C60 12–LEAD POST–ROSC ELECTROCARDIOGRAM DISCRIMINATES SURVIVAL TO HOSPITAL DISCHARGE. A SUB–ANALYSIS OF THE PEACE STUDY

Background

Once the return of spontaneous circulation (ROSC) after an out–of–hospital cardiac arrest (OHCA) is achieved in patients with an ST–elevation myocardial infarction, the acquisition of a 12–lead electrocardiogram (ECG) is strongly recommended in order to determine candidates for urgent coronary angiography. However, little is known so far about the association of ECG features and survival to hospital discharge in OHCA patients.

Methods

We analysed all the post–ROSC ECGs collected from January 2015 to December 2018 in three European centres (Pavia, Lugano and Vienna). For every ECG, the main features were analysed and filed in the database together with the pre–hospital data collected for every patient according to the Utstein style.

Results

We collected 370 ECGs: 287 males (77.6%); median age 62 years old (IQR 53–70 years); 121 from Pavia (32.7%), 38 from Lugano (10.3%) and 211 from Vienna (57.0%). In Cox univariable regression, age older than 62 years [HR 1.7 (95% IC 1.1–2.4), p = 0.007], QRS wider than 120 msec [HR 1.87 (95% IC 1.3–2.7), p < 0.001], ST elevation in more than one segment [HR 1.7(95% IC 1.2–2.5),p=0.003], the presence of left bundle branch block (LBBB) [HR 1.7 (95% IC 1.1–2.9), p = 0.03] and a right bundle branch block [HR 1.8 (95% IC 1.1–2.8), p = 0.01] were all associated with death before hospital discharge. In multivariable Cox regression, adjusted for the ROSC–to–ECG time, age older than 62 years [HR 1.6 (95% IC 1.1–2.3), p = 0.01], QRS wider than 120 msec [HR 1.7 (95%IC 1.2–2.5), p = 0.004] and the presence of ST elevation in more than one segment [HR 1.7 (95%IC 1.2–2.5), p = 0.004] were independently associated with death before hospital discharge. By considering these latter three risk factors, the rate of survival to hospital discharge was significantly influenced by their number [no risk factor: 80.8%; 1 factor: 71.2%; 2 factors: 61.9%; 3 factors: 34.4%; p < 0.001, p for trend <0.001]. With a Cox regression model, considering the absence of risk factor as a reference, we confirmed that having 2 or 3 risk factors was significantly associated with death before hospital discharge [HR 1.9 (95%IC 1–3.5), p = 0.037 e HR 5.1(95%IC 2.6–10.1), p < 0.001 respectively].

Conclusions

Our study confirms the central role of ECG in STEMI patients resuscitated after an OHCA and proves that post–ROSC ECG features can be used for both the selection of patients who may benefit from urgent coronary angiography as well as for prognostic stratifications.

Empathic Accuracy in Adolescent Girls with Turner Syndrome

To examine the potential mechanisms underlying social deficits in Turner Syndrome, we administered the empathic accuracy task (EAT) -a naturalistic social cognition task- and a (control) visual-motor line-tracking task to 14 girls with TS was compared to 12 age-matched typically developing girls (TD; ages 12 to 17). Empathic accuracy was compared across positive and negative emotionally valanced videos. We found that TS differs from TD on empathic accuracy ratings for negative videos; no differences were detected for the positive videos or for the control line tracking task. Thus, our findings suggest impaired detection of negatively valanced empathic interactions in TS and may help inform the future development of social-cognition treatment strategies for girls with TS.

Post-ROSC electrocardiogram timing in the management of out-of-hospital cardiac arrest: results of an international multicentric study (PEACE study)

Background

Electrocardiogram (ECG) is a key tool to triage out-of-hospital cardiac arrest (OHCA) patients after achieving a sustained return of spontaneous circulation (ROSC). According to current guidelines, an immediate coronary angiography is indicated only when the post-ROSC ECG discloses a ST-elevation myocardial Infarction (STEMI). Moreover, the 12-lead ECG should be recorded as soon as possible after ROSC, although it is reasonable that in the early post-ROSC stages ECG could reflect the ischemia secondary to cardiac arrest besides that of coronary origin possibly causing an overdiagnosis of STEMI (false positive).

Purpose

To assess whether the time from ROSC to ECG acquisition could affect the percentage of false positive ECG for STEMI.

Methods

We performed a retrospective, international, multicenter study (PEACE Study - NCT04096079). We included all patients over 18 years of age hospitalized after an OHCA due to medical cause at one of the three participating high-volume hospitals of three different European countries between 2015, 1st January and 2018, 31st December. We considered for the present study only patients who underwent coronary angiography and in whom a post-ROSC ECG was available. For the electrocardiographic diagnosis of STEMI the criteria established by the ESC 2017 guidelines were used, while the execution of a percutaneous coronary angioplasty (PTCA) was evaluated as an angiographic endpoint. We used logistic regression to evaluate the association of time to acquisition and the endpoint. We computed odds ratios and 95% confidence intervals (OR, 95% CI).

Results

Population consisted of 370 patients (77.6% male, mean age 61±13 years, median ROSC-ECG time 15 minutes). Post-ROSC ECG was positive for STEMI in 198 patients and in 39 of them (10.5%) a PTCA was not performed during urgent coronary angiography, representing the false positive (FP) ECG. Dividing the population in three tertiles according to the time from ROSC to ECG (≤7 mins; 8–33 mins; >33 mins), the percentage of FP-ECG in the first tertile (18.5%) was statistically significantly higher than in the second (7.2%, OR 2.9 (95% CI 1.1–7.5) p=0.025) and third (5.8%, OR 3.7 (95% CI 2.2–6.5) p<0.001) as also shown in the Figure. These differences remained significant when adjusting for sex, age, number of segments involved at ECG (anterior, lateral, posterior, inferior and right), QRS duration >120 msec, ECG heart rate >100 bpm and adrenaline administered >1 mg.

Conclusion

Our study offers the first demonstration that the acquisition of the 12-leads ECG too early after ROSC can misleadingly lead to the diagnosis of STEMI. Despite further validation are required, our data suggest that it may be reasonable to delay the acquisition of the ECG at least 8 minutes after ROSC or to repeat the acquisition if the first ECG, resulting diagnostic for STEMI, was performed very early.

Figure 1

Funding Acknowledgement

Type of funding source: None

Functional neuroanatomy of interoceptive processing in children and adolescents: a pilot study

In adults, interoception – the sense of the physiological condition of the body - appears to influence emotion processing, cognition, behavior and various somatic and mental health disorders. Adults demonstrate frontal-insula-parietal-anterior cingulate cortex activation during the heartbeat detection task, a common interoceptive measure. Little, however, is known about the functional neuroanatomy underlying interoception in children. The current pilot study examined interoceptive processing in children and adolescents with fMRI while using the heartbeat detection task. Our main findings demonstrate that children as young as the age of six activate the left insula, cuneus, inferior parietal lobule and prefrontal regions. These findings are similar to those in adults when comparing heartbeat and tone detection conditions. Age was associated with increased activation within the dACC, orbital frontal cortex and the mid-inferior frontal gyri. Thus, our pilot study may provide important information about the neurodevelopment of interoceptive processing abilities in children and a task for future interoception neuroimaging studies in children.

Student Learning Dispositions: Multidimensional Profiles Highlight Important Differences among Undergraduate STEM Honors Thesis Writers

Various personal dimensions of students-particularly motivation, self-efficacy beliefs, and epistemic beliefs-can change in response to teaching, affect student learning, and be conceptualized as learning dispositions. We propose that these learning dispositions serve as learning outcomes in their own right; that patterns of interrelationships among these specific learning dispositions are likely; and that differing constellations (or learning disposition profiles) may have meaningful implications for instructional practices. In this observational study, we examine changes in these learning dispositions in the context of six courses at four institutions designed to scaffold undergraduate thesis writing and promote students' scientific reasoning in writing in science, technology, engineering, and mathematics. We explore the utility of cluster analysis for generating meaningful learning disposition profiles and building a more sophisticated understanding of students as complex, multidimensional learners. For example, while students' self-efficacy beliefs about writing and science increased across capstone writing courses on average, there was considerable variability at the level of individual students. When responses on all of the personal dimensions were analyzed jointly using cluster analysis, several distinct and meaningful learning disposition profiles emerged. We explore these profiles in this work and discuss the implications of this framework for describing developmental trajectories of students' scientific identities.

Students Who Fail to Achieve Predefined Research Goals May Still Experience Many Positive Outcomes as a Result of CURE Participation

Course-based undergraduate research experiences (CUREs) provide students opportunities to engage in research in a course. Aspects of CURE design, such as providing students opportunities to make discoveries, collaborate, engage in relevant work, and iterate to solve problems are thought to contribute to outcome achievement in CUREs. Yet how each of these elements contributes to specific outcomes is largely unexplored. This lack of understanding is problematic, because we may unintentionally underemphasize important aspects of CURE design that allow for achievement of highly valued outcomes when designing or teaching our courses. In this work, we take a qualitative approach and leverage unique circumstances in two offerings of a CURE to investigate how these design elements influence outcome achievement. One offering experienced many research challenges that increased engagement in iteration. This level of research challenge ultimately prevented achievement of predefined research goals. In the other offering, students experienced fewer research challenges and ultimately achieved predefined research goals. Our results suggest that, when students encounter research challenges and engage in iteration, they have the potential to increase their ability to navigate scientific obstacles. In addition, our results suggest roles for collaboration and autonomy, or directing one's own work, in outcome achievement.

The Solubility of Unirradiated UO2 In Both Perchlorate And Chloride Test Solutions. Influence of the Ionic Medium

The solubility of a crystalline unirradiated UO2 (s) has been studied under reducing conditions at 25°C in three different ionic media: 0.008 mol dm–3 NaCIO4, 1 and 5 mol dm-3 NaCl+. The species responsible for the solubility in perchlorate medium are U(OH)3 and U(OH)4, with the stability constants log β13 = -0.4(±0.2) and log β14 = -5.7(±0.1), respectively. The solubility in both1! and 5 M chloride media is explained at pH values higher than 6 by the species U(OH)4 with log β14 = -5.5(±0.2) while at lower pH values an abnormal behaviour is observed, with higher uranium concentrations in solution and a proton independent solubility for pH values lower than 4. The XPS observations of the reacted solids do not show the presence of solid surface phases other than uranium dioxide, with an upper oxidation state of UO2.1.

Simfuel Dissolution Studies in Granitic Groundwater at 25°C

The dissolution of a non-radioactive chemical analogue of spent nuclear fuel (SIMFUEL) has been studied as a function of two different synthetic groundwaters at 25°C. The cumulative release of U, Mo, Ba, Y and Sr is presented after 170 days of total leaching time.

The results obtained show the potential usefulness of SIMFUEL to ascertain the kinetics and mechanisms of dissolution of the minor components of spent fuel. In the case of Sr, a good correlation is found with the dissolution of this minor component measured in spent fuel leaching experiments.

Denitrification in presence of acetate and glucose for bioremediation of nitrate-contaminated groundwater

With the current increasing interest in aquifer denitrification, recent attention has been given to cost-effective in-situ treatments such as Enhanced In-Situ Biological Denitrification (EISBD), which intends to stimulate the indigenous bacterial activity by injecting an external organic substrate and/or nutrients to the aquifer matrix. Within this context, laboratory batch assays have been conducted to develop a strategy for in-situ denitrification of a nitrate-contaminated aquifer in Argentona, Catalonia (Spain). The assays were run under aerobic and anaerobic conditions at a temperature of 17 degrees C to better simulate the conditions of the aquifer. Acetate and glucose were added to assess their potential to promote heterotrophic denitrifying bacteria activity. Overall, the results revealed that indigenous micro-organisms had the potential of reducing nitrate under appropriate conditions. Nitrate removal was complete and faster under anaerobic conditions, though high nitrate removals were also attained under initial aerobic conditions when a readily organic compound was amended at a sufficient dosage. The results also revealed that a significant amount of the available organic carbon was consumed by processes other than denitrification, namely aerobic oxidation and other microbial oxidation processes. To sum up, the results of this study demonstrated that addition of organic compounds into the groundwater is a promising method for in-situ bioremediation of nitrate in the Argentona aquifer. This approach could potentially be applied to a number of situations in which nitrate concentration is elevated and where indigenous micro-organisms with potential to reduce nitrate are present within the aquifer material.

Global biodiversity: indicators of recent declines

In 2002, world leaders committed, through the Convention on Biological Diversity, to achieve a significant reduction in the rate of biodiversity loss by 2010. We compiled 31 indicators to report on progress toward this target. Most indicators of the state of biodiversity (covering species' population trends, extinction risk, habitat extent and condition, and community composition) showed declines, with no significant recent reductions in rate, whereas indicators of pressures on biodiversity (including resource consumption, invasive alien species, nitrogen pollution, overexploitation, and climate change impacts) showed increases. Despite some local successes and increasing responses (including extent and biodiversity coverage of protected areas, sustainable forest management, policy responses to invasive alien species, and biodiversity-related aid), the rate of biodiversity loss does not appear to be slowing.

Experimental determination and chemical modelling of radiolytic processes at the spent fuel/water interface

The spent fuel matrix constitutes a dynamic redox system, due to the time-dependent generation of oxidants and reductants at the spent fuel/water interface by alpha, beta and gamma radiolysis. In this context it is critical to understand the main processes and mechanisms that control the radiolytic production of redox components at this interface and their impact on the stability of the UO2 matrix and in radionuclide release.

In order to achieve this, a series of carefully controlled experiments have been carried out in order to determine the time dependence of the radiolytic H2, O2 and H2O2 production and radionuclide release (U, Pu, Np, Tc, Mo, Sr and Cs). These tests have been performed by using PWR Ringhals spent fuel fragments in contact with 10 mM NaHCO3 solutions in an initially anoxic and closed system.

The results of these experiments indicate quite a consistent and reproducible behaviour of the radiolytically generated reductants and oxidants. The results indicate that it is possible to define an equilibrium redox potential for the main redox pairs in the bulk system and that the experimentally determined radionuclide release can be rationalised in terms of the system redox potential.

Experimental study and modeling of uranium (VI) transport through ferrous olivine rock columns

The Lovasjärvi intrusion (SE-Finland) contents a high percentage of ferrous olivine (> 65%). This material has been suggested as a redox-active backfill-additive in deep nuclear waste repositories, due to the large Fe(II) proportion in its mineral composition. In order to understand the processes involved in the redox buffering capacity of this material the transport of uranium (VI) through olivine columns was studied. The results showed considerable retardation factor for the U(VI), particularly in carbonate-free media. The experimental data were simulated by means of reactive transport modeling. The best agreement between the experimental and calculated data was obtained considering that the interaction of U(VI) with the olivine surface occurred at two different types of sorption sites. One type accounts for the sorption capacity of the olivine mineral, and a second type accounts for the sorption on amorphous Fe(OH)3(s) formed at expenses of the oxidative dissolution of olivine.

Modeling stem cell asymmetry in yeast

For adult stem cells to both self-renew and give rise to differentiating progenitors, they must undergo an inherently asymmetric division. This defining model of asymmetric cell division requires either that stem cells preferentially distribute internal factors, thereby maintaining a stem cell phenotype in one lineage, or that extrinsic signals determine the fate of daughter cells, allowing the maintenance of one stem cell lineage. Although microbial systems are often used to model asymmetry, lineage-specific asymmetry has not been characterized in these organisms. Recently, we identified a stem-cell-like lineage-specific pattern of kinetochore asymmetry in postmeiotic yeast spores. Because the function of the kinetochore is to segregate chromosomes, this asymmetry has the potential to segregate sister chromatids nonrandomly. This may be relevant to stem cells because more than 30 years ago, it was proposed that stem cells selectively segregate one strand of their chromosomes into the self-renewing stem cell lineage (Cairns 1975). Although advanced labeling methods have provided evidence to both support and refute this hypothesis, it remains unclear how nonrandom sister-chromatid segregation might be achieved in a stem cell lineage. We have identified a kinetochore-specific mechanism in yeast that could support lineage-specific nonrandom sister-chromatid segregation and we discuss the implications of this observation.

Magnetic resonance signal, rather than tendon volume, correlates to pain and functional impairment in chronic Achilles tendinopathy

PURPOSE

To depict abnormal tendon matrix composition using magnetic resonance imaging (MRI) in chronic Achilles tendinopathy, and correlate intratendinous signal alterations to pain and functional impairment.

MATERIAL AND METHODS

MRI of the Achilles tendon was performed on 25 patients with chronic Achilles tendinopathy (median age 50, range 37-71 years). All patients suffered from pain in the mid-portion of the Achilles tendon. Intratendinous signal was calculated from five different sagittal sequences, using a computerized 3D seed-growing technique. Pain and functional impairment were evaluated using a questionnaire completed by patients.

RESULTS

Severity of pain and functional impairment correlated to increased mean intratendinous signal in the painful tendon in all MR sequences (P < 0.05, median r = 0.38, range 0.28-0.43 for pain; P < 0.05, median r = 0.48, range 0.29-0.49 for functional impairment). However, tendon volume did not correlate to pain or functional impairment (P > 0.05). Difference in mean intratendinous signal between symptomatic and contralateral asymptomatic tendons was highly significant in all sequences (P < 0.05) except on T2-weighted images (P = 0.6).

CONCLUSION

Severity of pain and disability correlated to increased MR signal rather than to tendon volume in patients with unilateral mid-portion chronic Achilles tendinopathy.

Dynamic evolution of antibody populations in a rhesus macaque infected with attenuated simian immunodeficiency virus identified by surface plasmon resonance

BACKGROUND

Increasing evidence suggests that an effective AIDS vaccine will need to elicit broadly neutralizing antibody responses. However, the mechanisms of antibody-mediated neutralization have not been defined. Previous studies from our lab have identified significant differences in the rates of antibody binding to trimeric SIV envelope proteins that correlate with neutralization sensitivity. Importantly, these results demonstrate differences in monoclonal antibody (MAb) binding to neutralization-sensitive and neutralization-resistant envelope proteins, suggesting that one mechanism for virus neutralization may be related to the stability of antibody binding. To date, little has been done to evaluate the binding properties of polyclonal serum antibodies elicited by SIV infection or vaccination.

METHODS

In the current study, we translate these findings with MAbs to study antibody binding properties of polyclonal serum antibody responses generated in rhesus macaques infected with attenuated SIV. Quantitative and qualitative binding properties of well-characterized longitudinal serum samples to trimeric, recombinant SIV gp140 envelope proteins were analyzed using surface plasmon resonance (SPR) technology (Biacore).

RESULTS

Results from these studies identified two antibody populations in most of the samples analyzed; one antibody population exhibited fast association/dissociation rates (unstable) while the other population demonstrated slower association/dissociation rates (stable). Over time, the percentage of the total binding response of each antibody population evolved, demonstrating a dynamic evolution of the antibody response that was consistent with the maturation of antibody responses defined using our standard panel of serological assays. However, the current studies provided a higher resolution analysis of polyclonal antibody binding properties, particularly with respect to the early time-points post-infection (PI), that is not possible with standard serological assays. More importantly, the increased stability of the antibody population with time PI corresponded with potent neutralization of homologous SIV in vitro.

CONCLUSIONS

These results suggest that the stability of the antibody-envelope interaction may be an important mechanism of serum antibody virus neutralization. In addition, measurements of the 'apparent' rates of association and dissociation may offer unique numerical descriptors to characterize the level of antibody maturation achieved by candidate vaccine strategies capable of eliciting broadly neutralizing antibody responses.

The use of a high-FeO olivine rock as a redox buffer in a nuclear waste repository

Due to the higher stability of the spent nuclear fuel (mainly composed of UO2) under reducing conditions, and in order to enhance the retention/retardation of some key radionuclides, the olivine rock from the Lovasjärvi intrusion has been proposed as a potential redox-active backfill-additive in deep high-level nuclear waste (HLNW) repositories. In this work, two different approaches have been undertaken in order to establish the redox buffer capacity of olivine rock: (1) The capacity of the rock to respond to changes in pH or pe has been demonstrated and the final (pH, pe) coordinates agree with the control exerted by the system Fe(II)/Fe(III). (2) The rate of consumption of oxygen has been determined at different pH values. These rates are higher than the ones reported in the literature for other solids, what would point to the possibility of using this rock as an additive to the backfill material in a HLNW.

Modelling near- and far-field processes in nuclear waste management

In this chapter we present some of the recent advances concerning process understanding and modelling of radionuclide migration in nuclear waste disposal systems. The present geochemical modelling approaches used to quantify the processes concerning spent fuel dissolution, radionuclide interactions with the canister materials and the bentonite buffer are thoroughly discussed. Finally, some applications to natural analogue studies of spent nuclear fuel disposal, as testing ground for concepts and models developed for waste management systems, are presented.

Evaluation of maxillary sinus membrane response following elevation with the crestal osteotome technique in human cadavers

Implant placement in the posterior maxilla often requires elevation of the sinus floor, which can be achieved through either the modified Caldwell-Luc or the crestal osteotome technique. The objectives of this study were to evaluate (a) the resistance to perforation of maxillary sinus membranes obtained from formaldehyde-fixed cadavers in vitro, (b) the frequency and extent of membrane perforations occurring after sinus floor elevation in cadavers using the crestal approach, and (c) the amount of membrane elevation (doming) that can be achieved using the crestal approach. Pretreatment of maxillary sinus membrane tissues with commonly used tissue softeners did not have a statistically significant effect on resistance to perforation. Maxillary sinus membranes were elevated 4 to 8 mm in formaldehyde-fixed cadavers using the osteotome technique; implants were placed. Of the 25 sites that received implants, only 6 showed perforations, as assessed by double-blind investigation after dissection of the lateral wall of the nose, allowing direct examination of the sinus cavity. Perforations were categorized as Class I (< or = 2 mm with exposure of the implant into the sinus cavity and loss of doming); Class II perforations (> or = 2 mm) were associated with proximity of the osteotomy site to the medial wall of the sinus or the presence of septae. These results indicated that the crestal osteotome approach compared favorably to the modified Caldwell-Luc technique as it relates to the frequency of maxillary sinus membrane perforations and the degree of achievable membrane elevation.

Purification, characterization and molecular cloning of prophenoloxidases from Sarcophaga bullata

Prophenoloxidase (PPO) is a key enzyme associated with both melanin biosynthesis and sclerotization in insects. This enzyme is involved in three physiologically important processes viz., cuticular hardening, defense reactions and wound healing in insects. It was isolated from the larval hemolymph of Sarcophaga bullata and purified by employing ammonium sulfate precipitation, Phenyl Sepharose chromatography, DEAE-Sepharose chromatography, and Sephacryl S-200 column chromatography. The purified enzyme exhibited two closely moving bands on 7.5% SDS-PAGE under denaturing conditions. From the estimates of molecular weight on Sephacryl S-100, TSK-3000 HPLC column and SDS-PAGE, which ranged from 90,000 to 100,000, it was inferred that the enzyme is made up of a single polypeptide chain. Activation of PPO (K(a)=40 microM) was achieved by the cationic detergent, cetyl pyridinium chloride below its critical micellar concentration (0.8 mM) indicating that the detergent molecules are binding specifically to the PPO and causing the activation. Neither anionic, nor nonionic (or zwitterionic) detergents activated the PPO. The active enzyme exhibited wide substrate specificity and marked thermal unstability. Using primers designed to conserved amino acid sequences from known PPOs, we PCR amplified and cloned two PPO genes from the sarcophagid larvae. The clones encoded polypeptides of 685 and 691 amino acids. They contained two distinct copper binding regions and lacked the signal peptide sequence. They showed a high degree of homology to dipteran PPOs. Both contained putative thiol ester site, two proteolytic activation sites and a conserved C-terminal region common to all known PPOs.

Nitrate reductase alters 3-nitrotyrosine accumulation and cell cycle progression in LPS + IFN-gamma-stimulated RAW 264.7 cells

Nitrite (NO2-), an end product of nitrogen radical metabolism, has recently been shown to increase tyrosine nitration by activated leukocytes indicating that nitrite modulates the immune response. We investigated the hypothesis that nitrite may increase nitration of molecular targets within activated cells leading to altered cell cycle progression. Intracellular nitrite was increased by transfection of murine macrophage-like RAW 264.7 cells with the nitrate reductase gene obtained from barley. Nitrate reductase facilitates the conversion of nitrate to nitrite; thus when extracellular nitrate is present, intracellular nitrite will be increased. Results show that addition of KNO3 increases NO2- production and intracellular nitrotyrosine accumulation in the transfectant but not the parent. Inhibition of nitric oxide synthesis with L-NAME during activation with IFN-gamma + LPS reduced NO2- production to the same extent in both cell lines; however, cellular accumulation of nitrotyrosine was reduced by only 25% in the transfectant (P = 0.21) and 49% in the parent cell line (P = 0.007), suggesting that intracellular nitrite increased nitrotyrosine accumulation through a pathway not requiring NO synthesis, i.e., myeloperoxidase system. Approximately 15% of the transfected cells had 4n DNA content 24 h postactivation compared to < 1% of the parent cells. Increased DNA copy number was correlated to nitrotyrosine accumulation. These findings show that intracellular nitrite can increase accumulation of nitrotyrosine and that nitration is linked to cell cycle perturbation.

Novel cytokine release inhibitors. Part IV: analogs of podocarpic acid

Podocarpic acid derivatives as cytokine (IL-1beta) release inhibitors are discussed.

2-Substituted-4-methoxybenzimidazole-based PDE4 inhibitors

A new family of PDE4 inhibitors based on a benzimidazole framework is described. Several of these compounds are orally bioavailable and show efficacy in in vivo models of inflammatory disease.

Clinical validation of ineffective breathing pattern, ineffective airway clearance, and impaired gas exchange

PURPOSE

To describe the clinical validation of symptoms or defining characteristics of three respiratory diagnoses. The contributing factors or etiologies of the diagnoses were identified and the degree of importance of 30 nursing interventions, 15 direct care and 15 teaching, was rated for each diagnosis and each patient. Three nursing diagnoses--ineffective breathing pattern (IBP), ineffective airway clearance (IAC), and impaired gas exchange (IGE)--were among the most frequently used, yet no reported clinical studies validated the defining characteristics of these diagnoses. This study answers the research questions: What are the defining characteristics of IBP, IAC, and IGE? What are the etiologies of IBP, IAC, AND IGE? What are the most important interventions for IBP, IAC, and IGE?

DESIGN

Standardized clinical validation using a convenience sample of 76 people hospitalized with medical and surgical diagnoses, in one U.S. city, and identified as having one of the three diagnoses. Data were collected in 1992-1993.

METHODS

A literature-based concept analysis generated 37 possible defining characteristics for the three diagnoses which were included in the instrument. The nurse experts conducted a health history and physical examination of each patients and decided (a) whether the 37 defining characteristics were present or absent, (b) the degree of importance of each possible defining characteristic for making one or more of the diagnoses, (c) the etiologies, and (d) which of the 30 nursing interventions were important for each diagnosis and patient.

FINDINGS

For each diagnosis, many of the 37 possible defining characteristics were judged as present but few reached the criterion of .50 as important for making one of the diagnoses. Two of the possible defining characteristics reached this criterion for IBP, seven for IAC, and two for IGE. In contrast to the defining characteristics approved by NANDA, the subjective cues of "expresses fatigue" and "expresses anxiety" were judged as important for making one or more of the diagnoses.

CONCLUSIONS

Clinical validation methods allow discriminating among defining characteristics. Data that are present are not necessarily characteristic of a diagnosis, and the subjective cues of expresses fatigue or anxiety may be important for making these diagnoses.

Scintigraphic evaluation of malignant melanoma lesions with Tc-99m tetrofosmin

Two cases of malignant melanoma (primary and metastatic lesions) imaged with Tc-99m tetrofosmin are reported. One patient showed intense uptake in a primary skin lesion of the thorax, and the other patient had accumulation in skin, cerebellum, breast, and lymph node metastases. Like Tc-99m MIBI, Tc-99m tetrofosmin imaging may be of clinical relevance in the evaluation of suspicious skin lesions and in patients with known cutaneous malignant melanoma in the assessment of recurrent disease during follow-up evaluation.

Myeloma light chains are ligands for cubilin (gp280)

Although myeloma light chains are known to undergo receptor-mediated endocytosis in the kidney, the molecular identity of the receptor has not been characterized. We examined the interaction between cubilin (gp280) and four species of light chains isolated from the urine of patients with multiple myeloma. Four lines of evidence identify cubilin, a giant glycoprotein receptor, which is restricted in distribution to endocytic scavenger pathways and which has potent effects on endosomal trafficking, as a potentially physiologically relevant binding site for light chains: 1) light chains coeluted during immunoaffinity purification of cubilin; 2) polyclonal antisera to cubilin but not control sera, displaced human light chain binding from rat renal brush-border membranes; 3) cubilin bound to multiple species of light chains during surface plasmon resonance; 4) anti-cubilin antiserum interfered with light chain endocytosis by visceral yolk sac epithelial cells. However, both binding of light chains to brush-border membranes and endocytosis of light chains by yolk sac epithelial cells were only partially inhibited by anticubilin antibodies, suggesting presence of additional or alternate binding sites for light chains. Excess light chain had a potent inhibitory effect on endosomal fusion in vitro. Binding showed dose and time-dependent saturability with low-affinity, high-capacity equilibrium binding parameters. These data demonstrate that cubilin plays a role in the endocytosis and trafficking of light chains in renal proximal tubule cells.

A major cis activator of the IRBP gene contains CRX-binding and Ret-1/PCE-I elements

PURPOSE

Interphotoreceptor retinoid binding protein (IRBP) is expressed exclusively and to high levels in photoreceptive cells. This study was an attempt to delineate the minimal regulated control region of the murine IRBP promoter involved in this expression pattern.

METHODS

Fragments of the mouse IRBP 5' flanking region were tested for promoter activity in transient transfections of embryonic chick retina cells in primary culture. Electrophoretic mobility shift assays were used to identify specific cis-acting DNA elements within these fragments.

RESULTS

Nested deletion analysis of a 1783 bp fragment of the murine IRBP 5' flanking region shows that high promoter activity is maintained with truncated fragments as short as 70 bp 5' to transcription start, but is lost with truncation to 45 bases. The 1783 bp promoter is active in cultures of retina cells but not brain cells or fibroblasts. The 70 bp fragment is active in retina and brain cells but not fibroblasts. Within retina cell cultures, the 1783 bp fragment is active in photoreceptor-like and amorphous or unidentifiable cells whereas the 70 bp is additionally active in multipolar neuron-like cells. The -70 to -45 interval contains Ret-1/PCE-I (AATTAG in the IRBP gene), a proposed retina-specific consensus sequence cis element, and a same-strand reversed copy of this sequence, GATTAA, the consensus binding element of the photoreceptor-specific trans-acting factor CRX. Mutation of either element suppresses promoter activity. Paralleling promoter tissue-specificity, the -70 to -45 fragment binds a sequence-specific protein complex found in retina and brain extracts but not fibroblasts. Mutation of both or either element inhibits this binding.

CONCLUSIONS

These data suggest that a trans-acting complex binds a cis-element in the -70 to -45 sequence. This binding fully activates transcription but confers only partial tissue-specificity to IRBP gene expression.

Anionic- and lipophilic-mediated surface binding inhibitors of human leukocyte elastase

We report the synthesis of a series of diphenylmethane-based oligomers containing anionic and lipophilic functionalities that are potent inhibitors of human leukocyte elastase (HLE). The enzyme inhibition is regulated by the size of the oligomer, as well as, the number of charges. Lipophilicity is an important element in determining potency and specificity against other basic enzymes. Compounds whose scaffolds contain three phenoxyacetic acid groups and three alkyl ethers are competitive and specific inhibitors of HLE with Ki = 20 nM. The mechanism of action of this class of compounds is believed to involve multidendate interactions with the surface of HLE near the active site which prevents substrate access to the catalytic site.

Recurrent synovial chondromatosis treated with meniscectomy and synovectomy

Synovial chondromatosis is a rare benign intraarticular metaplasia of synovium. This process may result in the production of detached particles of highly cellular cartilage in the involved joint spaces. It is most often reported in the larger joints of the body including the knee, hip, elbow, and ankle. Since Axhausen in 1993 reported the first case affecting the temporomandibular joint, several articles have been listed in the literature regarding the presentation, diagnosis, and management of this form of an arthropathy. This is a case of a recurrent synovial chondromatosis that was approached with a meniscectomy and a complete synovectomy.

The 5' flanking regions of IRBP and arrestin have promoter activity in primary embryonic chicken retina cell cultures

Primary cultures of embryonic chicken cells from various tissues were transiently transfected with plasmid vectors containing reporter genes linked to a 1.8 kb fragment of the mouse interphotoreceptor retinoid-binding protein (IRBP) 5' flanking region, a 1.5 kb fragment of the mouse arrestin 5' flanking region, or a 3.4 kb sequence of the bovine arrestin 5' flanking region. Promoter activity was evident in retina-derived cells, but not in fibroblasts or cells from whole brain. Transfection response also varied with transfection method, plasmid DNA concentration, post-transfection incubation time, and cell density. The data suggest that the primary embryonic chicken retinal cell culture system is a useful tool in studying photoreceptor-specific gene regulation.

Isolation of angiopoietin-1, a ligand for the TIE2 receptor, by secretion-trap expression cloning

TIE2 is a receptor-like tyrosine kinase expressed almost exclusively in endothelial cells and early hemopoietic cells and required for the normal development of vascular structures during embryogenesis. We report the identification of a secreted ligand for TIE2, termed Angiopoietin-1, using a novel expression cloning technique that involves intracellular trapping and detection of the ligand in COS cells. The structure of Angiopoietin-1 differs from that of known angiogenic factors or other ligands for receptor tyrosine kinases. Although Angiopoietin-1 binds and induces the tyrosine phosphorylation of TIE2, it does not directly promote the growth of cultured endothelial cells. However, its expression in close proximity with developing blood vessels implicates Angiopoietin-1 in endothelial developmental processes.

Characterization of Eu(III) binding to a series of calmodulin binding site mutants using laser-induced Eu(III) luminescence spectroscopy

Laser-induced luminescence techniques were used in a rigorous evaluation of the Eu(3+)-binding behavior of a recombinant (Drosophila melanogaster) calmodulin and a series of calmodulin binding site mutants in which the bidentate glutamic acid residue in position 12 of each metal ion binding loop is systematically replaced with lysine. For the range of Ca2+ concentrations at which calmodulin functions (10(-5)-10(-6) M), Ca2+ binding is effectively eliminated at the mutated site; however, the luminescence studies show that the Eu3+ ion binds to the modified site with reduced affinity. The mutations do not significantly change the intermetal ion distances from their wild type values. These were determined by Eu3+-->Nd3+ Förster-type non-radiative energy transfer experiments. Consistent with the results of Ca(2+)-binding studies, mutation of sites II and IV in the N- and C-terminal domains, respectively, produces a larger alteration in the Eu(3+)-luminescence and Eu(3+)-binding behavior than does mutation of sites I and III. Modification of either of the sites in the C-terminus (III or IV, numbered from the amino terminus) causes two additional H2O molecules (four H2O molecules total) to bind to the Eu3+ ion in order to compensate for the loss of the bidentate glutamic acid residue. Consequently, the partner site in the domain loses an H2O molecule, thereby coordinating another ligand from the protein. Mutation of either of the high-affinity Ln(3+)-binding sites (I or II) has global effects on the Eu(3+)-binding behavior of the protein molecule.