Phosphorus flux from wetland soils affected by long-term nutrient loading

Wetland soils play a key role in the cycling of nutrients within an ecosystem. Since soils are potentially a source or a sink for inorganic nutrients, it is important to quantify their influence on overlying water quality in order to understand their importance in overall ecosystem nutrient budgets. Laboratory and field studies were performed in the northern Everglades (WCA-2A) to determine the magnitude of phosphorus (P) flux between the soil and the overlying water column, under various redox conditions. The P flux was estimated using three techniques: intact soil cores, in situ benthic chambers, and porewater equilibrators. There was reasonable agreement between the P flux estimated using intact soil cores and benthic chambers; however, P flux estimates using the porewater equilibrators were considerably lower than the other two techniques. Models of solute flux, based solely on soil physico-chemical characteristics, may substantially underestimate soil-water nutrient exchange processes. Phosphorus flux measured with the intact soil cores varied from 6.5 mg m(-2) d(-1) near nutrient inflow areas to undetectable flux 4 km away from the inflow. Oxygen consumption varied from 4 mg m(-2) d(-1) near the inflow to a constant 1 to 2 mg m(-2) d(-1) at a distance of 4 km from the inflow. Rate of consumption of NO3- -N and SO4(2-) showed no significant trend with respect to distance from inflow. Nitrate N and SO4 consumption rates averaged 120 and 130 mg m(-1) d(-1), respectively. Consumption of O2 was correlated with P flux, whereas NO3- -N and SO4(2-) consumption were not.

Effects of Resources and Trophic Interactions on Freshwater Bacterioplankton Diversity

In a study of bacterioplankton in an oligotrophic lake in northern Wisconsin, a community fingerprinting technique, automated ribosomal intergenic spacer analysis (ARISA), was used to determine the effect of resources and trophic interactions on bacterioplankton diversity. Inorganic nitrogen and phosphorus (NP), carbon in the form of glucose (G) or dissolved organic matter extracted from peat (DOM), and carbon and NP in combination were added to two types of experimental systems. Ten-liter mesocosms contained all components of the original aquatic community except for large zooplankton. One-liter dilution cultures were prepared so that the effects of grazers and phytoplankton were removed. During a 3-day incubation, bacterial production showed the greatest response to the carbon plus NP treatment in both experimental systems, but bacterial diversity was strikingly different between them. In the mesocosms, the number of ARISA-PCR fragments averaged 41 per profile, whereas the dilution culture communities were highly reduced in complexity, dominated in most cases by a single PCR fragment. Further analysis of the mesocosm data suggested that whereas the NPDOM addition caused the greatest aggregate bacterial growth response, the addition of NP alone caused the largest shifts in community composition. These results suggest that the measurement of aggregate responses, such as bacterial production, alone in studies of freshwater bacterial communities may mask the effects of resources on bacterioplankton.

Immunoassays in the diagnosis of anaphylaxis to neuromuscular blocking drugs: the value of morphine for the detection of IgE antibodies in allergic subjects

Radioimmunoassays (RIAs) for IgE antibodies to specific neuromuscular blocking drugs (NMBDs) are an important tool in the diagnosis of anaphylaxis during anaesthesia although they are performed in only a few laboratories throughout the world. NMBDs bind to antibodies by their substituted ammonium ions. We measured serum IgE antibodies to morphine and specific NMBDs in 347 patients with suspected anaphylaxis using blood specimens sent for mast cell tryptase assays. Morphine, which has a single substituted ammonium group, avidly binds in vitro to antibodies that react with NMBDs. The morphine RIA proved to be both a more sensitive and efficient test for the detection of IgE antibodies to NMBDs than the specific NMBD RIAs. We have adopted the morphine RIA in our laboratory in preference to the specific RIAs and predict that use of this single assay will become widespread for the in vitro diagnosis of allergic sensitivities to NMBDs.

Automated approach for ribosomal intergenic spacer analysis of microbial diversity and its application to freshwater bacterial communities

An automated method of ribosomal intergenic spacer analysis (ARISA) was developed for the rapid estimation of microbial diversity and community composition in freshwater environments. Following isolation of total community DNA, PCR amplification of the 16S-23S intergenic spacer region in the rRNA operon was performed with a fluorescence-labeled forward primer. ARISA-PCR fragments ranging in size from 400 to 1,200 bp were next discriminated and measured by using an automated electrophoresis system. Database information on the 16S-23S intergenic spacer was also examined, to understand the potential biases in diversity estimates provided by ARISA. In the analysis of three natural freshwater bacterial communities, ARISA was rapid and sensitive and provided highly reproducible community-specific profiles at all levels of replication tested. The ARISA profiles of the freshwater communities were quantitatively compared in terms of both their relative diversity and similarity level. The three communities had distinctly different profiles but were similar in their total number of fragments (range, 34 to 41). In addition, the pattern of major amplification products in representative profiles was not significantly altered when the PCR cycle number was reduced from 30 to 15, but the number of minor products (near the limit of detection) was sensitive to changes in cycling parameters. Overall, the results suggest that ARISA is a rapid and effective community analysis technique that can be used in conjunction with more accurate but labor-intensive methods (e.g., 16S rRNA gene cloning and sequencing) when fine-scale spatial and temporal resolution is needed.

Cisatracurium and atracurium as antigens

Seventy-five consecutive patients referred to an anaesthetic allergy clinic were intradermally tested with atracurium and cisatracurium. With the exception of one patient the results were identical, suggesting that allergy to either drug is associated with allergy to the stereoisomer. For skin testing for allergy to neuromuscular blocking drugs it is only necessary to use either atracurium or cisatracurium and cisatracurium is the preferred drug.

Failure to prevent an anaphylactic reaction to a second neuromuscular blocking drug during anaesthesia

Skin testing is used widely to determine the drug responsible for an anaphylactic reaction during anaesthesia. When a neuromuscular blocking drug in incriminated as the cause of a reaction, it is usual for neuromuscular blocking drugs which do not produce positive skin tests to be considered safe for subsequent use during anaesthesia. We describe three patients in whom false negative skin tests led to a second severe anaphylactic reaction to another neuromuscular blocking drug.

Adolescent pregnancy--current trends and issues: 1998 American Academy of Pediatrics Committee on Adolescence, 1998-1999

Although the prevention of unintended adolescent pregnancy is a primary goal of the American Academy of Pediatrics and society, many adolescents continue to become pregnant. Since the last statement on adolescent pregnancy was issued by the Academy in 1989, new observations have been recorded in the literature. The purpose of this new statement is to review current trends and issues on adolescent pregnancy to update practitioners on this topic.

Bacterial Abundance and Activity across Sites within Two Northern Wisconsin Sphagnum Bogs

Abstract Bacterial abundance, temperature, pH, and dissolved organic carbon (DOC) concentration were compared across surface sites within and between two northern Wisconsin Sphagnum peatlands over the summer seasons in 1995 and 1996. Sites of interest were the Sphagnum mat surface, the water-filled moat (lagg) at the bog margin, and the bog lake littoral zone. Significant differences in both bacterial populations and water chemistry were observed between sites. pH was highest in the lake and lowest in the mat at both bogs; the opposite was true for DOC. Large populations of bacteria were present in surface interstitial water from the mat; abundance in this site was consistently higher than in the moat or lake. Bacterial abundance also increased across sites of increasing DOC concentration and declining pH. Bacterial activities (rates of [3H]leucine incorporation) and growth in dilution cultures (with grazers removed) were also assessed in lake, moat, and mat sites. Results using these measures generally supported the trends observed in abundance, although high rates of [3H]leucine incorporation were recorded in the moat at one of the bogs. Our results indicate that bacterial populations in Sphagnum peatlands are not adversely affected by acidity, and that DOC may be more important than pH in determining bacterial abundance in these environments.

School-based health center utilization: a survey of users and nonusers

BACKGROUND

As school-based health centers (SBHCs) continue to grow, it remains important to study use of the centers. The extent to which mental health problems exist in the students with access to the centers, whether those students are using the available services, if they are satisfied with the services, and the reasons for nonuse by those students who do not enroll are all meaningful questions.

METHODS

The above issues were studied in an urban high school with a 2-year-old SBHC by administering questions during physical education classes on health center use and mental health concerns. The 630 respondents were 45% male, 55% female, 61% black, 29% Hispanic, 54% in grades 9 or 10, 46% in grades 11 or 12.

RESULTS

Sixty percent of the students were registered in the SBHC; 40% were not registered. Seventy-five percent of registered students reported average use (< or =3 visits); females were more likely than males (P=.017) to be frequent (>3 visits) users of SBHC services. Mental health problems among all participants included depression in 31%, use of alcohol 1 time or more per month in 21%, use of alcohol daily in 5%, suicidal ideation in 16%, history of a suicide attempt in 10%, knowing someone who had been murdered in 50%, and being in at least 1 fight at school in 26%. Frequent users, average users, and nonusers did not differ by age, grade, race, or any of the measured mental health problems. Among the 472 students who completed the survey section on SBHC perceptions, 305 described health center use: 92% were satisfied with health center services, 79% were comfortable being seen in the SBHC, 74% believed visits were kept confidential, 61% told their parents about each visit, and 51% considered the SBHC their regular health care source. The health center was used for mental health services by 34% and sexuality-related care by 15%. The 167 students who described reasons for not using the SBHC most frequently reported that they already had a physician (60%), did not need it (50%), prefer continuing previous health care (45%), did not get around to it (30%), parents were opposed (20%), were not comfortable (19%), did not know about the service (19%), and did not want problems known (19%).

CONCLUSIONS

We conclude that, in this urban high school, (1) average users, frequent users, and nonusers did not differ in the mental health problems measured in this study; (2) those who used the SBHC indicated strong satisfaction with the care received; and (3) those who did not use the SBHC chose to stay away for a variety of reasons, most commonly the availability of other care or the perception of lack of need.

Mast cell tryptase in anaesthetic anaphylactoid reactions

Increased concentrations of mast cell tryptase are a highly sensitive indicator of anaphylactic reactions during anaesthesia. We obtained serum specimens from 350 patients after possible anaphylactic reactions during anaesthesia. Serum was collected from patients in our own institution (27), and transported by mail and courier from other hospitals in response to a request in the medical literature (323). Concentrations of mast cell tryptase were measured in 416 specimens. Intradermal testing was performed in 217 patients and radioimmunoassay for drug-specific antibodies with serum in 198 patients. Mast cell tryptase concentrations were increased in 158 patients, equivocal in 10 and not increased in 182. There was a significant difference in the incidence of positive intradermal tests, radioimmunoassay tests and evidence of an IgE-mediated reaction in patients whose mast cell tryptase concentrations were increased. Seven of 143 patients whose mast cell tryptase concentrations were not increased at appropriate sampling times had positive tests for IgE antibodies, and in 33 of 158 patients with increased mast cell tryptase concentrations no IgE antibodies were detected. We conclude that increased mast cell tryptase concentrations are a valuable indicator of an anaphylactic reaction during anaesthesia. Their presence favours an IgE-mediated cause but does not always distinguish between anaphylactoid and anaphylactoid reactions, and patients in whom mast cell tryptase concentrations are not increased still require skin testing.

Alleged allergy to local anaesthetics

The aim of this study was to determine the incidence of true local anaesthetic allergy in patients with an alleged history of local anaesthetic allergy and whether subsequent exposure to local anaesthetics is safe. Two hundred and eight patients with a history of allergy to local anaesthesia were referred over a twenty-year period to our Anaesthetic Allergy Clinic. In this open study, intradermal testing was performed in three patients and progressive challenge in 202 patients. Four patients had immediate allergy and four patients delayed allergic reactions. One hundred and ninety-seven patients were not allergic to local anaesthetics. In 39 patients an adverse response to additives in local anaesthetic solutions could not be excluded. In all but one patient local anaesthesia has been given uneventfully subsequently. A history of allergy to local anaesthesia is unlikely to be genuine and local anaesthetic allergy is rare. In most instances LA allergy can be excluded from the history and the safety of LA verified by progressive challenge.

Health service reform: the perceptions of medical specialists in Australia (New South Wales), the United Kingdom and New Zealand

OBJECTIVE

To examine the effect of recent healthcare service changes (including significant resource constraint and a greater role for the non-medical manager) in the United Kingdom, Australia and New Zealand on medical specialists' perceptions of their healthcare organisation goals and service delivery, and their enthusiasm for their work.

DESIGN

Postal questionnaire survey, answered anonymously.

PARTICIPANTS AND SETTING

Medical specialists employed either part- or full-time in two United Kingdom National Health Service Trusts (one acute, one mental health/community service), an Australian Area Health Service and a New Zealand Crown Health Enterprise in 1995.

MAIN OUTCOME MEASURES

Participants' rating of their knowledge of employers' organisational goals, ability to influence management, perceptions of changes in resources and service availability since 1990 and changes in enthusiasm for their work over the past four years.

RESULTS

369 of 521 eligible specialists responded (71%); by country-United Kingdom, 123/186 (66%); New Zealand, 123/160 (77%); Australia, 123/175 (70%). New Zealand specialists were less aware of their employers' organisational goals and had less congruence between these and their own personal goals than United Kingdom or Australian specialists (P < 0.05). Interest in influencing central management was similar in the three countries, but Australian specialists felt management was less likely to follow their advice compared with United Kingdom specialists (P < 0.05). New Zealand specialists perceived that waiting times for non-urgent patients were currently longer than in 1990 compared to United Kingdom specialists (P = 0.02). In all three countries, inpatient beds were perceived to be less available than in 1990, but less so in New Zealand. The ease of replacing equipment was better in New Zealand than in Australia and the United Kingdom (P = 0.00001). More than 50% of participants in all three countries (183/361; 50.7%) reported that their enthusiasm for their work had decreased in the past four years.

CONCLUSION

The effects of health service reforms seem to have reduced enthusiasm for work among medical specialists in Australia, the United Kingdom and New Zealand.

Intradermal compared with prick testing in the diagnosis of anaesthetic allergy

We have tested the hypothesis that intradermal testing is a more effective method for determining the drug responsible for anaesthetic anaphylactic reactions than prick testing in 212 consecutive patients, aged more than 10 yr, referred to an anaesthetic allergy clinic over a 4-yr period. The study was a prospective, non-randomized design. Intradermal testing was conducted using a previously described method and diluted drugs, and prick testing using undiluted drugs (with the exception of opioid analgesics which were diluted 1:10). The tests were performed on individual patients' forearms on the same occasion. Patients were followed-up to determine the results of subsequent anaesthesia and the difference between tests was analysed using kappa and tau statistics. There was 93% agreement overall between the paired tests. Which test detected the drug responsible was dependent on diagnostic criteria for positivity. The differences between the tests were not statistically significant. Using both tests improved predictability by 67% (tau = 0.67, P < 0.001). We conclude that in the absence of data to support one test being superior, other factors influence the choice of test. Prick testing was cheaper, and the reduction in pain and trauma with prick testing makes it more suitable for children. However, there are no data available on the safety of subsequent anaesthesia based on the results of prick testing alone, and reliability with time has not been assessed. Intradermal testing may be easier for the infrequent user. Skin testing is valuable in the investigation of anaesthetic anaphylaxis whichever test is chosen. When there is doubt both tests should be performed.

Critical care. A specialty without frontiers

During its development, the specialty of Intensive Care has evolved from simple supportive ventilatory techniques to complex monitoring and decision making. The evidence suggests that a trained dedicated intensivist has beneficial effects on outcomes and costs compared to open units. The role of the intensivist and the need for interaction with other groups is discussed.

Postesophagectomy mediastinal chylothorax causing upper airway obstruction misdiagnosed as asthma: a report of two cases

Injury to the thoracic duct resulting in chylothorax is an uncommon but well-documented complication of esophagectomy. In two cases, which were associated with signs of life-threatening upper airway obstruction, an initial diagnosis of asthma was made. It appears that this complication of esophagectomy has not been reported previously.

Physician recognition of hypochondriacal patients

To examine primary care physician recognition of hypochondriacal patients, we identified a series of such patients in a general medicine clinic using the Whiteley Index. Clinic physicians made blind global ratings of severity of physical disease and unreasonable fear of illness (hypochondriasis) and completed a checklist of somatizing characteristics. Patient records were audited for diagnoses, laboratory tests, consultations, and medications prescribed. Twenty-nine (14%) of 210 patients scored above an established cutoff on the Whiteley Index. These hypochondriacal patients were rated by clinic physicians as more hypochondriacal and were more often given psychiatric diagnoses. Also, clinic physicians identified more somatizing features among hypochondriacal patients including their own reaction to them. This recognition of hypochondriac characteristics may have contributed to better management but may need to be raised to the diagnostic level for maximum benefit.

The impact of heat and moisture exchanging humidifiers on work of breathing

In this study the resistive work or breathing (WOB) associated with eleven commercially available heat and moisture exchangers (HMEs) was evaluated for gas flow rates of 20 to 60 l.min-1. The Gibeck Humid-Vent 2S Flex was also assessed after 24 hours patient usage (n = 50). The WOB associated with these devices was compared with that of standard endotracheal tubes and standard humidifying circuits with flex-tube connectors. The range of work imposed by the eleven HMEs approximated the range shown by water bath circuitry when used with two different commonly used flex-tube connectors. The excess WOB attributed to the HMEs was significantly less than that imposed by standard endotracheal tubes. After 24 hours of patient use, 96% of the Gibeck HMEs tested demonstrated a resistive WOB within the range of the two flex-tube connectors. To assess the clinical significance of this circuit-related WOB, we compared respiratory variables in 40 patients breathing on either CPAP or pressure support ventilation, using a variation in flex-tube resistance which imposed a range of WOB comparable to that shown by the HMEs. A small but statistically significant reduction was found for both the peak flow (48 +/- 1.4 vs 45 +/- 1.1 l.min-1, P < 0.0005) and the minute volume (8.6 +/- 0.35 vs 7.9 +/- 0.31, l, P < 0.0005). These data suggest that the range of resistive work imposed by commercially available HMEs has a small but potentially significant effect on clinical respiratory parameters.

Development, implementation, and evaluation of a health promotion program in a college setting

The authors developed, implemented, and evaluated a health promotion program for employees at a state college in New Jersey on the basis of a campus health survey. The resulting physical fitness and exercise program with educational components was assessed twice. Comparisons of experimental and control groups, using one-way analyses of variance, revealed significant differences on four variables: high-density lipoprotein (HDL), total cholesterol/HDL ratio, triglycerides, and body weight in pounds.

Pilot trials of PDF symbology as a means of transfering data on blood units between transfusion centres

PDF 417, a two-dimensional barcode, was used as a portable data file to transfer key information on blood units and delivery documentation between two Regional Blood Transfusion Centres. Multiple Codabar messages currently displayed on blood packs, as well as other useful information, i.e. microbiology conformance, were encoded in a 45-character single PDF barcode. The delivery note which accompanied each consignment of blood consisted of a series of PDF barcodes, each representing 20 blood units. Computer validation showed 100% reconciliation of PDF data with Codabar data. Readability of the code was excellent with a greater than 98% first-pass read rate. The delivery note PDF barcode identified eight operator errors which would have been undetected by the present manual system. We conclude that PDF 417 is an effective, secure and space efficient means of transferring data associated with the transfer of blood.

One-year follow-up of medical outpatients with hypochondriasis

To examine the diagnostic stability and outcome of hypochondriasis, the authors followed 50 patients with this disorder and 50 age- and sex-matched control subjects after 1 year. After 1 year, two-thirds of the subjects continued to meet criteria for hypochondriasis, and the remaining third had persisting hypochondriacal symptoms. The hypochondriacal subjects were improved on most measures but still differed from the control subjects with regard to attitudes, perceptions, and behaviors that had distinguished them initially. More severe symptoms, longer duration of illness, and coexisting psychiatric illness were predictive of a worse outcome. The data indicate that the diagnosis of hypochondriasis is stable over time, and that, although symptoms wax and wane, characteristic features persist. The findings underscore the importance of diagnosing and treating hypochondriasis in medical outpatients.