1991. Disturbance effects on aquatic vegetation in regulated and unregulated lakes in northern Minnesota. Can. J. Bot. 69: 1542-1551. The effects of water-level regulation on aquatic macrophyte communities were investigated by comparing two regulated lakes in northern Minnesota with a nearby unregulated lake. Natural annual fluctuations of about 1.8 m were replaced with fluctuations of 1.1 m and 2.7 m in the regulated lakes, and the timing of water-level changes was also altered. Quadrats were sampled along transects that followed depth contours representing different plant habitats in the unregulated lake. Ordinations showed that the macrophyte communities at all sampled depths of the regulated lakes differed from those in the unregulated lake. The unregulated lake supported structurally diverse plant communities at all depths. In the lake with reduced fluctuations, only four taxa were present along transects that were never dewatered; all were erect aquatics that extended through the entire water column. In the lake with increased fluctuations, rosette and mat-forming species dominated transects where drawdown occurred in early winter and disturbance resulted from ice formation in the sediments. The natural hydrologic regime at the unregulated lake resulted in intermediate disturbance and high diversity. There was either too little or too much disturbance from water-level fluctuations in the regulated lakes, both resulting in reduced structural diversity. ., et MEEKER, J. E. 1991. Disturbance effects on aquatic vegetation in regulated and unregulated lakes in northern Minnesota. Can. J. Bot. 69 : 1542-1551. En comparant deux lacs h niveau contr6lt avec un lac voisin non-contr61t dans le nord du Minnesota, les auteurs ont ttudit les effets du niveau de I'eau sur les comrnunautts de macrophytes aquatiques. Des fluctuations annuelles d'environ 1,8 m font place h des fluctuations de 1,l m et de 2,7 m dans les lacs i niveau contr6lt et la chronologie des variations est tgalement modifite.Les auteurs ont tchantillonnt des quadrats le long de transects qui suivent les courbes de niveau, reprtsentant difftrents habitats du lac non-contr6lt. Les ordinations font voir que les communautts de macrophytes, a toutes les profondeurs tchantillonntes dans le lac non-contr616, different de celles des lacs contr6lts. Le lac non-contr61ts comporte des communautts structurellement diverses h toutes les profondeurs. Dans le lac montrant des fluctuations rtduites, seulement quatre taxons sont presents le long des transects oh I'eau n'est jamais absente, i.e., toutes les plantes aquatiques dresstes qui s'ttendent sur toute la colonne d'eau. Dans le lac oh la fluctuation est augmentte, les espkces qui foment des rosettes et des coussins dominent les transects oh l'absence d'eau se fait au dtbut de l'hiver et le derangement provient de la formation de glace dans les stdirnents. Le regime hydrologique naturel, dans le lac non-contr61e, s'accompagne de dtrangernents intermtdiaires et d'une forte diversitt. Les fluctuations qui ont lieu da...

Interest by land-management and regulatory agencies in using biological indicators to detect wetland degradation, coupled with ongoing use of this approach to assess water quality in streams, led to the desire to develop and evaluate an Index of Biotic Integrity (IBI) for wetlands that could be used to categorize the level of degradation. We undertook this challenge with data from coastal wetlands of the Great Lakes, which have been degraded by a variety of human disturbances. We studied six barrier beach wetlands in western Lake Superior, six drowned-river-mouth wetlands along the eastern shore of Lake Michigan, and six open shoreline wetlands in Saginaw Bay of Lake Huron. Plant, fish, and invertebrate communities were sampled in each wetland. The resulting data were assessed in various forms against gradients of human disturbance to identify potential metrics that could be used in IBI development. Our results suggested that the metrics proposed as potential components of an IBI for barrier beach wetlands of Lake Superior held promise. The metrics for Lake Michigan drowned-river-mouth wetlands were inconsistent in identifying gradients of disturbance; those for Lake Huron open embayment wetlands were yet more inconsistent. Despite the potential displayed by the Lake Superior results within the year sampled, we concluded that an IBI for use in Great Lakes wetlands would not be valid unless separate scoring ranges were derived for each of several sequences of water-level histories. Variability in lake levels from year to year can produce variability in data and affect the reproducibility of data collected, primarily due to extreme changes in plant communities and the faunal habitat they provide. Substantially different results could be obtained in the same wetland in different years as a result of the response to lake-level change, with no change in the level of human disturbance. Additional problems included limited numbers of comparable sites, potential lack of undisturbed reference sites, and variable effects of different disturbance types. We also evaluated our conclusions with respect to hydrologic variability and other major natural disturbances affecting wetlands in other regions. We concluded that after segregation of wetland types by geographic, geomorphic, and hydrologic features, a functional IBI may be possible for wetlands with relatively stable hydrology. However, an IBI for wetlands with unpredictable yet recurring influences of climate-induced, long-term high water periods, droughts, or drought-related fires or weather-related catastrophic floods or high winds (hurricanes) would also require differing scales of measurement for years that differ in the length of time since the last major natural disturbance. A site-specific, detailed ecological analysis of biological indicators may indeed be of value in determining the quality or status of wetlands, but we recommend that IBI scores not be used unless the scoring ranges are calibrated for the specific hydrologic history pre-dating any sampling year.

Water-level regulation has altered the plant species composition and thus the structure ofnearshore aquatic macrophyte communities in two regulated lakes in northern Minnesota as compared with a nearby unregulated lake. Results of previous faunal studies in the regulated lakes were used as a basis for assessing the effects of vegetation changes on faunal communities. The unregulated lake with mean annual water-level fluctuations of 1.6 m supported structurally diverse plant communities and varied faunal habitat at all depths studied. Mean annual fluctuations on one regulated lake were reduced to 1.1 m, and dense beds of four erect aquatic macrophytes dominated the 1.75-m depth that was never dewatered. We suggest that this lack of plant diversity and structural complexity resulted in diminished habitat for invertebrates, reduced availability of invertebrates as food for waterbirds and fish, reduced winter food supplies for muskrats, and reduced feeding efficiency for adult northern pike, yellow perch, and muskellunge. Mean annual fluctuations in the other regulated lake were increased to 2.7 m, and rosette and mat-forming species dominated the 1.25-m depth that was affected by winter drawdowns. We suggest that the lack of larger canopy plants resulted in poor habitat for invertebrates, reduced availability of invertebrates as food for waterbirds and fish, and poor nursery and adult feeding habitat for many species of fish. In addition, the timing and extent of winter drawdowns reduced access to maerophytes as food for muskrats and as spawning habitat for northern pike and yellow perch. In regulated lakes throughout the world, indirect effects on aquatic fauna resulting from alteration of wetland and aquatic macrophyte communities should be considered when water-level management plans are developed.

Outcome measures evaluate various aspects of patient health, and when appropriately utilized can provide valuable information in both clinical practice and research settings. The orthopedic community has placed increasing emphasis on patient-reported outcome measures, recognizing their value for understanding patients' perspectives of treatment outcomes. Patient-reported outcomes are information directly reported by patients regarding their perceptions of health, quality of life, or functional status without interpretation by healthcare providers. The American Orthopaedic Foot & Ankle Society (AOFAS) supports the use of validated patient-reported outcome (PRO) instruments to assess patient general health, functional status, and outcomes of treatment. It is not possible to recommend a single instrument to collect quality orthopedic data as the selection is dependent on the population being examined and the question being asked. We support the use of the PROMIS Physical Function Computerized Adaptive Test (PF CAT) or Lower Extremity Computerized Adaptive Test (LE CAT), which can be assessed with other domains such as Pain Interference. In addition, a disease-specific measure can be used when available.

The mechanisms that regulate the differentiation program of multipotential stem cells remain poorly understood. In order to define the cues that delineate endothelial commitment from precursors, we screened for candidate regulatory genes in differentiating mouse embryoid bodies. We found that the PR/SET domain protein, PRDM6, is enriched in flk1(+) hematovascular precursor cells using a microarray-based approach. As determined by 5′ RACE, full length PRDM6 protein contains a PR domain and four Krüpple-like zinc fingers. In situ hybridization in mouse embryos demonstrates staining of the primitive streak, allantois, heart, outflow tract, para-aortic splanchnopleura (P-Sp)/ aorto-gonadal-mesonephric (AGM) region and yolk sac, all sites known to be enriched in vascular precursor cells. PRDM6 is also detected in embryonic and adult-derived endothelial cell lines. PRDM6 is co-localized with histone H4 and methylates H4-K20 (but not H3) in vitro and in vivo, which is consistent with the known participation of PR domains in histone methyltransferase activity. Overexpression of PRDM6 in mouse embryonic endothelial cells induces apoptosis by activating caspase-3 and inducing G1 arrest. PRDM6 inhibits cell proliferation as determined by BrdU incorporation in endothelial cells, but not in rat aortic smooth muscle cells. Overexpression of PRDM6 also results in reduced tube formation in cultured endothelial cells grown in Matrigel. Taken together, our data indicate that PRDM6 is expressed by vascular precursors, has differential effects in endothelial cells and smooth muscle cells, and may play a role in vascular precursor differentiation and survival by modulating local chromatin-remodeling activity within hematovascular subpopulations during development.

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Eight cases of fetal and infant death related to maternal methamphetamine abuse are presented. The mean fetal blood concentration of methamphetamine was 0.36 microgram/mL (range, 0.03-1.20 micrograms/mL), and the mean concentration of amphetamine was 0.05 microgram/mL (range, 0-0.08 microgram/mL). Both maternal and fetal blood methamphetamine concentrations were obtained in two cases. The maternal and fetal methamphetamine concentrations for these two cases were 0.21 and 0.40 microgram/mL and 0.18 and 1.20 micrograms/mL, respectively. The cause of death for each case, as listed by the pathologist, is also discussed.

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