Pontiac fever due to Legionella micdadei from a whirlpool spa: possible role of bacterial endotoxin.

During January 1998, a cluster of illnesses occurred among hotel guests in Wisconsin. Ill persons had been exposed to the hotel's whirlpool spa and swimming pool. Symptoms included headache, fever, chills, myalgia, shortness of breath, and fatigue. A diagnosis of Pontiac fever was made, based on serologic evidence of acute infection with Legionella micdadei. High concentrations of heterotrophic bacteria were recovered from the spa, despite apparently high disinfectant levels. L. micdadei was isolated from the swimming pool filter and water from the spa after heat enrichment but not from pools and spas at nearby hotels. Water from hotel pools and spas was tested to determine endotoxin levels; water from the spa of the implicated hotel contained the highest concentration of endotoxin (14,400 endotoxin units/mL). Additional studies are needed to determine the role of endotoxin from legionellae or other bacteria in the pathogenesis of Pontiac fever.

Early clinical experience with color three-dimensional intravascular ultrasound in peripheral interventions.

PURPOSE: To report early clinical experiences with color 3-dimensional intravascular ultrasound (3-D IVUS) in assisting peripheral interventions. TECHNIQUE: A 3.5-F, 20-MHz IVUS catheter that utilizes ChromaFlo computer software to demonstrate blood flow in color was evaluated in over 100 peripheral interventions. ChromaFlo captures up to 30 conventional IVUS frames every second and generates "real-time" imaging. The software compares sequential axial IVUS images and interprets any differences in the position of echogenic blood particles, which are displayed as colorized flow in axial or 3-D renderings. CONCLUSIONS: ChromaFlo-enhanced IVUS demonstrates colorized blood flow inside the vessel lumen, which is helpful in distinguishing echolucent disease from luminal blood flow and can also be used to perform peripheral interventions in patients with renal failure or allergy, avoiding the use of contrast media.

How best to utilize a deficiency.

This article is a commentary on Harriet Waters' discussion, in this issue, of strategy inefficiencies and strategy utilization, mediation, and production deficiencies. The author focuses on the importance and meaning of the degree of spontaneity in strategy production, and situates the concept of utilization deficiency within current work on strategy heterogeneity, contextual support, and situation-specific skills.

Contemplating fuzzy-trace theory: the gist of it.

Brainerd and Reyna (1998, this issue) have described fuzzy-trace theory as a basic-processing theory, emphasizing age differences in children's disposition to use verbatim versus gist representations. The theoretical climate of the 1980's, when fuzzy-trace theory was first formulated, is described. Fuzzy-trace theory integrated new ideas about how cognitive development was viewed into a coherent framework, which only gradually gained acceptance as critical aspects of the theory were confirmed, counterintuitive findings were predicted and demonstrated, and other researchers began applying the theory. Fuzzy-trace theory converges with other contemporary theoretical accounts in raising the general issue of the relation between two developing representational systems and is consistent with the idea that immature (a bias toward verbatim encoding) and mature (a bias toward gist encoding) have both advantages and disadvantages at different times in development. By integrating the theory with ideas from social-contextual perspectives, the theory may have a greater impact in the future for issues of social significance.

Pyrogenic reactions in patients undergoing cardiac catheterization associated with contaminated glass medicine cups.

Pyrogenic reactions are potentially life-threatening complications caused by bacterial endotoxin. After two cardiac catheterization patients developed rigors the same day, the procedures were halted and a case control study was conducted. To identify case patients (persons with rigors < or = 3 hr after catheterization during September 25-November 9, 1995), we reviewed medical records of all cardiac catheterization patients who had a blood culture or received intravenous meperidine. Twelve case patients and 40 randomly selected control patients were identified. No specific catheter was associated with case patients, but exposure to intracoronary-nitroglycerin (NTG) was (odds ratio = 12.0; 95% confidence interval 2.2, 75.6). NTG or indocyanine green dye was poured into glass medicine cups previously washed in an enzyme cleaner and then sterilized. The cleaner, used for an entire day, had elevated levels of gram-negative bacteria (> 10(4) colony forming units/mL) and endotoxin (434 endotoxin units [EU]/mL]); the reprocessed cups had no live bacteria but had elevated endotoxin levels (median 2,250 EU). Exposure to contaminated glass medicine cups probably resulted in pyrogenic reactions and contributed to death in two critically ill patients.

Atmospheric growth requirements for Alloiococcus species and related gram-positive cocci.

The growth of Alloiococcus otitis under different atmospheres and nutritional conditions was studied. The growth rates of 25 strains of gram-positive cocci representing five genera on heart infusion agar plates containing 5% rabbit blood and on brucella agar plates with and without sheep blood under aerobic, increased CO2, and anaerobic atmospheres were compared. Eight strains of alloiococci plated on heart infusion agar with rabbit blood and on brucella sheep blood agar grew under aerobic and candle jar atmospheres. Two of these strains showed poor anaerobic growth after 7 days. Strains of Aerococcus viridans, Aerococcus urinae, Helcococci kunzi, Dolosigranulum pigrum, Gemella haemolysans, and Gemella morbillorum grew well under all three atmospheres and on the three types of media and in thioglycolate broth. These results confirm all the aerobic atmospheric requirements for Alloiococcus strains and show that aerobic growth characteristics help distinguish the alloiococci from the other gram-positive cocci that are facultatively anaerobic.

Preschoolers' strategic behavior and performance on a same-different task.

Preschoolers' strategic behavior was examined on a task in which they must decide whether two arrays are the same. Fifty-six 3- and 4-year-olds selected doors to open which exposed parts of the arrays. Children made moderate use of an appropriate "vertical-pairs" strategy - viewing spatially corresponding parts of the two arrays - and it facilitated performance. Telling nonstrategic children to use the strategy or executing it for them improved their same-different judgments. However, increased spontaneous production of the vertical-pairs strategy over trials did not consistently improve judgments, which suggests a strategy utilization deficiency. Other microgenetic analyses revealed that children tended to use several strategies over the trials and that strategy changes often were not developmentally progressive or driven by failure of another strategy. The discussion addressed production and utilization deficiencies and the diversity of strategy development.

Evaluation of AnaeroGen system for growth of anaerobic bacteria.

The Oxoid AnaeroGen system was compared with the BBL GasPak for the production of an anaerobic atmosphere and was evaluated for its ability to support the growth of 135 clinically significant anaerobic bacteria. An anaerobe chamber was used as the "gold standard" for supporting the growth of anaerobes. The AnaeroGen requires no catalyst, produces no hydrogen, requires no water, and reduces preparation time to a minimum. The water-activated BBL GasPak generates hydrogen. For 132 of the 135 strains tested, better initial growth at 48 h was noted for the jar methods than for the anaerobe chamber. At 72 h, 113 of the 135 strains showed equal growth, and at 7 days, only marginal differences in growth patterns were noted. The AnaeroGen never failed to reduce the anaerobic indicator, while the BBL GasPak occasionally failed to do so. The AnaeroGen performed at least as well as, and sometimes better than, the established methods. The AnaeroGen is a good alternative for use in anaerobic jars.

Magnetic resonance spectroscopic study of parkinsonism related to boxing.

Proton magnetic resonance spectroscopy, localised to the lentiform nucleus, was carried out in three ex-professional boxers who developed a parkinsonian syndrome, six patients with idiopathic Parkinson's disease, and six age matched controls. The three ex-boxers all showed a pronounced reduction in the absolute concentration of N-acetylaspartate compared with the patients with idiopathic Parkinson's disease and the control group. This reduction is likely to reflect neuronal loss occurring in the putamen and globus pallidus and supports the hypothesis that the extrapyramidal syndrome that may occur in ex-boxers is a distinct entity from idiopathic Parkinson's disease.

Use of Presumpto Plates to identify anaerobic bacteria.

Identification of anaerobic bacteria requires special media and growth conditions that contribute to a higher cost per identification than that for aerobic isolates. Newer rapid methods streamline the identification process, but confirmation to the species level is often difficult. The Presumpto Plate method for the identification of commonly encountered anaerobes consists of three quadrant plates, each containing four conventional media, that result in the generation of 21 test parameters: growth on Lombard-Dowell medium; production of indole, indole derivative, catalase, lecithinase, and lipase; proteolysis of milk, H2S, and esculin; growth on 20% bile; precipitate on bile; DNase, glucose, casein, starch, and gelatin hydrolysis; and fermentation of lactose, mannitol, and rhamnose. Identification charts were developed by using the results from 2,300 anaerobic isolates. Because conventional media were used, there was a high degree of agreement between the Presumpto Plate method and the reference method when testing commonly encountered anaerobes. The Presumpto Plate method is as accurate as commercially available enzyme systems for the identification of many anaerobic species but is less expensive to perform.

Evaluation of API An-IDENT and RapID ANA II systems for identification of Actinomyces species from clinical specimens.

We compared the accuracy of the An-IDENT system (bioMerieux Vitek, Inc., Hazelwood, Mo.) and the RapID ANA II system (Innovative Diagnostic Systems, Norcross, Ga.) with that of conventional biochemical tests for the identification of 85 strains of Actinomyces species. In our hands, the overall accuracy of the An-IDENT was 59% and that of the RapID ANA II was 24%. The error rate for the An-IDENT was 18% and that for the RapID ANA II was 38%. The results of this study suggest that although the An-IDENT was more accurate than the RapID ANA II (P < 0.005), neither system, in our hands, was able to identify Actinomyces species with an acceptable degree of accuracy. It is recommended that suspected Actinomyces isolates be identified by conventional testing.

Strategy utilization deficiencies in children: when, where, and why.

By the early 1980s, a clear picture of the role of strategies in memory development was emerging. Strategies generally help recall and thus are a main contributor to memory development. Young children have a production deficiency that is overcome during the grade school years. By the early 1990s, the process appeared to be a good deal more complex. Although spontaneously produced strategies often help recall, they do not inevitably do so, especially among novice strategy producers--even when their strategy production appears proficient. In the 1980s and 1990s, a main theme of research on children's strategies of memory has been that children begin to use strategies earlier than previously thought. Researchers have identified rudimentary strategies of even 2- and 3-yr-olds. Our research suggests that we also need to take a careful look at the other end of the spectrum. A strategy may continue to develop well beyond the point at which an apparently full-blown strategy is produced. Producing a relevant strategy does not mark the end of strategy development. Rather, it marks the beginning of the development of a proficient, low-effort strategy that enhances recall. Even after a child spontaneously produces the strategy fully and consistently, the strategy gradually becomes less effortful to access and to execute and is integrated with other mnemonic strategies and activities. As a result, the strategy is increasingly likely to facilitate recall. Researchers need to conduct a fine-grained analysis of the actual implementation of a strategy--how the strategy of interest dovetails with a set of strategic, metamemorial, information-processing, and motor-control processes. The utilization deficiency phenomenon may challenge current conceptions of how and why skills develop. Why do children spontaneously use and continue to use a skill that helps them little or not at all? The usual assumption has been that children acquire and perfect skills because they have some benefit for them. This benefit is still true in the long run, but not the short run. The utilization deficiency, Bjorklund and Green's (1992) account of young children's overoptimism, and Siegler's (e.g., McGilly & Siegler, 1989) observation that children sometimes reject, at least temporarily, a strategy that helps them, describe behaviors that do not fit easily into current models of children as rational problem solvers. We need a different conceptualization of the course of strategy development and perhaps skill development more generally.

Age differences in the capacity demands of a strategy among spontaneously strategic children.

This study examined whether spontaneously strategic children from two age groups differed in the capacity required to execute a strategy. The strategic behavior of younger (grades K and 1) and older (grades 4 and 5) children (N = 104) was assessed on a selective memory task. Children selected objects to view from a larger pool of objects. The most mature strategy (i.e., selectivity) involves opening doors that reveal objects to be remembered and not opening those that do not. In a dual-task procedure in a second session, children performed a finger tapping task simultaneously with the selective strategy. The reduction of rate of finger tapping from the finger tapping baseline to the dual-task trials provided an assessment of the capacity required to execute the strategy. A control group followed the same procedure, but with a simpler door opening selective strategy. A significant age difference in the capacity required for the strategy, even among spontaneously strategic children, suggested that there is further development of strategies even after children spontaneously produce them. Results were discussed in terms of increased strategy effectiveness during development.

Discounting in preschoolers: effect of type of reward agent.

The effect of type of reward agent on children's discounting was examined. In Study 1, 49 preschool children were told two stories illustrated with small dolls and toys. Subjects discounted intrinsic interest in toy A when a "big, mean brother" told a sibling that if he played with toy A he could play with toy B. Discounting did not appear when the reward agent in the story was the child's mother, which is the typical outcome in previous research with young children. Studies 2 and 3 suggested that the combination of a negative valence and a particular social role/status accounted for the effect of the big, mean brother of Study 1. More specifically, neither a "big brother" nor a "mean mother" as reward agents elicited a significant amount of discounting. The results suggest that social knowledge guides the application of the discounting schema.

Social-cognitive correlates of children's understanding of displaced aggression.

The purpose of this research was (1) to provide a detailed description of developmental differences in the understanding of displaced aggression during the grade school years and (2) to identify social-cognitive correlates of this development. Seventy-two children aged 5, 7, and 9 viewed, and answered questions about, four videotaped stories involving displaced aggression. In another session they were given three tests of social cognition. One was a person perception task which tapped the tendency to refer to physical or psychological attributes. A second was a recursive thinking task which assessed their awareness that people can think about each other. Third, Selman's puppy story was used to assess their awareness that words or facial expressions do not always reflect the way a person feels, and that a person may not always know what he or someone else really feels. The understanding of displaced aggression increased significantly with increasing age. This understanding was significantly related to the person perception task for 5-year-olds, and to the Selman task for 7- and 9-year-olds. The results were discussed in terms of a developing awareness of possible discrepancies between feelings and physical behavior, facial expressions, or words.

The facilitation of selective attention in preschoolers.

Allocation of attention was examined on a selective attention task in which some items were relevant (i.e., their locations should be remembered) and some were irrelevant. 100 4- and 5-year-olds formed 4 experimental conditions and 1 control group. 3 experimental groups had 1 added feature to aid selectivity (fewer stimuli, increased perceptual salience of the difference between relevant and irrelevant stimuli, or extra reminders of the locations of relevant and irrelevant stimuli). The fourth experimental condition included all features. A story and explicit instructions identified which objects were relevant. During study times, children opened doors (marked with cages or houses) of a box to reveal animals or household objects. Selectivity (opening mainly relevant doors) was high, compared to previous studies using no story with 6-year-olds, even in the control condition. Selectivity increased significantly beyond the level in the control condition only when all facilitative features were combined. Selectivity was not significantly related to recall. This outcome, in conjunction with previous research, suggests a lag between the production of a strategy and its facilitative effect on recall.

The development of children's strategies for selective attention: evidence for a transitional period.

Previous research suggests a developmental lag between producing a strategy of selective attention and benefiting from it. This aspect of the transitional period during strategy acquisition was investigated in the present study by comparing recall following child-produced (Session 1) and experimenter-produced (Session 2) strategies. The 114 7-9-year-olds were told to remember a subset of 6 items (either animals or household) located beneath 2 rows of doors. Session 1 assessed each child's spontaneous strategy (pattern of opening doors) over 6 trials. Session 2 included 7 different trial types, during which the experimenter opened the doors, thereby equating the strategies for children of all ages. The results revealed gradual changes in children's ability both to produce and to benefit from a selective strategy. Whereas younger children performed differently on trial types during which only the 6 relevant versus all 12 items were shown, older children recalled a similar number of items for all trial types, regardless of the number or pattern of door openings provided. Adult-produced selectivity eliminated recall differences among the grades and suggested that strategy production is effortful for younger children and therefore may prevent their benefiting from the strategy.

Solubilization of hen brain neurotoxic esterase in dimethylsulfoxide.

Neurotoxic esterase is the putative site of initiation of organophosphorus-induced neuropathy. The protein is membrane-associated and will thus require solubilization before it can be purified. Its enzymic activity was retained in hen brain microsomes suspended in 10-60% (v/v in water) dimethylsulfoxide and 5-20% dimethylacetamide, but lost in 5-20% 1- and 2-propanol as well as higher concentrations of dimethylsulfoxide. Soluble activity (100,000 x g, 60 min supernatant) was not obtained with dimethylacetamide, but 24% of the recovered activity (67%) was solubilized in 40% dimethylsulfoxide, with retention of its native response to inhibitors. Solvent extraction of active enzyme is of intrinsic interest and expands the options for its purification.

Metacognitive components of visual search in children.

Two studies examined children's increasing ability to analyze tasks in terms of the perceptual features that affect task difficulty. Of particular interest was any understanding that perceptual confusions occur during the search for an object surrounded by objects similar in shape or color to that object. In Study 1, 32 pre-schoolers constructed arrays intended to make the search easy or difficult. They made the search difficult simply by putting many toys into the toy box. In a forced-choice situation, they indicated that task difficulty was influenced by the number of objects and the similarity in color and shape of the targets and the surrounding objects. Study 2 more thoroughly examined knowledge of color and shape confusions, using 96 children from Grades K, 1, 3, and 4, assigned to two age groups. The older children but not the younger ones showed a significant understanding of color and shape confusions. Both age groups understood that performance is affected by a person's interest level and degree of attention to the task. The results were discussed in terms of the accessibility of the children's knowledge under different conditions.

Children's reasoning about the causes of human behavior.

Three studies examined young children's ability to predict how certain internal and external conditions affect behavior. Study 1 included 136 children from early preschool, late preschool, kindergarten, and second grade. A forced choice procedure revealed that even the youngest group could predict the effect of various internal-personal causes (e.g., interest, intelligence) and external-situational causes (e.g., rewards, adult pressure). Older preschoolers and second graders considered these internal causes more powerful than these external causes. With the same procedure, in Study 2 the 16 preschoolers predicted that both physical characteristics (e.g., strength, energy level) and the internal-personal characteristics of Study 1 affect performance in athletic activities. In addition, they considered the physical causes more important. Study 3 examined more complex types of causal reasoning. Younger preschoolers responded randomly but older preschoolers combined two causes to create a greater effect than one cause and used an external cause to enhance, rather than discount, an internal cause. The discussion focused on the cognitive development underlying developmental differences in the ability to predict behavior on the basis of one or two causes.