Knowledge of and attitudes about blood-borne viruses and infection control in Brazilian dental practice

OBJECTIVE

To determine whether there were any recent changes in hepatitis B immunisation of dental staff, infection control or understanding of viral infections in Brazilian dentists.

DESIGN

A randomised survey was conducted on 740 dentists attending the National Dental Congress in Sao Paulo, Brazil in 1994.

SUBJECTS AND METHODS

The 740 dentists were questioned as to the presence of various viruses in saliva, the perceived risks of dental staff and long-term sequelae, the availability and uptake of vaccines, willingness to treat virus-infected persons, and means of infection control. Nearly 69% of respondents were female dentists, of mean age 30 years. Results were compared with a similar survey from 1990.

RESULTS

Most respondents knew that HIV and hepatitis viruses could appear in saliva and almost all knew of infective risks from hepatitis B (HBV), and the availability of the vaccine. Less than half knew of the association of HBV with liver cancer. There was a four-fold increase in those vaccinated against HBV since the low figure of 9% in 1990. Nearly two-thirds of respondents perceived an occupational risk to dental staff from HIV, and a similar proportion were also unwilling to treat virus-infected persons. A similar proportion also used chemical disinfection for some dental instruments.

CONCLUSIONS

The results show little improvement over a 4-year period except a much greater proportion of dentists were immunised against HBV. However, still only one third of dentists had been vaccinated, in a country with a high prevalence of infection in the general population.

Oral lichen planus and chronic active hepatitis B: a salutary tale

Oral lichen planus is occasionally associated with chronic active hepatitis or primary biliary cirrhosis. This paper describes a patient who presented with oral lichen planus and proved to have chronic active hepatitis, evidently related to hepatitis B virus infection. Oral lichen planus appears occasionally to be associated with systemic infection with hepatitis B or hepatitis C viruses, particularly in patients from southern Europe.

Oral paracoccidioidomycosis. A study of 36 South American patients

Paracoccidioidomycosis (South American blastomycosis) is an uncommon, progressive systemic mycosis, virtually only seen in persons who have visited Latin America. Reports of oral lesions are extremely rare in the English-language literature. Thirty-six adults with oral lesions as the first sign of paracoccidioidomycosis are described; this appears to be the largest series in the dental literature. All had chronic proliferative mulberry-like ulcerated oral lesions; the diagnosis was confirmed histologically. The gingiva or alveolar process was the typical site, but lesions were also seen particularly on the palate and lip. Most of the patients proved to have detectable pulmonary involvement. Patients with lesions in the oropharynx, tongue, or floor of mouth all had confirmed pulmonary lesions.

Autoradiographic evidence of opioid binding sites in rat growth plate chondrocytes

After 125I-beta-endorphin was intravenously injected in rats, an autoradiographic study of distal femur growth plates was performed. Results show a specific binding of the radiolabelled peptide to chondrocytes suggesting the possible existence of an opiate modulation of growth plate physiology.

Oral manifestations of paracoccidioidomycosis (South American blastomycosis)

Paracoccidioidomycosis (South American blastomycosis) is an uncommon, progressive systemic mycosis, potentially fatal if untreated. It is virtually restricted to persons spending time in Latin America. Reports of oral lesions are extremely rare in the English-language literature. Three adults with oral lesions as the first sign of paracoccidioidomycosis are described; this appears to be the largest series in the dental literature. The oral lesions had a characteristic appearance with a granular purpuric surface. The upper gingiva was a typical site, but lesions were also seen in the palate, tongue, and buccal mucosa. Two of the patients proved to have detectable pulmonary involvement. Long-term systemic ketoconazole therapy produced resolution of oral lesions in all cases.

Methylthiazolidine-4-carboxylate for treatment of acute T-2 toxin exposure

The effect of T-2 toxin on hepatic glutathione content and the protective effect of 2-methyl-thiazolidine-4-carboxylate (MTCA), an L-cysteine prodrug, were studied in mice. Acute exposure to T-2 toxin (4 mg kg-1, s.c.) resulted in a progressive decrease in glutathione content, reaching a minimum 6-8 h after toxin administration. Because T-2 toxin caused decreased food consumption, a condition known to deplete hepatic glutathione, glutathione was measured in both fed and fasted control and toxin-treated mice. Glutathione content (mumol g-1 tissue) was 9.01 +/- 0.66 (control) and 4.26 +/- 0.41 (toxin) for fed mice, 4.45 +/- 0.39 (control) and 2.45 +/- 0.26 (toxin) for 16-h fasted mice, and 7.18 +/- 0.26 (control) and 3.76 +/- 0.65 (toxin) for mice fed before, but fasted after exposure to toxin. In all cases, toxin treatment resulted in significant decreases in glutathione content compared to controls. Treatment of T-2-intoxicated mice with MTCA (750 mg kg-1, i.p.) not only maintained glutathione content at control levels or higher but significantly improved survival as well. Therefore, the toxicity and lethality of T-2 toxin may be associated with decreased hepatic glutathione content, since MTCA maintained glutathione content and improved survival.

Autoradiographic evidence of 125I-beta-endorphin binding sites in the articular cartilage of the rat

After 125I-beta-endorphin was intravenously injected to rats, an autoradiographic study of distal femur articular cartilage was performed. Results show a specific binding of 125I-beta-endorphin to chondrocytes, suggesting the possible existence of an opiate modulation of articular cartilage.

Beneficial effect of dexamethasone in decreasing the lethality of acute T-2 toxicosis

1. Steroidal and non-steroidal anti-inflammatory agents were evaluated for effectiveness for treatment of acute T-2 toxicosis in mice. 2. Non-steroidal agents, indomethacin, phenylbutazone, and acetylsalicylic acid, either were ineffective, or potentiated the lethality of T-2 toxin. 3. Of the anti-inflammatory steroids tested, dexamethasone was the most effective. 4. Dexamethasone was administered before, at the same time as, or after injection of T-2 toxin. 5. As the time between toxin exposure and treatment was increased, there was a corresponding increase in lethality. 6. In conclusion, steroidal, but not non-steroidal, anti-inflammatory agents were effective in decreasing T-2 toxin-induced lethality.

Assessment of efficacy of activated charcoal for treatment of acute T-2 toxin poisoning

"Superactive" charcoal was assessed for efficacy in decreasing the lethality of both oral and parenteral exposure to T-2 toxin, a fungal metabolite which can cause death or illness upon ingestion. In vitro binding studies, analyzed using the Langmuir adsorption isotherm, showed that activated charcoal had a maximal binding capacity of 0.48 mg toxin/mg charcoal and a dissociation constant of 0.078 mg charcoal/l. In vivo, orally administered, activated charcoal was assessed for treatment of acute oral or parenteral exposure to T-2 toxin in mice. Following oral toxin administration (5 mg/kg), untreated mice showed only 6% survival after 72 hr. Charcoal treatment (7 g/kg,po) either immediately or 1 hr after toxin exposure resulted in significant improvement in survival with values of 100% and 75%, respectively. Following parenteral toxin exposure (2.8 mg/kg, sc), untreated and charcoal-treated (7 g/kg, po) mice showed 50% and 90% survival, respectively, after 72 hr. LD50 value for T-2 toxin, determined at 96 hr after intoxication, increased significantly from 2 mg/kg for untreated controls to 4.5 mg/kg for activated charcoal treatment.