Early Colonial Diet in El Japón, Xochimilco, Mexico: Examining dietary continuity through stable isotope analysis of bone collagen and bioapatite.

OBJECTIVES: Early colonial documents from central Mesoamerica detail raising and planting of European livestock and crops alongside native ones. The extent to which Indigenous people, especially of the rural commoner class, consumed newly introduced foods is less known. This gap in knowledge is addressed through stable isotope analysis and comparison to published archaeological botanical, human, and faunal data. MATERIALS AND METHODS: Stable isotope analysis of bone collagen and bioapatite is applied to 74 skeletal samples of Indigenous human remains representing Colonial period individuals from El Japón-a farming hamlet in the Xochimilco area-to provide insight into long-term individual dietary practices in the context of a rapidly transforming Mesoamerican world. RESULTS: Carbon isotope ratios in collagen (δ13Ccollagen) average -8.10/00 VPDB (SD 0.55), while δ15N averages 8.90/00 AIR (SD 0.50). δ13Cbioapatite averages -2.90/00 VPDB (SD 0.60). Modest increase in carbon isotopic diversity is observed among more recent males from El Japón when compared to earlier males and females. DISCUSSION: Based on the isotopic results, it is estimated that the individuals of El Japón consumed maize or other C4 plants as a central source of carbohydrates. Dietary protein was largely supplied through domestic maize-fed fauna but potentially supplemented by wild terrestrial and aquatic fauna and fowl. Similarity in skeletal isotopic composition between precontact Mesoamericans from other sites and El Japón individuals of both earlier and later stratigraphy is interpreted as continuity in local diets and foodways despite potentially available European alternatives. Colonial taxation demands on preexisting agricultural regimes may have incentivized maize production, thus indirectly contributing to the maize-centered aspect of local foodways.

OBJETIVOS: Los textos de la época colonial temprana del centro de México documentan la producción de cultivos y ganado europeo a la par de los productos agropecuarios nativos. La magnitud a la cuál las comunidades indígenas consumieron estos productos se conoce con menos certeza en especial dentro de los asentamientos rurales. En este trabajo, se analiza la variabilidad de datos de isótopos estables en el sitio El Japón, Xochimilco y los resultados se comparan con respecto al sexo biológico y la cronología; así como también con datos publicados de muestras humanas y faunísticas. MATERIALES Y MÉTODOS: Se aplican los estudios de isotopos estables en colágeno y bioapatita a 74 muestras esqueléticas de El Japón de la época colonial temprana, una aldea agrícola del área de Xochimilco, con tal de abordar las practicas dietéticas en el contexto de un mundo Mesoamericano en transformación tras el contacto europeo. RESULTADOS: Los isótopos estables de carbono en colágeno (δ13Ccollagen) producen un promedio de −8.10/00 VPDB (DE 0.55), mientras tanto los isótopos estables de nitrógeno en el mismo tejido producen un promedio de 8.90/00 AIR (DE 0.50). Los isótopos estables de carbono en la bioapatita (δ13Cbioapatite) producen un promedio de −2.90/00 VPDB (DE 0.60). Se observa un incremento mínimo en la diversidad isotópica entre los individuos de sexo masculino en comparación a los individuos de sexo femenino de la etapa temprana y tardía del sitio. DISCUSIÓN: Con base en los resultados isotópicos, y con base en comparación a muestras humanas de contextos arqueológicos europeos y norteamericanos se estima que los individuos de El Japón consumieron maíz u otros cultivos tipo C4 como fuentes principales de carbohidratos. Las fuentes de proteína dietética posiblemente fueron fauna alimentada con maíz, pero también se pudieron haber suplementado con alimentos silvestres incluyendo aves silvestres, y fauna terrestre o acuática. La similitud en variación isotópica entre sitios mesoamericanos que preceden el contacto europeo y El Japón de ambas etapas (temprana y tardía) se interpretan como persistencia en fuentes de alimentación y tradiciones culinarias a pesar de las posibles alternativas europeas. Las demandas tributarias coloniales sobre la producción agrícola chinampera pudiesen haber contribuido indirectamente a la continuidad del maíz como fuente alimenticia principal.

Phosphatidylserine controls calcium phosphate nucleation and growth on lipid monolayers: A physicochemical understanding of matrix vesicle-driven biomineralization.

Bone biomineralization is an exquisite process by which a hierarchically organized mineral matrix is formed. Growing evidence has uncovered the involvement of one class of extracellular vesicles, named matrix vesicles (MVs), in the formation and delivery of the first mineral nuclei to direct collagen mineralization. MVs are released by mineralization-competent cells equipped with a specific biochemical machinery to initiate mineral formation. However, little is known about the mechanisms by which MVs can trigger this process. Here, we present a combination of in situ investigations and ex vivo analysis of MVs extracted from growing-femurs of chicken embryos to investigate the role played by phosphatidylserine (PS) in the formation of mineral nuclei. By using self-assembled Langmuir monolayers, we reconstructed the nucleation core - a PS-enriched motif thought to trigger mineral formation in the lumen of MVs. In situ infrared spectroscopy of Langmuir monolayers and ex situ analysis by transmission electron microscopy evidenced that mineralization was achieved in supersaturated solutions only when PS was present. PS nucleated amorphous calcium phosphate that converted into biomimetic apatite. By using monolayers containing lipids extracted from native MVs, mineral formation was also evidenced in a manner that resembles the artificial PS-enriched monolayers. PS-enrichment in lipid monolayers creates nanodomains for local increase of supersaturation, leading to the nucleation of ACP at the interface through a multistep process. We posited that PS-mediated nucleation could be a predominant mechanism to produce the very first mineral nuclei during MV-driven bone/cartilage biomineralization.

Amorphous calcium phosphate (ACP) in tissue repair process.

Synthetic biomaterials submitted to new structural technologies have become ideal for the recovery of traumatized bone tissues and some bone substitutes such as bioactive glass, ß-Tricalcium phosphate (ß-TCP) and amorphous calcium phosphate (ACP) are being used in areas of tissue defects. For this study, ACP was produced in the form of fibers and then submitted to cytotoxicity testing. A sample of ACP was inserted into the mandibular region of a patient with a lost implant so after removal and curettage, the remaining bone site was filled with the ACP biomaterial. Preliminary cytotoxicity test was negative. After 15 weeks of healing, a titanium implant was inserted at the site. Clinical and radiographic follow-up was conducted for 12 months and sequential radiographic analyses revealed tissue formation resembling spongy bone. Images under immunohistochemistry demonstrated efficient deposition and osteoconduction of the newly deposited tissue. Residual portion of the CaO:P2 O5 outer layers served as a substrate for osteoid matrix deposition, aiding growth, and the results of fiber absorption favored maturation of the new bone tissue.

Long-term resilience of late holocene coastal subsistence system in Southeastern South america.

Isotopic and molecular analysis on human, fauna and pottery remains can provide valuable new insights into the diets and subsistence practices of prehistoric populations. These are crucial to elucidate the resilience of social-ecological systems to cultural and environmental change. Bulk collagen carbon and nitrogen isotopic analysis of 82 human individuals from mid to late Holocene Brazilian archaeological sites (∼6,700 to ∼1,000 cal BP) reveal an adequate protein incorporation and, on the coast, the continuation in subsistence strategies based on the exploitation of aquatic resources despite the introduction of pottery and domesticated plant foods. These results are supported by carbon isotope analysis of single amino acid extracted from bone collagen. Chemical and isotopic analysis also shows that pottery technology was used to process marine foods and therefore assimilated into the existing subsistence strategy. Our multidisciplinary results demonstrate the resilient character of the coastal economy to cultural change during the late Holocene in southern Brazil.

A phosphate-buffered saline intracanal dressing improves the biomineralization ability of mineral trioxide aggregate apical plugs.

INTRODUCTION: Recently, it was shown that the biomineralization process promoted by the interaction of mineral trioxide aggregate (MTA) with dentin in phosphate-buffered saline (PBS) positively influenced the push-out bond strength of the cement. This study investigated if the use of a PBS intracanal dressing promotes the biomineralization process of MTA apical plugs using an ex vivo apexification model. METHODS: White MTA was introduced into single-rooted teeth with standardized artificially created open apices to form 5-mm-thick apical plugs. The specimens were randomly divided into the following three groups of 10 samples each: group 1: the remaining canal space was filled with PBS as an intracanal dressing; group 2: the root segments were introduced in plastic vials containing floral foams with 20 mL of PBS; and group 3: the root segments were placed in the floral foams with 20 mL of PBS and a PBS intracanal dressing was used. After 2 months, the samples were processed for scanning electron microscopic observations. Data were analyzed by using the Kruskall-Wallis test. RESULTS: In group 1, the formation of an interfacial layer (IL) with intratubular mineralization (ITM) was more evident at the cervical third; however, no mineralization was revealed at the apical third. In group 2, there was no IL and/or ITM formation at the cervical third, but samples denoted IL and ITM formation at the apical third. Group 3 displayed the formation of IL and ITM at the different levels. CONCLUSION: It was concluded that the use of a PBS intracanal dressing promotes the biomineralization process at the inner side of MTA apical plugs.

Fluoride release from CaF2 and enamel demineralization.

The anticaries effect of professional fluoride (F) application has been attributed to calcium-fluoride-like deposits (CaF(2)) formed on enamel, but this has not been clearly demonstrated. We hypothesized that CaF(2) formed on plaque-free enamel by F application would reduce enamel demineralization due to the increase of F availability in fluid of subsequently formed plaque. We created distinct levels of CaF(2) on enamel to evaluate a dose-response effect. Enamel blocks were mounted in contact with a S. mutans test plaque and used in situ by 10 volunteers. F released to the fluid phase of this substrate ("plaque fluid") was measured before a cariogenic challenge. "Plaque fluid" F concentration was highly correlated to the enamel CaF(2) concentration (r = 0.96, p < 0.001) and to consequent enamel demineralization (r = -0.75, p < 0.001). The results suggest that F released to plaque fluid from CaF(2) formed on enamel may play a significant role in the anticaries effect of professionally applied F agents.

Trophic level and macronutrient shift effects associated with the weaning process in the Postclassic Maya.

The weaning process was investigated at two Maya sites dominated by Postclassic remains: Marco Gonzalez (100 BC-AD 1350) and San Pedro (1400-AD 1650), Belize. Bone collagen and bioapatite were analyzed from 67 individuals (n < or = 6 years = 15, n > 6 years = 52). Five isotopic measures were used to reconstruct diet and weaning: stable nitrogen- and carbon-isotope ratios in collagen, stable carbon- and oxygen-isotope ratios in bioapatite, and the difference in stable carbon-isotope values of coexisting collagen and bioapatite. Nitrogen-isotope ratios in infant collagen from both sites are distinct from adult females, indicating a trophic level effect. Collagen-to-bioapatite differences in infant bone from both sites are distinct from adult females, indicating a shift in macronutrients. Oxygen-isotope ratios in infant bioapatite from both sites are also distinct from adult females, indicating the consumption of breast milk. Among infants, carbon- and nitrogen-isotope ratios vary, indicating death during different stages in the weaning process. The ethnohistoric and paleopathological literature on the Maya indicate cessation of breast-feeding between ages 3-4 years. Isotopic data from Marco Gonzalez and San Pedro also indicate an average weaning age of 3-4 years. Based on various isotopic indicators, weaning likely began around age 12 months. This data set is not only important for understanding the weaning process during the Postclassic, but also demonstrates the use of collagen-to-bioapatite spacing as an indicator of macronutrient shifts associated with weaning.

Familial osteoarthritis and Milwaukee shoulder associated with calcium pyrophosphate and apatite crystal deposition.

OBJECTIVE: To characterize and define the phenotypes observed in a large Italo-Argentinean kindred with osteoarthritis, chondrocalcinosis, and Milwaukee shoulder (MS). METHODS: Seventy-five members were evaluated with a history, examination, and radiographs of shoulders, spine, hands, and knees. Superior subluxation of the glenohumeral joint was graded using shoulder radiographs and tomography and nuclear magnetic resonance imaging and 3 dimensional computed tomography was performed on selected members. In 31 family members peripheral blood DNA was utilized for genetic linkage analysis of several candidate gene loci previously linked to chondrocalcinosis phenotypes, as well as those implicated in the proper patterning of skeletal elements and cartilage differentiation. In addition, direct sequence analysis of type II collagen gene (COL2A1), the gene that codes for the major structural protein of cartilage, was undertaken in 3 affected and 3 unaffected members of the family. RESULTS: MS was seen in one member of the first generation and 6 members of the 2nd generation, while 8 members of the 3rd generation showed an incomplete form of MS. Isolated superior subluxation of the shoulder was seen in 16 other family members of the 3rd and 4th generations. Osteoarthritis of the spine and peripheral joints was seen in 31 affected members, while chondrocalcinosis was observed in 6 members of the first generation. Shoulder synovial fluid from 2 patients showed the presence of both apatite and calcium pyrophosphate dihydrate crystals. Direct analysis of the COL2A1 gene indicated no known disease determining mutations in affected members, thus excluding this gene as a candidate gene in this family. Genetic linkage to several candidate loci, including the chondrocalcinosis loci on chromosomes 5p and 8q, as well as loci for HOX A and C were also excluded. Linkage analyses of other loci for the HOX B and D genes and the PAX 1 and 9 genes were uninformative in this kindred. CONCLUSION: This kindred illustrates an unusual type of osteoarthritis with secondary intraarticular and periarticular calcification and MS in the most severely affected elderly members. A search for linkage to some potential candidate genes was either excluded or uninformative. Further linkage analysis to identify potential candidate genes is in progress.

Immediate replantation of maxillary incisors in rats: effects of tooth immersion in sodium fluoride and subsequent removal of the periodontal ligament.

The advantages and disadvantages of maintaining the periodontal ligament (PDL) in immediate replantation as well as chemical treatment of the root surface have been a matter of discussion because the vitality of such tissue in surgery is always questioned. This study evaluated the effects of conserving the tooth in sodium fluoride and the removal of the PDL before replantation of incisors in rats. There was more cementum-dentin resorption in the group with the PDL. The group without the PDL showed more discreet resorption, repair occurred through the newly formed bone tissue in the PDL space and ankylosis was more extensive than in the group with the PDL.

Calcium crystal-associated diseases and miscellaneous crystals.

Calcium crystal-associated diseases are still a challenge in clinical and basic science. Advances in understanding crystal formation and dissolution and crystal participation in inflammation are reported here. Studies on different methods of identification are reviewed, emphasizing the need for accurate and reproducible ways to study and diagnose calcium crystal-associated diseases. Reports of uncommon presentations are also described, including a controlled study on calcification of the ligamenta flava of the spine and a study involving 19 years of clinical follow-up of families with hydroxyapatite chondrocalcinosis with spondyloepiphyseal dysplasia. Studies on miscellaneous crystals are few. Two recent reviews are described on cholesterol crystal embolization syndrome and cryocrystalglobulinemia.

Apatite deposition in polymyositis subluxing arthropathy.

We describe a 47-year-old woman who developed chronic subluxing arthropathy associated with polymyositis (PM) and positive anti-Jo1 antibodies. After a followup of 3 years, PM did not recur and polyarthritis dominated her clinical picture, leading to deformities and periarticular calcifications in her hands, shoulders, and feet. Patients with myositis, anti-Jo1 antibodies, and periarticular calcifications are at risk of developing deforming arthritis unresponsive to conventional therapy.