Characterization of Escherichia coli strains isolated from urine of secretors and non-secretors

Abstract Strains of Escherichia coli isolated from urine of secretors (242) and non-secretors (121) were compared for their serotype and their ability to express mannose-sensitive (MS) haemagglutinins and mannose-resistant (MR) haemagglutinins and to produce haemolysin. The results of the survey refuted our hypothesis that strains with characteristics associated with virulence, those with MR haemagglutinins and/or haemolysins, would be isolated more frequently from non-secretors. MR haemagglutinins were detected among 36.4% of isolates from secretors and 27.3% of isolates from non-secretors. Haemolysin production was detected among 19.8% of isolates from secretors and 12.5% of isolates from non-secretors. Both MR haemagglutinins and haemolysin were detected only on 12.4% of strains from secretors and 6.7% of strains from non-secretors.     

Standard Specimens for Stain Calibration: Application to Romanowsky-Giemsa Staining

Standardized specimens with reprodcible staining properties were fabricated from extracts of biological objects (bovine liver, nucleoprotamine and defatted muscle). The standard specimens were stained with two formulations of the Romanowsky-Giemsa stain (RG), using the same azure B and eosin Y. One formulation used methanol and Sorensen's buffer and the other DMSO and Hepes buffer as solvents. The standard specimens were stained either in the composite stain or in the individual dyes dissolved in the same solvents and at the same concentration as the composite stain. Solution spectroscopy demonstrated different spectra for the two formulations with some wavelength regions varying by more than an order of magnitude. The RG spectra were also very different from those of the individual dyes dissolved at the RG concentration in the respective solvents. The stained standard specimens were analyzed by microspectrophotometry and were found to have spectra similar to those of cell smears. Furthermore, the standard specimens were shown to be a repeatable substrate for stain uptake. The transmitted light intensity from random fields of the same standardized specimen varied ±5%. When specimens were stained at the same time, the specimen-to-specimen variation depended on preparation conditions and the measurement wavelength, but was as good as ±5% for some conditions. The quantitative stain performance of both formulations was studied and compared. The standardized specimens provide a tool for the quantitative study of staining processes and specimen preparation procedures and for stain calibration.     

Studies on Central African Pans III

Summary Measurement have been recorded of alkalinity, pH, and diurnal temperature variation in twelve shallow ephemeral rain pools on aeolian Kalahari sand in Central Africa. These twelve pools were representative of many throughout the region and covered a wide range of volumes. All the pools, however, were subject to rapid temperature fluctuations on hot sunny days, from temperatures in water and mud of 20°C–25°C in the morning to 35°C–38°C (water) and 30°C–35°C (mud) in the afternoon. Where vegetation was present in larger pools and where ungulate faeces were abundant, the pools developed organic sediments which were analysed during the dry season. Organic (faecal) pollution was common in pools lying on salt lick areas frequented by game animals, and was therefore most marked in alkaline pools.Macroscopic organisms were sampled by nets and with traps, and were analysed by number and by weight. Estimates are given of population density and of standing crop biomass. The biological properties of the pools (vegetation and pollution) had a marked effect on the macrofauna, qualitatively and quantitatively. This was reflected in mechanisms of dispersal and aestivation, and in respiratory mechanisms. Three probable food chains were demonstrated. The fauna comprised a restricted number of specialised species in certain groups — particularly well represented by species numbers were Coleoptera and Hemiptera, and quantitatively tadpoles, Odonata, Conchostraca and Anostraca were important. Predators formed a high proportion of the population. Standing crop biomass was highest in polluted alkaline pools in which tadpoles and Anisops were abundant.

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Zusammenfassung Aus zwölf seichten, flachen, ephemerischen Regenlöchern im äolischen Kalaharisand in Zentral-Afrika wurden Messungen von Alkalinität, pH und Tagestemperatur-Unterschieden aufgezeichnet. Diese zwölf Tümpel sind representativ für viele der ganzen Gegend und haben ganz verschiedenen Inhalt. Alle Tümpel waren rapiden Temperatur-Fluktuationen ausgesetzt an heißen, sonnigen Tagen, von Temperaturen von Wasser und Schlamm 20–25°C morgens, bis nachmittags von 35–38°C (Wasser), 30–35°C (Schlamm). Wo in größeren Teichen Vegetation vorhanden war und wo reichlich Ungulatkot war, entwickelten sich in den Teichen organische Sedimente, welche während der Trockenzeit analysiert wurden. Organische (Kot) Verunreinigung des Wassers war allgemein üblich in Teichen die in Salz-Lecke Gegenden, überhäuft von Wild, lagen, und fiel daher am meisten in alkalischen Teichen auf.Proben von makroskopischen Organismen wurden mit Netzen und Fallen genommen und nach Nummer und Gewicht analysiert. Berechnungen der Bevölkerungsdichte und der Ergiebigkeit (Biomasse) sind angegeben. Die biologischen Eigenschaften der Teiche (Vegetation und Wasserverunreinigung) hatten eine auffallende Wirkung auf die Makro-Fauna, qualitativ und quantitativ. Dies reflektierte sich in ihrer Weise der Ausbreitung und Ästivation, und im Atmungsprozeß. Drei wahrscheinliche Nahrungsketten wurden vorgeführt. Die Fauna bestand aus einer beschränkten Zahl spezialisierter Arten von bestimmten Gruppen — besonders gut representiert durch Anzahl der Spezies waren Coleoptera und Hemiptera, und quantitativ bedeutend waren Kaulquappen, Odonata, Conchostraca und Anostraca. Predatoren formten eine hohe Proportion der Bevölkerung. Die Ergiebigkeit (Biomasse) war am höchsten in verunreinigten, alkalischen Teichen in welchen reichlich Kaulquappen und Anisops anwesend waren.

     

Lewis a blood group antigen of non-secretors: a receptor for candida blastospores

Abstract This study tested the hypothesis that the Lewis ^a blood group antigen found predominantly on the cells of non-secretors might be one of the receptors for Candida species. Binding of strain 3118C to epithelial cells from either secretor or non-secretor donors was not inhibited by treating the cells with anti-Lewis ^a or anti-Lewis ^b antisera. Binding of strain 3091 to non-secretor cell was inhibited by pretreating the cells with anti-Lewis ^a, but this was not observed for secretor cells.
The results suggest that Lewis ^a might be one of the receptors for some yeast strains.     

Use of the Population Grouping Methodology of the Canadian Institute for Health Information to predict high-cost health system users in Ontario

BACKGROUND:Prior research has consistently shown that the heaviest users account for a disproportionate share of health care costs. As such, predicting high-cost users may be a precondition for cost containment. We evaluated the ability of a new health risk predictive modelling tool, which was developed by the Canadian Institute for Health Information (CIHI), to identify future high-cost cases.METHODS:We ran the CIHI model using administrative health care data for Ontario (fiscal years 2014/15 and 2015/16) to predict the risk, for each individual in the study population, of being a high-cost user 1 year in the future. We also estimated actual costs for the prediction period. We evaluated model performance for selected percentiles of cost based on the discrimination and calibration of the model.RESULTS:A total of 11 684 427 individuals were included in the analysis. Overall, 10% of this population had annual costs exceeding $3050 per person in fiscal year 2016/17, accounting for 71.6% of total expenditures; 5% had costs above $6374 (58.2% of total expenditures); and 1% exceeded $22 995 (30.5% of total expenditures). Model performance increased with higher cost thresholds. The c-statistic was 0.78 (reasonable), 0.81 (strong) and 0.86 (very strong) at the 10%, 5% and 1% cost thresholds, respectively.INTERPRETATION:The CIHI Population Grouping Methodology was designed to predict the average user of health care services, yet performed adequately for predicting high-cost users. Although we recommend the development of a purpose-designed tool to improve model performance, the existing CIHI Population Grouping Methodology may be used — as is or in concert with additional information — for many applications requiring prediction of future high-cost users.

A substantial literature across health systems shows that the highest users of services account for disproportionate shares of the public costs of health care. It has recently been reported that more than three-quarters of individual health care costs in Ontario were incurred by just 10% of the population.¹ Similarly, an Ontario Ministry of Health and Long-Term Care (MOHLTC) analysis of inpatient and home care costs found that the top 5% of patients were responsible for 61% of spending in those domains.² Consistent findings have been reported for Manitoba, Alberta and British Columbia.^3–7Some of the highest-cost cases may be explained by rare, unpredictable events, but others arise in the presence of multiple chronic conditions. Research from the United States has suggested that spending on chronic conditions accounts for the majority of health care expenditures.⁸ Predicting high-cost users may help us to understand and better manage public spending on health care.Cognizant of this need, the Ontario MOHLTC developed a predictive model for high-cost users based on sociodemographic, utilization and clinical diagnostic characteristics.⁹ Although the model performed well, it relied on a coarse categorization of 20 diagnostic variables consisting of broadly defined chapters of the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) and a small number of chronic conditions, which limited its utility for explaining predictions. Moreover, this model is not available for use outside the MOHLTC. As such, there is a need for a predictive model that can be applied more widely by researchers and other stakeholders with an interest in health policy and spending in Canada.The Canadian Institute for Health Information (CIHI) has recently released a new population-based case mix product, the Population Grouping Methodology, which uses diagnoses obtained from patient health care encounters in multiple settings to summarize the universe of diagnosis codes into a clinically meaningful set of 226 health conditions. The grouping and modelling methodologies are described in more detail in Appendix 1 (available at www.cmaj.ca/lookup/suppl/doi:10.1503/cmaj.191297/-/DC1) and in previous reports.^10,11 The CIHI grouping methodology was not designed to predict high-cost cases, and previous work has already shown that the model performs better for low- and moderate-cost users than for highest-cost users (i.e., those with annual costs exceeding $25 000).¹¹ We evaluated the suitability of CIHI’s model for predicting future high-cost users in Ontario by examining the predicted costs for individuals who exceeded the top 10%, 5%, and 1% thresholds of actual cost.