RESUMEN

BACKGROUND: Type 1 Diabetes poses a significant public health threat, especially in low-and-middle countries, where resources are limited. The use of geographical information systems in diabetes research has shown the potential to reveal several epidemiological risk factors. AIMS: This scoping review aimed to identify the scope and extent of the current literature and explore its limitations on the geographical mapping of children with type 1 diabetes. METHODS: A scoping review was conducted using five electronic databases and included studies published between the years 2000 and 2023. The search terms included: "Type 1 Diabetes Mellitus", "GIS mapping", "Juvenile Onset Diabetes Mellitus", "Spatial Epidemiology", "Spatial Clustering", "Spatial analysis", and "Geographic information system". Relevant full-text articles that met the inclusion criteria were selected for review. RESULTS: The search identified 17 studies that met the criteria for inclusion in the review. More than half the studies were conducted before 2015 (n=11; 61%). All studies were conducted in High-Income Countries. More than 10 articles studied environmental factors, 3 of them focused on the environment, 6 of them included sociodemographic factors, and 1 study incorporated nutrition (as a variable) in environmental factors. 2 studies focused on the accessibility of health services by pediatric patients. CONCLUSION: Studies on type 1 diabetes highlight the complex relationship between incidence and risk, suggesting comprehensive prevention and treatment. Geographical mapping has potential in low- and middle-income nations, but further research is needed to develop innovative strategies. The importance of geomappping in understanding the risk factors for Type 1 Diabetes is highlighted in this scoping review, which also suggests a possible direction for focused interventions, particularly in settings with low resources.

RESUMEN

The toxic effects of heavy metals, zinc and copper, in unary and binary solutions were studied using the Microtox acute toxicity test which relies upon the attenuation of light intensity emitted by Vibrio fischeri. The toxic effect Gamma (ratio of the light intensity lost at time t to the light intensity remaining at time t) of zinc could be related to its concentration [X] by a two-parameter equation Gamma=a(1-exp(-b[X])), where parameter a was a function of time and b equal to 0.88L/mg. The toxic effect of zinc asymptotically approached a maximum with respect of to concentration at all times. The toxic effect of copper was fundamentally different from that of zinc, and increased exponentially with concentration without any limiting maximum value. It could also be described by a two-parameter equation, however, the equation had the form Gamma=aexp(b[X]), where parameter a was a constant and b a function of time. The different functional dependencies (of the toxic effect on the metal concentration) of zinc and copper indicate that different toxicity/inhibition mechanisms were possibly responsible for the attenuation of light intensity for the two metals. The toxic effects of binary mixtures were substantially higher than those expected on the basis of additivity of individual metals. No simple correlations were obtained that could relate the toxic effect of binary mixture to those of individual metals. A better understanding of metal-microbe interactions is needed for achieving predictive capability for toxic effect of mixtures.

Asunto(s)

RESUMEN

Acid mine drainage (AMD) containing high concentrations of sulfate and heavy metal ions can be treated by biological sulfate reduction. It has been reported that the effect of heavy metals on sulfate-reducing bacteria (SRB) can be stimulatory at lower concentrations and toxic/inhibitory at higher concentrations. The quantification of the toxic/inhibitory effect of dissolved heavy metals is critical for the design and operation of an effective AMD bioremediation process. Serum bottle and batch reactor studies on metal toxicity to SRB indicate that insoluble metal sulfides can inhibit the SRB activity as well. The mechanism of inhibition is postulated to be external to the bacterial cell. The experimental data indicate that the metal sulfides formed due to the reaction between the dissolved metal and biogenic sulfide act as barriers preventing the access of the reactants (sulfate, organic matter) to the necessary enzymes. Scanning electron micrographs of the SRB cultures exposed to copper and zinc provide supporting evidence for this hypothesis. The SRB cultures retained their ability to effect sulfate reduction indicating that the metal sulfides were not lethally toxic to the SRB. This phenomenon of metal sulfide inhibition of the SRB has to be taken into account while designing a sulfate-reducing bioreator, and subsequently an efficient biotreatment strategy for AMD. Any metal sulfide formed in the bioreactor needs to be removed immediately from the system to maintain the efficiency of the process of sulfate reduction.

Asunto(s)