Detection and Sizing of Ti-Containing Particles in Recreational Waters Using Single Particle ICP-MS

Single particle inductively coupled plasma mass spectrometry (spICP-MS) was used to detect Ti-containing particles in heavily-used bathing areas of a river (Salt River) and five swimming pools. Ti-containing particle concentrations in swimming pools ranged from 2.8?×?10³ to 4.4?×?10³ particles/mL and were an order of magnitude lower than those detected in the Salt River. Measurements from the Salt River showed an 80% increase in Ti-containing particle concentration over baseline concentration during peak recreational activity (at 16:00 h) in the river. Cloud point extraction followed by transmission electron microscopy with energy dispersive X-ray analysis confirmed presence of aggregated TiO₂ particles in river samples, showing morphological similarity to particles present in an over-the-counter sunscreen product. The maximum particle mass concentration detected in a sample from the Salt River (659 ng/L) is only slightly lower than the predicted no effect concentration for TiO₂ to aquatic organisms (<?1 μg/L).     

Two-way cross-reactions between serotypes of Actinomyces viscosus.

Three antigen preparations were obtained from cultures of A. viscosus Serotypes 1 and 2. Ammonium sulphate (60 per cent w/v) and acetone precipitates were obtained from cellfree culture supernatants of late-log phase cultures of each organism. The third preparation consisted of the supernatant obtained after homogenization of late-log phase cells of each organism. Immunodiffusion and immunoelectrophoresis using rabbit antisera to each serotype were used to identify the soluble antigens present in each preparation. Ammonium sulphate preparations proved to be the most reproducible and contained the greatest number of identifiable antigens. Homologous and cross-reacting antigens were identified and two-way cross-reactions were observed between the serotypes.     

The role of xeroradiography in cephalometric radiology.

The advantages of xeroradiography in the precise identification of anatomical landmarks for orthodontic analysis are overwhelming. In addition, the soft tissues of the face are shown fully and in detail. The tongue and soft palate can also be visualized. However, there is undue anxiety among clinicians and radiologists about the risk of excessive radiation exposure to patients. This has hitherto been regarded as unavoidable for the purposes of xeroradiography.This paper sets out in detail the advantages of xeroradiography for cephalometry and also clarifies the problem of patient exposure by presenting detailed measurements of the parameters affecting exposure and of the incident skin exposure. In this way it can be shown that by choice of correct kilovoltage and adequate filtration the incident skin exposure can actually be reduced when compared with conventional techniques using film.     

Assessing oral cancer knowledge among dental students in South Carolina

BACKGROUND: Because South Carolina has the fourth highest mortality rate for oral cancer among the 50 states, dental students in the state must be knowledgeable about prevention and early detection of the disease. METHODS: In 2002, the authors surveyed 163 students using a written questionnaire (response rate, 79.1 percent). The questionnaire included questions about oral cancer risk and nonrisk factors as well as oral cancer diagnostic signs, symptoms and examination procedures. The authors performed univariate and bivariate analyses (alpha < or = .025). RESULTS: At least 93 percent of the students replied that tobacco, alcohol and previous oral cancer lesions were risk factors. One hundred six students (65 percent) knew that the most likely site for oral cancer is the ventrolateral border of the tongue. Students differed in their overall knowledge of risk factors (P = .002), nonrisk factors (P < .001) and diagnostic procedures (P < .001). CONCLUSION: Although students' level of knowledge increased with academic year, educators and policy-makers need to place greater emphasis on oral cancer education and training in dental schools. PRACTICE IMPLICATIONS: Morbidity and mortality are likely to be reduced if dentists know how to prevent and detect oral cancer.     

Spine surgeons’ requirements for imaging at the time of referral: a survey of Canadian spine surgeons

Background

Routine imaging of patients with spine-related complaints referred for surgical assessment may represent an inefficient use of technological resources. Our objective was to explore Canadian spine surgeons’ requirements with respect to imaging studies accompanying spine-related referrals.

Methods

We administered an 8-item survey to all 100 actively practising surgeon members of the Canadian Spine Society that inquired about demographic variables and imaging requirements for patients referred with spine-related complaints.

Results

Fifty-five spine surgeons completed our survey, for a response rate of 55%. Most respondents (43; 78%) required imaging studies to accompany all spine-related referrals. The type of imaging required was highly variable, with respondents endorsing 7 different combinations. Half (47%) required magnetic resonance imaging and 38% required plain radiographs either alone or in combination with other forms of imaging. Half of the respondents refused to see 20% or more of all patients referred for spine-related complaints.

Conclusion

Most Canadian spine surgeons require imaging studies to accompany spine-related referrals; however, the type and combination of studies is highly variable, and many patients who are referred are never seen (for a consultation). Standardization and optimization of imaging practices for patients with spine-related complaints referred for surgical assessment may be an important area for cost savings.     

Lysis of complement-sensitive Entamoeba histolytica by activated terminal complement components. Initiation of complement activation by an extracellular neutral cysteine proteinase.

Activation of complement by Entamoeba histolytica may be initiated by the extracellular 56-kD neutral cysteine proteinase which cleaves the alpha chain of C3. To determine the relationship between the fluid-phase activation of complement and our observation that only strains isolated from patients with invasive disease are resistant to complement-mediated lysis, we investigated the fate of C3 with recent amebic isolates. When 125I-C3 was incubated with trophozoites in serum, C3 in the fluid phase was cleaved to C3b or C3bi, but the alpha chain of the C3 molecules on the cell surface appeared intact. Since the lysis of nonpathogenic strains takes place in the absence of bound C3b, we demonstrated that this reaction occurs by reactive lysis initiated in the fluid phase: (a) the killing of nonpathogenic strains was enhanced when alternative pathway activation was accelerated by the addition of cobra venom factor; (b) non-pathogenic strains were lysed by purified terminal components; and (c) sera incubated with pathogenic E. histolytica produced passive lysis of chicken erythrocytes. These results demonstrate for the first time that complement-sensitive E. histolytica are lysed by activation of the terminal complement components in the fluid phase where the 56-kD neutral cysteine proteinase cleaves C3, and not by the surface deposition of activated C3.     

Airway management for the uninitiated

The 21(st) century has witnessed burgeoning interest in airway management. Pertinent basic sciences are covered in numerous texts and lectures. This article presents clinical information required to perform airway management. It serves as a primer for those interested in learning airway management skills. It does not replace extensive practice under the tutelage of expert airway managers.