Socio-environmental assessment of a landfill using a mixed study design: A case study from México.

Municipal solid waste management is a challenge for local authorities since mismanagement leads to environmental damage and social discontent. The objective of this study was to assess in an integrated manner the socio-environmental situation of a municipal landfill from México, using a design of mixed methods, which considered a quantitative evaluation of physicochemical and microbiological variables measured in leachates, surface and groundwater samples, soil and air, and a qualitative evaluation by in-depth interviews with the near-by inhabitants about their perception of the impacts of the landfill. The results show that leachates polluted the soil and surface water in a radius of up to 500 m from the landfill, but did not reach the groundwater, while the mean concentrations of PM10, Mn, and Ni measured in air samples at the landfill of 146 µg m-3, 0.12 µg m-3, 0.10 µg m-3, respectively, in the dry season and of Mn and Ni of 0.13 µg m-3 and 0.11 µg m-3, respectively, in the rainy season, surpassed permissible limits. From the residents perspective the landfill pollutes soil, water and air and it contributes to vehicle traffic and noise, promotes harmful fauna and disturbs the esthetic view. Air measurements coincide with social perception and in general, the applied mixed study design helped to assess in an integrated manner the socio-environmental concerns and to give advice to improve the current management of the landfill.

Human sperm handling in intracytoplasmic sperm injection processes: In vitro studies on mouse oocyte activation, embryo development competence and sperm oxidation-reduction potential.

Polyvinylpyrrolidone (PVP) and hyaluronic acid (HA) are routinely used in handling spermatozoa for intracytoplasmic sperm injection (ICSI). As there are still concerns about possible adverse effects on the embryo, this study investigated sperm handling in a mouse ICSI model to (i) evaluate oocyte activation after injection of spermatozoa selected for rotational or linear motion in PVP; (ii) assess the effect of sperm selection in PVP, HA and medium on oocyte activation; (iii) examine the effects of PVP and HA on parthenogenetic oocyte activation and embryo development; and (iv) assess the oxidation-reduction potential (ORP) of spermatozoa exposed to PVP, HA or medium. Oocyte activation was higher when spermatozoa exhibited rotational motion rather than linear motion (79% vs. 52%; p = .05). There was no difference in oocyte activation and embryo development after parthenogenetic oocyte activation after sperm injection using PVP, HA or medium-incubated spermatozoa. PVP-selected spermatozoa exhibited lower (p < .0001) ORP levels than using HA. Thus, results indicate that the sperm handling method and the type of medium used impact ICSI outcomes. Overall, sperm incubation in PVP, HA and medium yields similar outcomes with regard to oocyte activation and embryo development. However, PVP provides more antioxidative protection than HA and should therefore be preferred for sperm manipulation.

Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City.

Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized areas. A principal components analysis established that the concentrations of each pollen type differed across the urbanization gradients. Additionally, it was found that a large number of allergenic pollens are produced by ornamental trees, some only recently introduced by urban planners.

Patterns and significance of exhaled-breath biomarkers in lung transplant recipients with acute allograft rejection.

BACKGROUND: Obliterative bronchiolitis (OB) remains one of the leading causes of death in lung transplant recipients after 2 years, and acute rejection (AR) of lung allograft is a major risk factor for OB. Treatment of AR may reduce the incidence of OB, although diagnosis of AR often requires bronchoscopic lung biopsy. In this study, we evaluated the utility of exhaled-breath biomarkers for the non-invasive diagnosis of AR. METHODS: We obtained breath samples from 44 consecutive lung transplant recipients who attended ambulatory follow-up visits for the Johns Hopkins Lung Transplant Program. Bronchoscopy within 7 days of their breath samples showed histopathology in 21 of these patients, and we included them in our analysis. We measured hydrocarbon markers of pro-oxidant events (ethane and 1-pentane), isoprene, acetone, and sulfur-containing compounds (hydrogen sulfide and carbonyl sulfide) in exhaled breath and compared their levels to the lung histopathology, graded as stable (non-rejection) or AR. None of the study subjects were diagnosed with OB or infection at the time of the clinical bronchoscopy. RESULTS: We found no significant difference in exhaled levels of hydrocarbons, acetone, or hydrogen sulfide between the stable and AR groups. However, we did find significant increase in exhaled carbonyl sulfide (COS) levels in AR subjects compared with stable subjects. We also observed a trend in 7 of 8 patients who had serial sets of breath and histopathology data that supported a role for COS as a breath biomarker of AR. CONCLUSIONS: This study demonstrated elevations in exhaled COS levels in subjects with AR compared with stable subjects, suggesting a diagnostic role for this non-invasive biomarker. Further exploration of breath analysis in lung transplant recipients is warranted to complement fiberoptic bronchoscopy and obviate the need for this procedure in some patients.

Papel de la valoración cervicalpor ecografía transvaginal en laprevención del parto prematuroen una población noseleccionada / Role of cervical evaluation by transvaginal ultrasonography in the prevention of preterm delivery in a non-selected population

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Induction of the lung myofibroblast PDGF receptor system by urban ambient particles from Mexico City.

Platelet-derived growth factor (PDGF) and its receptor system regulate mesenchymal cell proliferation. We recently reported that emission-source fly-ash particles and asbestos fibers induce the PDGF alpha-receptor through a macrophage-dependent pathway, and upregulation of this receptor greatly enhances the mitogenic response of lung myofibroblasts to PDGF (Lindroos and colleagues, Am. J. Respir. Cell Mol. Biol. 1997;16:283-292). In the present study we investigated the effect of particulate matter <= 10 micrometers in size (PM10) from the southern, central, and northern regions of Mexico City on PDGF receptor induction and compared these urban, ambient particles with Mt. St. Helen's volcanic ash particles as a negative control. All Mexico City PM10 samples, but not volcanic ash, stimulated rat alveolar macrophages to secrete a soluble, upregulatory factor(s) for the PDGF alpha-receptor on early passage rat lung myofibroblasts. The macrophage-derived upregulatory activity was blocked by the interleukin (IL)-1 receptor antagonist. The ability of PM10 to stimulate IL-1beta release was blocked in part by a recombinant endotoxin neutralizing protein (rENP). Lipopolysaccharide/endotoxin (LPS) and vanadium, both constituents that were present within these PM10 samples, also stimulated macrophages to secrete factor(s) that upregulated PDGF-Ralpha on lung myofibroblasts. Direct exposure of myofibroblasts to PM10 also elicited upregulation of the PDGF alpha-receptor, and this effect was blocked by rENP and mimicked by LPS, but not vanadium. These findings suggest that PM10 particles induce expression of the PDGF receptor system through macrophage-dependent and -independent mechanisms involving endotoxin and metals.

Analysis of the relationships between environmental factors (aeroallergens, air pollution, and weather) and asthma emergency admissions to a hospital in Mexico City.

There have been several studies of the relationships between environmental factors, particularly air pollution, and attacks of asthma. Most of these studies have ignored the potential confounding effects of aeroallergens such as pollens and fungal spores. We report a statistical analysis of the relationships between emergency admissions for asthma to a hospital in Mexico City and daily average airborne concentrations of pollen, fungal spores, air pollutants (O3, NO2, SO2, and particulates) and weather factors. Asthma admissions had a seasonal pattern with more during the wet season (May-October) than the dry season (November-April). There were few statistical associations between asthma admissions and air pollutants for the three age groups studied (children under 15 years, adults, and seniors [adults over 59 years]) in either season. Grass pollen was associated with child and adult admissions for both the wet and dry seasons, and fungal spores were associated with child admissions during both the wet and dry seasons. The analysis was done with environmental data averaged over the day of admission and the 2 previous days. Our results suggest that aeroallergens may be statistically associated more strongly with asthma hospital admissions than air pollutants and may act as confounding factors in epidemiologic studies.

Escherichia coli in settled-dust and air samples collected in residential environments in Mexico City.

Escherichia coli, an important indicator of the presence of fecal material, was isolated from indoor and outdoor environments in Mexico City. The heterogeneity of E. coli was represented by 89 serotypes, most of them coming from settled-dust indoor samples; 21% of them presented antibiotic multiresistance. The numbers of plasmids were higher among the antibiotic-resistant strains. The results of this study suggest that intestinal infections produced by environmental strains could be of more epidemiological impact than previously thought.

Tropisetrón en la prevención de náuseas y vómitos por quimioterapia: estudio clínico multicéntrico / Tropisetron in the prevention of nausea and vomiting due to chemotherapy: multicentric clinical study

The antiemetic effect of tropisetron was studied in 97 cancer patients (67 men, 30 women) receiving cisplatin in doses of 75 mg/m² or higher. On 279 chemotherapy cycles studied (max 6 per patient) 5 mg of tropisetron was admonistered once a day i.v. on day 1 and p.o. on day 2 to 6. Efficacy preventing vomiting and nausea was measured in 24 hour period as: complete control 0 episodes, major control 1 to 2 episodes, minor control 3 to 4 episodes and no control 5 or more episodes. Satisfactory vomiting control (complete and major) was 69 percent, 63 percent, 82 percent,88 percent, 96 percent and 96 percent in days 1 to 6 of cycle 1. Satisfactory nausea control (complete and major) for the same day was 70, 66, 72, 85 92 and 97 percent. Similar data was obtained for the subsequeny cycles. Complete vomiting control was obtained in 47, 35, 56, 72, 81 and 84 percent and for nausea in 42, 39, 48, 64, 81 and 87 percent. 19 patients presented adverse effects (19,6 percent). Only 2 headache episodes had a definitive relation with antiemetic drug. 12 patients discontinued the medication; 6 due to drug inefficacy, 2 to illness unrelated to the drug, 1 to lack of collaboration, and 3 due to other reasons. We conclude that tropisetron allows satisfactory control of acute and delayed vomiting in a high percentage of patients treated with high doses of cisplatin. The drug does not have significant secondary effects. Tropisetron administration in only 1 daily dose implies an evident advantage and a treatment cost reduction

Abundance of airborne Penicillium CFU in relation to urbanization in Mexico City.

Air was sampled simultaneously at three localities in Mexico City differing in urbanization index and air pollution level on 22 days during a period covering both dry and rainy seasons. An Andersen two-stage microbial sampler was used for 15 min at 28 liters min-1 to isolate culturable fungi on malt extract agar. After exposure, plates were incubated at 25 degrees C for 48 to 72 h before colonies were counted and identified to give concentrations of total fungal spores and of Penicillium spp., expressed as CFU per cubic meter of air. Total fungi numbered 91 to 602 CFU m-3 in Tlalpan Borough (southern area), 40 to 264 CFU m-3 in Cuauhtémoc Borough (downtown), and 26 to 495 CFU m-3 in Gustavo A. Madero Borough (northern area). Although Penicillium spp. were the second most frequently isolated fungal genus, concentrations were small, with a maximum of only 133 CFU m-3. Twice as many colonies were isolated in the southern area, with an urbanization index of 0.25 (arithmetic mean, 41 CFU m-3), as at other sampling stations with greater urbanization indices (arithmetic means, 19 and 20 CFU m-3). In the downtown area, with an urbanization index of 1.0, Penicillium spp. were more numerous than any other genus and formed 25% of the total fungal count compared with 14 and 17% in the other areas. Concentrations of airborne Penicillium spp. did not differ significantly between rainy and dry seasons.(ABSTRACT TRUNCATED AT 250 WORDS)

The algal community as an indicator of the trophic status of Lake Patzcuaro, Mexico.

An evaluation of water quality and phytoplankton composition position was carried out in order to determine the trophic conditions of Lake Patzcuaro (2035 m above sea level), a high altitude tropical lake. Temperatures ranged from 15 to 23 degrees C. Total phosphorus and inorganic nitrogen showed a seasonal variation; highest values coincided with the rainy season (0.48 and 2.1 mg litre(-1), respectively). Dissolved oxygen ranged from 2 to 7.9 mg litre(-1) at the surface and from 0.6 to 7.3 mg litre(-1) on the bottom, the lowest values being found in shallow zones. Average transparency varied from 0.62 to 1.4 m Secchi depth. Rainfall was a primary factor in seasonal variability as it influenced both physical and biological conditions by contributing to the transport and deposition of silt, which mixed with sinking algal cells. The composition of the surface phytoplankton segregated along five major divisions comprising a total of 49 species. General seasonal patterns of dominance alternated in a sequence beginning with Bacillariophyta, through Chlorophyta to Cyanophyta. Diatoms, the dominant group from February to early June, included Melosira granulata, Stephanodiscus sp., Synedra sp. and Fragilaria sp. During the rainy season (late June to September), Microcystis aeruginosa, Oscillatoria sp., Anabaena sp., Merismopedia sp., Crucigenia cuadrata, Oocystis lacustris, Selenastrum gracile, Mallomonas sp. and Tetraediella sp. were important. Melosira granulata was present throughout the period of study. Spatial and temporal variability in both physical and biological conditions make it difficult to assign a specific trophic state to Lake Patzcuaro. Nevertheless, analysis of the algal community indicates a generally mesotrophic condition.

Formaldehyde levels in air and wet precipitation at Mexico City, Mexico.

Formaldehyde concentrations in ambient air and in rain water were measured at the University of Mexico, Mexico City. Air samples were taken twice a day, from 9:00 to 13:00 h and from 13:00 to 16:00 h local time from July to December 1985. Rain water was collected on daily bases from July to October, i.e. during the rainy season. The ambient air mean value was 24.4 x 10(-3) ppmv for morning hours, while the afternoon mean value was 18.5 x 10(-3) ppmv. The formaldehyde concentration in wet precipitation ranged from 0.10 to 0.80 mg liter(-1) (3.3 to 26.6 micromoles liter(-1)) 0.41 mg liter(-1) (13.7 microoles liter(-1)). A comparison of the results of this study with some measurements made at remote maritime sites, rural and urban areas, indicated that the formaldehyde levels in the atmosphere and rain water of Mexico City are among the highest reported in the literature, including the data reported by Grosjean (1982) for Los Angeles, California, during severe photochemical pollution conditions.

Respuesta de los trabajadores a los microorganismos suspendidos en la atmósfera de una fábrica de papel / Response of workers to airbone microorganisms at a paper manufacturing plant

Se realizó una investigación sobre la respuesta inmunológica de los trabajadores de una fábrica de papel. Un grupo de 44 trabajadores expuestos a microorganismos presentes en el aire de la fabrica provenientes del bagazo de la caña enmohecido constituyó el grupo expuesto y 23 individuos que laboran en un hospital integraron el grupo testigo. Se registró un alto grado de contaminación tanto por microorganismos como por material particulado en la atmósfera del cuarto de molienda (25.168 hon os/m3 y 27.8 mg/m3 respectivamente). Al analizar el bagazo y las muestras de aire fue posible aislar diferentes actinomicetos y hongos incluyendo a Thermoactinomyces vulgaris un actinomiceto, que puede producir Alveolitis Alérgica. Las reacciones inmunológicas de los trabajadores señalan la presencia de anticuerpos contra la mayoría de los antígenos de los microorganismos aislados, pero solamente un individuo con bagazosis presento una respuesta positiva contra T. Vulgaris

Amoebae isolated from the atmosphere of Mexico City and environs.

A protozoological analysis was performed from June to August, 1982 to isolate small free-living amoebae from the atmosphere by using an air vacuum sampler and several filters. Monoxenic medium (nonnutritive agar plus Escherichia coli) and axenic medium (De Jonckheere, 1977) were used to culture the isolates. The species isolated included Naegleria sp. Alexeieff emend. Calkins, Acanthamoeba polyphaga Puschkarew, Vahlkampfia jugosa Page, Acanthamoeba astronyxis Ray and Hayes, Acanthamoeba castellanii Douglas, Acanthamoeba culbertsoni Singh y Das, Vahlkampfia ustiana Page, Saccamoeba stagnicola Page, Hyalodiscus sp. Hertwig and Lesser, Platyamoeba placida Page, Rugipes sp. Schaeffer, Vannella platypodia Gläser, Vahlkampfia russelli Singh, Vahlkampfia ovis Schmidt, and Leptomyxa flabellata Goodey. Among the species isolated Naegleria sp., A. polyphaga, A. culbertsoni, and A. castellanii include strains, known to be pathogenic in humans.

Pathogenic and free-living protozoa cultured from the nasopharyngeal and oral regions of dental patients: II.

Protozoa of the nose, mouth, and pharynx of 30 randomly chosen male caries patients at an odontological clinic of the National Autonomous University of Mexico, in Mexico City, were surveyed by culture from swabs. Culture tubes from swabs were observed every other day for 5 weeks. Pathogens found included Entamoeba histolytica, Naegleria fowleri, Acanthamoeba castellanii, A. culbertsoni, A. polyphaga, and Giardia lamblia. Such isolations of pathogens suggest that patients may be healthy carriers of cysts and trophic forms of protozoa responsible for several human diseases. Amoebae responsible for primary amoebic meningoencephalitis were well represented in the samples. Small pathogenic free-living amoebae have not been isolated before from healthy males in Mexico. Many species of free-living cyst-forming protozoa and some commensals without cysts were also cultured from swabs.

Bacteriological quality of crops irrigated with wastewater in the Xochimilco plots, Mexico City, Mexico.

Xochimilco county plots (Mexico City), one of the most fertile agricultural areas in the Valley of Mexico, produce a large portion of the fresh vegetables consumed in the city. These plots are generally irrigated with domestic wastewater, and for this reason, it was deemed important to examine and evaluate the bacteriological quality of the water, soil, and vegetables from these plots that are harvested and marketed. The soils were also examined for the classical parameters such as nitrates, ammonia, etc., and organic matter and texture. The crops selected for this study were radishes, spinach, lettuce, parsley, and celery because they are usually consumed raw. The highest bacterial counts were encountered in leafy vegetables, i.e., spinach (8,700 for total coliform and 2,400 for fecal coliform) and lettuce (37,000 for total coliform and 3,600 for fecal coliform). Statistically significant differences in bacterial counts between rinsed and unrinsed edible portions of the crops were observed even in rinsed vegetables, and high densities of fecal coliform were detected, indicating that their consumption represents a potential health hazard. The total coliform values found in irrigation water ranged from 4 X 10(4) to 29 X 10(4), and for fecal coliform the values ranged from 5 X 10(2) to 30 X 10(2).

Cytogenetic effects of cadmium accumulation on water hyacinth (Eichhornia crassipes).

Cadmium was bioassayed to observe cytogenetic effects in the water hyacinth (Eichhornia crassipes). Plants were exposed for 96 hr to freshwater containing 0.01, 0.05, 0.10, 1.5, and 10 mg/liter of cadmium. Metal concentrations in tissues were determined by atomic absorption spectrophotometry. The highest level was found in roots, thus root-tip cells were used for cytogenetic studies; after 24 hr of exposure, micronuclei, c-mitotic effects, and pycnosis were detected and after 48 hr polyploidy was observed. A linear relationship between frequencies of micronuclei and cadmium concentrations was found: at 1.5, and 10 mg/liter micronuclei numbers were always the lowest. The inhibition of cell proliferation. shown by the low mitotic index, was proportional to the concentration and time of exposure. From the results presented in this paper it may be concluded that water hyacinth is a good sensor, due to its fast rate of metal accumulation, which allows an easy way to determine the presence of potential mutagenic compounds in water.