Comparative analysis of the street generation of inorganic urban solid waste (IUSW) in two neighborhoods of Mexico City.

Inorganic urban solid waste (IUSW) is a serious problem in developing countries, and IUSW in the street that does not have adequate final disposal is responsible for serious environmental effects. The aim of this work was to determine the dynamics of the generation of IUSW in the streets of two neighborhoods of different socioeconomic strata in Mexico City during 5 weeks in 2006. The amount of IUSW was recorded every day from 9:00 to 12:00 h, separated, classified, and registered. It was found that plastic (50%) and paper (44.5%) wastes were found most frequently, whereas, textiles (0.4%) and glass (0.5%) wastes were present less frequently in all samples. The IUSWs without commercial brands were more abundant. Branded plastic wrappers of PepsiCo and Bimbo, as well as polyethylene terephthalate (PET) containers of Coca Cola, registered the highest values, while Gatorade, Barrilitos, and Peñafiel registered the lowest. The neighborhood with a higher income and more vegetation on sidewalks or in jardinières, which are used to hide solid waste, had more IUSW than the neighborhood with lower income, where IUSW was thrown out directly into the street. The knowledge of the real generation and composition of IUSW will contribute to the prevention of its negative environmental and social impacts, as well as guarantee the efficiency of its sustainable management.

Matrix metalloproteinases expressed in squamous cell carcinoma of the oral cavity: correlation with clinicopathologic features and neo-adjuvant chemotherapy response.

Secretion of gelatinases A (MMP-2) and B (MMP-9) from 21 tumoral explants of squamous cell carcinoma (SCC) and five samples of normal mucosa of the oral cavity is demonstrated here. The explants were cultured into fetal bovine serum- and phenol red-deprived medium for 48 hours. The gelatinases secreted into the medium were revealed and quantified by zymography and densitometry, respectively. The results showed high medians of the 66 kDa forms of gelatinase A in tumoral explants, in comparison to normal explants: 31.0 vs 5.9 densitometric units (DU) (p <0.01). There was also a relatioship between clinical response to neo-adjuvant chemotherapy and low activity of 66 kDa form of gelatinase A, as well as 84 kDa and 92 kDa forms of gelatinase B. The median of gelatinolysis of the inactive form of gelatinase A (72 kDa form) was higher in those patients who exhibited a complete response to neo-adjuvant chemotherapy. We conclude that gelatinase A is a useful and objective tool to evaluate the response to chemotherapy and the aggressiveness of carcinomas of the oral cavity.

Ferruginous bodies as markers of environmental exposure to inorganic particles: experience with 270 autopsy cases in Mexico.

Ferruginous bodies (FB) were quantified in lung digests from 270 autopsy cases over 20 years of age. The cases were autopsied in three different hospitals of the Secretaria de Salud, Mexico, DF. Two hundred seventy samples of peripheral lung tissue were digested in commercial bleach, and all morphologic types of ferruginous bodies were quantified. The results showed that numbers of ferruginous bodies per gram of dry tissue increased over the years: 4.2 FB/g in cases from 1975 to 42.5 FB/g in cases from 1988 (r = 0.86). Higher counts of ferruginous bodies were seen in males, smokers, and Mexico City dwellers. However, more than 70% of them presented less than 100 FB/g. Our study demonstrates that most of our cases had a nonoccupational exposure to fibers.

[Presence of ferruginous bodies in cancerous pulmonary tissue]. / Presencia de cuerpos ferruginosos en tejido pulmonar canceroso.

The correlation between high counts of ferruginous bodies (FB) and pulmonary cancer was investigated. Autopsy cases between 1982 and 1988 were chosen, and studied at Instituto Nacional de Enfermedades Respiratorias. Two grams of lung tissue were digested with sodium hypochlorite. We found no differences in the histologic types of cancer: 18.0 FB per gram (FB/g) for the adenocarcinoma group and 16.0 FB/g for both the epidermoid and anaplastic groups. The asbestos core was predominant in all FB analysed (greater than 85%). Males, Mexico city residents and smokers showed to higher amounts of FB. We concluded that there is an environmental exposure to particles in the cases studied.

[The identification of ferruginous bodies in human lungs. A retrospective study of 1975, 1982 and 1988]. / Identificación de cuerpos ferruginosos en pulmones humanos. Estudio retrospectivo de 1975, 1982 y 1988.

The presence of ferruginous bodies (FB) at 90 autopsy cases were analysed. The cases belong to 1975, 1982 and 1988. Two grams of lung was digested and observed the following results: 4.2 FB/g in 1975, 17.0 FB/g in 1982 and 42.5 FB/g in 1988. Males, Mexico City dowlers, smokers and carcinoma bronchogenic group were exposed to higher FB. The correlation between employment and FB was observed. Three parameters of FB concentration: 0-100 environmental exposure, 100.1-1,000 environmental and occupational exposures, and more 1,000 to occupational exposure was observed. The asbestos core was predominant in all FB analysed. No correlation between age and FB was observed. Finally there is a nonoccupational exposure to asbestos fibres in our environment.