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1.
J Clin Endocrinol Metab ; 109(6): 1526-1539, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38127956

ABSTRACT

CONTEXT: Pancreatic ß-cell function impairment is a key mechanism for developing gestational diabetes mellitus (GDM). Maternal and placental exosomes regulate maternal and placental responses during hyperglycemia. Studies have associated exosomal micro-RNAs (miRNAs) with GDM development. To date, no studies have been reported that evaluate the profile of miRNAs present in maternal and placental exosomes in the early stages of gestation from pregnancies that develop GDM. OBJECTIVE: We assessed whether early-pregnancy serum maternal and placenta-derived exosomes miRNA profiles vary according to pancreatic ß-cell function in women who will develop GDM. METHODS: A prospective nested case-control study was used to identify exosomal miRNAs that vary in early-pregnancy stages (<18 weeks of gestation) from women with normoglycemia and those who developed GDM based on their pancreatic ß-cell function using the homeostasis model assessment of pancreatic ß-cell function (HOMA-%ß) index. Early-pregnancy serum maternal and placenta-derived exosomes were isolated to obtain miRNA profiles. Potential target and pathway analyses were performed to identify molecular and metabolic pathways associated with the exosomal miRNAs identified. RESULTS: In early-pregnancy stages, serum maternal exosome size and concentration are modified in GDM group and fluctuate according to HOMA-%ß index. Serum maternal exosomal hsa-miR-149-3p and hsa-miR-455-3p in GDM are related to insulin secretion and signaling, lipolysis, and adipocytokine signaling. Early-pregnancy serum placenta-derived exosomes hsa-miR-3665 and hsa-miR-6727-5p in GDM are related to regulating genes involved in response to immunological tolerance of pregnancy and pathways associated with placental dysfunction. CONCLUSION: Early serum exosomal miRNAs differ depending on their origin (maternal or placental) and pancreatic ß-cell function. This research provides insights into the interactions between maternal and placental exosomal miRNAs and may have implications for identifying potential biomarkers or therapeutic targets for GDM.


Subject(s)
Diabetes, Gestational , Exosomes , Insulin-Secreting Cells , MicroRNAs , Placenta , Humans , Female , Pregnancy , Diabetes, Gestational/blood , Diabetes, Gestational/genetics , Exosomes/metabolism , Exosomes/genetics , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/physiology , Adult , Placenta/metabolism , MicroRNAs/blood , Case-Control Studies , Prospective Studies , Pregnancy Trimester, First/blood
2.
Arch Osteoporos ; 17(1): 130, 2022 09 30.
Article in English | MEDLINE | ID: mdl-36178593

ABSTRACT

The study analyzes whether the COVID-19 pandemic affects annual hip fractures (HF) rates and weekly emergency department (ED) consultations and hospitalizations due to trauma in older people. During the COVID-19 pandemic, HF rates and ED consultation and hospitalization rates due to trauma decreased. PURPOSE: To describe the effect of the COVID-19 pandemic on annual HF rates and weekly ED consultation and hospitalization rates due to trauma in Chile in 2020, compared to 2016-2019. METHODS: A retrospective study was conducted based on data from Chile's Department of Statistics and Health Information. Annual HF admissions, weekly ED consultations and hospitalizations due to trauma were described for the years 2016-2020, grouping the years 2016-2019 to compare them with 2020. Rates were calculated per 100.000 inhabitants. RESULTS: From 2016 to 2020, a total of 35.050 patients aged ≥ 65 years were hospitalized in Chile with a diagnosis of HF, with the lowest number of admissions in 2020 (6.423). During 2020, annual HF rate was 273.6/100.000, representing a decrease of 18.5% compared to the average annual HF rate of 2016-2019 (335.7/100.000). In 2020, the weekly consultation rate due to trauma in older adults decreased by 20.8% and the weekly hospitalization rate due to trauma in older adults decreased by 18.5%. CONCLUSION: During the COVID-19 pandemic, osteoporotic HF rates decreased, along with ED consultation and hospitalization rates due to trauma in older adults. This could be a result of mobility restrictions and a significant increase in the proportion of self-reliant older adults in the Chilean population.


Subject(s)
COVID-19 , Hip Fractures , Osteoporotic Fractures , Aged , COVID-19/epidemiology , Chile/epidemiology , Emergency Service, Hospital , Hip Fractures/epidemiology , Hospitalization , Humans , Osteoporotic Fractures/epidemiology , Pandemics , Retrospective Studies
3.
J Virol ; 96(14): e0084822, 2022 07 27.
Article in English | MEDLINE | ID: mdl-35762754

ABSTRACT

Viral gastroenteritis has a global distribution and represents a high risk for vulnerable population and children under 5 years due to acute diarrhea, fever and dehydration. Human astroviruses (HAstV) have been identified as the third most important cause of viral gastroenteritis in pediatric and immunocompromised patients. Furthermore, HAstV has been reported in biopsies taken from patients with encephalitis, meningitis and acute respiratory infection, yet it is not clear how the virus reaches these organs. In this work we have tested the possibility that the released astrovirus particles could be associated with extracellular vesicles. Comparison between vesicles purified from HAstV Yuc8 infected and mock-infected cells showed that infection enhances production of vesicles larger than 150 nm. These vesicles contain CD63 and Alix, two markers of vesicular structures. Almost 70% of the extracellular virus present in clarified supernatant at 18 h postinfection was found associated with vesicular membranes, and this association facilitates cell infection in the absence of trypsin activation and protects virions from neutralizing antibodies. Our findings suggest a new pathway for HAstV spread and might represent an explanation for the extra-intestinal presence of some astrovirus strains. IMPORTANCE Astroviruses are an important cause of diarrhea in vulnerable population, particularly children; recently some reports have found these viruses in extra-intestinal organs, including the central nervous system, causing unexpected clinical disease. In this work, we found that human astrovirus strain Yuc8 associates with extracellular vesicles, possibly during or after their cell egress. The association with vesicles doubled astrovirus infectivity in less susceptible cells and rendered virus particles insensitive to neutralization by antibodies. These data suggest that extracellular vesicles could represent a novel pathway for astrovirus to disseminate outside the gastrointestinal tract.


Subject(s)
Astroviridae Infections , Extracellular Vesicles , Gastroenteritis , Mamastrovirus , Antibodies, Neutralizing , Astroviridae Infections/immunology , Astroviridae Infections/virology , Extracellular Vesicles/virology , Gastroenteritis/virology , Humans , Mamastrovirus/immunology
4.
Arch Osteoporos ; 17(1): 26, 2022 01 29.
Article in English | MEDLINE | ID: mdl-35091883

ABSTRACT

Our aim was to analyze trends in hip fracture rates in people aged ≥ 65 years, from 2001 to 2019 in Chile. Age-standardized incidence rates decreased significantly in both genders over the study period. PURPOSE: To describe and analyze the characteristics and trends of osteoporotic hip fractures in Chile from 2001 to 2019, by age and sex. METHODS: We assessed hip fractures in people aged ≥ 65 years using data from the hospital discharge register of Chile's Department of Statistics and Health. The Joinpoint regression analysis software was used to perform a trend analysis. RESULTS: From 2001 to 2019, a total of 107.972 patients aged ≥ 65 years were hospitalized in Chile with a diagnosis of hip fracture (S72.0, S72.1, and S72.2). 77.4% of the patients were females, and 63.7% were adults aged ≥ 80 years. The average annual incidence rate over this period was 358.3/100.000 in the whole population (95% CI: ± 12.8), 195.2/100.000 in men (95% CI: ± 9), and 482/100.000 in women (95% CI: ± 15.5). After an adjustment for age, hip fracture rates decreased annually on average by 1.0% (p < 0.001, 95% CI: - 1.4%, - 0.7%), from 358.5/100.000 in 2001 to 331.7/100.000 in 2019. Hip fracture rates decreased annually in both men (- 1.4%, p < 0.001) and women (- 0.9%, p < 0.001). CONCLUSION: The incidence of osteoporotic hip fractures has been decreasing annually and significantly in Chile since 2001, both in men and women. This may be caused by increased levels of obesity and a lower risk of falling among older adults. We recommend further studies to assess all factors contributing to this change in hip fracture rates.


Subject(s)
Hip Fractures , Osteoporotic Fractures , Age Distribution , Aged , Aged, 80 and over , Chile/epidemiology , Female , Hip Fractures/epidemiology , Humans , Incidence , Male , Osteoporotic Fractures/epidemiology , Patient Discharge
5.
Viruses ; 12(7)2020 07 16.
Article in English | MEDLINE | ID: mdl-32708544

ABSTRACT

Rotaviruses are the leading cause of viral gastroenteritis among children under five years of age. Rotavirus cell entry has been extensively studied; however, rotavirus cell release is still poorly understood. Specifically, the mechanism by which rotaviruses leave the cell before cell lysis is not known. Previous works have found rotavirus proteins and viral particles associated with extracellular vesicles secreted by cells. These vesicles have been shown to contain markers of exosomes; however, in a recent work they presented characteristics more typical of microparticles, and they were associated with an increase in the infectivity of the virus. In this work, we purified different types of vesicles from rotavirus-infected cells. We analyzed the association of virus with these vesicles and their possible role in promotion of rotavirus infection. We confirmed a non-lytic rotavirus release from the two cell lines tested, and observed a notable stimulation of vesicle secretion following rotavirus infection. A fraction of the secreted viral particles present in the cell supernatant was protected from protease treatment, possibly through its association with membranous vesicles; the more pronounced association of the virus was with fractions corresponding to cell membrane generated microvesicles. Using electron microscopy, we found different size vesicles with particles resembling rotaviruses associated from both- the outside and the inside. The viral particles inside the vesicles were refractory to neutralization with a potent rotavirus neutralizing monoclonal antibody, and were able to infect cells even without trypsin activation. The association of rotavirus particles with extracellular vesicles suggests these might have a role in virus spread.


Subject(s)
Extracellular Vesicles/virology , Rotavirus Infections/metabolism , Rotavirus/metabolism , Caco-2 Cells/virology , Extracellular Vesicles/ultrastructure , Humans , Microscopy, Electron, Transmission , Rotavirus/ultrastructure , Virion/metabolism , Virus Release
6.
J Osteoporos ; 2020: 5360467, 2020.
Article in English | MEDLINE | ID: mdl-32273971

ABSTRACT

The osteoporotic hip fracture is associated with a high impact on morbidity, mortality, and health expenditure. The Chilean health system is made up of a mixed care system, with the public system called FONASA and the private system called ISAPRE. The people with lower incomes are listed on FONASA and correspond to 80.8% of the population. The aims of this study were to describe the incidence of hip fracture in the Chilean population from the age of 45 years and to estimate the direct medical cost of this disease. The records of the Department of the Health Statistics and Information of the Ministry of Health were used, from which the number of national hospital discharges due to hip fractures was obtained (codes S720, S721, and S722 of the ICD-10), in adults aged 45 years or older, by sex, from 2006 to 2017. The cost of osteoporotic hip fracture treatment in the public health system was obtained from the data of the surgical treatment according to the payment method associated with diagnosis (PAD bonus). A surgical intervention budget was used in a private clinic to calculate the direct cost of osteoporotic hip fracture in the private system. Between 2006 and 2017, the number of hospital discharges due to osteoporotic hip fracture in adults aged 45 years and older has increased progressively, registering 9.583 hospital discharges for this cause in 2017, which corresponds to 50% more than those recorded in 2006, with a 3 : 1 F/M ratio. The mean annual rate of hip fractures is 148.7 per 100,000 inhabitants aged above 45 years. The individual cost of managing an osteoporotic hip fracture in the public system was USD$ 3,919, and USD$ 9,092 in the private health system. The incidence of hip fracture was comparable with data from Southern European countries and from neighboring countries, such as Argentina and Uruguay. Hospitalization cost of hip fracture in Chile was 34 million USD per year. Hip fracture constitutes a serious healthcare problem in Chile, and efforts for the prevention and management of osteoporosis are needed.

7.
Carbohydr Polym ; 220: 110-117, 2019 Sep 15.
Article in English | MEDLINE | ID: mdl-31196528

ABSTRACT

High quality cellulose nanoparticles (CNP) were isolated from water hyacinth stem cellulose (Cel-WH) extracted via successive thermochemical and alkaline-peroxide treatments, and further enzymatically hydrolysed using the commercial cellulase complex, NS22086, at 50ºC. The maximum CNP concentration was reached after 120 min of enzymatic hydrolysis, with a hydrodynamic diameter in the order of 200-250 nm and an increase of 5% in crystallinity as compared with Cel-WH. The obtained rod-shaped cellulose nanocrystals, as revealed by atomic force microscopy (AFM), exhibited a nominal diameter of 15.6-29.4 nm, a length of 56-184.8 nm, and a height of 2.85-6.43 nm, indicating a low tendency to form aggregates. In the present study, it was found that water hyacinth stems are a valuable source for the isolation of high-quality CNP using an environmentally friendly procedure, with potential applications in nanomedicine and nanopharmacology.


Subject(s)
Cellulose/chemistry , Eichhornia/chemistry , Nanoparticles/chemistry , Plant Stems/chemistry , Cellulase/chemistry , Hydrolysis , Microscopy, Atomic Force/methods , Nanomedicine/instrumentation , X-Ray Diffraction/methods
8.
Spectrochim Acta Part B At Spectrosc ; 116: 21-27, 2016 Feb 01.
Article in English | MEDLINE | ID: mdl-27076699

ABSTRACT

This investigation reports a rapid and simple screening technique for the quantification of titanium and zinc in commercial sunscreens using portable X-ray fluorescence spectroscopy (pXRF). A highly evolved technique, inductively coupled plasma-mass spectroscopy (ICP-MS) was chosen as a comparative technique to pXRF, and a good correlation (r2 > 0.995) with acceptable variations (≤25%) in results between both techniques was observed. Analytical figures of merit such as detection limit, quantitation limit, and linear range of the method are reported for the pXRF technique. This method has a good linearity (r2 > 0.995) for the analysis of titanium (Ti) in the range of 0.4-14.23 wt%, and zinc (Zn) in the range of 1.0-23.90 wt%. However, most commercial sunscreens contain organic ingredients, and these ingredients are known to cause matrix effects. The development of appropriate matrix matched working standards to obtain the calibration curve was found to be a major challenge for the pXRF measurements. In this study, we have overcome the matrix effect by using metal-free commercial sunscreens as a dispersing media for the preparation of working standards. An easy extension of this unique methodology for preparing working standards in different matrices was also reported. This method is simple, rapid, and cost-effective and, in comparison to conventional techniques (e.g., ICP-MS), did not generate toxic wastes during sample analysis.

9.
ACS Nano ; 7(9): 7833-43, 2013 Sep 24.
Article in English | MEDLINE | ID: mdl-23964846

ABSTRACT

A quartz crystal microbalance with dissipation (QCM-D) monitoring can be an alternative tool to characterize nanoparticle size by virtue of its acoustic principle to sense adsorbed mass. In this study, sizes obtained by QCM-D for polymer-coated metallic nanoparticles and polydisperse polystyrene latex particle suspensions were compared with those obtained by transmission electron microscopy (TEM) and dynamic light scattering (DLS). We describe the obtained "QCM-D mass", which is weighted over surface area, by a general particle height distribution equation that can be used to determine the average particle diameter of a distribution of particles deposited on the QCM-D surface. Because the particle height distribution equation can be used for any particle geometry and surface packing geometry, it is described how the QCM-D can also be used to study the orientation of deposited nonspherical particles. Herein, the mean nanoparticle sizes obtained by QCM-D were generally in closer agreement with the primary particle size determined by TEM than with the sizes obtained by DLS, suggesting that primarily smaller particles within the particle population deposited on the sensor surface. Overall, the results from this study demonstrate that QCM-D could serve as an alternative and/or complementary means to characterize the size of nanoparticles deposited on a surface from suspensions of varying complexity.


Subject(s)
Materials Testing/instrumentation , Micro-Electrical-Mechanical Systems/instrumentation , Nanoparticles/chemistry , Nanoparticles/ultrastructure , Nanotechnology/instrumentation , Energy Transfer , Equipment Design , Equipment Failure Analysis , Particle Size , Quartz/chemistry , Surface Properties
10.
Environ Sci Technol ; 47(5): 2212-20, 2013 Mar 05.
Article in English | MEDLINE | ID: mdl-23421856

ABSTRACT

A clear understanding of the factors controlling the deposition behavior of engineered nanoparticles (ENPs), such as quantum dots (QDs), is necessary for predicting their transport and fate in natural subsurface environments and in water filtration processes. A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the effect of particle surface coatings and water chemistry on the deposition of commercial QDs onto Al2O3. Two carboxylated QDs (CdSe and CdTe) with different surface coatings were compared with two model nanoparticles: sulfate-functionalized (sPL) and carboxyl-modified (cPL) polystyrene latex. Deposition rates were assessed over a range of ionic strengths (IS) in simple electrolyte (KCl) and in electrolyte supplemented with two organic molecules found in natural waters; namely, humic acid and rhamnolipid. The Al2O3 collector used here is selected to be representative of oxide patches found on the surface of aquifer or filter grains. Deposition studies showed that ENP deposition rates on bare Al2O3 generally decreased with increasing salt concentration, with the exception of the polyacrylic-acid (PAA) coated CdTe QD which exhibited unique deposition behavior due to changes in the conformation of the PAA coating. QD deposition rates on bare Al2O3 were approximately 1 order of magnitude lower than those of the polystyrene latex nanoparticles, likely as a result of steric stabilization imparted by the QD surface coatings. Adsorption of humic acid or rhamnolipid on the Al2O3 surface resulted in charge reversal of the collector and subsequent reduction in the deposition rates of all ENPs. Moreover, the ratio of the two QCM-D output parameters, frequency and dissipation, revealed key structural information of the ENP-collector interface; namely, on bare Al2O3, the latex particles were rigidly attached as compared to the more loosely attached QDs. This study emphasizes the importance of considering the nature of ENP coatings as well as organic molecule adsorption onto particle and collector surfaces to avoid underestimating ENP mobility in natural and engineered aquatic environments.


Subject(s)
Aluminum Oxide/chemistry , Nanoparticles/chemistry , Polystyrenes/chemistry , Quantum Dots/chemistry , Water/chemistry , Electrolytes/chemistry , Kinetics , Osmolar Concentration , Surface Properties
11.
Environ Sci Technol ; 46(8): 4449-57, 2012 Apr 17.
Article in English | MEDLINE | ID: mdl-22423631

ABSTRACT

Quantum dots (QDs) are one example of engineered nanoparticles (ENPs) with demonstrated toxic effects. Yet, little is known about the behavior of QDs in the natural environment. This study assessed the transport of two commercial carboxylated QDs (CdTe and CdSe) and carboxylated polystyrene latex (nPL) as a model nanoparticle using saturated laboratory-scale columns. The influence of solution ionic strength (IS) and cation type (K(+) or Ca(2+)) on the transport potential of these ENPs was examined in two granular matrices - quartz sand and loamy sand. The retention of all three particles was generally low in the quartz sand columns within the range of studied IS (0.1-100 mM) for the monovalent salt (KCl). In contrast, the retention of the three ENPs in the quartz sand was significant in the presence of 10 mM Ca(2+). Moreover, ENP attachment efficiencies (α) were enhanced by at least 1 order of magnitude in columns packed with loamy sand (for IS between 0.1-10 mM KCl). Although all three ENPs used here are carboxylated, they differ in the type of surface coating (e.g., choice of polymers or polyelectrolytes). Regardless of the surface coatings, the three ENPs exhibit comparable mobility in the quartz sand. However, the ENPs demonstrate variable transport potential in loamy sand suggesting that differences in the binding affinities of surface-modified ENPs for specific soil constituents can play a key role in the fate of ENPs in soils.


Subject(s)
Nanoparticles/chemistry , Polystyrenes/chemistry , Quantum Dots , Silicon Dioxide/chemistry , Calcium Chloride/chemistry , Hydrogen-Ion Concentration , Particle Size , Potassium Chloride/chemistry , Surface Properties
12.
Colloids Surf B Biointerfaces ; 91: 198-204, 2012 Mar 01.
Article in English | MEDLINE | ID: mdl-22119565

ABSTRACT

The use of engineered nanoparticles (ENPs) in commercial products has increased substantially over the last few years. Some research has been conducted in order to determine whether or not such materials are cytotoxic, but questions remain regarding the role that physiological media and sera constituents play in ENP aggregation or stabilization. In this study, several characterization methods were used to evaluate the particle size and surface potential of 6 ENPs suspended in a number of culture media and in the presence of different culture media constituents. Dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS) were employed for size determinations. Results were interpreted on the basis of ENP surface potentials evaluated from particle electrophoretic mobilities (EPM). Measurements made after 24h of incubation at 37°C showed that the cell culture medium constituents had only moderate impact on the physicochemical properties of the ENP, although incubation in bovine serum albumin destabilized the colloidal system. In contrast, most of the serum proteins increased colloidal stabilization. Moreover, the type of ENP surface modification played a significant role in ENP behavior whereby the complexity of interactions between the ENPs and the medium components generally decreased with increasing complexity of the particle surface. This investigation emphasizes the importance of ENP characterization under conditions that are representative of cell culture media or physiological conditions for improved assessments of nanoparticle cytotoxicity.


Subject(s)
Nanoparticles , Culture Media , Surface Properties , Water
13.
J Clin Densitom ; 13(4): 467-9, 2010.
Article in English | MEDLINE | ID: mdl-21029978

ABSTRACT

Shift workers have been reported to have an increased bone resorption. However, no existing evidence indicates lower bone mineral density (BMD) in this group. The objective of this study was to test the hypothesis that a rotating-shift work schedule is associated with low BMD and osteoporosis. We evaluated 70 postmenopausal nurses from the Naval Hospital in Concepcion, Chile. The participants were categorized according to the type of work schedule: 39 had a rotating shift and 31 were daytime workers. Medical history, a health examination, a questionnaire on health-related behaviors and biochemical determinations, and BMD examination were obtained for all participants. When comparing the 2 groups, the rotating-shift workers had lower BMD in the lumbar spine (L1-L4: 0.957 ± 0.15 vs 1.104 ± 0.13; p<0.05) and lower bone density in both femoral neck bones (right: 0.936 ± 0.17 vs 1.06 ± 0.12; p<0.05 and left: 0.956 ± 0.19 vs 1.05 ± 0.12; p<0.05). Additionally, the T-scores for 10 (25.6%) of the rotating-shift workers indicated osteoporosis at lumbar spine (T-score>-2.5). No evidence of osteoporosis was found for daytime workers. When comparing the 2 groups, the rotating-shift workers had a higher prevalence of osteopenia (T-score=-1.0 to -2.5) than the daytime workers: 46.2% vs 35.5%, respectively. We found significant evidence that rotating-shift workers have lower BMD in the trabecular and cortical bones, thus suggesting that this type of work may be a risk factor for osteoporosis. Because this is the first time that this osteoporosis risk factor has been reported, the association needs to be replicated and confirmed in other settings.


Subject(s)
Bone Density , Osteoporosis, Postmenopausal/epidemiology , Work Schedule Tolerance , Absorptiometry, Photon , Biomarkers/blood , Female , Humans , Middle Aged , Risk Factors , Surveys and Questionnaires
14.
Environ Sci Technol ; 44(17): 6532-49, 2010 Sep 01.
Article in English | MEDLINE | ID: mdl-20687602

ABSTRACT

The ever-increasing use of engineered nanomaterials will lead to heightened levels of these materials in the environment. The present review aims to provide a comprehensive overview of current knowledge regarding nanoparticle transport and aggregation in aquatic environments. Nanoparticle aggregation and deposition behavior will dictate particle transport potential and thus the environmental fate and potential ecotoxicological impacts of these materials. In this review, colloidal forces governing nanoparticle deposition and aggregation are outlined. Essential equations used to assess particle-particle and particle-surface interactions, along with Hamaker constants for specific nanoparticles and the attributes exclusive to nanoscale particle interactions, are described. Theoretical and experimental approaches for evaluating nanoparticle aggregation and deposition are presented, and the major findings of laboratory studies examining these processes are also summarized. Finally, we describe some of the challenges encountered when attempting to quantify the transport of nanoparticles in aquatic environments.


Subject(s)
Chemical Phenomena , Ecosystem , Engineering , Nanostructures/chemistry , Water/chemistry , Colloids/chemistry
15.
Environ Sci Technol ; 43(9): 3176-82, 2009 May 01.
Article in English | MEDLINE | ID: mdl-19534131

ABSTRACT

Recent reports underline the potential environmental and public health risks linked to the "nano" revolution, yet little is known regarding the environmental fate and impacts of most nanomaterials following release in natural soils and groundwaters. Quantum dots (QDs) are one example of engineered nanomaterials that have been demonstrated to exhibit cytotoxic effects; hence the fate of this material in aqueous environments is of particular interest. In this study, a quartz crystal microbalance (QCM) was used to examine the interaction of a commercially available carboxyl terminated CdTe QD with a model sand (i.e., silica) surface. The deposition kinetics of the QD onto clean silica coated QCM crystals were measured over a wide range of solution conditions, in the presence of either monovalent (K+) or divalent cations (Ca2+). QD deposition rates onto silica were significantly greater in the presence of calcium versus potassium. Solution pH also influenced QD deposition behavior, with increased deposition observed ata lower pH value. The rate of QD release from the silica surface was also monitored using QCM measurements and found to be comparable to the rate of particle deposition when the monovalent salt was used. In contrast, the rate of QD release was considerably lower than the rate of deposition when particles were deposited in the presence of Ca2+. Physicochemical characterization of the QD suspended in varying electrolytes provided insights into the role of solution chemistry on particle size and electrophoretic mobility(surface charge). Measurements of QD size using dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to interpret the QD deposition behavior in different solution chemistries. Lower particle deposition rates observed at high ionic strengths were attributed to aggregation of the QDs resulting in decreased convective-diffusive transport to the silica surface.


Subject(s)
Cadmium Compounds/chemistry , Chemistry Techniques, Analytical/instrumentation , Chemistry Techniques, Analytical/methods , Quantum Dots , Quartz/chemistry , Tellurium/chemistry , Electrolytes/chemistry , Electrophoresis , Kinetics , Light , Microscopy, Electron, Transmission , Scattering, Radiation , Solutions/chemistry , Surface Properties
16.
Rev Med Chil ; 133(7): 813-6, 2005 Jul.
Article in Spanish | MEDLINE | ID: mdl-16341388

ABSTRACT

Patients with hypothyroidism may have a minor increase in their bleeding tendency, causing easy bruising and menorrhagia. There is a positive correlation between factor VIII coagulant activity and thyroxin serum levels. Thus, patients with hypothyroidism have an acquired coagulation defect that is reversible with thyroxin supplementation. We report two sisters, aged 13 and 11 years, who met the criteria for von Willebrand's disease at the age of eight. Both sisters had a primary hypothyroidism due to Hashimoto's thyroiditis, diagnosed three years later. Thyroid hormone replacement normalized von Willebrand factor, factor VIII, and the bleeding diathesis disappeared. Acquired von Willebrand's disease is an unusual manifestation of hypothyroidism. However the possibility of hypothyroidism should be considered in patients presenting with von Willebrand disease.


Subject(s)
Hypothyroidism/complications , von Willebrand Diseases/etiology , von Willebrand Factor/analysis , Adolescent , Child , Female , Hashimoto Disease/complications , Humans , Hypothyroidism/diagnosis , Thyroxine/therapeutic use , von Willebrand Diseases/diagnosis , von Willebrand Diseases/drug therapy
17.
Rev Med Chil ; 133(8): 929-34, 2005 Aug.
Article in Spanish | MEDLINE | ID: mdl-16163431

ABSTRACT

BACKGROUND: The occurrence and timing of menstrual and reproductive events such as menarche, regularity of menses, births, maternal breastfeeding and menopause play an important role in a woman's life. AIM: To study the variability of reproductive live from menarche to menopause in different age groups in Chilean Caucasian and Mapuche aborigine females in a southern location of Chile. SUBJECTS AND METHODS: A questionnaire about reproductive history was answered by 502 women consulting in six general emergency rooms of different public hospitals of the 8th region of Chile, between May and September 2002. RESULTS: The median age at menarche was 12.8 years among adolescents and 13.7 years among older women (p <0.001). Fecundity rate was 5.2, 3.9 and 1.8 among older women, adults and young adults, respectively. Forty seven percent of adolescent had at least one child. The median age for natural menopause was 47 years. Eighty one percent of older women and 65% of adult women had given breastfeeding for more than six months. No statistical differences in reproductive characteristics were observed between Chilean Caucasians and Mapuche aborigines. CONCLUSIONS: Among these women, the age of menarche in younger women is similar to that of women from industrialized countries. Fecundity has been progressively decreasing. Menopause tends to occur sooner than in other geographical regions, probably due to the high number of surgical sterilizations in our population. Adolescent pregnancy still is a problem.


Subject(s)
Menarche/ethnology , Menopause/ethnology , Reproductive History , Adolescent , Adult , Aged , Aged, 80 and over , Chile , Educational Status , Emergency Service, Hospital , Female , Humans , Indians, South American/statistics & numerical data , Middle Aged , Pregnancy , Surveys and Questionnaires
18.
Rev Med Chil ; 132(7): 857-9, 2004 Jul.
Article in Spanish | MEDLINE | ID: mdl-15379334

ABSTRACT

Strumal carcinoid is an unusual form of monodermal ovarian teratoma with thyroid-like follicles mixed with typical carcinoid tumor patterns. We report a 49 years old woman presenting with an acromegaly. At the age of 45, an ovarian strumal carcinoid was excised and at three years of follow up, she complained of finger and feet growth. Laboratory showed an elevated serum IGF-1 and a sella turcica magnetic resonance imaging showed an 8 mm microadenoma. She was subjected to a transphenoidal excision and the pathological study disclosed a solid acidophilic pituitary adenoma. Two months after surgery, there was a significant decrease in serum IGT-I levels.


Subject(s)
Adenoma/pathology , Ovarian Neoplasms/pathology , Pituitary Neoplasms/pathology , Struma Ovarii/pathology , Acromegaly/complications , Adenoma/surgery , Biopsy , Female , Humans , Magnetic Resonance Spectroscopy , Middle Aged , Pituitary Neoplasms/surgery , Sella Turcica/pathology
19.
Rev Med Chil ; 132(4): 485-8, 2004 Apr.
Article in Spanish | MEDLINE | ID: mdl-15382521

ABSTRACT

Poems syndrome (polyneuropathy, organomegaly, endocrine abnormality, M-protein, plasma cell dyscrasia, and skin lesions) is a plasma cell dyscrasia whose pathogenesis is unknown. We report a 60 years old woman that presented a tetraparesis caused by a sensitive motor polyneuropathy. The subsequent work up revealed an IgA type monoclonal gammopathy, hepatomegaly, hyperestrogenism, primary adrenal failure, hypothyroidism, hyperpigmentation and erythematous lesions in the skin and ankle edema. The patient is being treated with prednisone 0.5 mg/kg and levothyroxine 100 microg/day, with partial remission of her symptoms.


Subject(s)
POEMS Syndrome/diagnosis , Anti-Inflammatory Agents/therapeutic use , Female , Humans , Immunoglobulin A/analysis , Middle Aged , POEMS Syndrome/drug therapy , Paraproteinemias/diagnosis , Paraproteinemias/drug therapy , Prednisone/therapeutic use
20.
Rev Med Chil ; 130(2): 167-72, 2002 Feb.
Article in Spanish | MEDLINE | ID: mdl-11974529

ABSTRACT

BACKGROUND: Anti thyroglobulin antibodies are present in 25% of patients treated for a differentiated thyroid cancer, invalidating thyroglobulin determination. Those patients subjected to total thyroidectomy and free of disease, should reduce the production of these antibodies, due to the lack of antigenic stimulus. Therefore, anti thyroglobulin antibodies could be useful to detect early relapses. AIM: To assess the relationship between anti thyroglobulin antibodies and the evolution of the disease in patients treated for thyroid cancer. MATERIAL AND METHODS: Retrospective analysis of 26 patients treated for thyroid cancer with positive anti thyroglobulin antibodies, followed for three years. These were divided in those with or without lymphocytic thyroiditis (19 and 7 respectively). RESULTS: At the first year of follow up, anti thyroglobulin antibody concentration was 401 +/- 94.9 UI/ml (x +/- sem) in patients with thyroiditis and 38.9 +/- 8.9 UI/ml in those without thyroiditis (p < 0.005). During the three years of follow up, no differences in anti thyroglobulin antibodies were observed between patients with or without tumor relapse. CONCLUSIONS: Concentration of anti thyroglobulin antibodies was higher in patients with thyroiditis and did not differentiate patients with tumor relapse.


Subject(s)
Autoantibodies/blood , Biomarkers, Tumor/blood , Neoplasm Recurrence, Local/blood , Thyroglobulin/immunology , Thyroid Neoplasms/blood , Adult , Case-Control Studies , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/immunology , Neoplasm, Residual , Retrospective Studies , Thyroid Neoplasms/immunology , Thyroidectomy
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