Green Synthesis for Carbon Quantum Dots via Opuntia ficus-indica and Agave maximiliana: Surface-Enhanced Raman Scattering Sensing Applications.

In this study, we present an alternative method for synthesizing carbon quantum dots (CQDs) using a green synthesis approach via extracts from Agave maximiliana and Opuntia ficus-indica(Ofi). The extracts from both plants were used as the carbon source for the CQDs. The synthesis method employs mesoporous zeolite 4A as a refractory for the thermal treatment of the samples. Transmission electron microscopy analysis established that the size of the CQDs shows a narrow distribution centered around 2 nm with a maximum size of less than 3 nm for both cases. The CQDs exhibit absorption bands associated with π-π* transitions located around 220 nm. In both cases, photoluminescence (PL) phenomenon was detected by irradiating the samples with a UV wavelength and detecting emissions close to the blue wavelength. Additionally, both kinds of CQDs were tested as surface-enhanced Raman scattering (SERS) substrates against methylene blue (MB), indicating an enhancement associated with ring deformation and stretching modes of the v(C-C) and v(C-N) bonds located around 1400 and 1620 cm-1, respectively. Complementarily, in the framework of density functional theory, H2nC2(2m+1) structures (with n = 3-5 and m = 1-3) were used as a theoretical representation of CQDs in interaction with the MB molecule. It is used for developing the analysis of charge transfer effects between both systems and for specifying elements that generate the SERS effect associated with the chemical enhancement mechanism.

Silver nanoparticles are lethal to the ciliate model Tetrahymena and safe to the pike silverside Chirostoma estor.

Ciliate ectoparasites are one of the most important groups of pathogens in fish culture, and the traditional treatments are sometimes harmful to the fish and the environment. Thus, the search for novel compounds that are effective at low concentrations and safe for fish are necessary to optimise treatments in aquaculture. The antiprotozoal capacity of silver nanoparticles (AgNPs) against the ciliate Tetrahymena has been documented; however, their toxicity may vary with the synthesis methodology and nanoparticle size. The objectives of this study were a) to evaluate the acute toxicity in vitro of two AgNPs (Argovit™ and UTSA) on Tetrahymena sp., a biological model for ciliated ectoparasites of fish and b) to test the safety of lethal and higher doses of UTSA AgNPs for ciliates on the fish C. estor. Light microscopy and scanning electron microscopy (SEM) were used to determine whether AgNPs affected the structure of the cell surface of Tetrahymena. The mortality, histopathological alterations and metagenomics of the fish were used to determine the major effects of UTSA AgNPs. In Tetrahymena, the median lethal concentration (LC50) for Argovit™ was 2501 ± 1717 ng/L at 15 min and 796 ± 510 ng/L at 60 min, while the LC50 for UTSA AgNPs was 4 ± 2 and 1 ± 0.6 ng/L at 15 min and 60 min, respectively. A concentration of 3300 ng/L Argovit™ and 10.6 ng/L UTSA AgNPs for 15 and 60 min, respectively, was 100% effective against Tetrahymena. After 60 min of exposure to 0.25 and 0.50 ng/L UTSA AgNPs, the number of cilia significantly reduced, there were small holes on the cell surface, and the cellular membrane was ruptured. In fish exposed to lethal (10.6 ng/L) and higher (31.8 and 95.4 ng/L) doses of UTSA, the AgNPs did not affect fish survival after 96 h, and there were no signs of histopathological damage or gut microbial changes. This study is the first report on microscopic and ultrastructural changes in Tetrahymena after exposure to significantly low concentrations of UTSA AgNPs with antiprotozoal efficacy without evidence of harmful effects on fish. These results provide the basis for further studies of both pet aquarium and commercial fish that may validate these findings at a larger experimental scale, taking into account AgNPs bioaccumulation, safety for human consumption and environmental impact.

Comparative study of the accuracy of different technique for the laboratory diagnosis of schistosomiasis mansoni in areas of low endemicity in Barra Mansa City, Rio de Janeiro State, Brazil

Schistosomiasis constitutes a major public health problem, with an estimated 200 million people infected worldwide. Many areas of Brazil show low endemicity of schistosomiasis, and the current standard parasitological techniques are not sufficiently sensitive to detect the low-level helminth infections common in areas of low endemicity (ALEs). This study compared the Kato-Katz (KK); Hoffman, Pons, and Janer (HH); enzyme-linked immunosorbent assay- (ELISA-) IgG and ELISA-IgM; indirect immunofluorescence technique (IFT-IgM); and qPCR techniques for schistosomiasis detection in serum and fecal samples, using the circumoval precipitin test (COPT) as reference. An epidemiological survey was conducted in a randomized sample of residents from five neighborhoods of Barra Mansa, RJ, with 610 fecal and 612 serum samples. ELISA-IgM (21.4%) showed the highest positivity and HH and KK techniques were the least sensitive (0.8%). All techniques except qPCR-serum showed high accuracy (82­95.5%), differed significantly from COPT in positivity , and showed poor agreement with COPT. Medium agreement was seen with ELISA-IgG (Kappa = 0.377) and IFA (Kappa = 0.347). Parasitological techniques showed much lower positivity rates than those by other techniques. We suggest the possibility of using a combination of laboratory tools for the diagnosis of schistosomiasis in ALEs.

Evaluation of the sensitivity of IgG and IgM ELISA in detecting Schistosoma mansoni infections in a low endemicity setting.

Schistosomiasis is a major public health concern, with 200 million people infected worldwide. In Brazil, this disease has been reported in 19 states, and its prevalence in the city of Barra Mansa in Rio de Janeiro State is 1 %. The parasitological diagnostic methods currently available in these areas lack sensitivity; however, enzyme-linked immunosorbent assays (ELISAs) have been employed successfully for the diagnosis of schistosomiasis by using antibodies against antigens of Schistosoma mansoni adult worms and eggs, and for the detection of circulating antigens. The objective of this study was to determine systematically the prevalence of S. mansoni infection in the peripheral areas of Barra Mansa. A cross-sectional study was conducted from April to December 2011 by using probabilistic sampling that collected 610 fecal samples and 612 serum samples. ELISA-IgG with total extracts and ELISA-IgM with trichloroacetic acid-soluble fractions were employed to detect antibodies against S. mansoni and were compared with the Kato-Katz and Hoffman parasitological techniques. Among the individuals studied, anti-S. mansoni antibodies were detected in 11.16 % (n = 71) by ELISA-IgG and in 20.75 % (n = 132) by ELISA-IgM, while the parasitological techniques showed 0.82 % (n = 5) positivity. The agreement between the two ELISA tests was 85.38 % (n = 543), and 8.65 % (n = 55) of the serum samples showed positive results in both tests. The higher positivity of the ELISA-IgM test corroborates the results of previous reports and indicates that the test may be a useful tool in epidemiological studies, particularly in areas of low endemicity for S. mansoni.

The autonomic condition of children with congenital hypothyroidism as indicated by the analysis of heart rate variability.

Early treatment by thyroid hormone in congenital hypothyroidism (CH) prevents for mental retardation, but the autonomic condition could well remain impaired. The aim of this study was to get insights about the cardiovascular regulation of CH children by analysing their heart rate variability (HRV) data. RR-interval data of 34 early treated CH children, 24 to 48 months of age, were collected at rest in a clinical environment. In all these cases, CH resulted from an abnormal development of thyroid gland. Data from 29 age matched-controls were also collected in a scholar environment. Short time series were then analysed in time and frequency domains. Detrended fluctuation analysis (DFA) was also applied to obtain the scaling exponent α(1). We found that the HRV obtained from children with CH is diminished as suggested by statistical differences (p<0.05) in the following parameters: RMSDD, pNN20, total power, LF and HF. However, no significant differences were found in the LF/HF ratio, the central frequencies of the LF and HF bands, as well as in α(1). Given that the significant differences were basically reflected in static parameters rather than in the frequency distribution or scale-invariant behaviour of the studied data, we consider that the analysis points toward the effect of treatment on rising heart rate by the thyroid hormone, and not necessarily toward any residual autonomic dysfunction, as the dominant underlying cause of the diminished HRV exhibited by CH children.

Immunohistochemical localization of low density lipoprotein receptor-related protein 1 and alpha(2)-Macroglobulin in retinal and choroidal tissue of proliferative retinopathies.

The immunolocalization of the low density lipoprotein receptor-related protein 1 (LRP1) and its ligand alpha 2-Macroglobulin (alpha(2)M) was examined in tissues from human donor eyes of normal, diabetic and sickle cell disease subjects. Streptavidin alkaline phosphatase immunohistochemistry was performed with a mouse anti-human LRP1 and rabbit anti-human alpha(2)M antibodies. Retinal and choroidal blood vessels were labeled with mouse anti-human CD34 antibody in adjacent tissue sections. Mean scores for immunostaining from the pathological and control eyes were statistically compared. LRP1 immunoreactivity was very weak to negative in the neural retina of normal subjects except in scattered astrocytes. LRP1 expression in diabetic eyes was detected in the internal limiting membrane (ILM), astrocytes, inner photoreceptor matrix, choriocapillaris and choroidal stroma. The ligand alpha(2)M, however, was limited mainly to blood vessel walls, some areas of the inner nuclear layer (INL), photoreceptors, RPE-Bruch's membrane-choriocapillaris complex, intercapillary septa, and choroidal stroma. In sickle cell eyes, avascular and vascular retina as well as choroidal neovascularization (CNV) were analyzed. In avascular areas, LRP1 immunoreactivity was in innermost retina (presumably ILM, astrocytes, and Muller cells) and INL as well as RPE-Bruch's membrane-choriocapillaris complex and choroidal stroma. alpha(2)M was very weak in avascular peripheral retina compared to vascularized areas and limited to stroma in choroid. In contrast, in areas with CNV, LRP1 immunoreactivity was significantly decreased in overlying retina and in RPE-Bruch's membrane and choroidal stroma compared to the controls, while alpha(2)M was elevated in RPE-Bruch's membrane near CNV compared to normal areas in sickle cell choroid. The mean scores revealed that LRP1 and alpha(2)M in neural retina were significantly elevated in astrocytes and ILM in diabetic eyes (p < or = 0.05), whereas in sickle cell eyes scores were elevated in ILM and INL (p < or = 0.05). In addition, alpha(2)M immunoreactivity was in photoreceptors in both ischemic retinopathies. In choroid, the patterns of LRP1 and alpha(2)M expression were different and not coincident. This is the first demonstration of the presence of LRP1 and alpha(2)M in human proliferative retinopathies. Elevated LRP1 expression in sickle cell neural retina and diabetic inner retina and choroid suggests that LRP1 plays an important role in ischemic neovascular diseases.

Repeatability of heart rate variability in congenital hypothyroidism as analysed by detrended fluctuation analysis.

The analysis of heart rate fluctuations, or heart rate variability (HRV), may be applied to explore children's neurodevelopment. However, previous studies have reported poor reliability (repeatability) of HRV measures in children at rest and during light exercise. Whether the reliability can be improved by controlling variables such as physical activity, breathing rate and tidal volume, or by selecting non-conventional techniques for analysing the data remains as an open question. We evaluated the short-term repeatability of RR-interval data from medicated children with congenital hypothyroidism (CH). The alpha(1) exponents, obtained by detrended fluctuation analysis (DFA), from the data of 21 children collected at two different sessions were compared. Elapsed days between sessions were 59 +/- 33, and data were obtained during 10 min, trying to restrict the children's activity while being seated. We found statistical agreement between the means of alpha(1) exponents for each session (p = 0.94) and no bias with a low-coefficient variation (9.1%); an intraclass correlation coefficient ri = 0.48 ([0.14 0.72], 95% confidence interval) was also estimated. These findings, which were compared with results obtained by conventional time and frequency techniques, indicate the existence of agreement between the alpha(1) exponents obtained at each session, thereby providing support concerning the repeatability of HRV data as analysed by DFA in children with congenital hypothyroidism. Of particular interest was also the agreement found by using the central frequency of the high-frequency band and the parameter pNN20, both showing better or similar ri than alpha(1) (0.77 [0.57 0.89] and 0.51 [0.17 0.74], respectively), yet considerably better repeatability than other conventional time and frequency parameters.

[Type A behaviour and life events as risk factors for cerebral infarct]. / Patrón de conducta tipo A y acontecimientos vitales como riesgo para el infarto cerebral.

INTRODUCTION: The role of psychosocial factors in cerebral infarct has been little studied and is therefore still undefined. OBJECTIVE and methods. To evaluate the effect of a pattern of behaviour which predisposes to stress, and of life events, on the occurrence of cerebral infarct, we studied a group and control involving 88 patients with cerebral infarcts diagnosed clinically and on imaging studies, and a control group of 99 persons paired for age and sex who lived in our health district. To evaluate the behaviour pattern we used Jenkins abbreviated questionnaire and for life events the Holmes and Rahe questionnaire. RESULTS: The type A behaviour pattern had a highly statistically significant association with cerebral infarct, which was not associated with the effects of other variables. This relation was the greater the lower the age of the person. It was not seen after the age of 75 years. The behaviour pattern was not related to arterial hypertension or with the aetiopathological mechanisms of the patients. In relation to the life events questionnaire, the number of events was significantly associated in the group of patients, but not with the total score of the questionnaire. However, the latter was significantly related to hypertensive patients and persons with a type A behaviour pattern. The commonest life events in both groups were related to the death or health problems of family members, the previous illnesses of the person and to financial and work problems. CONCLUSION: The type A behaviour pattern is individually associated with cerebral infarct, whilst stressful life events were involved in the cerebral infarcts of hypertensive and type A behaviour patients.

Differential binding properties of human pregnancy zone protein- and alpha2-macroglobulin-proteinase complexes to low-density lipoprotein receptor-related protein.

Human pregnancy zone protein (PZP) is a major pregnancy-associated plasma protein strongly related to alpha2-macroglobulin (alpha2-M). Both alpha-macroglobulins (alpha-Ms) covalently bind proteinases, which is accompanied by the exposure of carboxy terminal receptor recognition domains important for the rapid clearance from the circulation and tissues. It is accepted that the molecule responsible for the clearance of alpha2-M- and PZP-proteinase complexes is the low-density lipoprotein receptor-related protein (LRP). Although both alpha-M-proteinase complexes bind to the same receptor, differences in the binding properties have been reported. In addition, although it is known that the binding of alpha2-M-proteinase complexes to LRP can be blocked by Ni2+, the effect on PZP-proteinase has never been examined. In order to investigate differences in the binding properties of both alpha-Ms to the receptor, we purified LRP from human placenta by affinity chromatography and then analyzed the specificity and affinity of binding of alpha2-M- and PZP-proteinase complexes to the receptor by enzyme immunoassay. Our results clearly established that although both alpha-M-proteinase complexes specifically bind to LRP, PZP-chymotrypsin complexes bind to the receptor with lesser apparent affinity (Kd approximately equal 320 nM) than alpha2-M-chymotrypsin complexes (Kd approximately equal 40 nM). We also demonstrated that Ni2+ blocks the binding of alpha2-M-chymotrypsin complexes, but not PZP-chymotrypsin complexes, to LRP. These data suggest that the binding to LRP involves conformational differences between both alpha-Ms in a region immediately upstream of the carboxy terminal receptor recognition domain. The possibility that PZP-proteinase complexes interact with other receptors not available to alpha2-M-proteinase complexes could be considered.

[The quality of life of patients with strokes: from the point of view of factors which may affect it]. / La calidad de vida del paciente con accidente cerebrovascular: una visión desde sus posibles factores determinantes.

OBJECTIVE: To evaluate the effect of clinical and psychosocial factors on the quality of life of patients with stroke. PATIENTS AND METHODS: A non-experimental transverse study was done on 39 patients with strokes seen in the cerebrovascular diseases clinic of the Institute de Neurología y Neurocirugía in La Havana (Cuba). We recorded data on clinical variables (age, sex, race, previous illnesses, type of stroke, vascular territory, classification of prognosis, etiopathogenesis and function on the Rankin scale) and on psychosocial variables (pattern of behavior, anxiety as a feature and state, depression, manner of coping and social support received). Correlations were established with the dependent variable Quality of life, evaluated on the Nottingham Health Profile. RESULTS: Of the clinical variables there was no correlation with age, female sex was related to greater isolation and the presence of diabetes mellitus with less energy. Greater isolation was seen to be correlated with increased score on the Rankin scale, but this association was not statistically significant. Similarly the clinical characteristic of anxiety was related to greater difficulty in sleeping, as also occurred in depression. The latter was also associated with less energy and greater social isolation. The characteristics of self-control, acceptance of responsibility and positive reevaluation had a positive relation with energy and physical mobility. The greater the social support, especially in the area of health, the better the quality of life in the realms of pain, sleep and social isolation. CONCLUSION: The psychosocial aspects had more influence on the quality of life of these patients than the clinical factors did.

Pregnancy zone protein-tissue-type plasminogen activator complexes bind to low-density lipoprotein receptor-related protein (LRP).

Tissue-type plasminogen activator (t-PA), is a serine proteinase that catalyzes the initial and rate-limiting step in the fibrinolytic cascade. Its plasma activity is determined by the rate of release into the bloodstream, the rate of inhibition by plasminogen-activator inhibitor type 1 (PAI-1) and the rate of hepatic clearance. Two receptor systems contribute to the clearance of t-PA: the mannose receptor and the low-density lipoprotein receptor-related protein (LRP) that removes free t-PA as well as t-PA-PAI-1 complexes from the blood. During pregnancy a significant rise in the plasma levels of pregnancy zone protein (PZP) is observed, while alpha(2)-macroglobulin (alpha(2)-M) remains constant. Interestingly, the fibrinolytic activity is decreased during this period. In this context, we have recently demonstrated the in vitro formation of PZP-t-PA complexes. Here, we purified LRP from human placenta by affinity chromatography and then analyzed the binding specificity and affinity of PZP-proteinase complexes to the receptor by enzyme immunoassay (EIA). Our results clearly established that the binding of PZP-t-PA complexes to LRP was specific, saturable, and with K(d) = 337 +/- 31 nM. Moreover, by using the same EIA, we further observed that this binding was inhibited by receptor-associated protein. These data suggest that PZP, by binding to t-PA and promoting its clearance via LRP, might contribute in vivo to the downregulation of the fibrinolytic activity during pregnancy.

[Women's attitudes to menopause and predictive variables]. / Actitudes de las mujeres ante la menopausia y variables predictoras.

OBJECTIVE: To find what women's attitudes to the menopause are and how these attitudes relate to certain personal variables. DESIGN: Multi-centre, transversal study. SETTING: 5 clinics at three urban and teaching health centres in Granada. PARTICIPANTS: A systematic randomised sample of women = 18 who attended on demand in June 1998: alpha = 0.05, accuracy = 3 and standard deviation from the scale of attitudes (SA), found through prior sampling, was 15.4. N = 101 women. INTERVENTIONS: Questionnaire through interview after consultation. MEASUREMENTS AND MAIN RESULTS: Dependent variable: scale of attitudes to the menopause with 29 items. INDEPENDENT VARIABLES: age, marital status, educational qualifications, work situation, cultural group, religion, continuity with her doctor, utilisation, menopausal status, perception of autonomy, opinion of the menopause, feelings towards the menopause, perceived health. ANALYSIS: homogeneity and validity of SA. Descriptive, univariate analysis of SA with independent variables. Multiple linear regression: we found 7 factors that explained 66.5% of variance. Age 43.4 +/- 17.5. 50.5% had not reached the menopause; 10.9% were in the peri-menopause; and 37.6% in the menopause. 70.3% had feelings of relief or were neutral; 54.5% had a positive view; and 21.8% expressed no opinion. The variables explaining attitudes were feeling, continuity, opinion, utility, autonomy and perceived health. CONCLUSIONS: Women had positive or neutral feelings and opinions about the menopause. Their attitudes to it were related to these variables and not to other social or demographic variables or to their menopausal status.

Stabilization of homogeneous preparations of pregnancy zone protein lyophilized in the presence of saccharose. Structural and functional studies.

Human pregnancy zone protein (PZP) is a macromolecule of 360 kDa, organized as a disulfide-linked homodimer of two 180 kDa subunits, with an amino acid sequence and structure remarkably similar to that of human alpha2-Macroglobulin. Homogeneous PZP samples undergo fast aging forming oligomeric aggregates of high molecular weight. This aged PZP loses its ability to interact with proteinases and consequently, non-recognition of receptors occurs. In the present work, we assessed the effect of saccharose on the stability of native PZP on lyophilized samples kept for a long period of time. Herein, we demonstrate that the addition of 0.25 M saccharose to homogeneous PZP and further lyophilization is enough to prevent aging and preserve functional activity for more than 1 year. Hence, high quality samples, in terms of purity, stability and functional activity will allow to develop biochemical studies in order to know the PZP role in physiological and pathological states where the protein levels are increased, such as pregnancy and tumoral disorders.

[Clinical and cytogenetic variability in 12 Mexican families with Fanconi's anemia and its relationship with the complement gruoup to which they belong]. / Variabilidad clínica y citogenética en doce familias mexicanas con anemia de fanconi y su relación con el grupo de complementación al que pertenecen.

OBJECTIVE: To describe the clinical and cytogenetic features of Mexican patients with Fanconi anemia, while assessing whether the phenotypic variation is related to the complementation group. MATERIAL AND METHODS: The cytogenetic diagnosis was done using mitomycin C and diepoxybutane on peripheral blood lymphocytes. The severity of the anemia and each patient's clinical manifestations were classified using Alter's and Auerbach's clinical scores, respectively. Lymphoblastoid cell lines were established for eight patients and complementation group determined following cell fusion procedures in four propositi. RESULTS: Twenty-five Fanconi anemia patients from 12 families were studied. All patients had high, spontaneous and induced chromosomal breakages, no relationship was found between the clinical severity of the disease and the anemic state. Twelve patients were considered severely ill, while the remaining 13 were considered mild cases. Three individuals were anemia-free, while in 13 the anemia was mild, moderate in 7, and severe in 1. The mortality rate was 32% (8/25). No relationship was found between the clinical picture and degree of the anemia or mortality rate. Eleven patients were assigned to complementation group A with mild clinical findings and anemia. Their cytogenetic results showed variability. One patient assigned to group C was considered as a severe case with transfusion-dependent anemia and high sensitivity to mutagens. Thirteen patients were not classified. A lymphoblastoid cell line resistant to mitomycin C was obtained suggesting somatic mosaicism. CONCLUSIONS: The establishment of a complementation group does not necessarily explain variability. There are other important factors, such as somatic mosaicism, that modify the cellular phenotype.