Teaching infection control: a theoretical and practical essay

This article contains reflections concerning infection prevention and control measures starting from the adherence of health professionals to prevention measures. It points out worrisome environment-related aspects stemming from the use of disposable materials in spite of the benefits that they represent in terms of safety and reduction of operational costs, among others. All these issues are presented as a challenge to infection control teaching in the education of health professionals. Some guiding presuppositions are also presented.     

Mercury Biomagnification in a Tropical Black Water,Rio Negro,Brazil

The population living along the riverbanks of the Amazon basin depends heavily on fish for nutritional support. Mono-methyl-mercury (MMHg) concentrates in fish, which can contaminate humans, the risk depending not only on fish MMHg concentration but also on the amount of fish consumed. We sampled nine locations of the Rio Negro basin, differing in water pH, Hg concentrations, and dissolved organic carbon (DOC), and determined total Hg from 951 fish samples of species representative of the food web: herbivorous, detritivorous, omnivorous, and piscivorous. Mercury concentrations varied widely in all species but showed a trend that depended on fish feeding strategies. The highest mean concentration was found in the piscivorous species (688.90 ng/g^–1), followed by omnivorous (190.30 ng/g^–1), detritivorous (136.04 ng/g^–1), and herbivorous (70.39 ng/g^–1). Fish Hg concentrations exceeding current safe limits (500 ng/g^–1) for human consumption were found mainly in the piscivorous species (60%). Significant positive correlation between fish weight and Hg concentration was seen for the piscivorous Serrasalmus spp. (n = 326; r = 0.3977; p < 0.0001), Cichla spp. (n = 125; r = 0.4600; p < 0.0001), and Pimelodus spp. (n = 12; r = 0.8299; p = 0.0008), known locally as Piranha, Tucunaré, and Mandi, respectively. However, a negative correlation was seen for nonpiscivorous Potamorhina latior (n = 30; r –0.3763; p = 0.0404) and Leporinus spp. (n = 44; r = –3987; p = 0.0073), known as Branquinha (detritivorous) and Aracu (omnivorous). Fish-Hg concentrations in the acidic waters (pH range, 4.09–6.31) of the Rio Negro habitat, with its wide gradient of Hg concentrations (3.4–11.9 g/L^–1) and DOC (1.85–15.3 mg/L^–1)—but no history of gold mining activity—are comparable to other Amazonian rivers. Opportunity fish catches in the Rio Negro habitat show high muscle-Hg derived from natural sources, but no systematic association with site-dependent geochemistry.     

Changes in hemopoietic precursors after treatment of low-risk myelodysplasia with amifostine

BACKGROUND: Clinical studies have shown that amifostine (AMF) improves peripheral cytopenias in myelodysplastic syndromes (MDS). We studied the expression of Fas/FasL on CD34+ cells in low risk MDS and its change after AMF treatment. PATIENTS AND METHODS: Patients received AMF 400 mg/m2 3x/week for 3 weeks and 2 weeks off treatment. Peripheral blood counts and BM cytology were analysed before and after 2 courses. Quantification of CD34+ cells and CD34/CD95 and CD34/CD95L ones were performed by flow cytometry. RESULTS: Seventeen patients were treated. After 2 months, 8 patients showed a rise in neutrophil count. Hemoglobin increased in 1 and thrombocytes in 2 patients. Before treatment, responding patients presented a significantly lower expression of Fas (median 53%) and FasL (median 26%) than non-responders (85% and 70%, respectively). BM lymphocytes were significantly lower in responders (median 14.5% and 27.4%, respectively). In responders CD34+ cells decreased after treatment. The change in neutrophil count after treatment presented an inverse correlation with the percentage of BM lymphocytes before treatment (r = 0.0-0.58; p = 0.02). CONCLUSION: Response to AMF may be influenced by the intensity of the immune reaction in BM.     

Benefits of intraluminal injection of glutamine for intestinal mucosa during ischemia-reperfusion

BACKGROUND: We investigated the effect of intraluminal glutamine on the intestinal mucosa in the presence of ischemia-reperfusion injury (IRI). METHODS: Six blind sacs were created in the small bowel (3 at the jejunum and 3 at the ileum) in 10 Wistar rats. The lateral sacs of both bowel regions were submitted to IRI (30/30 min), while the medial sacs were left free to receive blood supply. In the lateral sacs, a solution containing either saline plus 4% glutamine or pure saline was injected at the bowel lumen. No fluid was injected in the medial sacs. RESULTS: Both at the jejunum and at the ileum, the score of the mucosal injury was higher in saline-injected sacs than in either glutamine-injected or control sacs. There was a significantly greater number of neutrophils in the sacs treated with saline than in the other two groups of sacs. CONCLUSION: Glutamine protects the mucosa and diminishes the accumulation of neutrophils at the lamina propria of the small bowel in IRI.     

Prognostic factors for the survival of surgically treated patients for non-small cell lung cancer

The survival and outcome rates of 284 patients who underwent surgical treatment for non-small cell lung cancer were assessed retrospectively. Resectability rate was 94.1%, hospital mortality 3.9% (n=11) and the mortality rates in patients who underwent pneumonectomy or lobectomy were 8.9% and 0.6%, respectively. The overall 5-year survival was 43.6%. Female gender, earlier stages of disease and a complete resection were strongly predictive for a long-term survival. Women in stage IA disease had a 5-year survival rate of 92.7%. The 5-year survival rate for patients in stages IIIA and N2 disease who underwent a complete resection was 21.9%, and 9% for those who did not undergo a complete resection. It is concluded that the best surgical results were observed in women who were operated on at an early stage of disease. A complete resection also contributed to a better outcome, even for patients in stage IIIA and N2 disease.     

Inhibition of cyclophosphamide-induced teratogenesis by beta-ionone

Beta-ionone (BI) is a degraded (C 13) sesquiterpene found in plant essential oils. It has been used in the synthesis of perfume chemicals and vitamin A. Recently, it was reported that BI is a rather potent in vitro inhibitor of CYP2B1-catalysed reactions in rat liver microsomes. The present study was performed to investigate whether inhibition of CYP2B1 reactions by BI could lead to an attenuation of cyclophosphamide (CP)-induced embryotoxicity in the rat. In a preliminary experiment, a dose-dependent prolongation of pentobarbital sleeping time in male and female Wistar rats suggested that BI inhibits CYP2B1 in vivo as well. In a second experiment, rats were treated by gavage with BI (0, 250, 500, 750 or 1000 mg/kg body wt) 45 min prior to a subcutaneous injection of either CP (7.5 mg/kg body wt) or its vehicle (saline) on day 11 of pregnancy. BI alone, at the highest dose tested, caused a high proportion of resorptions. Lower doses of BI, however, clearly attenuated CP-induced embryolethality and teratogenicity. These results seem to support the view that, as far as rats are concerned, CYP2B1 plays an important role in the conversion of CP into its embryolethal and teratogenic metabolites.     

Reaction of rat connective tissue to implanted dentin tube filled with mineral trioxide aggregate, Portland cement or calcium hydroxide

The subject of this study was to observe the rat subcutaneous connective tissue reaction to implanted dentin tubes filled with mineral trioxide aggregate, Portland cement or calcium hydroxide. The animals were sacrificed after 7 or 30 days and the undecalcified specimens were prepared for histological analysis with polarized light and Von Kossa technique for mineralized tissues. The results were similar for the studied materials. At the tube openings, there were Von Kossa-positive granules that were birefringent to polarized light. Next to these granulations, there was an irregular tissue like a bridge that was Von Kossa-positive. The dentin walls of the tubes exhibited in the tubules a structure highly birefringent to polarized light, usually like a layer and at different depths. The mechanism of action of the studied materials has some similarity.     

Gingival erosive lichen planus: case report

A case of gingival erosive lichen planus is presented with special emphasis on its clinical and microscopic characteristics. The differential diagnosis and the controversy associated with the malignant potential of oral lichen planus is also discussed.     

Acellular dermal matrix graft as a membrane for guided bone regeneration: a case report

Guided bone regeneration has been successfully used to treat several types of bone defects. Problems associated with the procedure, such as premature exposure of the membranes to the oral cavity and, consequently, contamination, may occur. The acellular dermal matrix graft material is presently used to treat several soft tissue problems. It could be used for guided bone regeneration with the advantage of forming soft tissue while acting as a barrier membrane. A patient in need of guided bone regeneration for the staged placement of an implant was treated by using the acellular dermal matrix graft material as a barrier membrane. Healing progressed uneventfully with the formation of adequate new bone and an increase in the width of keratinized tissue.