Analysis and risk estimates to workers of Brazilian granitic industries and sandblasters exposed to respirable crystalline silica and natural radionuclides

Occupational exposure to respirable crystalline silica and to radiation emitted by natural radionuclides present both in rocks and sands was studied in the Brazilian extractive process and granite product manufacture. Respirable airborne dust samples were collected in working environments, where workers perform different tasks with distinct commercial granites types, and also in places where sandblasters work with sands from different origins. The free crystalline silica contents were determined using X-ray diffraction of the respirable particulate fraction of each sample. Dust samples from granite cutting and sandblasting ambient had the natural radionuclides concentrations measured by gamma spectrometry. Dust concentrations in the workplaces were quite variable, reaching values up to 10 times higher than the respirable particle mass threshold limit value (TLV) set by the American Conference for Governmental Industrial Hygienists of 3 mg m(-3). Also the free crystalline silica concentrations were high. reaching values up to 48 times the TLV of 0.025 mg m(-3). Additionally, our results suggest that the risk of radiation-induced cancer in the granite or marble industries is negligible. However, the combined exposure to dust, gamma radiation, and radon daughter products could result in the enhancement of lung cancer risks associated to sandblasting activities. (C) 2010 Elsevier Ltd. All rights reserved.

Occupational airborne contamination in South Brazil: 2. Oxidative stress detected in the blood of workers of incineration of hospital residues

One of the most useful methods for elimination of solid residues of health services (SRHS) is incineration. However, it also provokes the emission of several hazardous air pollutants such as heavy metals, furans and dioxins, which produce reactive oxygen species and oxidative stress. The present study, which is parallel to an accompanied paper (Avila Jr. et al., this issue), investigated several enzymatic and non-enzymatic biomarkers of oxidative stress in the blood (contents of vitamin E, lipoperoxidation = TBARS, reduced glutathione = GSH, oxidized glutathione = GSSG, and activities of glutathione S-transferase = GST, glutathione reductase = GR, glutathione peroxidase = GPx, catalase = CAT and superoxide dismutase = SOD), in three different groups (n = 20 each) exposed to airborne contamination associated with incineration of SRHS: workers directly (ca. 100 m from the incinerator) and indirectly exposed (residents living ca. 5 km the incineration site), and controls (non-exposed subjects). TBARS and GSSG levels were increased whilst GSH, TG and alpha-tocopherol contents were decreased in workers and residents compared to controls. Increased GST and CAT activities and decreased GPx activities were detected in exposed subjects compared to controls, while GR did not show any difference among the groups. In conclusion, subjects directly or indirectly exposed to SRHS are facing an oxidative insult and health risk regarding fly ashes contamination from SRHS incineration.

Preliminary studies on the effects of d-limonene to workers of the leaf-cutting ant Atta sexdens rubropilosa and its implications for control

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Selectivity of Workers of the Grass-Cutting Ants Atta bisphaerica and Atta capiguara (Hymenoptera: Formicidae) to Vegetable Oils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrastructural modifications in the venom glands of workers of Apis mellifera L. (Hymenoptera : Apidae) promoted by topical application of juvenile hormone

The present study analyzed, the influence of the treatment with juvenile hormone on the ultrastructure of Apis mellifera L. workers' venom glands. Newly emerged workers received topical application of 1 mu l of juvenile hormone diluted in hexane, in the concentration of 2 mu g/mu l. Two controls were used; one control received no treatment (group C1) and other received topical application of 1 mu l of hexane (group C2). The aspect of the glandular cells, in not treated newly emerged workers, showed that they are not yet secreting actively. Cellular modifications happened according to the worker age and to the glandular area considered. The most active phase of the gland happened from the emergence to the 14th day. At the 25th day the cells had already lost their secretory characteristic, being the distal area the first to suffer degeneration. The treatment with juvenile hormone and hexane altered the temporal sequence of the glandular cycle, forwarding the secretory cycle and degeneration of the venom gland.

Morphohistological study of the venom gland in workers of the ant Pachycondyla striata F. Smith (Hymenoptera : Ponerinae)

Themorphology of the venom gland in workers of the ant Pachycondyla striata (F. Smith) (Hymenoptera: Ponerinae) consists of an elongated sac that is directly connected to the sting apparatus. Three distinct regions compose this gland: the external secretory portion, composed by a secretory filament that bifurcates to originate another two; the internal secretory portion, which is represented by the convoluted gland from which rises the excretory duct that liberates the venom; and the storage portion, consisting of a large sac-shaped reservoir. The histology showed that the gland possesses a strong musculature on its distal third. Underneath these muscle layers, we noted the presence of an epithelium that envelops the internal wall of the reservoir. The presence of a convoluted gland as well as secretion inside the reservoir was also noted.

Enzymatic activity of hypopharyngeal gland extractsfrom workers of Apis mellifera (Hymenoptera, Apidae, Apinae)

This research presents a comparative study of enzymatic activity of the hypopharyngeal gland extracts from workers of Apis mellifera in three physiologic stages: newly emerged, nurse and forager workers, with the objective of contributing to the comprehension of the gland function. In order to determinate the enzymes present in the extracts, the Api Zym kit (Bio Merieux) was used to test the activity of 19 different enzymes. The enzymes found in larger amounts only in the hypopharyngeal glands from certain individuals were the following: in newly emerged workers, the N-acetyl-double down arrow-glucosaminidase that may be digesting the chitin of some food ingested by the bee; in forager workers, the acid phosphatase that is likely acting in authophagic processes, the a-glucosidase, in the processing of nectar into honey, and the double down arrow-glucosidases, in the pollen digestion.

Morphology of the sternal gland in workers of Coptotermes gestroi (Isoptera, Rhinotermitidae)

The sternal gland is considered the only source of trail pheromones in termites. The morphology of the sternal gland was investigated in workers of Coptotermes gestroi using transmission and scanning electron microscopy. The results showed a small bilobed gland at the anterior part of the fifth abdominal sternite. The cuticular surface of the sternal gland showed a V-shaped structure with two peg sensilla in elevated socket and various campaniform sensilla. Pores and cuticular scale-like protuberances also occur in the glandular area. The ultrastructure showed a gland composed of class I cells and two different types of class 3 cells distinguished by location, different size and electron-density of secretory vesicles. Small class 3 cells (type 1) of the anterior lobe are inserted among class I cells and have weakly electron-dense vesicles associated with mitochondria, glycogen and smooth endoplasmic reticulum. The class 3 cells (type 2) of posterior lobe showed many round electron-lucent vesicles of secretion, abundant free ribosomes and a well-developed Golgi apparatus. Each class 3 cell is connected to the cuticle by a cuticular duct constituted by the receiving canal and the conducting canal. The secretion of class I cells is stored in an inner subcuticular reservoir that is delimited by the microvilli of these cells. This inner reservoir is large and crossed by the campaniform sensilla and ducts of two types of class 3 cells that open outside of the insect body. An exterior reservoir also is present between the fourth and fifth sternite. The complex structure of the sternal gland suggests multicomponents for the trail pheromone in the worker of C gestroi. (c) 2005 Elsevier Ltd. All rights reserved.