Heart rate and autonomic biomarkers distinguish convulsive epileptic vs. functional or dissociative seizures

OBJECTIVE

20-40% of individuals whose seizures are not controlled by anti-seizure medications exhibit manifestations comparable to epileptic seizures (ES), but there are no EEG correlates. These events are called functional or dissociative seizures (FDS). Due to limited access to EEG-monitoring and inconclusive results, we aimed to develop an alternative diagnostic tool that distinguishes ES vs. FDS. We evaluated the temporal evolution of ECG-based measures of autonomic function (heart rate variability, HRV) to determine whether they distinguish ES vs. FDS.

METHODS

The prospective study includes patients admitted to the University of Rochester Epilepsy Monitoring Unit. Participants are 18-65 years old, without therapies or co-morbidities associated with altered autonomics. A habitual ES or FDS is recorded during admission. HRV analysis is performed to evaluate the temporal changes in autonomic function during the peri‑ictal period (150-minutes each pre-/post-ictal). We determined if autonomic measures distinguish ES vs. FDS.

RESULTS

The study includes 53 ES and 46 FDS. Temporal evolution of HR and autonomics significantly differ surrounding ES vs. FDS. The pre-to-post-ictal change (delta) in HR differs surrounding ES vs. FDS, stratified for convulsive and non-convulsive events. Post-ictal HR, total autonomic (SDNN & Total Power), vagal (RMSSD & HF), and baroreflex (LF) function differ for convulsive ES vs. convulsive FDS. HR distinguishes non-convulsive ES vs. non-convulsive FDS with ROC>0.7, sensitivity>70%, but specificity<50%. HR-delta and post-ictal HR, SDNN, RMSSD, LF, HF, and Total Power each distinguish convulsive ES vs. convulsive FDS (ROC, 0.83-0.98). Models with HR-delta and post-ictal HR provide the highest diagnostic accuracy for convulsive ES vs. convulsive FDS: 92% sensitivity, 94% specificity, ROC 0.99).

SIGNIFICANCE

HR and HRV measures accurately distinguish convulsive, but not non-convulsive, events (ES vs. FDS). Results establish the framework for future studies to apply this diagnostic tool to more heterogeneous populations, and on out-of-hospital recordings, particularly for populations without access to epilepsy monitoring units.

Asymmetrical forward and reverse developmental trajectories determine molecular programs of B cell antigen receptor editing

During B lymphopoiesis, B cell progenitors progress through alternating and mutually exclusive stages of clonal expansion and immunoglobulin (Ig) gene rearrangements. Great diversity is generated through the stochastic recombination of Ig gene segments encoding heavy and light chain variable domains. However, this commonly generates autoreactivity. Receptor editing is the predominant tolerance mechanism for self-reactive B cells in the bone marrow (BM). B cell receptor editing rescues autoreactive B cells from negative selection through renewed light chain recombination first at Igκ then Igλ loci. Receptor editing depends on BM microenvironment cues and key transcription factors such as NF-κB, FOXO, and E2A. The specific BM factor required for receptor editing is unknown. Furthermore, how transcription factors coordinate these developmental programs to promote usage of the λ chain remains poorly defined. Therefore, we used two mouse models that recapitulate pathways by which Igλ light chain-positive B cells develop. The first has deleted J kappa (Jκ) genes and hence models Igλ expression resulting from failed Igκ recombination (Igκdel). The second models autoreactivity by ubiquitous expression of a single-chain chimeric anti-Igκ antibody (κ-mac). Here, we demonstrated that autoreactive B cells transit asymmetric forward and reverse developmental trajectories. This imparted a unique epigenetic landscape on small pre-B cells, which opened chromatin to transcription factors essential for Igλ recombination. The consequences of this asymmetric developmental path were both amplified and complemented by CXCR4 signaling. These findings reveal how intrinsic molecular programs integrate with extrinsic signals to drive receptor editing.

Cross neutralization of emerging SARS-CoV-2 variants of concern by antibodies targeting distinct epitopes on spike

Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have arisen that exhibit increased viral transmissibility and partial evasion of immunity induced by natural infection and vaccination. To address the specific antibody targets that were affected by recent viral variants, we generated 43 monoclonal antibodies (mAbs) from 10 convalescent donors that bound three distinct domains of the SARS-CoV-2 spike. Viral variants harboring mutations at K417, E484 and N501 could escape most of the highly potent antibodies against the receptor binding domain (RBD). Despite this, we identified 12 neutralizing mAbs against three distinct regions of the spike protein that neutralize SARS-CoV-2 and the variants of concern, including B.1.1.7 (alpha), P.1 (gamma) and B.1.617.2 (delta). Notably, antibodies targeting distinct epitopes could neutralize discrete variants, suggesting different variants may have evolved to disrupt the binding of particular neutralizing antibody classes. These results underscore that humans exposed to wildtype (WT) SARS-CoV-2 do possess neutralizing antibodies against current variants and that it is critical to induce antibodies targeting multiple distinct epitopes of the spike that can neutralize emerging variants of concern.

Medication adherence patterns in aortic dissection survivors

Background & objectives:

Beta-blockers have been shown to improve survival in both type A and type B acute aortic dissection (AAD) patients. Calcium channel blockers have been shown to selectively improve survival only in type B AAD patients. There is a lack of data on medication adherence in AAD survivors. The purpose of this study was to assess medication adherence in patients who survived an AAD.

Methods:

This was a cross-sectional survey-based study of individuals from a single medical centre which was part of the larger International Registry of Acute Aortic Dissection (IRAD). Patients with type A or B AAD who survived to discharge were included in this study. Individuals who were deceased based on the results of an online Social Security Death Index were excluded from the study. Data were obtained from both a survey and also from abstraction from the local academic institution's IRAD registry. A survey packet was sent to patients. One section of this survey was dedicated to assessing medication adherence using the 4-item Morisky scale.

Results:

Eighty two completed surveys were returned; 74 patients completed the section of the survey pertaining to medication adherence (response rate 38%). Morisky score was ≥1.0 for 27 (36%) patients and 0 for 47 (64%) patients. Thirty three patients reported yes to ‘forget to take medications’ and eight reported yes to ‘careless with medications.’ Medication non-adherence (defined as a score of ≥1.0 on Morisky) was associated with increased follow up recurrence of chest pain at one year of follow up. Only two patients stopped their antihypertensive on their own and did not cite a reason for doing this.

Interpretation & conclusions:

The medication adherence rate for patients who survived an AAD was 64 per cent at a median (Q1, Q3) of 7.1 yr (5.6, 11.5) after discharge, as per the Morisky scale. The clinicians should educate their patients on the importance of antihypertensive therapy and assess for forgetfulness and carelessness at each clinic visit, as well as understand patients’ beliefs about drug therapy, all of which have been shown to increase medication adherence.

Abstract P4-11-06: The role of patient perceptions in under reporting chemotherapy induced peripheral neuropathy (CIPN)

Background: Although paclitaxel remains one of the most efficacious and commonly used agents in the treatment of breast cancer, it can cause a number of side effects. Decisions to delay, decrease, or discontinue treatment are made based on the severity of chemotherapy induced peripheral neuropathy (CIPN), which is not objectively measured but relies on patient's accurately reporting symptoms to their clinical team. There is some concern that patients do not accurately or completely report CIPN symptoms during treatment. A previous study reported that 3 of 24 patients (12.5%) considered or could understand another patient's decision to under-report CIPN symptoms to avoid treatment disruption. The objective of this follow-up study was to determine whether under-reporting occurred and to understand patient perspectives on topics previously found relevant to a patient's decision to under-report CIPN.

Methods: Ten patients with early stage breast cancer who received adjuvant paclitaxel 80 mg/m2 for up to 12 weeks, who had no prior neuropathy or neurotoxic chemotherapy participated in a recorded, semi-structured, phone-based interview that followed an interview guide designed to cover topics relevant to patient under-reporting

Themes identified in patient perceptions of objectives found relevant to under reportingObjectiveResultPatient Understanding1. Patients had consistent descriptions of their expectations for CIPN prior to treatment. 2. Understanding of the long-term potential of CIPN varied among patients.Patient Education1. Patients used a variety of sources to find information about CIPN, with the most commonly used sources being medical staff and patient handouts.Patient Input1. Patients agree on the importance of reporting side effects, but not to what extent. 2. Patients felt included in the treatment decision-making process, but some felt the doctor ultimately made the decision. 3. Providers may plan an important role in the extent to which patients report their symptoms.Treatment Cycles1. Patients recognized that they may not complete all 12 cycles, but were determined to do so.Perception Changes1. Before treatment, patients are much more focused on efficacy and were not particularly concerned with side effects. 2. During treatment, patients reflected on their desire to complete treatment and the tolerability of the side effects they were experiencing. 3. After treatment, patients felt they should have asked more questions before starting treatment.

. The interviews were then transcribed and qualitatively analyzed using NVivo software to identify common themes.

Results: No patients in this study admitted to under-reporting neuropathy. Themes that emerged from the interviews are presented in Table 1.

Conclusion: Insight as to how patients perceive various aspects of paclitaxel treatment revealed that comfort level with providers, inclusion in the decision-making process, and encouragement to fully disclose all symptoms played an important role when patients considered whether to report adverse effects. Future research may focus on whether a lack of health literacy and/or health care related work experience predisposes to CIPN under-reporting.

Citation Format: Hertz DL, Krumbach E, Nobles B, Erickson S, Farris KB. The role of patient perceptions in under reporting chemotherapy induced peripheral neuropathy (CIPN) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-11-06.

Chained Bell Inequality Experiment with High-Efficiency Measurements

We report correlation measurements on two ^{9}Be^{+} ions that violate a chained Bell inequality obeyed by any local-realistic theory. The correlations can be modeled as derived from a mixture of a local-realistic probabilistic distribution and a distribution that violates the inequality. A statistical framework is formulated to quantify the local-realistic fraction allowable in the observed distribution without the fair-sampling or independent-and-identical-distributions assumptions. We exclude models of our experiment whose local-realistic fraction is above 0.327 at the 95% confidence level. This bound is significantly lower than 0.586, the minimum fraction derived from a perfect Clauser-Horne-Shimony-Holt inequality experiment. Furthermore, our data provide a device-independent certification of the deterministically created Bell states.

Experience with high frequency oscillation ventilation during the 2009 H1N1 influenza pandemic in Australia and New Zealand

During the 2009 H1N1 pandemic, large numbers of patients had severe respiratory failure. High frequency oscillation ventilation was used as a salvage technique for profound hypoxaemia. Our aim was to compare this experience with high frequency oscillation ventilation during the 2009 H1N1 pandemic with the same period in 2008 by performing a three-month period prevalence study in Australian and New Zealand intensive care units. The main study end-points were clinical demographics, care delivery and survival. Nine intensive care units contributed data. During 2009 there were 22 H1N1 patients (17 adults, five children) and 10 non-H1N1 patients (five adults, five children), while in 2008, 18 patients (two adults, 16 children) received high frequency oscillation ventilation. The principal non-H1N1 high frequency oscillation ventilation indication was bacterial or viral pneumonia (56%). For H1N1 patients, the median duration of high frequency oscillation ventilation was 3.7 days (interquartile range 1.8 to 5) with concomitant therapies including recruitment manoeuvres (22%), prone ventilation (41%), inhaled prostacyclins (18%) and inhaled nitric oxide (36%). Seven patients received extracorporeal membrane oxygenation, six having H1N1. Three patients had extracorporeal membrane oxygenation concurrently, two as salvage therapy following the commencement of high frequency oscillation ventilation. In 2008, no high frequency oscillation ventilation patient received extracorporeal membrane oxygenation. Overall hospital survival was 77% in H1N1 patients, while survival in patients having adjunctive extracorporeal membrane oxygenation was similar to those receiving high frequency oscillation ventilation alone (65% compared to 71%, P = 1.00). Survival rates were comparable to published extracorporeal membrane oxygenation outcomes. High frequency oscillation ventilation was used successfully as a rescue therapy for severe respiratory failure. High frequency oscillation ventilation was only available in a limited number of intensive care units during the H1N1 pandemic.

Abstract P209: Obesity in Middle School Students: Are Self-Efficacy and Body Mass Index Related?

Background: Childhood obesity represents the nation's #1 health problem. Understanding the underpinnings of this epidemic, including children's perception of self-efficacy (SE), is critical to designing effective interventions.

Methods: We measured body mass index (BMI) and conducted surveys in 208 middle school students(St), average age 11.7 years, with 11 questions relating to SE as part of a school-based intervention program in 5 Ann Arbor and 2 Ypsilanti Middle schools (PHS). Consenting St agreed to BMI using standard height-weight conversion adjusted for age. The 11 survey questions were scored from 1-5, 5 the most positive. A total SE score was calculated (per St), scores ranging from 11 (lowest SE) to 55. A scatter-plot was created comparing BMI to SE score using linear regression for all St and by gender.

Results: Of the 109 girls and 99 boys in the study, 34% were overweight/obese (>85 th percentile for BMI); 20% obese (>95 th %). Obesity was more common in boys; girls more underweight. SE scores varied from 27 to 54; BMI from 14-39. There was no significant linear association between BMI and SE scores overall (Figure), however, a trend was observed for lower SE with higher BMI among girls.

Conclusions: In PHS, 34% of Ann Arbor/Ypsilanti St are overweight or obese. We observed no significant correlation between BMI and a global SE score. This is not surprising in a society which has increasingly viewed overweight as the norm. The trend for lower SE in girls with higher BMI requires confirmation in a larger cohort.

Drug approval processes in Australian Paediatric Hospitals

OBJECTIVE

To describe and evaluate the decision-making processes for drug approval in Australian paediatric hospitals.

DESIGN

Multicentre descriptive study involving face-to-face interviews of drug and therapeutics committee chairs and secretaries, review of committee documents and drug submissions for all Australian paediatric hospital drug and therapeutics committees over a 1-year period.

SETTING

All eight paediatric hospitals in Australia.

PARTICIPANTS

Eight committee chairs and seven secretaries or delegates.

MAIN OUTCOME MEASURES

Total drug expenditure, number of formulary submissions, individual-patient use approvals and approval rates for each hospital from 1 July 2006 to 30 June 2007, stratified by therapeutic class. Qualitative description of the approval processes.

RESULTS

Total drug expenditure varied from $A1.7 million (US$1.5 million) to $A11.1 million (US$9.8 million) per hospital. The number of formulary submissions also varied, from 7 to 21, but approval rate was high (76%-100%) and not significantly different among hospitals (p=0.17). Several committees approved identical submissions for five drugs. The number of individual-patient use applications varied considerably, ranging from 10 to 456 per hospital. Where estimable, individual-patient use approval was 76%-100% and variable (p=0.03). Quality of evidence relating to safety and efficacy of drugs being considered was regarded as the most important factors influencing decision making, with the cost less important. Most committees had poor infrastructural support for approval processes. No committee formally included a pharmaco-economic evaluation.

CONCLUSIONS

Most drug submissions in tertiary paediatric hospitals are approved; however, workload, drug expenditure and individual-patient use schemes vary considerably. Duplication of effort occurs, and few committees are resourced sufficiently given their terms of reference.

Impaired c-Jun amino terminal kinase activity and T cell differentiation in death receptor 6-deficient mice

During an immune response naive T helper (Th) cells differentiate into two functionally distinct subsets, Th1 and Th2, based on their cytokine secretion profile and immunomodulatory function. c-Jun amino terminal kinase (JNK) regulates Th cell differentiation by activating a transcriptional program required for cytokine production. We have recently identified a TNFR superfamily death domain-containing molecule, death receptor (DR)6, which potently activates JNK. T cells from DR6-deficient mice are substantially impaired in JNK activation. When DR6(-/-) mice were challenged with protein antigen, their T cells hyperproliferate and display a profound polarization toward a Th2 response whereas Th1 differentiation is not equivalently affected. In addition, DR6(-/)- T cells showed preference toward Th2 differentiation in vitro. The phenotype seen in the DR6(-/)- mice is not due to the apoptotic pathway. Therefore, DR6, working through JNK, rather than apoptosis, functions to attenuate the Th2 response. This is the first demonstration of a role in the activation and differentiation of Th cells by DR6 in particular and DRs in general.

Activation and accumulation of B cells in TACI-deficient mice

The tumor necrosis factor (TNF)-related ligand B lymphocyte stimulator (BLyS) binds two TNF receptor family members, transmembrane activator and calcium-modulating and cyclophilin ligand interactor (TACI) and B cell maturation molecule (BCMA). Mice that are transgenic for BLyS show B cell accumulation, activation and autoimmune lupus-like nephritis. The existence of at least two distinct BLyS receptors raises the question of the relative contribution of each to B cell functions. We therefore generated mice that were deficient in TACI. TACI-/- mice showed increased B cell accumulation and marked splenomegaly. Isolated TACI-/- B cells hyperproliferated and produced increased amounts of immunoglobulins in vitro. In vivo antigen challenge resulted in enhanced antigen-specific antibody production. Thus, TACI may play an unexpected inhibitory role in B cell activation that helps maintain immunological homeostasis.

Proximal fourth metatarsal injuries in athletes: similarity to proximal fifth metatarsal injury

Proximal fourth metatarsal injuries are rarely reported. We present five case histories in which athletic patients sustained injuries at the shaft-base junction of the fourth metatarsal. Similar to proximal fifth metatarsal injuries, adduction of the forefoot appears to be associated. Our patients returned to their activities in two to eight months. These patients injuries tended to take longer to heal than other lesser metatarsal fractures and stress fractures (which are typically more distal). Some patients were continually symptomatic, even after three months of rest and immobilization. This coincides with proximal fifth metatarsal injuries and stress fractures. For treatment of proximal fourth metatarsal injuries to be successful, ideal treatment appears to involve nonweightbearing below-knee cast/boot immobilization for three weeks. This is followed by an additional three or more weeks of weightbearing immobilization. Healing may still be prolonged.

Interferon alpha down-regulates telomerase reverse transcriptase and telomerase activity in human malignant and nonmalignant hematopoietic cells

Recently, the derepressed expression of the catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT), the enzyme that elongates telomeres, has been implicated as an important step in the immortalization process. The exact regulation of hTERT expression, which is the rate-limiting factor for telomerase activity, is at present unclear. As transformed cells seem to be dependent on a constitutive telomerase activity, the availability of inhibitors would potentially be of great value in antineoplastic therapy. Interferons (IFNs) have been successfully used in the treatment of several forms of malignancies, but the underlying molecular mechanisms responsible for the antitumor activity are poorly defined. In this study we have investigated the effects of IFNs on hTERT expression and telomerase activity. We found that IFN-alpha rapidly (commonly within 4 hours) and significantly down-regulates the expression of hTERT and telomerase activity in a number of human malignant hematopoietic cell lines, primary leukemic cells from patients with acute leukemia as well as T-lymphocytes from healthy donors. This effect of IFN-alpha did not seem to depend on IFN-alpha-mediated cell growth arrest or alterations in c-myc expression. The finding that IFN induces a repression of hTERT and a decrease in telomerase activity suggests a novel mechanism that may play a significant role in the antitumor action of IFN. (Blood. 2000;96:4313-4318)

Evaluation of the gemini infusion pump for the safe delivery of peripheral blood progenitor cells (stem cells)

The purpose of this in vitro study was to determine whether the Gemini PC-2TX infusion pump could safely deliver peripheral stem cells (PSC) for an autologous PSC transplant. For purposes of hypothesis testing, it was assumed that there would be no significant difference in CD34+ cell counts and colony-forming units-granulocyte, macrophage (CFU-GM) when the PSCs were administered by an IMED PC-2TX infusion pump as opposed to an intravenous push method. The American Red Cross collected 50-ml samples of PSCs from four donors by apheresis. These cells were tested for CD34+ using flow cytometry and for functional progenitor cells using a CFU-GM assay. The cells were cryopreserved after testing. For our study, samples were tested simultaneously at a single facility. Each sample was individually thawed and a baseline thaw sample collected; 10 ml of the donor specimen was pushed through a syringe into a specimen container (intravenous push sample). The remainder of the specimen was infused through the IMED Gemini PC-2TX pump into a specimen container (intravenous pump sample). All samples were assayed for CD34+ cell counts and CFU-GM. Data analyses were conducted using the t-test for paired samples, with values of P < 0.05 considered significant. Results failed to demonstrate a statistically significant difference between the CD34+ or CFU-GM results of the intravenous push and intravenous pump specimens. Additionally, we failed to find a statistically significant difference when we compared the intravenous push and the intravenous pump specimens with the baseline thaw sample. The results of this study support the hypothesis that the Gemini PC-2TX infusion pump can safely deliver PSCs for the purposes of stem cell transplantation.

Heregulin, but not ErbB2 or ErbB3, heterozygous mutant mice exhibit hyperactivity in multiple behavioral tasks

Genetic redundancy is a problem in gene targeting studies because functionally relevant sister proteins can compensate for the lack of protein product of a targeted gene. A molecular system is chosen in which it is hoped to demonstrate both the lack and presence of compensation after disruption of particular single genes. Mammals may not be able to compensate for the lack of heregulin, a single ligand for multiple ErbB receptors, however, compensation is expected when a single ErbB receptor is knocked out. To investigate this the heregulin-1, ErbB2, or ErbB3 locus was disrupted in a targeted manner and mice heterozygous for the mutation were analyzed. Heregulin and its receptors were shown to be involved in embryonic brain development and, more recently, in plastic changes associated with adult brain function in rodents. Although they have never been shown to play roles in mammalian behavior, it was decided to characterize the mice behaviorally using a battery of simple tests. Heregulin mutant mice exhibited elevated activity levels in the open field, showed improved rotorod performance, and finished T-maze spontaneous alternation task faster compared to control wild type littermates, findings that suggest a consistent hyperactivity across tests. ErbB2 and ErbB3 mutant mice, whose strain origin was identical to that of heregulin mutants, showed no sign of the behavioral alterations. It is suggested that the abnormalities seen in heregulin mutant mice are due to mutation at that locus and the lack of alterations seen in ErbB2 and ErbB3 mutant mice is the result of compensation by unaltered sister receptors.

Mechanisms of interferon-induced cell cycle arrest

The interferons (IFNs) are a group of cytokines, which in addition to their antiviral activity are capable of modulating a variety of cellular responses. One such prominent effect of IFNs is their potent antimitogenic action, which can be observed both on malignant and non-malignant cells of many different origins. IFNs are also used in the clinic, mainly in malignant and viral diseases, and their cell growth -inhibitory effect has been suggested to be of major importance in their antitumour and antiviral action. The aim of the present review is to provide insight into the molecular mechanisms by which IFNs modulate cell cycle progression in various cell types. With the recent progress in our understanding of how the cell cycle is regulated at the molecular level, it has become possible to delineate intracellular effectors of IFN in this respect. Understanding the antiproliferative effects of IFN may not only help in understanding its antineoplastic and antiviral activities, but may also provide an insight into cell cycle regulation in general and aid in making IFNs a more useful tool in treating disease.

The protein kinases Rck1 and Rck2 inhibit meiosis in budding yeast

The genes RCK1 and RCK2 of budding yeast were initially identified as suppressors of checkpoint mutations in fission yeast. Here, we show that homozygous diploid rck1/rck1 mutants in standard sporulation medium enter meiosis in about half the time required by wild-type cells. A similar, but weaker, effect is seen in rck2/rck2 mutants, whereas double homozygous rck1/rck1 rck2/rck2 mutants display a phenotype similar to that of the rck1/rck1 single mutants. In diploids with mutations in either of the meiotic checkpoint genes MEC1 and RAD24, overexpression of RCK1 or RCK2 reduces meiotic proficiency, most prominently seen with RCK2. The rate of meiotic recombination was unaltered in rck1 and rck2 mutants. There is a transient shift in the relative abundance of the two RCK2 transcripts in meiotic cells. We propose that one function of Rck1 and Rck2 is to inhibit meiosis.

Allosteric inhibitors of inducible nitric oxide synthase dimerization discovered via combinatorial chemistry

Potent and selective inhibitors of inducible nitric oxide synthase (iNOS) (EC ) were identified in an encoded combinatorial chemical library that blocked human iNOS dimerization, and thereby NO production. In a cell-based iNOS assay (A-172 astrocytoma cells) the inhibitors had low-nanomolar IC(50) values and thus were >1,000-fold more potent than the substrate-based direct iNOS inhibitors 1400W and N-methyl-l-arginine. Biochemical studies confirmed that inhibitors caused accumulation of iNOS monomers in mouse macrophage RAW 264.7 cells. High affinity (K(d) approximately 3 nM) of inhibitors for isolated iNOS monomers was confirmed by using a radioligand binding assay. Inhibitors were >1,000-fold selective for iNOS versus endothelial NOS dimerization in a cell-based assay. The crystal structure of inhibitor bound to the monomeric iNOS oxygenase domain revealed inhibitor-heme coordination and substantial perturbation of the substrate binding site and the dimerization interface, indicating that this small molecule acts by allosterically disrupting protein-protein interactions at the dimer interface. These results provide a mechanism-based approach to highly selective iNOS inhibition. Inhibitors were active in vivo, with ED(50) values of <2 mg/kg in a rat model of endotoxin-induced systemic iNOS induction. Thus, this class of dimerization inhibitors has broad therapeutic potential in iNOS-mediated pathologies.

Interferon-alpha inhibits proliferation in human T lymphocytes by abrogation of interleukin 2-induced changes in cell cycle-regulatory proteins

IFN-alpha exerts prominent regulatory functions on the immune system. One such effect is the inhibition of proliferation of in vitro stimulated T lymphocytes. The exact physiological function of this activity is not known, but it has been implicated in the antiviral effects of IFN, its antitumor action in T-cell malignancies, and the regulation of the in vivo T-cell response. Here, we have investigated the mechanism underlying the IFN-alpha-mediated growth inhibition of normal human PHA- and IL-2-stimulated T lymphocytes by an analysis of how IFN-alpha treatment influences known molecular events that normally accompany the transition from quiescence to proliferation in these cells. IFN-alpha treatment was found to profoundly block S-phase entry of stimulated T lymphocytes. This correlated with a strong inhibition of IL-2-induced changes in G1-regulatory proteins, including the prevented up-regulation of G1 cyclins and cyclin-dependent kinases as well as an abrogation of mitogen-induced reduction of p27Kip1 levels. This latter effect was due to a maintained stability of the p27Kip1 protein in the IFN-alpha-treated cells. In line with these findings, phosphorylation of the pocket proteins was abrogated in IFN-alpha-treated cells. Furthermore, our data indicate that IFN-alpha has selective effects on the pathways that emerge from the IL-2 receptor because IFN-alpha treatment does not block IL-2-induced up-regulation of c-myc or Cdc25A.

Molecular mechanisms underlying interferon-alpha-induced G0/G1 arrest: CKI-mediated regulation of G1 Cdk-complexes and activation of pocket proteins

One prominent effect of IFNs is their cell growth-inhibitory activity. The mechanism behind this inhibition of proliferation is still not fully understood. In this study, the effect of IFN-alpha treatment on cell cycle progression has been analysed in three lymphoid cell lines, Daudi, U-266 and H9. Examination of the growth-arrested cell populations shows that Daudi cells accumulate in a G0-like state, whereas U-266 cells arrest later in G1. H9 cells are completely resistant to IFN-alpha's cell growth-inhibitory effects. The G0/G1-phase arrest is preceded by a rapid induction of the cyclin-dependent kinase inhibitors (CKIs), p21 and p15. In parallel, the activities of the G1 Cdks are significantly reduced. In addition to p21/p15 induction, IFN-alpha regulates the expression of another CKI, p27, presumably by a post-transcriptional mechanism. In the G1 Cdk-complexes, there is first an increased binding of p21 and p15 to their respective kinases. At longer exposure times, when Cdk-bound p15 and p21 decline, p27 starts to accumulate. Furthermore, we found that IFN-alpha not only suppresses the phosphorylation of pRb, but also alters the phosphorylation and expression of the other pocket proteins p130 and p107. These data suggest that induction of p21/p15 is involved in the primary IFN-alpha response inhibiting G1 Cdk activity, whereas increased p27 expression is part of a second set of events which keep these Cdks in their inactive form. Moreover, elevated levels of p27 correlated with a dissociation of cyclin E/Cdk2-p130 or p107 complexes to yield cyclin E/Cdk2-p27 complexes. In resistant H9 cells, which possess a homozygous deletion of the p15/p16 genes and lack p21 protein expression, IFN-alpha causes no detectable changes in p27 expression and, furthermore, no effects are observed on either pocket proteins in this cell line. Taken together, these data suggest that the early decline in G1 Cdk activity, subsequent changes in phosphorylation of pocket proteins, and G1/G0 arrest following IFN-alpha treatment, is not primarily due to loss of the G1 kinase components, but result from the inhibitory action of CKIs on these complexes.

Enzyme-linked immunoassay for respiratory syncytial virus is not predictive of bronchiolitis in sudden infant death syndrome

Although respiratory syncytial virus (RSV)-infected infants may present with apnea, the role that RSV plays in sudden infant death syndrome (SIDS) is speculative. To determine whether RSV is associated with bronchiolitis in these patients, we examined histologic sections of lungs from 41 apparent SIDS cases and compared the results with those of enzyme-linked immunofluorescent assay (EIA) from nasal washings. Bronchiolitis was defined by a bronchiolar inflammatory cell infiltrate plus epithelial necrosis. A positive EIA was associated with bronchiolitis in 8 instances, compared with 6 having a positive EIA and negative histology, 14 having a negative EIA and positive histology, and 13 having EIA and histology both negative. These results yield a predictive value of a positive test of 57% and a predictive value of a negative test of 48% (P > .9 by chi square analysis). Although RSV of the upper respiratory tract may be related to SIDS, our results indicate that EIA of nasal washings is not predictive of bronchiolitis, and we recommend other means of verification of histologic results.

Involvement of the Ink4 proteins p16 and p15 in T-lymphocyte senescence

Little is known about the molecular background to senescence in T-lymphocytes. In fibroblast systems replicative senescence has been shown to correlate with a number of changes in the expression of the proteins normally regulating progression through the G1 phase of the cell cycle, and recently the Ink4 inhibitor p16 was implicated as a central regulator of replicative senescence in human fibroblasts. It has, however, been claimed that p16 is not expressed in T-lymphocytes. In the present study we have analysed G1 regulating proteins in ageing human T-lymphocytes. We show that PHA and IL-2 stimulated T-lymphocytes cease to proliferate after around 20 population doublings, these cells can not thereafter be restimulated to growth, and were also found to exhibit markers for senescence. We found that T-lymphocytes accumulate p16 and p15 protein during successive population doublings and display high levels of these proteins as they enter into replicative senescence. There was also an increased binding of p16 to the Cdk6 kinase in senescent cells, and a decreased Cdk6 as well as Cdk2 kinase activity. The levels of other G1 regulating proteins were also altered in the senescent cells, such as slightly elevated levels of p21/WAF1, and downregulation of Cdk2 and cyclinD3. The levels of p27/ Kip1 is down regulated in proliferating cells but rise to approximately 15% of the levels in un-stimulated quiescent cells. As a high proportion of T-cell childhood acute lymphoblastic leukaemias have deletions of both p15 and p16, our data suggest that inactivation of these genes makes it possible for leukemic cells to avoid senescence.

The impact of an individual tutorial session on MEDLINE use among obstetrics and gynaecology residents in an academic training programme: a randomized trial

Over the past decade, on-line databases have become increasingly popular among health care professionals. As a group, these 'end-users' report utilizing databases to keep abreast of medical progress, to conduct research and to address specific patient care issues. Throughout the literature, medical professionals ('content experts') have proved to be less effective searchers than librarians ('search experts'). The potential implications of this discrepancy are worrysome. For any given clinical scenario, for example, published reports may reach contradictory conclusions. A poorly skilled searcher may not retrieve enough articles to appreciate this fact. Optimizing searching skills is therefore a worthwhile goal. As a first step, many medical schools introduce students to on-line databases, most notably MEDLINE. Residency is an ideal time to continue this training. A recognized obstacle to provide residents with formal MEDLINE instruction is time constraint. We therefore conducted this study to ascertain the impact an individual 1-hour tutorial session would have on MEDLINE utilization among obstetrics and gynecology residents training at an academic medical centre. Outcome measures included MEDLINE search frequency, duration, recall, precision and searcher satisfaction. Search recall measures the searcher's ability to retrieve articles deemed relevant to the question at hand. Search precision gauges the searchers' ability to eliminate irrelevant articles. Although the sessions were well received, we were unable to demonstrate an improvement in the outcome measures analysed. Further research is therefore indicated so that cost-effective educational strategies can be recommended for wide-scale use.

Managed care and the cystic fibrosis patient

Since the first published report of mortality in cystic fibrosis in 1969, the median survival among cystic fibrosis patients has risen from 14 to 31 years. The reasons for this improved survival are complex and include earlier diagnosis; improved control of pulmonary infection; aggressive nutritional intervention; and enhanced monitoring of patients in peer-reviewed, accredited centers for cystic fibrosis care, teaching, and research. Emphasis on the importance of research on changing and improved treatment has been effectively communicated to patients and families. As a result, a group of highly educated medical consumers has been created. During the last decade, another focus of rapid change has appeared, that of cost containment in the medical profession, creating the field of managed care. Practicing medical professionals perceive the need for reduction in excessive spending in medicine and have taken a variety of approaches to balance better the value and cost of medical care while maintaining superb quality. Physicians and consumers continue to have concerns about the potential negative impact of managed care on a relatively rare, specialized, and chronic illness such as cystic fibrosis if managed care concepts are applied without proper understanding of the disease. A great concern is that managed care in cystic fibrosis may cause reversal of trends in improved quality and length of survival. The increased length of survival places an increasing demand on the already stressed system of health care financing. Understanding the changing area of managed care is therefore of paramount importance to clinicians involved in cystic fibrosis care. The Cystic Fibrosis Foundation has presented symposia on managed care at each of the last three annual meetings, including the North American Cystic Fibrosis Meeting, October 1996. The following issues were addressed by speakers and panel discussants, with portions excerpted for this review: trends in managed care, measures and guidelines useful in managed care, Medicaid managed care and cystic fibrosis, and practical aspects of using pathways in caring for patients with cystic fibrosis.

Clinical pathways and case management in anesthesia practice: new tools and systems for the evolving healthcare environment

Clinical care pathways and case management are strategies utilized by increasing numbers of hospitals to meet the challenges of capitated reimbursement and managed care. A clinical pathway is an outcome-focused tool used to define a multidisciplinary plan of care. A case manager coordinates patient care across an episode of illness or hospitalization. These tools and systems have great potential for use by nurse anesthetists in ensuring that high-quality anesthesia care is delivered in a cost-effective manner.