Ultrastructural changes in acute nonstreptococcal glomerulonephritis associated with mixed cryoglobulinemia

A kidney biopsy specimen obtained from a patient with mixed cryoglobulinemia and glomerulonephritis was studied by electron microscopy. The glomeruli showed focal proliferations of endothelial and mesangial cells, a focal increase of the mesangial matrix, and various electron-dense deposits, including discrete subepithelial deposits. To our knowledge, such deposits have not previously been illustrated in this syndrome. The finding of subepithelial deposits indicates that immune complexes are implicated in the pathogenesis of the glomerulonephritis. The cryoglobulins may have constituted the immune complexes. The differential diagnostic significance of subepithelial deposits is discussed.     

Optically guided patient positioning techniques

Optical tracking determines an object's position by measuring light either emitted or reflected from the object. The hallmark of optical tracking systems is their high spatial resolution and measurement in real time; such systems can resolve the position of a point source within a fraction of a millimeter and report at a rate of 10 Hz or faster. Several systems have been developed for radiation therapy, all of which track infrared markers attached to the patient's external surface. The positions of the optical markers relative to the target volume, together with the desired marker positions relative to treatment isocenter, are determined during computed tomography simulation. In the treatment room, the real marker positions are measured relative to isocenter; rigid-body mathematics then determine marker displacements from their desired positions and hence target displacement from isocenter. Real-time feedback allows one to correct the patient's position. The first systems were used for intracranial stereotaxis radiotherapy; rigid arrays of optical markers were attached to the patient via a biteplate linkage. Subsequent systems for extracranial radiotherapy tracked external markers to determine patient position and/or gate the radiation beam based on patient motion. Lastly, optical tracking has been integrated with ultrasound or stereoscopic x-ray imaging to determine the position of internal anatomy targets relative to isocenter.     

Presentation and diagnosis of imported schistosomiasis: relevance of eosinophilia, microscopy for ova, and serology

BACKGROUND: In nonendemic countries a steady rise in cases of imported schistosomiasis has been observed. The objective of this study was to describe the presentation of patients diagnosed with schistosomiasis in the Outpatient Department (OPD) for Tropical Diseases in the Academic Medical Center, Amsterdam, the Netherlands. METHODS: In a retrospective study, patients with schistosomiasis from our OPD (1997-1999), including a subgroup of persons asking for screening for schistosomiasis and found positive, were analyzed. Diagnosis was based on freshwater exposure in an endemic area and positive serology for schistosomal antibodies. The following data were recorded: age, gender, country of birth, travel destination, symptoms, eosinophil count, and results of serology and stool and urine microscopy. RESULTS: Seventy-eight patients (42 travelers, 16 expatriates, and 20 immigrants) were diagnosed with schistosomiasis; 47% were infected in southern Africa. Twenty-four percent had specific symptoms, 57% had eosinophilia, and in 17 patients (22%) Schistosoma ova were found. Eleven travelers suffered from Katayama syndrome. Of the subgroup of 42 persons screened for schistosomiasis, 15 (36%) had schistosomal antibodies; the majority of these persons (10/15 [67%]) were infected in southern Africa. CONCLUSION: In our OPD schistosomiasis was diagnosed in about 26 patients per year, 3% of all new presentations. Infections were almost exclusively acquired in Africa. In travelers high eosinophilia was due to acute schistosomiasis; in immigrants it was due to concomitant helminthic infections. One of three people asking to be screened for schistosomiasis had schistosomal antibodies. Eosinophilia was indicative but an insufficient screening tool, and stool and urine microscopy for ova were not sensitive. Screening by serology is easy and reliable and the method of choice in asymptomatic persons with a history of freshwater exposure in a high-risk area.     

Outlook: directed development: catalysing a global biotech industry

Governments are increasingly relying on directed development tools or proactive public-policy approaches to stimulate scientific and economic development for their biotechnology industries. This article will discuss the four main tools of directed development in biotechnology and the lessons learned from current global efforts utilizing these tools.     

Interseasonal variability in biomarkers of exposure in fish inhabiting a southwestern Australian estuary

The Swan-Canning Estuary, in southwestern Australia, undergoes distinct seasonal changes, with freshwater discharge predominant in the winter (wet) season and low flow with high salinity predominant in the dry summer season. To investigate seasonal variability in biomarkers of exposure in fish, black bream (Acanthopagrus butcheri) were collected from seven sites in the Swan-Canning Estuary in winter 2000 and in summer 2001. No interseasonal or intersite differences in serum sorbitol dehydrogenase concentration were found, indicating the measured mixed-function oxygenase (MFO) enzymes were not influenced by liver damage. The ethoxyresorufin-O-deethlyase (EROD) activity of the postspawning females was higher in summer than in winter but was significantly lower than that in males in both seasons, suggesting estradiol suppression in females. Sexual differences in ethoxycoumarin-O-deethylase (ECOD) activity were not evident in either season. Both EROD and ECOD activities and polycyclic aromatic hydrocarbons (PAH) biliary metabolites had significantly different patterns of induction between seasons. The ratio of naphthalene-type to benzo(a)pyrene-type biliary metabolites was significantly higher in summer, indicating the sources of petroleum hydrocarbons were petrogenic compared to in winter, when the source was a mixture of pyrogenic and petrogenic PAHs. There was no upstream or downstream gradient of response in any biomarker in either season, demonstrating that there were multiple sources of contaminant input into the estuary. Although winter biomarker levels were triggered by the discharge runoff from major roads and drains, summer biomarker levels appear to have been related to recreational boating use on the estuary.     

Measuring progress in the management of ambient air quality: the case for population health

Although progress has been made in the last few decades at reducing ambient concentrations of air pollutants, scientific evidence suggests that there remains a risk to human health from exposure to these pollutants at current levels in Canada. Much of the motivation for air pollution reduction efforts is to protect population health. This article presents a method of monitoring changes in air pollution-related health outcomes over time in conjunction with temporal changes in ambient pollution concentrations. The progress measure is a function of temporal changes in location-specific ambient concentrations and the potentially time-dependent association between those concentrations and daily deaths. The progress measure can be determined for a single location or at a national level. The measure can also be extended to include several pollutants. The progress measure is illustrated with an example of how changes in nitrogen dioxide levels in 12 Canadian cities from 1981 to 1999 have translated into changes in the percent of nonaccidental mortality burden attributable to this pollutant over time.