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Biomedical subjects

R Desjardins

Publications and source records attributed to R Desjardins.

17 recordsLinked to original sources

Immunosuppression by chronic exposure to N-nitrosodimethylamine (NDMA) in mice.

Immunosuppression of humoral and cellular responses following chronic oral exposure to 1, 5, 10, and 20 ppm N-nitrosodimethylamine (NDMA) was examined in CD-1 mice. Monitoring of cumulative mortality and the incidence of peritoneal ascites in animals showed an NDMA dose-related mortality and hepatotoxicity. No visible changes in immunological parameters were noted at the 1 ppm NDMA dose. Immunosuppression of immunoglobulin M (IgM) antibody response by NDMA to sheep red blood cells (SRBC) was time-related, dose-related, and could be reversed within 30 d by removal of the chemical from the drinking water. Cellular immune response, monitored by allogeneic stimulation of cells in mixed lymphocyte reaction (MLR), was markedly suppressed by 10 and 20 ppm NDMA. Thus, chronic exposure to NDMA, except for the low-hepatotoxic doses of nitrosamine, resulted in a marked and persistent immunosuppression of cellular and humoral responses in CD-1 mice. In conclusion, chronic exposure to the hepatotoxic (ascite-inducing) doses of NDMA suppressed humoral and cellular immunity. The persistent immunosuppression could be reversed after the removal of NDMA from the drinking water. Although no direct NDMA-related cancer was reported in humans, our data point to a potential epigenetic carcinogenicity of nitrosamines due to chronic immunosuppression.

Animals

Comparative effects of intravenously administered alizapride and prochlorperazine in cisplatin-induced emesis.

A randomized, double blind crossover trial compared the antiemetic effects of alizapride, a benzamide, and prochlorperazine, a phenothiazine, both administered intravenously to 32 patients treated with chemotherapy combinations containing cisplatin. The total dose of alizapride administered to each patient was 14 mg/kg, and of prochlorperazine .56 mg/kg, divided in five doses. Although alizapride resulted in complete protection against emesis in 31% of the patients during their first course of cisplatin therapy, 42% of those who received alizapride had five or more episodes of emesis. Although prochlorperazine was less effective in offering complete protection against emesis, only 15% of the patients receiving this drug vomited more than five times. The duration of emesis during prochlorperazine treatment was also significantly shorter than during alizapride therapy (p less than 0.02). Optimal dosage and pharmacokinetic distribution of both drugs should be investigated further.

Adult

Post-myringotomy care: a prospective study.

Children with tympanostomy tubes have always been considered somewhat handicapped in regard to swimming and bathing. Their parents had to maintain constant surveillance to prevent then from getting water in their ears. A prospective study involving more than 1,000 children was conducted between June 1981 and August 1982 on two groups of randomly selected patients to determine the prevalence of suppurative otitis media and its relationship to bathing and swimming. One group had to follow strict rules to prevent water entering the ear (bathing caps, earplugs) whereas the other group was allowed to bathe and swim without any precaution upon the condition of using a polymyxin B/gramicidin ear drop combination at bedtime on the day they swam. The study shows no increase in prevalence of suppurative otitis media in the "open canal" group as compared to the "closed canal" group. Furthermore, the monthly distribution of infections shows a relatively evan distribution throughout the year. This study implies that swimming and bathing are safe for the vast majority of children with tympanostomy tubes and thus simplifies enormously the post-myringotomy care for the child, the parents, and the physician.

Baths

[Nasotracheal intubation and tracheostomy in acute epiglottitis and laryngotracheal bronchitis].

Acute infectious respiratory distress in children has known different modalities of treatment during these past few years, but controversy remains between tracheostomy and naso-tracheal intubation as ways to cope with the problem. This study, which was undertaken at St. Justine's Hospital in Montreal, reports our complications with the two methods and shows that non-fatal complications are about the same but less serious with naso-tracheal intubation, whereas mortality was 3.2% with tracheostomy and 0% with naso-tracheal intubation. These results entitle us to think that naso-tracheal intubation is the treatment which should be used. This study also reviews different incidence in regards to age, sex, and seasonal prevalence between croup and epiglottitis and also compares the duration of hospital care between the two modalities.

Acute Disease

Acute epiglottitis in children: management of 27 consecutive cases with nasotracheal intubation, with special emphasis on anaesthetic considerations.

Twenty-seven consecutive cases of acute epiglottitis in children were treated by nasotracheal intubation during a 25-month period. The duration of intubation averaged 44.2 hours. No mortality or morbidity occurred. Mean hospitalization was 4.5 days. Anaesthetic techniques are discussed. Ketamine is a somewhat controversial choice for these patients as it can enhance excitement, restlessness, and accidental extubation. This study reconfirms the ease of maintaining an assured airway by nasotracheal intubation in cases of acute epiglottitis.

Age Factors