Assessment of the use of ethanol instead of MTBE as an oxygenated compound in Mexican regular gasoline: combustion behavior and emissions.

The energy reforms implemented in Mexico promote the use of ethanol in gasoline but exclude the country's ozone nonattainment areas oxygenated with methyl-tert-butyl ether (MTBE) in view that further scientific studies are required. To address a potential implementation scenario in areas of ozone high VOC-sensitive regimes, the impact on performance and emissions characteristics between the regular MTBE fuel available and a formulated gasoline containing 10% v/v ethanol having similar Reid vapor pressure (RVP) were compared in a single cylinder spark-ignited engine and a set of tier I vehicles. Included in the assessment were the "criteria" pollutants (THC, CO, and NOx), toxic compounds, and speciated hydrocarbons in order to calculate the ozone-forming potential (OFP). The change in combustion speed of ethanol fuel vs. regular gasoline seems to be small and depends mainly on base gasoline formulation. Vehicle dynamometer testing showed no statistically significant differences in the average THC, CO, and NOx results when comparing both fuels. Statistically significant differences were seen in total speciated hydrocarbons, total carbonyls emitted, the increases in acetaldehyde emissions, and the decreases in OFP with E10. The results show roughly 20% increase in evaporative emissions when E10 is used, but the OFP of the emissions is lower than that of the Metropolitan Area of Mexico City fuel (MAMC). The increase in the oxygen content using ethanol fuel seems to have no deleterious effect on the vintage of vehicles tested. Taking into consideration that the evaporative emissions standard in Mexico is less stringent than that in other countries, the substitution of the actual regular gasoline for ethanol fuels should uphold the least volatile AA class in areas with ozone problems.

Single dose of propofol causing propofol infusion syndrome in a newborn.

Propofol infusion syndrome (PRIS) is a rare syndrome originally described in critically ill children undergoing long-term (> 48 h) propofol infusion at high doses (> 4 mg/kg/h). Severe metabolic acidosis, rhabdomyolysis, renal failure and fatal cardiac failure are the features. Herein, we present a case of a newborn who developed PRIS after a single bolus dose of propofol at 3.2 mg/kg/do, developing rhabdomyolysis and severe metabolic acidosis, with a successful outcome after medical therapy.

Fluorescence characteristics in the deep waters of South Gulf of México.

Vertical profiles of deep-water fluorescence determined by the chlorophyll sensor, polycyclic aromatic hydrocarbons, biomarkers, and other miscellaneous parameters measured in the southern Gulf of Mexico are reported. In the course of the survey, unexpected deep fluorescences were recorded (>1100m depth) in half of the 40 stations studied, a novel finding in this area of the Gulf. Currently, the deep-water fluorescence phenomenon is not completely understood, however we observe linear correlation between the fluorescence intensity and chlorophyll-α concentrations and coincidence of higher number of hydrocarbonoclastic bacteria in samples collected precisely in the deep-water fluorescence. This information is particularly interesting in relation to the Deepwater Horizon oil spill in 2010, in view that the aftermaths of the spill can be observed till today as oil plumes trapped in deep water layers that may disturb the natural water ecosystem.

Long-term effects of discharges of produced water the marine environment from petroleum-related activities at Sonda de Campeche, Gulf of México.

Produced water from offshore oil platforms is a major source of oil and related chemicals into the sea. The large volume and high salinity of produced water could pose severe environmental impacts upon inadequate disposal. This study is based on direct field sampling of effluents released into the ocean in the years 2003 and 2013 at the Sonda de Campeche located in the southern part of the Gulf of Mexico. Metals and hydrocarbons were characterized in water, sediments, and fish tissues at the discharge site and compared with those obtained at two reference sites. Chemicals that exceeded risk-based concentrations in the discharge included the metals As, Pb, Cd, and Cr, and a variety of compounds polycyclic aromatic hydrocarbon (PAHs), including naphthalene, fluorenes, and low molecular weight PAHs. The values of low to high molecular weight polycyclic aromatic hydrocarbon (PAHs), and carbon preference index indicate that hydrocarbons in sediments of the discharge zone are originated from the produced water and combustion sources. Fish tissues at the discharge zone and reference site are contaminated with PAHs, dominated by 2- and 3-rings; 4-ring accounted for less than 1% of total PAHs (TPAHs) in 2003, but increased to 7% in 2013. Results suggest that, from 2003 to 2013, discharges of produced water have had a non-negligible impact on ecosystems at a regional level, so the possibility of subtle, cumulative effects from operational discharges should not be ignored.

The contribution of evaporative emissions from gasoline vehicles to the volatile organic compound inventory in Mexico City.

The strategy for decreasing volatile organic compound emissions in Mexico has been focused much more on tailpipe emissions than on evaporative emissions, so there is very little information on the contribution of evaporative emissions to the total volatile organic compound inventory. We examined the magnitudes of exhaust and evaporative volatile organic compound emissions, and the species emitted, in a representative fleet of light-duty gasoline vehicles in the Metropolitan Area of Mexico City. The US "FTP-75" test protocol was used to estimate volatile organic compound emissions associated with diurnal evaporative losses, and when the engine is started and a journey begins. The amount and nature of the volatile organic compounds emitted under these conditions have not previously been accounted in the official inventory of the area. Evaporative emissions from light-duty vehicles in the Metropolitan Area of Mexico City were estimated to be 39 % of the total annual amount of hydrocarbons emitted. Vehicles built before 1992 (16 % of the fleet) were found to be responsible for 43 % of the total hydrocarbon emissions from exhausts and 31 % of the evaporative emissions of organic compounds. The relatively high amounts of volatile organic compounds emitted from older vehicles found in this study show that strong emission controls need to be implemented in order to decrease the contribution of evaporative emissions of this fraction of the fleet.

Application of the positive matrix factorization approach to identify heavy metal sources in sediments. A case study on the Mexican Pacific Coast.

During the last two decades, sediments collected in different sources of water bodies of the Tehuantepec Basin, located in the southeast of the Mexican Pacific Coast, showed that concentrations of heavy metals may pose a risk to the environment and human health. The extractable organic matter, geoaccumulation index, and enrichment factors were quantified for arsenic, cadmium, copper, chromium, nickel, lead, vanadium, zinc, and the fine-grained sediment fraction. The non-parametric SiZer method was applied to assess the statistical significance of the reconstructed metal variation along time. This inference method appears to be particularly natural and well suited to temperature and other environmental reconstructions. In this approach, a collection of smooth of the reconstructed metal concentrations is considered simultaneously, and inferences about the significance of the metal trends can be made with respect to time. Hence, the database represents a consolidated set of available and validated water and sediment data of an urban industrialized area, which is very useful as case study site. The positive matrix factorization approach was used in identification and source apportionment of the anthropogenic heavy metals in the sediments. Regionally, metals and organic matter are depleted relative to crustal abundance in a range of 45-55 %, while there is an inorganic enrichment from lithogenous/anthropogenic sources of around 40 %. Only extractable organic matter, Pb, As, and Cd can be related with non-crustal sources, suggesting that additional input cannot be explained by local runoff or erosion processes.

Weighing the evidence of ecological risk from PAHs contamination in the estuarine environment of Salina Cruz Bay, México.

Results of bulk-phase chemical measurements, toxicological tests combined with bioaccumulation measures in fishes, were used to evaluate the toxicity of the 16 USEPA priority polycyclic aromatic hydrocarbons from the sediment collected from eight stations of the Ventosa Estuarine System, located close to the main center of processing oil in the Mexican Pacific coast. Levels of the sum of polycyclic aromatic hydrocarbons varied from 22 to 6,850 microg kg(-1) dry weight. Based on sediment quality guidelines, the compounds with high environmental priority were acenaphtylene, acenaphtene, and phenanthrene. Acute toxicity tests with Vibrio fischeri and Daphnia magna as well as chronic toxicity with Panagrellus redivivus were performed. The quantification of hepatic ethoxyresorufin O-deethylase activity was used to assess the induction of the mixed function oxygenase system of brown trout. However, because it is often difficult to blend the results from such very different assays into a unified decision about the potential for impacts, a weight-of-evidence (WOE) approach to sediment quality investigations was followed. These assays provided measurement endpoints that could be used to develop an overall evaluation of the potential for environmental impacts from the oil processing operations. WOE provides a valuable tool for assessing the results of environmental investigations because it provides a framework for considering the strengths and weaknesses of environmental measurements, an approach for addressing uncertainty in the measurements, and documentation of the evaluation and its assumptions.

Assessment of benthic changes during 20 years of monitoring the Mexican Salina Cruz Bay.

In this work a non-parametric multivariate analysis was used to assess the impact of metals and organic compounds in the macro infaunal component of the mollusks benthic community using surface sediment data from several monitoring programs collected over 20 years in Salina Cruz Bay, Mexico. The data for benthic mollusks community characteristics (richness, abundance and diversity) were linked to multivariate environmental patterns, using the Alternating Conditional Expectations method to correlate the biological measurements of the mollusk community with the physicochemical properties of water and sediments. Mollusks community variation is related to environmental characteristics as well as lead content. Surface deposit feeders are increasing their relative density, while subsurface deposit feeders are decreasing with respect to time, these last are expected to be more related with sediment and more affected then by its quality. However gastropods with predatory carnivore as well as chemosymbiotic deposit feeder bivalves have maintained their relative densities along time.

Clinical and capillaroscopic evaluation in the treatment of chronic venous insufficiency with Ruscus aculeatus, hesperidin methylchalcone and ascorbic acid in venous insufficiency treatment of ambulatory patients.

AIM: Clinical and capillaroscopic evaluation of an association of Ruscus aculeatus, hesperidin methylchalcone (HMC) and ascorbic acid in chronic venous insufficiency METHODS: A prospective, multicenter and open clinical study. Chronic venous insufficiency patients were studied using clinical, etiological, anatomical, physiological classification (CEAP) symptom scale. Symptomatology, CEAP scale, and baseline, 2-, 4-, 6- and 8-week skin capillaroscopy were assessed. Treatment consisted of two capsules per day of Ruscus aculeatus 150 mg/HMC 150 mg/ascorbic acid 100 mg during 8 weeks. RESULTS: A total of 124 patients were studied, 109 female (89.28%), with a mean age of 52.5 (33-80+9.8). Initial intense reports were 79% pain, 85% heaviness, 74% cramps, 82% edema, decreasing to 20%, 12%, 8% and 14%, respectively, within two weeks, and symptomatology being absent at the end of treatment. Capillaroscopy changes at treatment completion were: 98% to 20% inter-capillary fluid decrease; 80% to 20% efferent loop thickening; 5% to 2% peri-capillary bed, and 5% to 4% mega-capillaries. CONCLUSION: Severe symptom decrease started from the second week until there were no symptoms at the end of treatment. It is the first time morphologic changes were observed in chronic venous insufficiency through capillaroscopy following a pharmacological intervention. Capillary-level effect was proportional to symptom decrease. Improvement was seen from the second week of treatment.

[Distal tibial reconstruction and ankle arthrodesis in osteosarcoma (salvage technique). A case presentation]. / Reconstrucción de tibia distal y artrodesis de tobillo en osteosarcoma (cirugía de salvamento). Presentación de un caso.

UNLABELLED: Treatment of bone sarcomas is aimed in healing and secondarily rescuing the limb. With the use of chemotherapy, radiation therapy, new prostheses and availability of graft, now most tumors can be resected, reducing functional deficit. OBJECTIVE: To present a surgical option in management of osteosarcoma of distal tibia. CASE REPORT: Fifteen year-old man, starting in April 2003 with a mass in the left ankle area. June 2003 pulsatile progressive pain started, increased with activity, decreased with rest. November 2003 the physical exam: limping by left lower limb, with a tumor in the posteromedial ankle surface (3 x 2 cm), hard, not movable, regular edges, painful on palpation, Radiographic observations (November 2003), showed blastic oval stone image (4 x 3.5 cm) with expanded posterior and medial cortices with periosteal reaction. The initial biopsy report (chondroblastoma) was not consistent with the diagnostical assumption. So resection was performed 10 cm wide, placing a methylmethacrylate spacer. The final histological report was positive to osteogenic sarcoma. The patient received 11 sessions of chemotherapy. The reconstruction of the distal tibia and arthrodesis with autologous graft from the fibula, heterologous graft and stabilization with transcalcaneal nail, was done in March 2005. RESULTS: Successful evolution without tumor activity with graft integration to arthrodesis and plantigrade gait.

Polyaromatic hydrocarbons (PAHs) and metal evaluation after a diesel spill in Oaxaca, Mexico.

Pollution in the marine environment due to a diesel spill takes days to months to complete natural remediation owing to its low volatility. Metal and PAH contamination caused by an accidental diesel spill were studied. V, Ni and Hg levels increased immediately after the spill, while PAH levels decreased after 1 month (79.4-7.6 microg kg(-1)). At the diesel spill point, fluoranthene exceeded acute and chronic levels, although most of the PAHs were within the range of low effects. In fish body burden, the highest bioaccumulation factor (2.63 for naphthalene) was related to the lower molecular weight PAHs.

Environmental assessment of aromatic hydrocarbons-contaminated sediments of the Mexican Salina Cuz Bay.

Concentrations of total aromatic hydrocarbons and extractable organic matter in the water column and sediment were determined in samples collected in the course of the last 20 years from the Salina Cruz Harbor, México, to assess the degree of organic contamination. In sediments, organic compounds accumulate in shallow areas mostly associated with extractable organic matter and fine fractions. Calculated geocumulation index and enrichment factors suggest that contamination could be derived from anthropogenic activities attributed to harbor and ship scrapping activities, as well as transboundary source. Concentration of total aromatic hydrocarbons (as chrysene equivalents) ranged from 0.01 to 534 microg l(-1) in water, and from 0.10 to 2,160 microg g(-1) in sediments. Total aromatic concentration of 5 microg g(-1) is proposed as background concentration.

Autologous bone-marrow mononuclear cell implantation in patients with severe lower limb ischaemia: a comparison of using blood cell separator and Ficoll density gradient centrifugation.

Different studies have provided evidence that implantation of bone-marrow mononuclear cells (BM-MNC) into ischaemic limbs can improve tissue vascularization. Based on these results we performed a pilot study in patients with critical lower limb ischaemia to assess efficacy and safety of implantation of autologous BM-MNC. The amount and efficacy of BM-MNC purified either by an automated method or by a manual procedure were compared. Twelve patients with severe unilateral lower limb ischaemia were entered into this study. They were randomly assigned to be injected with BM-MNC sorted on a blood cell separator or isolated by density gradient on Ficoll-Hypaque. BM-MNC were implanted into the ischaemic legs. Patients were monitored with resting ankle-brachial pressure index (ABI), arterial oxygen saturation (SaO(2)), pain-free walking time and rest pain scale evaluation. The automated and manual methods used for mononuclear cell separation gave results not significantly different. Monitored variables improved in both groups. Improvement of ischaemic condition persisted during 24 weeks follow-up. Limb salvage was achieved in five cases. Our results indicate that BM-MNC implantation into ischaemic limbs is a practical, safe and effective method that may significantly contribute to the management of patients with limb ischaemia. The Ficoll method is a simple and effective procedure for BM-MNC concentration that may be useful, mainly in hospitals without sophisticated facilities.

Triggering receptor expressed on myeloid cells (TREM-1) is regulated post-transcriptionally and its ligand is present in the sera of some septic patients.

Inflammation is necessary for survival, but it is also an important cause of human morbidity and mortality, as exemplified by sepsis. During inflammation, cells of the innate immune system are recruited and activated in response to infection, trauma or injury. These cells are activated through receptors, such as Toll-like receptors (TLRs), which recognize microbial ligands such as lipopolysaccharide (LPS). Triggering receptor expressed on myeloid cells (TREM)-1 amplifies the inflammatory response initiated by TLRs, and its expression on the surface of monocytes increases in the presence of TLR ligands. Here we have shown that in monocytes TREM-1 mRNA levels, measured by reverse transcription-polymerase chain reaction (RT-PCR), remained unchanged and TREM-1 protein levels, measured by flow cytometry, increased, indicating that LPS increases TREM-1 expression by a post-transcriptional mechanism. We also showed that TREM-1/Fc fusion protein decreased the ability of the sera of some patients with sepsis to activate monocytes, indicating that the TREM-1 ligand, whose identity is unknown, may be present in the sera of some of these patients. We describe a mechanism for the regulation of TREM-1 expression on monocytes and the possible presence of its ligand in serum; these findings help to explain the contribution of TREM-1 during systemic inflammation.

Distribution, enrichment and accumulation of heavy metals in coastal sediments of Salina Cruz Bay, méxico.

Surface sediment samples collected from the Salina Cruz Bay in the last twenty years, were analyzed for the total available trace elements (Cr, Cu, Fe, Pb, Ni, V, and Zn) to evaluate metal contamination due to possible anthropogenic inputs. Normalization of metals to iron and fine-grained fraction (< 63 microm) indicated relatively high enrichment factors for lead during the last two decades. Sediment Quality Guidelines suggest that lead must be considered as a chemical of potential concern in the marine and estuarine ecosystem. Concentration levels of lead ranged from 5-124 microg/g, while Ni and V below 70 and 30 microg/g, respectively. Geoaccumulation and enrichment factors for the rest of elements show comparable values to those reported for sites with similar activities in the world. Spatial distribution suggests that in addition to harbor activities, a transboundary source for Pb must account for the observed trends.

Air emissions assessment from offshore oil activities in Sonda de Campeche, Mexico.

Air emission data from offshore oil platforms, gas and oil processing installations and contribution of marine activities at the Sonda de Campeche, located at the Gulf of Mexico, were compiled and integrated to facilitate the study of long range transport of pollutants into the region. From this important region, roughly 76% of the total Mexican oil and gas production is obtained. It was estimated that the total air emissions of all contaminants are approximately 821,000 tons per year. Hydrocarbons are the largest pollutant emissions with 277,590 tons per year, generated during flaring activities, and SOx in second place with 185,907 tons per year. Marine and aviation activities contribute with less than 2% of total emissions. Mass of pollutants emitted per barrel of petroleum produced calculated in this work, are in the range reported by similar oil companies.

[Drug supplies in primary care units at the Ministry of Health in Mexico]. / Abastecimiento de medicamentos en unidades de primer nivel de atención de la Secretaría de Salud de México.

OBJECTIVE: To identify the availability of some essential drugs (ED) at primary health care units of the Mexican Ministry of Health (SSA), using data from a research work conducted in 1996 and 1997. MATERIALS AND METHODS: A random sample of the 18 sanitary jurisdictions of states participating in the Extension of Coverage Program (ECP) was drawn. All primary care units from selected jurisdictions were evaluated through an inspection visit, using a checklist that included 36 ED. In phase I of the analysis, the absolute number and proportion of units without a single item of any of the 36 drugs were calculated. In the units with available drugs, the median of the distribution was also calculated. In phase II, the medians according to the type of health unit and state was obtained. The statistic utilized for the comparison of the medians was the Scheffé test with one way variance analysis. In addition, the drugs were classified according to their therapeutic indication and the medians and proportion of available drugs were calculated. The differences in proportion were evaluated with the statistic chi 2. RESULTS: During the visits, on average, 18 of the 36 drugs included in the list of the study were found in the health units. The availability of antibiotics, antituberculosis drugs, and antimalarial drugs was particularly poor. In contrast, oral rehydration salts, family planning methods and vaccines were usually available. In general, the PAC3 states presented the best availability figures. CONCLUSIONS: The Ministry of Health of México will have to develop an enormous effort to overcome the obstacles related to the supply of essential drugs in primary health care units. Otherwise, all other efforts directed to meet the needs of the non-insured population will end up being useless, and enormous amounts of the already scarce resources of the health sector will be wasted since drugs are a vital component of the long chain of health care.

Breast carcinoma presents a decade earlier in Mexican women than in women in the United States or European countries.

BACKGROUND: In Mexico, breast carcinoma is the second most frequent malignancy, representing 10.6% of all cases and 16.4% of all cancers in women, with an increase in breast carcinoma mortality rates from 3.6 per 100,000 women in 1985 to 6 per 100,000 women in 1994. Most of the tumors are diagnosed in advanced stages with little chance of cure. METHODS: To determine the age of patients in Mexico at presentation of breast carcinoma, the authors analyzed the cases registered from 1993 to 1996 from the database of the Histopathological Registry of Malignant Neoplasms in Mexico. RESULTS: There were 29,075 cases of breast carcinoma. The median age of Mexican women with breast carcinoma is 51 years, and 45.5% of all breast carcinomas develop before patients reach age 50 years. The most frequently affected age group is that of 40-49 years (29.5%), whereas the groups from 30 to 39 and from 60 to 69 years of age have a similar percentage (14%) of frequency. This contrasts with women from the United States, as well as with women from European countries, where the median age at presentation is 63 years, and only one-fourth of the patients are younger than 50 years of age, and three-fourths are postmenopausal. Similar to Mexico, in Venezuela and in Japan nearly one-half of women with breast carcinoma are younger than 50 years of age, and this resembles rates in many Latin American countries. CONCLUSIONS: It is necessary to change the guidelines of breast carcinoma screening in Mexican women, to increase the possibility of early diagnosis and better survival.

Expression and functional activity of the very late activation antigen-4 molecule on human natural killer cells in different states of activation.

In the present study we describe the expression and functional activity of the alpha4beta1 heterodimer molecule on human natural killer (NK) cells. Flow cytometric analyses showed that fresh and activated NK cells expressed high levels of very late activation antigen-4 (VLA-4) molecules. These cells bound to fibronectin (FN) and to its 38 000-MW proteolytic fragment through the VLA-4 integrin that was blocked with HP2/1 anti-alpha4 monoclonal antibodies (mAbs) and with the FN peptide fragment CS1. No inhibitory effects were observed in the presence of anti-alpha5 mAb, FN peptide fragment CS2 or other irrelevant mAb. Fresh NK cells were unable to aggregate, despite their expression of VLA-4, and only activated (cultured and lymphocyte-activated killer cells) NK cells showed homotypic aggregation with HP1/7 and HP2/4 anti-alpha4 mAb related to cellular activation. These results underline new evidence of how NK cells in different states of activation maintain different constitutive levels of alpha4beta1 integrin activity, and highlight the possibility of a different functional regulation by the cells bearing VLA-4, in the expression of these epitopes and their ability to interact with their ligands.