The Dose of Case Management Interventions

Case management programs need to be evaluated for outcomes achievement and efficient use of resources. As a provider intervention, case management is interactional and situational. Little is known about how to measure the actual dose delivered in order to assess quality and manage outcomes. Case management is interdisciplinary, has identifiable dimensions, and serves as a practical example of conceptualizing and measuring the dosage of a provider's intervention. The basic elements of the dosage of an intervention are amount, frequency, duration, and breadth. A three-dimensional model illustrates dosage of case management.

Telephone management in substance abuse treatment

The purpose of this article is to describe the results of a clinical trial in which telephonic case management was evaluated as a supplement to substance abuse treatment. An interactive voice response system (IVR) was developed by the research team for use in the case management of randomly assigned participants in a clinical trial research project. The features of the software program facilitated a double caseload for the case manager as well as real-time data capture. At intake, no significant differences were found between participants in the telecommunication condition and the general project. Thus, the effectiveness of random assignment was supported. An IVR was useful for case management services, was less costly, and showed acceptability to clients. A reduction in time expenditure by using telecommunication occurred within three activity areas. Telecommunication facilitated client interaction and the use of case management, and it reduced provider time expenditure. As an alternative strategy, telecommunication case management can enhance cost effectiveness improvements.

Chemorepellent signaling through the PACAP/lysozyme receptor is mediated through cAMP and PKC in Tetrahymena thermophila

Pituitary adenylate cyclase-activating peptide and lysozyme are potent chemorepellents which act through the same receptor in Tetrahymena. Using in vivo behavioral studies, we have found that the pituitary adenylate cyclase-activating peptide/lysozyme receptor appears to signal through a G-protein pathway which is mediated through both adenosine 3'5'monophosphate and protein kinase C. Avoidance to pituitary adenylate cyclase-activating peptide and lysozyme is inhibited by the G-protein inhibitor, guanosine 5'-O-(2thiodiphosphate), the adenosine 3'5'monophate analog, Rp-adenosine-3', 5' cyclic monophosphorothioate, and the protein kinase C inhibitors, calphostin C and bisindolylmaleimide IV. A proposed model for signaling through the pituitary adenylate cyclase-activating peptide/lysozyme receptor is briefly outlined.

Early and late reactions after the use of iopamidol 340, ioxaglate 320, and iodixanol 320 in cardiac catheterization

BACKGROUND

Although modern contrast agents have tolerability superior to older agents, significant differences remain between the agents currently in use.

METHODS

To investigate the incidence of early (<24 hours) and late (>24 hours to 7 days) reactions to 3 contrast agents commonly used in cardiac catheterization, we performed a randomized, prospective, double-blind trial in which 2001 patients received one of the following agents: iopamidol 340, a nonionic monomer; ioxaglate 320, an ionic dimer; and iodixanol 320, a nonionic dimer. Possible reactions to contrast were recorded during the hospital admission and after discharge by means of a questionnaire, telephone follow-up, or both.

RESULTS

Early reactions occurred in 22.2% of those receiving ioxaglate, 7.6% of those receiving iodixanol, and 8.8% of those receiving iopamidol (P <.0001). Late skin reactions occurred in 12.2% of those receiving iodixanol, 4.3% of those receiving ioxaglate, and 4.2% of those receiving iopamidol (P <.0001).

CONCLUSIONS

The early side effect profile of certain ionic contrast agents suggests that these agents should no longer be used routinely in cardiac catheterization. The use of nonionic agents, however, is associated with late skin reactions, but there are notable differences between the monomeric and dimeric compounds. Although the skin reactions are generally benign, this is not always the case. Patients should be advised accordingly.

Crystal structures of the maltodextrin/maltose-binding protein complexed with reduced oligosaccharides: flexibility of tertiary structure and ligand binding

The structure of the maltodextrin or maltose-binding protein, an initial receptor for bacterial ABC-type active transport and chemotaxis, consists of two globular domains that are separated by a groove wherein the ligand is bound and enclosed by an inter-domain rotation. Here, we report the determination of the crystal structures of the protein complexed with reduced maltooligosaccharides (maltotriitol and maltotetraitol) in both the "closed" and "open" forms. Although these modified sugars bind to the receptor, they are not transported by the wild-type transporter. In the closed structures, the reduced sugars are buried in the groove and bound by both domains, one domain mainly by hydrogen-bonding interactions and the other domain primarily by non-polar interactions with aromatic side-chains. In the open structures, which abrogate both cellular activities of active transport and chemotaxis because of the large separation between the two domains, the sugars are bound almost exclusively to the domain rich in aromatic residues. The binding site for the open chain glucitol residue extends to a subsite that is distinct from those for the glucose residues that were uncovered in prior structural studies of the binding of active linear maltooligosaccharides. Occupation of this subsite may also account for the inability of the reduced oligosaccharides to be transported. The structures reported here, combined with those previously determined for several other complexes with active oligosaccharides in the closed form and with cyclodextrin in the open form, revealed at least four distinct modes of ligand binding but with only one being functionally active. This versatility reflects the flexibility of the protein, from very large motions of interdomain rotation to more localized side-chain conformational changes, and adaptation by the oligosaccharides as well.

Selective use of abciximab in coronary stenting: overall outcomes can still be equivalent to those in the EPISTENT treatment group

BACKGROUND: The EPISTENT trial reported improved early outcomes with routine use of abciximab after coronary stenting. Increasing use of stents means that routine abciximab adds significantly to costs of percutaneous coronary intervention (PCI). This paper reports the results of a protocol encouraging restriction of abciximab therapy to high-risk patients only. METHODS: Data were collected prospectively over a 34-month period for patients undergoing PCI with stenting. In addition to those who fulfilled criteria for inclusion in the EPISTENT trial, patients treated in the setting of acute myocardial infarction (AMI) were studied. Demographic data, procedural details and early clinical outcomes were recorded. RESULTS: Of 808 patients studied, 601 fulfilled EPISTENT inclusion criteria and comprised 367 patients (45%) treated for stable angina and 234 (30%) treated for unstable or post-infarct angina. The additional 207 patients (25%) were treated during AMI. The 808 patients received a total of 981 stents. Abciximab was given in only 88 cases (10.9%). Major adverse clinical events occurred in 39 patients (4.8%). CONCLUSION: Selective use of abciximab for patients undergoing coronary stenting can be associated with outcomes equivalent to those reported for routine use, but with significant cost savings.

Electrode impedance: an indicator of electrode-tissue contact and lesion dimensions during linear ablation

Pre-ablation impedance was evaluated for its ability to detect electrode-tissue contact and allow creation of long uniform linear lesions with a multi-electrode ablation catheter. The study consisted of 2 parts, both of which used the in vivopig thigh muscle model. In part 1, a 7 Fr. multi-electrode catheter was held in 3 electrode-tissue contact conditions: (1) non-contact; (2) light contact with a 30g downward force; and (3) tight contact with a 90g downward force. Impedances were measured in unipolar, modified unipolar and bipolar configurations using a source with frequencies from 100Hz to 500kHz. Compared with non-contact, the impedance increased 35 +/- 22 % with 30g contact pressure and 68 +/- 40% when the contact pressure was increased to 90g across the range of frequencies studied. In part 2, the same catheter was held against the tissue with different forces. Pre-ablation impedance was measured using a 10kHz current. Phased radiofrequency energy was applied to the 5 electrodes simultaneously using 10W power at each electrode for 120s. A total of 32 linear lesions were created. The lesion dimensions correlated with pre-ablation impedance. A unipolar impedance > or = 190 Omega indicates 95% possibility to create a uniform linear lesion of at least 3mm depth with our ablation system. We conclude that pre-ablation impedance may be a useful indicator for predicting electrode-tissue contact and the ability to create a continuous and transmural linear lesion with a multi-electrode catheter.

Development of a vital fluorescent staining method for monitoring bacterial transport in subsurface environments

Previous bacterial transport studies have utilized fluorophores which have been shown to adversely affect the physiology of stained cells. This research was undertaken to identify alternative fluorescent stains that do not adversely affect the transport or viability of bacteria. Initial work was performed with a groundwater isolate, Comamonas sp. strain DA001. Potential compounds were first screened to determine staining efficiencies and adverse side effects. 5-(And 6-)-carboxyfluorescein diacetate, succinimidyl ester (CFDA/SE) efficiently stained DA001 without causing undesirable effects on cell adhesion or viability. Members of many other gram-negative and gram-positive bacterial genera were also effectively stained with CFDA/SE. More than 95% of CFDA/SE-stained Comamonas sp. strain DA001 cells incubated in artificial groundwater (under no-growth conditions) remained fluorescent for at least 28 days as determined by epifluorescent microscopy and flow cytometry. No differences in the survival and culturability of CFDA/SE-stained and unstained DA001 cells in groundwater or saturated sediment microcosms were detected. The bright, yellow-green cells were readily distinguished from autofluorescing sediment particles by epifluorescence microscopy. A high throughput method using microplate spectrofluorometry was developed, which had a detection limit of mid-10(5) CFDA-stained cells/ml; the detection limit for flow cytometry was on the order of 1,000 cells/ml. The results of laboratory-scale bacterial transport experiments performed with intact sediment cores and nondividing DA001 cells revealed good agreement between the aqueous cell concentrations determined by the microplate assay and those determined by other enumeration methods. This research indicates that CFDA/SE is very efficient for labeling cells for bacterial transport experiments and that it may be useful for other microbial ecology research as well.

Reappraising the role of immediate intervention following thrombolytic recanalization in acute myocardial infarction

Early studies indicated that after successful thrombolytic recanalization, adjunctive percutaneous transluminal coronary angioplasty (PTCA) was not appropriate, even when a significant residual stenosis was present. The aim of this study was to assess in-hospital clinical outcomes of patients with acute myocardial infarction (AMI) who underwent successful recanalization after thrombolytic therapy. The relation between repeat AMI/unstable angina and the severity of the stenosis, as well as other angiographic and clinical features was also examined. One hundred patients with AMI of <10 hours underwent coronary angiography 2 hours after receiving thrombolytic therapy. Salvage PTCA +/- stenting was performed if recanalization was unsuccessful (Thrombolysis In Myocardial Infarction [TIMI] trial grade 0 to 2), and no PTCA was undertaken if there was brisk anterograde flow (TIMI 3). Angiographic analysis was performed to assess the severity of the residual lesion, as well as the presence or absence of thrombus. Forty patients had unsuccessful recanalization, and of these, 36 underwent attempted PTCA. Of the 60 patients with TIMI 3 flow, 15 required repeat angiography and PTCA after repeat AMI (n = 13) or unstable angina (n = 2) within 5 days. Receiver-operating characteristic analysis indicated an optimum percent diameter stenosis predictor of 85% for repeat AMI/unstable angina. There was no additional relation to age, gender, time to thrombolysis, the infarct-related artery, or the presence of culprit lesion thrombus. After recanalization, a high-grade stenosis >85% is common (n = 25, 42.4%). This is associated with a 54% repeat AMI/unstable angina risk-a ninefold increase in the incidence of such events than in patients with lesions <85%. Thus, patients with narrowings >85% may benefit from early intervention rather than a conservative approach. Narrowings <85% have a 94% probability of no repeat AMI/unstable angina and do not require early intervention.

Iowa Case Management for rural drug abuse. Preliminary results

The Iowa Case Management Project (ICMP) was developed to evaluate the effectiveness of a comprehensive, solution-focused model of case management with rural clients in drug abuse treatment. For this preliminary report, 483 clients who were admitted to residential or outpatient treatment at a local facility volunteered to participate and were randomly assigned to one of four research conditions. Clients in three of the conditions received Iowa Case Management (ICM), while clients in the fourth condition received standard treatment services and served as the control group. Clients were assessed regarding psychosocial characteristics at intake and three additional times during the subsequent 12 months.

Failure of thrombolysis: experience with a policy of early angiography and rescue angioplasty for electrocardiographic evidence of failed thrombolysis

OBJECTIVE

To assess the outcome of a policy of emergency coronary angiography with or without rescue angioplasty in patients with acute myocardial infarction and ECG evidence of failed reperfusion after thrombolysis.

DESIGN

A cohort study.

SETTING

Regional cardiothoracic unit.

PATIENTS

197 patients with acute myocardial infarction fulfilling a simple ECG criterion of failed reperfusion.

INTERVENTIONS

Emergency coronary angiography proceeding to rescue angioplasty for inadequate antegrade flow.

MAIN OUTCOME MEASURES

Hospital mortality for all 197 patients; incidence of successful and failed rescue angioplasty; need for additional revascularisation in those receiving rescue angioplasty compared with those not treated in this way.

RESULTS

197 patients had emergency angiography for ECG evidence of failed reperfusion; 156 patients received immediate rescue angioplasty. Overall hospital mortality for those undergoing rescue angioplasty was 11.5%. Rescue angioplasty achieved TIMI 2 (11) or TIMI 3 (124) in 135 patients, who had a hospital mortality of 5.9%. Failure to achieve at least TIMI 2 flow following rescue angioplasty occurred in 21 patients, with a hospital mortality of 48%. In the 41 patients in whom immediate rescue angioplasty was not performed, reinfarction or requirement for revascularisation occurred in 37%. Reinfarction occurred in three patients (1.9%) who had immediate rescue angioplasty. Hospital mortality for the whole cohort was 10.7%.

CONCLUSIONS

A policy of emergency coronary angiography proceeding to rescue angioplasty where appropriate reduces mortality in a high risk group to a level less than expected for patients with acute myocardial infarction and ECG evidence of failed reperfusion. Unsuccessful rescue angioplasty is associated with a high mortality.

Use of a nonionic detergent (Triton WR 1339) in healthy cats to assess hepatic secretion of triglyceride

OBJECTIVE

To determine whether a nonionic detergent (Triton WR 1339) can be used in cats to assess hepatic secretion of triglyceride.

ANIMALS

28 healthy cats.

PROCEDURE

Triton WR 1339 was administered IV according to the following schedule: 5, 50, 150, and 250 mg/kg of body weight. Control cats did not receive an injection or received 0.9% NaCl or PBS solutions at the same osmolarity and volume as the 250 mg/kg group. Blood samples were collected throughout the 48-hour period after administration for determination of triglyceride and cholesterol concentrations and for RBC morphology and osmotic fragility studies.

RESULTS

Administration of Triton WR 1339 at 150 and 250 mg/kg caused profound hypertriglyceridemia. Triglyceride concentrations increased in a curvilinear fashion for the first 2 hours and remained increased for approximately 24 hours. Area under the time-concentration curve for triglyceride at 5 hours differed significantly among groups. At 12 and 24 hours, cholesterol was significantly higher in cats receiving 250 mg/kg. The most dramatic changes in osmotic fragility and RBC morphology were in cats receiving 250 mg/kg; 1 of these cats developed severe icterus and died 5 days later. Feeding rice and casein before administering Triton WR 1339 at 150 mg/kg did not appear to affect the hypertriglyceridemia response.

CONCLUSIONS AND CLINICAL RELEVANCE

Triton WR 1339 can be administered IV to cats at a rate of 150 mg/kg to assess hepatic triglyceride secretion, although some cats may have increased RBC osmotic fragility. Higher dosages caused substantial adverse effects, whereas lower dosages did not alter plasma triglyceride concentration.

Failure of thrombolysis by streptokinase: detection with a simple electrocardiographic method

OBJECTIVE

To determine whether simple, readily applicable ECG criteria will allow early prediction of inadequate (< TIMI 3) flow in the infarct related vessel in patients receiving thrombolytic treatment for acute myocardial infarction; and to determine the success of streptokinase in achieving adequate antegrade flow in the infarct related vessel two hours after starting treatment.

DESIGN

Cohort study.

SETTING

Regional cardiothoracic unit.

PATIENTS

100 sequential patients with acute myocardial infarction.

INTERVENTIONS

Coronary angiography two hours after the initiation of thrombolytic treatment, proceeding to rescue angioplasty for inadequate flow in the infarct related vessel where appropriate.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of six ECG criteria for the detection of inadequate antegrade flow in the infarct related vessel.

RESULTS

The ECG test that performed best as a positive test for < TIMI 3 flow in the infarct related vessel was < 50% resolution of the ST segment elevation in the worst lead and no accelerated idioventricular rhythm. This had a sensitivity of 81%, specificity of 88%, positive predictive value of 87%, negative predictive value of 83%, and overall accuracy of 85%.

CONCLUSIONS

Sensitive, specific, and simple ECG criteria are defined for diagnosing failure of thrombolytic treatment with streptokinase. These allow the early detection of patients at high risk of further adverse events from a persistently occluded vessel. They may be used without recourse to sophisticated equipment or complex analyses. Such patients can then be considered for alternative treatments or enrollment into appropriate research protocols.

Fatty acid deficiency signs predict the severity of reading and related difficulties in dyslexic children

It has been proposed that developmental dyslexia may be associated with relative deficiencies in certain highly unsaturated fatty acids (HUFA). In children with attention-deficit/hyperactivity disorder, minor physical signs of fatty acid deficiency have been shown to correlate with blood biochemical measures of HUFA deficiency. These clinical signs of fatty acid deficiency were therefore examined in 97 dyslexic children in relation to reading and related skills, and possible sex differences were explored. Children with high fatty acid deficiency ratings showed poorer reading (P<0.02) and lower general ability (P<0.04) than children with few such clinical signs. Within males (n=72) these relationships were stronger, and fatty acid deficiency signs were also associated with poorer spelling and auditory working memory (P<0.05, P<0.005 respectively). Within females (n=25) no associations were significant. These results support the hypothesis that fatty acid deficiency may contribute to the severity of dyslexic problems, although sex differences merit further investigation.

Dyslexia in adults is associated with clinical signs of fatty acid deficiency

Developmental dyslexia is a complex syndrome whose exact cause remains unknown. It has been suggested that a problem with fatty acid metabolism may play a role, particularly in relation to the visual symptoms exhibited by many dyslexics. We explored this possibility using two self-report questionnaires, designed on the basis of clinical experience, to assess (1) clinical signs of fatty acid deficiency; and (2) symptoms associated with dyslexia in known dyslexic and non-dyslexic subjects. Dyslexic signs and symptoms included the auditory-linguistic and spoken language difficulties traditionally associated with the disorder, as well as visual problems (both with reading and more generally) and motor problems. Fatty acid deficiency signs were significantly elevated in dyslexic subjects relative to controls, particularly within males (P<0.001). In addition, the severity of these clinical signs of fatty acid deficiency was strongly correlated with the severity of dyslexic signs and symptoms not only in the visual domain, but also with respect to auditory, linguistic and motor problems. The pattern of relationships differed somewhat between dyslexic and control groups, and sex differences were also observed. Our findings support the hypothesis that fatty acid metabolism may be abnormal in developmental dyslexia, and indicate the need for further studies using more objective measures.

Severe left main stem stenosis in a cardiac transplant recipient: successful treatment by coronary stenting

A 58-year-old male underwent orthotopic cardiac transplantation for ischemic cardiomyopathy. At routine coronary angiography 2 years later, he was found to have severe concentric stenosis of the left main coronary artery but was asymptomatic. Revascularization was recommended on prognostic grounds and after discussion with his cardiac transplant surgeon, percutaneous coronary intervention with elective stenting was offered. This was performed successfully with a single stent and a good angiographic result was maintained 6 and 18 months later.

The Jomed Covered Stent Graft for coronary artery aneurysms and acute perforation: a successful device which needs careful deployment and may not reduce restenosis

The Jomed Covered Stent Graft (Jomed International AB, Helsingborg, Sweden) is marketed for treatment of coronary artery aneurysms, perforations, dissection or thrombus. Three cases are presented, two with aneurysms, one with an acute coronary perforation. Intravascular ultrasound (IVUS) identified the need for high-pressure deployment of the stent. Although it has been suggested that this stent might lead to reduced rates of restenosis, one case later developed proliferative and occlusive in-stent restenosis and another suffered stent thrombosis at one month shortly after discontinuing clopidogrel. This niche stent clearly has an important role, but high-pressure deployment, IVUS evaluation and prolonged antiplatelet therapy are strongly recommended.

Cerebellar hypoactivity in frequent marijuana users

It is uncertain whether frequent marijuana use adversely affects human brain function. Using PET, regional cerebral blood flow was compared in frequent marijuana users and comparable, non-using controls after at least 26 h of monitored abstention by all subjects. Marijuana users showed substantially lower brain blood flow than controls in a large region of posterior cerebellum, indicating altered brain function in frequent marijuana users. A cerebellar locus of some chronic and acute effects of marijuana is plausible, e.g. the cerebellum has been linked to an internal timing system, and alterations of time sense are common following marijuana smoking.

Effect of pharmaceuticals on radiographic appearance of selected examinations of the abdomen and thorax

Pharmacologic agents may have a significant effect on the outcome of radiographic interpretation in small animal imaging. Alterations in the abdomen and thorax may represent artifactual or transient changes or changes reflecting cytotoxicity. Examples of agents that may influence the appearance of radiographs include anticonvulsants, sedatives, anesthetics, analgesics, antiinflammatories, gastrointestinal prokinetic drugs, antineoplastics, and hormones such as megestrol acetate. Radiographic studies may be part of a disease-monitoring process. It is important to understand how pharmaceuticals (e.g., chemotherapeutics or therapy for an underlying medical condition) affect the radiographic appearance. Caution should be exercised in the interpretation of radiographic studies because the findings may relate to the drug therapy rather than the underlying condition.

Effects of frequent marijuana use on brain tissue volume and composition

To investigate CNS effects of frequent marijuana use, brain tissue volume and composition were measured using magnetic resonance imaging (MRI) in 18 current, frequent, young adult marijuana users and 13 comparable, non-using controls. Automated image analysis techniques were used to measure global and regional brain volumes, including, for most regions, separate measures of gray and white matter. The marijuana users showed no evidence of cerebral atrophy or global or regional changes in tissue volumes. Volumes of ventricular CSF were not higher in marijuana users than controls, but were, in fact, lower. There were no clinically significant abnormalities in any subject's MRI. Sex differences were detected in several global volume measures.

The sleep of healthy people--a diary study

To provide baseline data for various research studies at the University of Pittsburgh over a 10-year period, 266 healthy subjects (144 male, 122 female, aged 20-50 years) meeting certain criteria each completed a 14-night sleep diary. For each night, the diary allowed the subjective measurement of bedtime, wake time, time in bed (TIB), sleep efficiency, number of minutes of wake after sleep onset (WASO), alertness on awakening, and percentage of morning needing an alarm (or a person functioning as one). Weeknight versus weekend night differences in TIB (TIBdiff), weekday altertness, and reliance on alarms were examined as possible indicators of sleep debt. In addition, general descriptive data were tabulated. On average, bedtimes were at 23:48 and wake times at 07:23, yielding a mean TIB of 7 hours 35 minutes. As expected, bedtimes and wake times were later on weekend nights than on weeknights. Bedtimes were 26 minutes later, wake times 53 minutes later, yielding a mean weekend TIB increase of 27 minutes. Overall, subjects perceived their sleep latency to be 10.5 minutes, reported an average of one awakening during the night (with an average of 6.4 minutes of WASO), had a diary sleep efficiency of 96.3%, and awoke with an alterness rating of 69.5%. These variables differed little between weeknight and weekend nights. Subjects used an alarm (or a person functioning as an alarm) on 60.9% nights overall, 68.3% on weeknights, 42.5% on weekends. When TIBdiff was used as an estimate of sleep debt (comparing subjects with TIBdiff > 75 minutes with those with a TIBdiff < 30 minutes), the group with more "catch-up sleep" on weekends had shorter weeknight TIB durations (by about 24 minutes) and relied more on an alarm for weekday waking (by about 22%), indicating the possible utility of these variables as sleep debt indices.

Isotopic composition of inorganic carbon as an indicator of benzoate degradation by pseudomonas putida: temperature, growth rate and pH effects

Degradation experiments of benzoate by Pseudomonas putida resulted in enzymatic carbon isotope fractionations. However, isotopic temperature effects between experiments at 20 and 30 degrees C were minor. Averages of the last three values of the CO(2) isotopic composition (delta(13)C(CO2(g))) were more negative than the initial benzoate delta(13)C value (-26.2 per thousand Vienna Pee Dee Belenite (VPDB)) by 3.8, 3.4 and 3.2 per thousand at 20, 25 and 30 degrees C, respectively. Although the maximum isotopic temperature difference found was only 0.6 per thousand, more extreme temperature variations may cause larger isotope effects. In order to understand the isotope effects on the total inorganic carbon (TIC), a better measure is to calculate the proportions of the inorganic carbon species (CO(2)(g), CO(2)(aq) and HCO(3)(-)) and to determine their cumulative delta(13)C(TIC). In all three experiments delta(13)C(TIC) was more positive than the initial isotopic composition of the benzoate at a pH of 7. This suggests an uptake of (12)C in the biomass in order to match the carbon balance of these closed system experiments.