Determining exhaust fumes exposure in chainsaw operations.

The objective of this study was to investigate the inhalation exposure of forest operators to polycyclic aromatic hydrocarbons (PAHs) and BTEX (benzene, toluene, ethylbenzene and total xylenes) contained in the exhaust fumes released from chainsaws and to suggest possible countermeasures. The study was carried out in four silvicultural treatments (coppice clearcut, conifer thinning, conifer pruning, and sanitary cut), using three types of chainsaw fuel (normal two-stroke petrol mix and two alkylate fuels). Eighty personal air samples were collected; IOM samplers combined with Amberlite XAD-2 sorbent tubes were used for collecting PAHs and Radiello® samplers were used for BTEX. Results indicate that none of the four silvicultural treatments significantly affected the PAHs and BTEX inhalation exposure of forest workers. On the other hand, statistically significant differences were recorded in the inhalation exposure to PAHs and BTEX when using different fuel types. In particular, the inhalation exposure to PAHs and BTEX was generally one order of magnitude lower when using modern alkylate fuels as compared to the traditional oil and lead-free petrol mixture. The small, non-statistically significant differences in inhalation exposure recorded between the two alkylate fuels suggests that the two fuels might be equivalent in terms of quality. Our study indicates that while forest workers are exposed to PAHs and BTEX, the maximum values are generally well below accepted occupational exposure limits.

Lead poisoning in monkeys during pregnancy and lactation.

Twenty-two female monkeys (Macaca irus) were given lead acetate by an intramuscular route during pregnancy and/or lactation. A high dose of lead (5 mg Pb2+/kg/day) can induce abortions and death in pregnant monkeys. At a lower dose (1 mg Pb2+/kg/day), the foetus can be exposed to lead via placenta and/or maternal milk. Studies using optical microscopy showed the typical renal lesions in mothers treated during pregnancy (five months) and an erythrodiapedesis in cerebral matter of the new-born at birth.

Adverse influence of diazepam upon resistance to Klebsiella pneumoniae infection in mice.

Male and female mice, IOPS OF1 strain, received an i.p. injection of diazepam 1,2,4 or 8 mg/kg daily for 3 days prior to i.p. challenge with Klebsiella pneumoniae. Diazepam pretreatment increased mortality due to Klebsiella pneumoniae indicating that diazepam alters natural resistance to infection. The mechanism has not been elucidated but would appear to involve T cells and/or macrophages.

Influence of lead and nickel on passive cutaneous anaphylaxis in the rat.

Male rats, IOPS OFA strains, were injected s.c. with doses of lead acetate (0.5 to 30 mg Pb2+/kg/day) and nickel chloride (0.05 to 5 mg Ni2+/kg/day), for 3 days prior to being challenged for immediate hypersensitivity induced by ovalbumin/antiovalbumin system. The vascular permeability was statistically increased in animals of each group (P less than 0.001, Student's t-test). These results may indicate an action of lead and nickel salts on mast cells and their membranes, but also an action on the vasodilation induced by vasoactive amines.

[Anti-anaphylactic properties of verapamil. First experimental assessment]. / Propriétés anti-anaphylactiques du vérapamil. Première évaluation expérimentale.

1. In order to confirm the potential anti-anaphylactic properties of verapamil, the effects of this calcium antagonist were assessed on several experimental models: anaphylactic shock in mice, passive cutaneous anaphylaxis in Rats, and degranulation of Rat peritoneal mast cells. 2. At a dose of 5 mg/kg IP, half-an-hour before challenge, verapamil decreased systemic anaphylaxis-induced lethality significantly. On the reverse, in the same conditions, it was unable to inhibit passive cutaneous anaphylaxis at 0.1-0.5-1 or 10 mg/kg; it did even increase it at a dose of 5 mg/kg IP over the last 3 days. However, specific degranulation of rat peritoneal mast cells was significantly decreased after in vitro incubation with verapamil (0.25 and 1.25 micrograms/ml or after pretreatment with 5 mg/kg/day over 3 days). 3. These early results confirm the hypothesis of verapamil anti-anaphylactic properties whose consequences warrant further investigation.

Effects of variations in time and dose of diazepam injection on delayed hypersensitivity.

Administration of diazepam was suggested to exert immuno-suppressive properties in mice. In the present study, we explored the time and dose-dependence of diazepam effects on delayed hypersensitivity to sheep erythrocytes in Balb/c mice. DTH response was only depressed when diazepam was injected shortly after immunization and this effect on DTH induction was found with doses of 4 and 8 mg/kg ip while lower doses (0, 5, 1 and 2 mg/kg) remained ineffective.