SG causes less, although not significant, bone mass loss compared to RYGB.
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Densidad Ósea , Enfermedades Óseas Metabólicas/etiología , Gastrectomía/efectos adversos , Gastrectomía/métodos , Derivación Gástrica/efectos adversos , Obesidad Mórbida/cirugía , Femenino , Humanos , Persona de Mediana Edad , Proyectos Piloto , Estudios ProspectivosRESUMEN
OBJECTIVE: Aromatase inhibitors (AI) treatment leads to an increased risk of bone loss and fractures. In a group of women with early breast cancer (EBC) and baseline Vitamin D deficiency (<30 ng/ml) who are treated with AI, we aim to describe: serum levels of Vitamin D, bone mineral density (BMD), calcium intake, and the increase of serum 25(OH)D accomplished in 3 months of treatment with Vitamin D supplements. STUDY DESIGN: Prospective, non-randomized clinical trial. METHODS: In 232 consecutively included women with EBC in treatment with AI, we assessed baseline calcium intake, serum levels of 25(OH)D, BMD and, spine X-ray. All received Calcium and Vitamin D supplements, and those with vitamin deficiency received 16,000 IU Vitamin D every 2 weeks. Serum levels of 25(OH)D were newly assessed after treatment. All the baseline evaluation was performed before starting AI treatment. RESULTS: Mean age at baseline (+/-SD) was 63.2+/-8.8 years. In 150 (64.9%) cases, the women had been treated previously with tamoxifen; 101 (43.7%) started exemestane, 119 (51.5%) letrozole, and 11 (4.8%) anastrozole. The AI were initiated within 6 weeks after surgery or after the last cycle of chemotherapy. At baseline, 88.1% had 25(OH)D levels <30 ng/ml, 21.2% had severe deficiency (<10 ng/ml), and 25% of the participants had osteoporosis. Mean daily calcium intake was low (841+/-338). We found a significant association between 25(OH)D levels and BMD at baseline, which remained significant in femoral neck BMD after multivariate adjustment. Plasma 25(OH)D levels improved significantly at 3 months follow-up in those treated with high dose Vitamin D supplements: mean increase 32.55 ng/ml (95%CI 28.06-37.03). CONCLUSIONS: Our study suggests a high prevalence of commonly unrecognized Vitamin D deficiency in women with EBC treated with AI, a known osteopenic agent. Our results support the need for a routine assessment of 25(OH)D levels and, when necessary, supplementation in these patients.
Asunto(s)
Inhibidores de la Aromatasa/efectos adversos , Densidad Ósea/efectos de los fármacos , Neoplasias de la Mama/complicaciones , Osteoporosis Posmenopáusica , Deficiencia de Vitamina D , Vitamina D/análogos & derivados , Vitamina D/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Antineoplásicos/administración & dosificación , Inhibidores de la Aromatasa/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Calcio/administración & dosificación , Femenino , Fémur , Humanos , Persona de Mediana Edad , Osteoporosis Posmenopáusica/complicaciones , Osteoporosis Posmenopáusica/tratamiento farmacológico , Osteoporosis Posmenopáusica/epidemiología , Posmenopausia , Estudios Prospectivos , Vitamina D/sangre , Deficiencia de Vitamina D/complicaciones , Deficiencia de Vitamina D/tratamiento farmacológico , Deficiencia de Vitamina D/epidemiologíaRESUMEN
Bone tissue mechanical properties are deemed a key component of bone strength, but their assessment requires invasive procedures. Here we validate a new instrument, a reference point indentation (RPI) instrument, for measuring these tissue properties in vivo. The RPI instrument performs bone microindentation testing (BMT) by inserting a probe assembly through the skin covering the tibia and, after displacing periosteum, applying 20 indentation cycles at 2 Hz each with a maximum force of 11 N. We assessed 27 women with osteoporosis-related fractures and 8 controls of comparable ages. Measured total indentation distance (46.0 +/- 14 versus 31.7 +/- 3.3 microm, p = .008) and indentation distance increase (18.1 +/- 5.6 versus 12.3 +/- 2.9 microm, p = .008) were significantly greater in fracture patients than in controls. Areas under the receiver operating characteristic (ROC) curve for the two measurements were 93.1% (95% confidence interval [CI] 83.1-100) and 90.3% (95% CI 73.2-100), respectively. Interobserver coefficient of variation ranged from 8.7% to 15.5%, and the procedure was well tolerated. In a separate study of cadaveric human bone samples (n = 5), crack growth toughness and indentation distance increase correlated (r = -0.9036, p = .018), and scanning electron microscope images of cracks induced by indentation and by experimental fractures were similar. We conclude that BMT, by inducing microscopic fractures, directly measures bone mechanical properties at the tissue level. The technique is feasible for use in clinics with good reproducibility. It discriminates precisely between patients with and without fragility fracture and may provide clinicians and researchers with a direct in vivo measurement of bone tissue resistance to fracture.