The qualitative similarities between water and silica have long been appreciated [1,2]. The molecular structure of both substances is dominated by tetrahedral bonding arrangements under ambient pressure, in both the liquid and the solid states. As a consequence, several of the low-pressure ice phases have isomorphic analogs among the crystalline phases of silica (e.g., ice Ih and tridymite). Th...

Scanning electron microscopy demonstrates that crystalline silica destroys liver Kupffer cells but has no other obvious deleterious effects on the liver. Silica-treated livers still retain the ability to trap large numbers of bacteria perfused through the portal vein even though the rate of clearance is well below normal. In vivo, silica treatment decreases the rate of bacterial clearance from ...

An epidemiological investigation was carried out to determine the relationship between silicosis in hardrock miners in Ontario and cumulative exposure to silica (free crystalline silica--alpha quartz) dust. This second report describes a side-by-side air-sampling program used to derive a konimeter/gravimetric silica conversion curve. A total of 2,360 filter samples and 90,000 konimeter samples ...

Occupational exposure to crystalline silica has received renewed attention. The National Conference to Eliminate Silicosis in March 1997, was extensive. The conference included workshops that covered silica exposures and the risks in construction, the mining industry, quarries, and foundries.(1) The Occupational Safety and Health Administration (OSHA) launched a special emphasis program in May ...

In 1997, the International Agency for Research on Cancer (IARC) upgraded its evaluation of crystalline silica to a Group 1 human carcinogen. Criticism against such decision is based on the lack of consistency in experimental results across animal species, violation of an important principle for causality, such as the replication of findings under different circumstances of exposure, and the lac...

Inhalation of dust containing crystalline silica is associated with a number of acute and chronic diseases including systemic autoimmune diseases. Evidence for the link with autoimmune disease comes from epidemiological studies linking occupational exposure to crystalline silica dust with the systemic autoimmune diseases systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis...

Background Tomaso Casoni (Figure 1A &1B) earned his fame by the test named after him [1]. Casoni was first to describe a test for immediate allergic reaction to hydatid fluid injected into the skin (Figure 2). This was in a time when hydatid disease caused by infection by Echinococcus granlulosus was endemic in Europe, Africa and the Middle East in addition to many other parts of the world. The...