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Biomedical subjects

S A Norton

Publications and source records attributed to S A Norton.

At least 19 recordsLinked to original sources
PubMed2006

Controls on mercury and methylmercury deposition for two watersheds in Acadia National Park, Maine.

Throughfall and bulk precipitation samples were collected for two watersheds at Acadia National Park, Maine, from 3 May to 16 November 2000, to determine which landscape factors affected mercury (Hg) deposition. One of these watersheds, Cadillac Brook, burned in 1947, providing a natural experimental design to study the effects of forest type on deposition to forested watersheds. Sites that face southwest received the highest Hg deposition, which may be due to the interception of cross-continental movement of contaminated air masses. Sites covered with softwood vegetation also received higher Hg deposition than other vegetation types because of the higher scavenging efficiency of the canopy structure. Methyl mercury (MeHg) deposition was not affected by these factors. Hg deposition, as bulk precipitation and throughfall was lower in Cadillac Brook watershed (burned) than in Hadlock Brook watershed (unburned) because of vegetation type and watershed aspect. Hg and MeHg inputs were weighted by season and vegetation type because these two factors had the most influence on deposition. Hg volatilization was not determined. The total Hg deposition via throughfall and bulk precipitation was 9.4 microg/m(2)/year in Cadillac Brook watershed and 10.2 microg/m(2)/year in Hadlock Brook watershed. The total MeHg deposition via throughfall and bulk precipitation was 0.05 microg/m(2)/year in Cadillac Brook watershed and 0.10 microg/m(2)/year in Hadlock Brook watershed.

Ecosystem↗
PubMed2006

Use of Br and Se in peat to reconstruct the natural and anthropogenic fluxes of atmospheric Hg: A 10000-year record from Caribou Bog, Maine.

Using Br and Se as reference elements, the natural and anthropogenic fluxes of atmospheric Hg were reconstructed for the past 10,000 years using peat cores from Caribou Bog, ME. In the ombrotrophic peat layers, the average background Hg accumulation rate (AR) was 1.7 +/- 1.3 microg m(-2) year(-1) which is comparable with the natural rate of atmospheric Hg accumulation reported in other retrospective studies. The average Hg AR determined using all peat samples dating from preindustrial times, including minerotrophic peat, was slightly greater (3.1 +/- 2.3 microg m(-2) year(-1)) which may reflect differences in canopy interception due to the changes in plant communities, aquatic inputs, or possibly climatic factors. The maximum Hg AR (32 microg m(-2) year(-1)) occurred ca. 1961 A.D. In samples predating the settlement by Europeans, there is a linear correlation between the AR of Hg and those of Br and Se; this relationship allows both Br and Se to be used to calculate the natural AR of Hg (Hgnat). The difference between Hg AR and Hg(nat) is the Hg AR in excess of background (Hg(ex)). Because Hg(ex) was positive only after ca. 1840 A.D., it is assumed to represent the anthropogenic Hg component. By the late 19th century, Hg(ex) deposition was equal to the natural flux. At the peak in Hg deposition in 1961 A.D., Hgex made up >90% of total atmospheric Hg deposition. The AR in the uppermost peat decreased to 25% of peak values by 2000 A.D.

Air Pollutants↗
PubMed2005

Does changing the configuration of a motor racing circuit make it safer?

OBJECTIVES: To assess the pattern of injuries presenting to a racing circuit medical centre in two three-year periods before and after two chicanes were built into the track. METHODS: Medical centre records were used to identify all patients assessed during the two time periods. Those referred to hospital were categorised by injury severity into three groups. RESULTS: The proportions of those attending the medical centre that were referred and admitted to hospital were the same in both periods (12-13% and 3% respectively). During the two study periods, the risk of a severe injury for a car driver decreased from 0.1% to 0.03% (p<0.05). For a motorcyclist, similar values were 0% and 0.2% (not significant). CONCLUSIONS: Chicanes have improved the safety of the racing circuit for car drivers, reducing the risk of injury.

Accident Prevention↗
PubMed2004

Development and experience with an algorithm to evaluate suspected smallpox cases in the United States, 2002-2004.

Concerns that smallpox, an eradicated disease, might reappear because of a bioterror attack and limited experience with smallpox diagnosis in the United States prompted us to design a clinical algorithm. We used clinical features of classic smallpox to classify persons presenting with suspected smallpox rashes into 3 categories: those with high, those with moderate, and those with low risk of having smallpox. The classification guides subsequent diagnostic strategies, limiting smallpox laboratory testing to high-risk persons to minimize the number of false-positive test results. From January 2002 through June 2004, the Centers for Disease Control and Prevention (CDC) received 43 consultations regarding suspected smallpox cases. No patient was at high risk for having smallpox. One patient was tested for the presence of variola virus. Varicella was the diagnosis for 23 cases (53%). The algorithm worked well to guide clinical and public health responses to suspected smallpox cases. The poster is available from CDC, and an interactive version and laboratory protocol are available at http://www.bt.cdc.gov/agent/smallpox/diagnosis/riskalgorithm/index.asp. We recommend use of the algorithm in the United States and elsewhere.

Adolescent↗
PubMed2004

Development of an ombrotrophic peat bog (low ash) reference material for the determination of elemental concentrations.

Given the increasing interest in using peat bogs as archives of atmospheric metal deposition, the lack of validated sample preparation methods and suitable certified reference materials has hindered not only the quality assurance of the generated analytical data but also the interpretation and comparison of peat core metal profiles from different laboratories in the international community. Reference materials play an important role in the evaluation of the accuracy of analytical results and are essential parts of good laboratory practice. An ombrotrophic peat bog reference material has been developed by 14 laboratories from nine countries in an inter-laboratory comparison between February and October 2002. The material has been characterised for both acid-extractable and total concentrations of a range of elements, including Al, As, Ca, Cd, Cr, Cu, Fe, Hg, Mg, Mn, Na, Ni, P, Pb, Ti, V and Zn. The steps involved in the production of the reference material (i.e. collection and preparation, homogeneity and stability studies, and certification) are described in detail.

Environmental Monitoring↗
PubMed2001

Working toward consensus: providers' strategies to shift patients from curative to palliative treatment choices.

End-of-life decision making is a complex phenomenon and providers, patients, and families often have different views about the appropriateness of treatment choices. The results presented here are part of a larger grounded-theory study of reconciling decisions near the end of life. In particular, we examined how providers (N = 15) worked near the end of patients' lives toward changing the treatment decisions of patients and families from those decisions that providers described as unrealistic (i.e., curative) to those that providers described as more realistic (i.e., palliative). According to providers, shifting patients' and families' choices from curative to palliative was usually accomplished by changing patients' and families' understanding of the patient's overall "big picture" to one that was consistent with the providers' understanding. Until patients and families shifted their understanding of the patient's condition-the big picture-they continued to make what providers judged as unrealistic treatment choices based on an inaccurate understanding of what was really going on. These unrealistic choices often precluded possibilities for a "good death." According to providers, the purpose of attempting to shift the patient or proxy's goals was that realistic goals lead to realistic palliative treatment choices that providers associated with a good death. In this article we review strategies used by providers when they believed a patient's death was imminent to attempt to shift patients' and families' understandings of the big picture, thus ultimately shifting their treatment decisions.

Decision Making↗
PubMed2001

An assessment of clinical guidelines for the management of acute pancreatitis.

BACKGROUND: Recent guidelines have been issued for the management of acute pancreatitis. The aim of this study was to audit the management of acute pancreatitis in one district general hospital, to determine the problems and benefits associated with the implementation of such guidelines. METHODS: Data were collected over the period 1991-1995 for all patients diagnosed as having acute pancreatitis who were admitted to one district general hospital. Data regarding severity grading, determination of aetiology and treatment of mild and severe pancreatitis were analysed in conjunction with the recommendations issued by the British Society of Gastroenterology Working Party on the management of acute pancreatitis in 1995. RESULTS: A total of 210 patients were admitted on 263 occasions; 16% of cases were severe but severity prediction was inaccurate. 56.1% had gallstone pancreatitis and 20.9% had idiopathic pancreatitis. Definitive treatment of gallstones was within the recommended time limit in only 70.1%. 27 patients experienced recurrent attacks of pancreatitis before definitive treatment of their gallstones, due either to inadequate investigation for gallstones after suboptimal ultrasound examination (n = 12) or to inappropriate delay before definitive treatment of gallstones (n = 15). Recommendations for the management of severe cases with early ITU/HDU admissions and CT scanning were not followed. 28 day mortality was 6.3%, median age of those dying was 80.5 years. CONCLUSIONS: Acceptable mortality can be achieved for acute pancreatitis despite failure to implement BSG guidelines for the management of severe acute pancreatitis. Inadequate investigation and treatment of gallstone disease leads to an unacceptable incidence of recurrent acute pancreatitis.

Acute Disease↗
PubMed2000

Did the Medicaid expansions for children displace private insurance? An analysis using the SIPP.

Using data from the 1990 panel of the Survey of Income and Program Participation (SIPP), we address the question: Did the Medicaid expansions for children cause declines in private coverage? We use a multivariate approach that attributes a displacement effect to declines in private coverage for children targeted by the Medicaid expansions exceeding declines for a comparison group of older low-income children. We find that 23% of the movement from private coverage to Medicaid due to the expansions was attributable to displacement. There is no evidence of displacement among those starting uninsured, leading to an overall displacement effect of 4%.

Adolescent↗
PubMed2000

Endoscopic ultrasonography in the evaluation of idiopathic acute pancreatitis.

BACKGROUND: 'Idiopathic' pancreatitis may be diagnosed when gallstones are excluded by transabdominal ultrasonography and less common causes are not implicated by history or other investigations. Transabdominal ultrasonography may not, however, detect small stones responsible for acute pancreatitis. The aim of this study was to determine if endoscopic ultrasonography (EUS) is able to identify undetected gallstones in cases of 'idiopathic' pancreatitis. METHODS: Consecutive patients presenting with 'idiopathic' pancreatitis were assessed using EUS for the presence of gallstones or other potential causes of the attack. A control group was also imaged. RESULTS: Forty-four patients with 'idiopathic' pancreatitis were assessed. Ten had suffered earlier attacks of pancreatitis before this study. EUS revealed proven pathology in 18 patients. Unconfirmed pathology was evident in 14. No abnormality was seen in only nine patients. EUS failed in one patient and there were two possible false-positive results. CONCLUSION: EUS is able to identify significant pathology in patients in whom a diagnosis of 'idiopathic' pancreatitis has been made following standard investigations. Patients with untreated gallstones are at risk of recurrent attacks. Idiopathic pancreatitis should not be diagnosed unless EUS has been performed.

Acute Disease↗
PubMed2000

Facilitating end-of-life decision-making: strategies for communicating and assessing.

End-of-life decision-making is often a difficult process and one that many elderly patients and their families will undergo. The grounded theory study of nurses, physicians, and family members (n = 20) reported in this article examined provider behaviors that facilitated the process of decision-making near the end of patients' lives. According to participants, providers who are experienced and comfortable are more likely to engage in communication and assessment strategies that facilitate end-of-life decision-making. Communication strategies included: being clear, avoiding euphemisms, spelling out the goals and expectations of treatment, using words such as "death" and "dying," and being specific when using such words as "hope" and "better." Assessment strategies included: assessing patients' physical conditions and end-of-life wishes, patients' and family members' understandings of the disease and prognosis, and their expectations and goals. An important first step for improved care is making explicit the provider's communicating and assessing strategies that facilitate end-of-life decision-making.

Aged↗
PubMed2000

Federally qualified health centers: surviving Medicaid managed care, but not thriving.

This article reviews the experiences of federally qualified health centers (FQHCs) in Hawaii, Rhode Island, and Tennessee before and after Medicaid managed care demonstrations began. Adapting to managed care proved challenging, but all FQHCs survived. Overall, FQHCs performed better financially than anticipated, partly because demonstrations expanded coverage to previously uninsured individuals, and because FQHCs in two States formed plans that paid FQHCs more than other plans. Service encounters declined; it is unclear if this is negative, since it may indicate more efficient care delivery. In some cases, supportive State policies aided FQHCs' survival. Continued adaptation is critical for FQHCs' longer term prospects.

Community Health Centers↗