Betaproteobacteria are a key component of surface water biofilters that maintain sustained manganese removal in response to fluctuations in influent water temperature

The health risks associated with manganese (Mn) in drinking water, and an improved understanding of Mn accumulation within, and subsequent release from, distribution systems, have increased the need for robust, sustainable treatment options to minimize Mn concentrations in finished water. Biofiltration is an established and effective method to remove Mn in groundwater however, Mn removal in surface water biofilters is an emerging treatment process that has not been extensively studied. Seasonal variations in water temperature can present an operational challenge for surface water biofilters which may see reduced Mn removal under colder conditions. This study examined the microbiomes of surface water biofilters at three utilities (ACWD WTP, WTP B, and WTP D) which all experienced similar seasonal fluctuations in influent water temperature. High Mn removal was observed at the ACWD WTP for much of the year, but Mn removal decreased with a concurrent decrease in the influent water temperature (58% ± 22%). In contrast, both WTP B and WTP D achieved year-round Mn removal (84% ± 5% and 93% ± 8% respectively). Marker gene (16S rRNA) sequencing analysis of the biofilter microbiomes identified a high abundance of Betaproteobacteria in WTP B and WTP D (37% ± 12% and 21% ± 3% respectively), but a low abundance of Betaproteobacteria in the ACWD WTP (2% ± 2%). The microbiomes of new bench-scale biofilters, in operation at the ACWD WTP, were also investigated. The abundance of Betaproteobacteria was significantly greater (p < 0.05) after the biofilters had acclimated than before acclimation, and differential abundance analysis identified 6 genera within the Betaproteobacteria class were enriched in the acclimated microbiome. Additionally, the acclimated biofilters were able to maintain high Mn removal performance (87% ± 10%) when the influent water temperature decreased to 10 °C or less. Further analysis of previously published studies found the abundance of Betaproteobacteria was also significantly greater (p < 0.001) in biofilters with sustained Mn removal than in biofilters which did not treat for Mn as a contaminant, despite differences in design scale, source water, and media type. Microbiome network analysis identified multiple co-occurrence relationships between Betaproteobacteria and Mn oxidizing bacteria in the WTP B and WTP D biofilters, suggesting indirect contributions by Betaproteobacteria to biological Mn oxidation. These co-occurrence relationships were not present in the full-scale ACWD WTP microbiome. Whether the role of Betaproteobacteria in biological Mn oxidation is direct, indirect, or a combination of both, they are consistently present at a high abundance in both groundwater and surface water biofilters with sustained Mn removal, and their absence may contribute to the seasonal fluctuations in Mn removal observed at the ACWD WTP. This new insight to Betaproteobacteria and their role in Mn biofiltration could contribute to water innovation and design that would improve the reliability of Mn removal.

Biological and physico-chemical mechanisms accelerating the acclimation of Mn-removing biofilters

This study investigated treatment strategies which accelerated the acclimation of new Mn-removing biofilters to help utilities respond to changing Mn regulations, such as the recent introduction of a health-based maximum acceptable concentration and a reduction in the aesthetic objective for Mn in drinking water by Health Canada. Bench-scale filters of either GAC or anthracite media were fed with applied water containing Mn (17-61 μg/L) from a full-scale plant over 294 days. Treatment strategies included the addition of H₂O₂ (1 mg/L) and/or an increase in pH from 6.8 to 7.5 through the addition of NaOH. The potential physico-chemical and biological mechanisms responsible for accelerated biofilter acclimation under the various redox conditions were investigated through thermodynamic modelling, to predict homogeneous Mn oxide formation, and 16S rRNA gene amplicon sequencing, to characterize the microbial community within the filters. GAC filters treated with NaOH, and both H₂O₂ and NaOH, were the first to acclimate (< 20 μg/L Mn in filter effluent) after 59 and 63 days respectively, while the ambient GAC filter took almost 3 times as long to acclimate (168 days), and the anthracite filters which received the same chemically adjusted water took almost 4 times as long (226 and 251 days, respectively). The accelerated acclimation in the treated GAC filters was likely due to physico-chemical oxidation via three potential mechanisms: (1) homogeneous oxidation of dissolved Mn(II) to Mn(III)/Mn(IV) oxides and the subsequent removal of oxides from solution through adherence to the GAC surface, (2) adsorption of dissolved Mn(II) to GAC and subsequent homogeneous or biological oxidation, or (3) formation of colloidal Mn(III)/Mn(IV) oxides and subsequent adsorption of dissolved Mn(II) to the Mn colloids. In the untreated GAC filter and all anthracite filters, which did not benefit from improved redox conditions or an active surface, physico-chemical mechanisms alone were insufficient for consistent Mn removal to less than 20 μg/L. Acclimation in these filters was delayed until a microbiome enriched with bacteria capable of biological nitrification and Mn oxidation evolved within the filters. The acclimated microbiome was consistent between GAC and anthracite filters and was significantly different from the non-acclimated microbiome (p < 0.001) initially formed during the early operation of the filters. Interestingly, treatment with NaOH, and NaOH and H₂O₂, which accelerated physico-chemical oxidation in GAC filters, was observed to delay the development of biological oxidation in anthracite filters, and thus deferred acclimation. Although some filters took longer to acclimate than others, once acclimation was reached all filters had a similar microbiome and were able to consistently remove Mn to below 20 µg/L.

Validation of a Quantitative Food Frequency Questionnaire for a Japanese Population in Hawaii

Objective: To measure the validity of a quantitative food frequency questionnaire (QFFQ). Design: A cross-sectional validation study of the QFFQ against a four-day food record (4DR) using Spearman correlation, cross-classification, kappa statistics, and Bland-Altman plotting. Setting: The Gastroenterology Department of Kaiser Permanente Hawaii. Subjects: 76 healthy Japanese American men and women, aged 40-75 years. Results: Somewhat stronger average correlations were observed between the QFFQ and the 4DR for macronutrients compared to micronutrients (Spearman rho of 0.47 vs. 0.35). Moderate correlations between the two tools were observed for macronutrients (including saturated fatty acids and dietary fibre), iron, β-carotene, vitamin C, and ethanol (rho: 0.38-0.58). Overall, stronger correlations were found among men than women between the two tools (mean rho 0.41 vs. 0.26). In a cross classification analysis, for more than 75% of the observations, a complete to relative agreement between the two methods was observed for fat, α-carotene, folate, vitamin D, and ethanol. Sex difference in agreement was minimal in cross-classification (overall extreme misclassification of 9.80% for men and 12.40% for women). Bland-Altman plots showed over-estimations of dietary fibre and α-carotene intake and an under-estimation of cholesterol intake by the QFFQ at high levels of consumption. However, the QFFQ estimation for fat, dietary fibre, folate, cholesterol, α-carotene, vitamins D and C, and ethanol intake was less than 7% different compared to the 4DR. Conclusions: The QFFQ has an adequate validity for fat, folate, vitamin D, and ethanol and can correctly categorize participants for intakes of cholesterol, dietary fibre, α-carotene, and zinc.

The future of informed consent in British common law

Within the common law world, the use of the term informed consent implies the American doctrine. Informed consent as a doctrine is not part of the law in the United Kingdom. However, it is possible to predict a way forward in disclosure cases yet to be heard in the courts of the United Kingdom. These predictions are based on current developments in the common law in the United Kingdom as well as those in Canada and Australia, on the European Convention on Human Rights and Biomedicine and on trends within the medical profession itself in the light of the Bolam test.

Outcome of pediatric intensive care at six centers in Mexico and Ecuador

OBJECTIVE

To improve understanding of the causes of morbidity and mortality among critically ill children in the countries studied.

DESIGN

Survey of hospital records between 1992 and 1994.

SETTING

Six pediatric intensive care units (ICUs) (four ICUs in Mexico City and two ICUs in Ecuador).

PATIENTS

Consecutive patients (n = 1,061) admitted to the units studied.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The mortality rate for low-risk patients (pediatric Risk of Mortality [PRISM] score of < or = 10, n = 701) was more than four times the rate predicted by the PRISM score (8.1% vs. 1.8%, p < .001), with an additional 11.3% of this group incurring major morbidity. The mortality rate for moderate-risk patients (PRISM scores of 11 to 20, n = 232) was more than twice predicted (28% vs. 12%, p < .001). For low-risk patients, death was significantly associated with tracheal intubation, central venous cannulation, pneumonia, age of < 2 months, use of more than two antibiotics, and nonsurgical diagnosis (after controlling for PRISM score). Central venous cannulation and tracheal intubation in the lower-risk groups were performed more commonly in units in Mexico than in one comparison unit in the United States (p < .001).

CONCLUSIONS

For six pediatric ICUs in Mexico and Ecuador, mortality was significantly higher than predicted among lower-risk patients. Tracheal intubation, central catheters, pneumonia, sepsis, and nonsurgical status were associated with poor outcome for low-risk groups. We speculate that reducing the use of invasive central catheters and endotracheal intubation for lower-risk patients, coupled with improved infection control, could lower mortality rates in the population studied.

Enhancing communication. The physician and family in the pediatric intensive care unit

How well does the intensivist communicate with the parents of critically ill children? The authors' experience suggests that this process can be enhanced in a number of ways. The article reviews methods to improve communication by emphasizing the importance of the first meeting, trust, and understanding parental needs and coping mechanisms.

Controlled localized heating and isotretinoin effects in canine squamous cell carcinoma

Controlled localized radiofrequency heating and systemic isotretinoin were used serially as therapy in a hairless dog that developed multiple cutaneous squamous cell carcinomas in chronically sun-damaged skin. During the course of therapy, four superficial tumors regressed completely, both clinically and histologically. Two larger, deeper tumors showed clinical signs of regression but histologic clearing did not occur. Both treatment modalities are known to have antitumor effects independently and may exert their effects in an additive fashion. However, it is also possible that heat-induced injury to tumor cells could lead to retinoid-mediated enhancement of an immunologic response to tumor antigens or some other process that might lead to regression.

Use of granulocyte-macrophage colony-stimulating factor in patients with malignancy and bone marrow failure

Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered to 10 patients with refractory malignancies, 2 patients who had myelodysplastic syndromes with severe neutropenia and to a patient who had delayed marrow recovery after 3 cycles of therapy for acute leukemia. A marked neutropenia and monocytopenia was observed within 5 min after an i.v. injection of GM-CSF. This persisted for 1-2 h and seemed related to activation of an adhesive glycoprotein (MO1) on the surface of these cells. With continued daily i.v. administration of GM-CSF, all patients with refractory malignancies developed a striking leukocytosis. Total leukocyte counts reached 75,000/microliters within 2 weeks of treatment. This was due to an increase in band and segmented neutrophils, eosinophils and monocytes. Accelerated myelopoiesis required the continuous presence of GM-CSF; with pump failure for 24 h or discontinuation after 14 days, leukocyte counts returned to normal levels in 24-48 h. GM-CSF also increased myelopoiesis in the patients with myelodysplastic syndromes or following anti-leukemic treatment. These observations suggest that this growth factor should prove a useful adjunct in the treatment of patients with malignancies and bone marrow failure.

Effect of recombinant human granulocyte-macrophage colony-stimulating factor on myelopoiesis in patients with refractory metastatic carcinoma

The effect of human recombinant GM-colony-stimulating factor (CSF) was evaluated in ten patients with refractory metastatic carcinoma. Initially they received an intravenous (IV) bolus injection of 5 or 25 micrograms/m2 for assessment of acute responses. Six days later, continuous IV infusions of 100 or 500 micrograms/m2 were initiated for a 14-day treatment course. All patients developed profound leukopenia within five to 30 minutes of the bolus injection. This appeared to result from increased expression of an adhesion-promoting glycoprotein (GP) on neutrophils and monocytes as judged by increased reactivity to the Mo1 monoclonal antibody (MoAb). Leukocyte counts returned to normal levels within two hours as cells were released from marrow stores. With the continuous infusion, leukocyte counts increased by 24 hours; peak values of 22,960 and 75.900/microL were achieved after ten to 14 days of treatment with the two dose levels of GM-CSF. This leukocytosis was due to an increase in virtually all cell types. At the high dose level, there was a striking increase in neutrophils (49,400/microL) and eosinophils (20,905/microL) with a sixfold increase in monocytes and two- to threefold increase in lymphocytes. Leukocyte counts declined promptly after cessation of the infusion but remained above baseline for as long as 2 weeks in some patients. These results suggest that GM-CSF may be useful as an adjuvant therapy by stimulating myelopoiesis in cancer patients.

Phenotypic resemblance in birth weight between first cousins

Birth weight data on 72,078 liveborn singletons representing 5981 paternal and 7036 maternal single first cousin kinships were assembled by computerized record linkage from all marriages and livebirths registered in Hawaii during a 38-year period from 1942 to 1979. These kinships represented incrosses of five selected racial groups. An additional 15,536 livebirths from 1134 paternal and 1679 maternal cousin kinships provided data on outcrossing between racial groups, and 28,952 livebirths from 2379 paternal and 3538 maternal cousin kinships provided data on both incrossing and outcrossing within kinships. Phenotypic resemblance in birth weight between single first cousins was estimated by the covariance and intraclass correlation. The covariances between maternal cousins were generally much higher than those between paternal cousins. Neither heterogeneity in maternal genotypes nor heterogeneity in newborn genotypes had any significant effect on the resemblance between first cousins. These observations have led to the conclusion that maternal influences of non-hereditary origin are of primary importance in determining birth weight in man. The observed non-zero correlation in several groups of paternal cousins was explained in part by the process of preferential selection of mates within and among racial groups by brothers, and probably by the similarity in some maternal characteristics associated with age at childbearing among their wives.