Light-Emitting Carbon Nanodots. Synthesis and Development of Novel Applications

Fluorescent Carbon Nanodots, “CNDs”, are a new type of carbon nanomaterials that have emerged recently, and have attracted intense interest as a potential alternative to classical semiconductor Quantum Dots. CNDs possess high biocompatibility, easy and low-cost synthesis, good colloidal stability and appealing optical properties. CNDs also hold a huge potential as novel and versatile luminescent nanomaterials for a wide range of applications such as bioimaging, drug delivery, chemical sensing, photocatalysis, and as sensitizers for photovoltaic solar cells. This Thesis deals first with the development of different strategies to produce non-toxic, inexpensive carbon nanoparticles with good and tunable emission properties spanning an activation window from the ultraviolet (UV) to the near infrared (NIR). On the other hand, the prepared CNDs have been applied in different fields: theranostics, sensing and catalysis. The aims of this PhD Thesis have been: (i) to synthesize fluorescent CNDs from abundant and inexpensive precursors by improving state-of-the-art methods and by the development of novel synthesis strategies; (ii) to understand and optimize the structural and optical properties of the as-synthesized CNDs; and (iii) to use the CNDs as fluorescent Biomarkers and Photodynamic Therapy agents, as luminescent Nanosensors and as photosensitisers in Catalytic applications. After an introductory section, the thesis is structured in three blocks:I. Synthesis of CNDs, evaluation of different synthesis methods: hydrothermal treatment, pyrolysis of organic compounds and flash-thermal pyrolysis of carbon precursors contained in the channels of inorganic mesoporous templates.II. Characterization of CNDs: evaluation of their structural and optical properties with special attention to the role of functional groups generated in the CNDs and the chemical composition of the different precursors to induce an enhanced response in the visible-NIR range.III. Applications of CNDs: evaluation of their role as biomarkers, theranostic agents, and ion sensors, especially in the NIR range. Evaluation as sensitizers/light harvesters able to expand the response of other photocatalysts or to mimic the enzymatic activity of peroxidase.Finally, a conclusion section contains the main conclusions reached in this work.<br /

Seroprevalence of Leishmania infection among asymptomatic renal transplant recipients from southern Spain

Support: E.K. Elmahallawy has a PhD scholarship (number 736) from Erasmus Mundus Scholarship Program (ELEMENT Action 1 First call).Background: The aim of this article is to assess the seroprevalence of Leishmania infection among asymptomatic renal transplant recipients in a population in the south of Spain. Methods: Serum samples were screened for immunoglobulin-G antibodies against Leishmania with an indirect fluorescent antibody test. Results: Of 625 examined serum samples, 30 (4.8%) samples were positive for Leishmania antibodies. Thirteen samples showed titers of 1:80, 15 samples showed titers of 1:160, and 2 samples showed titers of 1:320. None of the patients with positive serology to Leishmania showed signs or symptoms compatible with leishmaniasis. Conclusion: The prevalence of Leishmania infection found among asymptomatic renal transplant patients reinforces the need for attention in evaluation of these patients in endemic areas.Erasmus Mundus Scholarship Program (ELEMENT Action 1 First call

A multicentre study investigating parameters which influence direct bacterial identification from urine

Rapid diagnosis is one of the best ways to improve patient management and prognosis as well as to combat the development of bacterial resistance. The aim of this study was to study parameters that impact the achievement of reliable identification using a combination of flow cytometry and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF-MS).The study was carried out in nine hospitals in Spain and included 1,050 urine samples with bacterial counts of 5x106 bacteria/ml. MALDI-ToF-MS-based identification was performed according to a previously described protocol. Valid identification by direct MALDI-ToF-MS was obtained in 72.8% of samples, in 80.3% of samples found to be positive by culture, 32.2% of contaminated samples, and 19.7% of negative samples. Among the positives samples with a valid identification the concordance at the species level was 97.2%. The parameters related to success of direct identification were: high bacterial count, the presence of Escherichia coli as a pathogen and rod-bacteria morphology provided by flow cytometry. The parameters related to failure were a high epithelial cell (EC) count, a high white blood cell (WBC) count and urine samples obtained from in-patients. In summary, this multicentre study confirms previously published data on the usefulness and accuracy of direct MALDI-ToF-MS-based identification of bacteria from urine samples. It seems important to evaluate not only the bacterial count, but also other parameters, such as EC and WBC counts, bacterial species and morphology, and the health care setting, to decide whether the sample is suitable for direct identification

Tuberculous prosthetic knee joint infection: a case report and literature review

Introducción. La infección protésica tardía se presenta a partir del segundo mes tras la cirugía en el contexto de una di seminación hematógena desde otro foco. La infección protésica por micobacterias es una complicación rara cuyo manejo clínico no está estandarizado. Caso. Paciente de 77 años sin antecedentes personales de interés salvo diabetes y un recambio protésico de rodilla derecha por gonartrosis tres años antes. Acude a urgencias del hospital por un cuadro de unos 6 meses de evolución de intenso dolor en rodilla derecha de tipo mecánico con signos inflamatorios pero sin fiebre asociada. A los 5 días de su reingreso y presentando empeoramiento clínico se informa del crecimiento de Mycobac terium tuberculosis en la primera muestra de aspirado de rodilla y se instaura tratamiento antituberculoso durante 9 meses. Las imágenes de resonancia magnética nuclear confirmaron también el diagnóstico de espondilitis tuberculosa en el contexto clínico de la paciente. Tras la intervención quirúrgica se seguía aislando en el cultivo de las muestras intraoperatorias M. tuberculosis y por ello la paciente recibió de nuevo otra tanda de 9 meses con antituberculosos. La evolución al año de seguimiento fue acep table, aunque unos meses después la paciente falleció por causas cardiovasculares. En la revisión bibliográfica se encontraron 15 publicaciones con un total de 17 casos clínicos en los últimos 25 años de infección protésica por M. tuberculosis. Conclusión. La artritis protésica tuberculosa, aunque es una presentación infrecuente, debe tenerse presente, especialmente en aquellos pacientes con condiciones predisponentes y con an tecedentes de infección tuberculosa.Objective: Prosthetic late infection occurs in the second month after surgery in the context of haematogenous spread from another source. Prosthetic mycobacterial infection is a rare complication whose clinical management is not standardized. Case: Patient of 77 years with no personal history except for diabetes and a prosthetic replacement of right knee with osteoarthritis three years ago. Patient goes to hospital emergency box for 6 months pain in the right knee with mechanical inflammatory signs but no fever associated. After their return within 5 days and clinical worsening is reporting growth of Mycobacterium tuberculosis in knee aspirate and antitubercular treatment is established for 9 months. Nuclear magnetic resonance imaging studies also confirmed the diagnosis of tuberculosis spondylitis in the clinical context of the patients. After surgery, M. tuberculosis was again isolated from intraoperative samples and therefore the patient received another batch of treatment for 9 months. After a year of monitoring, the development was acceptable but few months later, the patient died for cardiovascular causes. In the literature review, 15 publications with a total of 17 clinical cases of prosthetic infection by M. tuberculosis were found from 1980 to 2014. Conclusions: Prosthetic tuberculous arthritis, although it is a rare presentation, it should be noted, especially in patients with predisposing conditions with a history of tuberculosis infection

Psychological distress in health sciences college students and its relationship with academic engagement

Objective: To determine the prevalence of psychological distress and its relationship with academic engagement (absorption, dedication and vigor), sex and degree among students from four public universities. Method: A non-experimental,comparative correlational, quantitative investigation without intervention. Study population: 1840 nursing and physical therapy students. The data collection tool used was a questionnaire. Results: A 32.2% prevalence of psychological distress was found in the subjects; a correlation between vigor and psychological distress was found for all of the subjects and also for women. High absorption and dedication scores and low psychological distress scores predicted higher vigor scores. Conclusion: The risk of psychological distress is high, especially for women. Women seem to have a higher level of psychological distress than men. Vigor, energy and mental resilience positively influence psychological distress and can be a vehicle for better results during the learning and studying process

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Colonización materna por streptococcus agalactiae: comparación de métodos diagnósticos y relación con datos clínicos y epidemiológicos

Tesis Univ. Granada. Departamento de Microbiologí

Specimen storage in transport medium and detection of group B streptococci by culture

Recovery of group B streptococci (GBS) was assessed in 1,204 vaginorectal swabs stored in Amies transport medium at 4 or 21°C for 1 to 4 days either by direct inoculation onto Granada agar (GA) or by culture in blood agar (BA) and GA after a selective broth enrichment (SBE) step. Following storage at 4°C, GBS detection in GA was not affected after 72 h by either direct inoculation or SBE; however, GBS were not detected after SBE in the BA subculture in some samples after 48 h of storage and in GA after 96 h. After storage at 21°C, loss of GBS-positive results was significant after 48 h by direct inoculation in GA and after 96 h by SBE and BA subculture; some GBS-positive samples were not detected after 24 h of storage followed by SBE and BA subculture or after 48 h of storage followed by SBE and GA subculture. Storage of swabs in transport medium, even at 4°C, produced after 24 h an underestimation of the intensity of GBS colonization in most specimens. These data indicate that viability of GBS is not fully preserved by storage of vaginorectal swabs in Amies transport medium, mainly if they are not stored under refrigerationYe

Prevalence among males from the general population of agents responsible of not ulcerative genital tract infections, assisted in specialized care

Objetivo: Las infecciones de los órganos genitales en el hombre representan un grave problema por su frecuencia, morbilidad e implicación en casos de infertilidad masculina. En este trabajo se investiga, en varones asistidos en atención especializada, la presencia de los agentes productores de infecciones no ulcerativas del aparato genital. Material y métodos: Se estudiaron de forma descriptiva y retrospectiva los resultados microbiológicos de 3.066 muestras de pacientes varones, con diagnóstico de sospecha de episodio de infección del tracto genital, recibidas entre el 1 de enero de 2016 y 31 de diciembre de 2017. La detección de los microorganismos en la muestra se realizó mediante técnicas de cultivo en medios artificiales y de PCR (BD-MAX). Resultados: 451 (14,71%) muestras fueron positivas, siendo, mediante cultivo, los patógenos más frecuentes enterobacterias (18,40%), Enterococcus (13,75%), Haemophilus (8,65%), Neissseria gonorrhoeae (8,43%), Ureaplasma (5,10%) y Candida (3,77%). Mediante PCR se detectaron N. gonorrhoeae (28,37%), Chlamydia trachomatis (26,95%), Ureaplasma urealyticum (17,73%), Mycoplasma hominis y Ureaplasma parvum (10,64%), y Mycoplasma genitalium (7,10%). Se encontró mayor edad en el grupo de pacientes con presencia de enterobacterias, Candida o Enterococcus, y menor para los que tuvieron N. gonorrhoeae. Conclusiones: N. gonorrhoeae y C. trachomatis siguen siendo los patógenos más frecuentes en la infección genital masculina, aunque otros microorganismos cultivables tienen un importante papel. Los ponen de manifiesto la importancia del uso sistemático tanto del cultivo tradicional como de las nuevas técnicas de PCR para la detección de patógenos.Objective: Male genital infections are a major problem due to their high frequency and morbidity and their role in cases of male infertility. We studied the presence, in males assisted in specialized care, of non-ulcerative genital tract infections-producing agents. Methods: We studied descriptively and retrospective microbiological results of 3,066 samples of male patients, with diagnosis of genital tract infection episode, received between January 1, 2016 and December 31, 2017. Detection of microorganisms in the sample was performed using techniques of artificial culture and PCR (BD-MAX). Results: Positive results were obtained in 451 samples (14.71%). By culture, the most frequent pathogens were Enterobacterales (18.40%), Enterococcus (13.75%), Haemophilus (8.65%), Neisseria gonorrhoeae (8.43%), Ureaplasma (5.10%), and Candida (3.77%). By polymerase chain reaction (PCR), the most frequent were N. gonorrhoeae (28.37%), Chlamydia trachomatis (26.95%), Ureaplasma urealyticum (17.73%), Mycoplasma hominis/Ureaplasma parvum (10.64%), and Mycoplasma genitalium (7.10%). The age was older in patients infected with Enterobacterales, Candida, or Enterococcus and younger in those infected with N. gonorrhoeae. Conclusions: N. gonorrhoeae and C. trachomatis are still more common in male genital infection pathogens, although other culturable microorganisms have an important role. These findings demonstrate the importance of systematically applying both conventional culture and PCR techniques for pathogen detection

Preliminary evaluation of a new kit for differentiation of Mycobacterium tuberculosis complex species using Speed-Oligo MTBC.

We present the first evaluation of a novel molecular assay, the Speed-Oligo Mycobacterium tuberculosis complex (SO-MTBC), which is based on PCR combined with a dipstick for the differentiation of M. tuberculosis complex (MTBC) members. The results of this assay were compared with findings obtained using the Genotype MTBC assay. In this study, 189 strains of MTBC isolates from 2011 to 2014 were evaluated to determine the MTBC species. Most (174, 92 %) of the strains were identified as M. tuberculosissensu stricto, 7 (3.7 %) as Mycobacteriumbovis, 5 (2.6 %) as M. bovis bacillus Calmette-Guérin, 2 (1.1 %) as Mycobacteriumafricanum and 1 (0.5 %) as Mycobacteriumcaprae; no strains belonged to Mycobacteriummicroti and Mycobacteriumcanettii subsp. The concordance κ coefficient obtained was 0.96 with the results of the Genotype MTBC assay. SO-MTBC may represent a fast and easy-to-use alternative for differentiating among MTBC subspecies in laboratories with standard equipment