Using lexical semantic cues to mitigate interference effects during real-time sentence processing in aphasia

We examined the auditory sentence processing of neurologically unimpaired listeners and individuals with aphasia on canonical sentence structures in real-time using a visual-world eye-tracking paradigm. The canonical sentence constructions contained multiple noun phrases and an unaccusative verb, the latter of which formed a long-distance dependency link between the unaccusative verb and its single argument (which was base generated in the object position and then displaced to the subject position). To explore the likelihood of similarity-based interference during the real time linking of the verb and the sentence's subject noun, we manipulated the animacy feature of the noun phrases (matched or mismatched). The study's objectives were to examine whether (a) reducing the similarity-based interference by mismatching animacy features would modulate the encoding and retrieval dynamics of noun phrases in real-time; and (b) whether individuals with aphasia would demonstrate on time sensitivity to this lexical-semantic cue. Results revealed a significant effect of this manipulation in individuals both with and without aphasia. In other words, the mismatch in the representational features of the noun phrases increased the distinctiveness of the unaccusative verb's subject target at the time of syntactic retrieval (verb offset) for individuals in both groups. Moreover, individuals with aphasia were shown to be sensitive to the lexical-semantic cue, even though they appeared to process it slower than unimpaired listeners. This study extends to the cue-based retrieval model by providing new insight on the real-time mechanisms underpinning sentence comprehension.

POS1557-HPR PATIENT-CENTRIC INTERPROFESSIONAL EDUCATION AS A MEANS TO INCREASE HEALTH PROFESSIONAL STUDENTS’ AWARENESS AND UNDERSTANDING OF SCLERODERMA

Background

Incorporating a complex chronic disease into an interprofessional education (IPE) event is an appropriate method to increase knowledge and awareness of diseases that require multiple disciplines to manage. Scleroderma is one example of a rheumatic condition that requires an interprofessional (IP) team management approach. In practice, the rheumatologist must rely heavily on other healthcare professionals to provide optimal care to a scleroderma patient. Core competencies such as teamwork, leadership, and accomplishing common patient care aims are promoted by IPE1. The foundation of the patient-centric approach is seldom learned in a classroom setting while IPE can promote the observation of the patient-lived experience, the value of patients as a knowledge resource, and the emphasis of patient diversity2.

Objectives

At each event we aim to increase awareness and understanding of scleroderma among health care professional students and enable patients to draw on their health histories to act as lead educators. Based on the success to date, we hope to promote replication of this model at other scleroderma centers.

Methods

Over four years, approximately 800 students from Russell Sage College, Albany College of Pharmacy and Health Sciences, and most recently The State University of New York at Albany, have participated in an IPE event which included individuals living with scleroderma and/or caregivers. For the first three years the event was held in person and the most recent was hosted virtually following the same structure as years prior. The event includes introductions of the moderators and words from a patient advocate followed by guidance on active listening and patient interview techniques. Eight to ten students enrolled in health-related programs including nutrition, psychology, occupational therapy, physical therapy, pharmacy, nursing and public health are assigned into small IP teams. Each team joins a round table or breakout room with one patient and/or caregiver. Students ask discipline specific questions which allows the patient and/or caregiver to share their narrative(s), enabling students to cultivate active listening skills and elicit the perspective of the patient. As the disease presentation and symptoms vary, the student IP teams will then interview another patient and/or caregiver. During the event students also hear best practices through a facilitated patient interview. An expert panel reflective of the disciplines represented on the student IP teams who have experience working with those diagnosed with scleroderma and other chronic conditions answer student questions. All attendees are asked to complete an anonymous pre and post event survey.

Figure 1.

Results

Including patients with scleroderma as educators is effective in increasing student awareness and knowledge of the disease. The implementation of this model into IPE also allows students to practice IP collaboration specific to the needs of an individual living with scleroderma, as it would occur in the health care setting.

Conclusion

This patient-centric IPE enables patients to share their medical journey as lead educators in increasing future health care professionals’ awareness and knowledge of scleroderma. Replication of this pilot model at other scleroderma centers worldwide could promote the collaboration needed from healthcare professionals to assure the best quality of care for those living with scleroderma.

References

[1]Buring, S. et al. Interprofessional education: definitions, student competencies, and guidelines for implementation. American Journal of Pharmaceutical Education. 2009; 73(4): 59

[2]Towle A, Godolphin W. Patients as educators: interprofessional learning for patient-centred care. Med Teach. 2013; 35(3): 219-225

Acknowledgements

Steffens Scleroderma Foundation, Russell Sage College, Albany College of Pharmacy and Health Sciences

Disclosure of Interests

Hannah Bowen: None declared, Michelle Morgan: None declared, Lee Shapiro Consultant of: Actelion 2020

AB1398 CORRELATES OF CANCELLED HEALTHCARE APPOINTMENTS IN PATIENTS WITH SYSTEMIC SCLEROSIS DURING THE COVID-19 PANDEMIC

Background

Rheumatologists have noted challenges in treating patients with systemic sclerosis (SSc) during the COVID-19 pandemic, such as patients on immunosuppressants and those with preexisting pulmonary issues.1 Also of potential concern was patients delaying treatment due to fears of COVID.

Objectives

This study examined to what extent patients with SSc cancelled health-care appointments due to fears of COVID, how this correlated with their mental and physical functioning, and their levels of anxiety and depression.

Methods

Participants were 60 people with SSc who had not had COVID-19 or been vaccinated for COVID. Participants had a mean age of 58 years (SD=11.5) and were primarily female (92%) and white (87%).

Participants completed an online survey after learning about it from a scleroderma organization newsletter or at their visit with a rheumatologist specializing in scleroderma in New York State, USA. Data were collected August 2020 through March 2021. Participants completed measures assessing health-related appointments attendance, Patient Reported Outcome Measurement Information System (PROMIS) measures (anxiety, depression, fatigue, sleep disturbance, pain intensity, physical function), coping strategies to deal with the pandemic, and reported functioning relevant to SSc (hand, gastrointestinal, dyspnea, and Raynaud’s disease).

Results

Due to COVID-19 concerns, 28 respondents (47%) cancelled one or more appointments with their primary care physician, specialist, physical or occupational therapist, pulmonologist, or dentist. Compared to those who did not cancel appointments due to COVID concerns, participants who cancelled reported higher anxiety, t(58) = 2.46, p = .02, higher sleep disturbance, t(56) = 3.31, p = .002, worse physical functioning, t(56) = 2.00, p = .05, more constipation, t(55) = 2.05, p = .045, and lower positive reframing as a coping strategy, t(56) = 2.08, p = .04.

Many participants reported moderate or severe anxiety (36%), depression (22%), fatigue (32%), sleep disturbance (28%), and physical dysfunction (40%). As shown in Table 1, anxiety scores were positively correlated with scores on measures of fatigue, sleep disturbance, physical dysfunction, diarrhea, and the coping strategies of substance use, self-distraction, emotional support, behavioral disengagement, and venting. Depression scores were positively correlated with scores on measures of fatigue, sleep disturbance, physical dysfunction, pain intensity, dyspnea, diarrhea, and behavioral disengagement as a coping strategy.

Table 1.

Correlations Between Anxiety and Depression with Patient-Reported Outcomes and Coping with the Pandemic

MeasureAnxietyDepressionFatigue.38**.43**Sleep disturbance.35**.34**Physical dysfunction.28*.49**Pain intensity.16.36**Reflux.25.15Distention/bloating.28*.24Fecal soilage-.001.07Diarrhea.34**.28*Constipation.21-.03Dyspnea.18.32*Raynaud’s disease activity-.08-.02Hand functioning.06.25Coping strategy Substance use.29*.21 Self-distraction.32*.18 Behavioral disengagement.37**.41** Using emotional support.43**.06 Venting.34**.14

Note. *p < .05; **p < .01

Conclusion

Almost half of participants cancelled one or more health appointments due to COVID fears. This subgroup reported significantly higher anxiety, sleep disturbance, constipation, worse physical functioning, and less coping with the pandemic by looking for the positive. Anxiety and/or depression also played a role in 42% of SSc patients and were related to a variety of worse mental and physical health correlates. Future research should examine the extent to which changes in health-related care during the pandemic have implications for disease progression in patients with SSc.

References

[1]Orlandi M, Lepri G, Bruni C, et al. The systemic sclerosis patient in the COVID-19 era: The challenging crossroad between immunosuppression, differential diagnosis and long-term psychological distress. Clin. Rheumatol. 2020;39(7):2043-2047. doi:/10.1007/s10067-020-051932

Disclosure of Interests

Nancy Dorr: None declared, Patricia Fennell: None declared, Lee Shapiro Consultant of: Actelion (January 2020, participated as consultant for Actelion as part of a panel of rheumatologists regarding future needs in management of pulmonary hypertension.)

Rethinking interleukin-6 blockade for treatment of COVID-19

Interleukin-6 (IL-6) is a pleiotropic cytokine with effects in immune regulation, inflammation, and infection. The use of drugs that inhibit IL-6 biological activity has been proposed as a treatment for patients with Coronavirus Disease 2019 (COVID-19). The rationale for this approach includes commitment to the concept that inflammation is a cause of lung damage in COVID-19 and belief that IL-6 is a pro-inflammatory molecule. Observational data thought to support IL-6 inhibition include elevated circulating IL-6 levels in COVID-19 patients and association between elevated IL-6 and poor clinical outcomes. However, IL-6 has significant anti-inflammatory properties, which calls into question the rationale for employing IL-6 blockade to suppress inflammation-induced tissue injury. Also, studies suggesting a beneficial role for IL-6 in the host response to infection challenge the strategy of using IL-6 blockade to treat COVID-19. In studies of recombinant IL-6 injected into human volunteers, IL-6 levels exceeding those measured in COVID-19 patients have been observed with no pulmonary adverse events or other organ damage. These observations question the role of IL-6 as a contributing factor in COVID-19. Clinical experience with IL-6 receptor antagonists such as tocilizumab demonstrates increase in severe and opportunistic infections, raising concern about using tocilizumab and similar agents to treat COVID-19. Trials of drugs to inhibit IL-6 activity in COVID-19 are ongoing and will shed light on the role of IL-6 in COVID-19 pathogenesis. However, until more information is available, providers should exercise caution in prescribing these therapies given the potential for patient harm.

Thyroid Function Screening of Psychiatric Inpatient Admissions: A Worthwhile Procedure?

A thyroid function screening programme of admissions to a general psychiatric service was established. Over a 22-week period 588 patients were admitted and thyroid function tests were performed on 336, a screening rate of 57.1%. Initial investigation showed that 21.3% had a total thyroxine outside the range 75–130 nmol/l. On further investigation only 9 patients (1 thyrotoxic, 8 hypothyroid) had confirmed thyroid disease. In 7 of the 9 patients the disease had been clinically suspected. Thus the screening programme identified only 2 unsuspected cases of thyroid dysfunction and we conclude that this level of detection does not warrant a formal screening programme.

Isolation of a Caulobacter gene cluster specifying flagellum production by using nonmotile Tn5 insertion mutants

Caulobacter crescentus assembles a single polar flagellum from protein components synthesized at a specific time in the cell cycle. Of the 26 genes required for flagellum production, at least 4 of them-flaY, E, F, and G-map together in a single cluster. We have isolated DNA from this region of the chromosome by using a nonmotile mutant with a Tn5 insertion into flaE. C. crescentus DNA carrying the Tn5-flaE region and adjacent sequences was cloned into pBR325 and selected by transposon-encoded kanamycin resistance. The resulting plasmid was used as a probe to isolate the flaE region from a wild-type gene bank and to determine the chromosomal location of several deletion and insertion mutations within the flaY/E/F/G cluster. At least three promotors and three major transcripts were shown to originate from the cloned gene cluster. The role of these genes in flagellar biogenesis was examined by immunoprecipitation of mutant cell extracts with antiflagellin antibody. Deletions extending rightward into this gene cluster eliminated one of the two flagellin proteins normally synthesized by C. crescentus. Mutations mapping to the left permitted synthesis of both normal flagellins but at significantly decreased levels. These results suggest that the leftward end of this cluster contains a region that may function in a regulatory capacity whereas the rightward end may contain sequences overlapping a flagellin structural gene.

Phosphorylation of the beta' Subunit of RNA Polymerase and Other Host Proteins upon phiCd1 Infection of Caulobacter crescentus

A protein kinase activity is induced early after infection of Caulobacter crescentus by the DNA phage phiCd1. After phage infection at least 40 proteins are phosphorylated; these include DNA-binding proteins, a membrane-associated protein, and several ribosomal proteins. One of the phosphorylated DNA-binding proteins was identified as the beta' subunit of the host RNA polymerase.

Specific Assay for Differentiation in the Stalked Bacterium Caulobacter crescentus

The bacterium Caulobacter crescentus carries out a distinct differentiation process during its life cycle. Cultures of the bacterium have been synchronized and an assay has been developed for monitoring the course of morphogenesis by the selective adsorption of radioactive RNA bacteriophage.

Why and how bacteria localize proteins

Despite their small size, bacteria have a remarkably intricate internal organization. Bacteria deploy proteins and protein complexes to particular locations and do so in a dynamic manner in lockstep with the organized deployment of their chromosome. The dynamic subcellular localization of protein complexes is an integral feature of regulatory processes of bacterial cells.

Dynamic chromosome organization and protein localization coordinate the regulatory circuitry that drives the bacterial cell cycle

The bacterial cell has less internal structure and genetic complexity than cells of eukaryotic organisms, yet it is a highly organized system that uses both temporal and spatial cues to drive its cell cycle. Key insights into bacterial regulatory programs that orchestrate cell cycle progression have come from studies of Caulobacter crescentus, a bacterium that divides asymmetrically. Three global regulatory proteins cycle out of phase with one another and drive cell cycle progression by directly controlling the expression of 200 cell-cycle-regulated genes. Exploration of this system provided insights into the evolution of regulatory circuits and the plasticity of circuit structure. The temporal expression of the modular subsystems that implement the cell cycle and asymmetric cell division is also coordinated by differential DNA methylation, regulated proteolysis, and phosphorylation signaling cascades. This control system structure has parallels to eukaryotic cell cycle control architecture. Remarkably, the transcriptional circuitry is dependent on three-dimensional dynamic deployment of key regulatory and signaling proteins. In addition, dynamically localized DNA-binding proteins ensure that DNA segregation is coupled to the timing and cellular position of the cytokinetic ring. Comparison to other organisms reveals conservation of cell cycle regulatory logic, even if regulatory proteins, themselves, are not conserved.

Treatment of sound errors in aphasia and apraxia of speech: Effects of phonological complexity

BACKGROUND: Recent research suggests that the complexity of treatment stimuli influences the effectiveness of treatment. However, no studies have examined the role of complexity on sound production treatment in adult individuals with sound production impairments. AIMS: This study examines effects of syllable complexity on treatment outcome in two patients with acquired sound production problems. Complexity is defined in terms of syllable structure: clusters are more complex than singletons. Using a single-subject multiple-baseline design, we address the question: Is treatment of complex syllables more effective than treatment of simple syllables? METHODS #ENTITYSTARTX00026; PROCEDURES: Two patients with aphasia and apraxia of speech were trained to produce complex or simple syllables (using modelling). Improvement was measured by percent correct on a word and nonword repetition test. OUTCOMES #ENTITYSTARTX00026; RESULTS: We found that both treatment on simple syllables and treatment on complex syllables led to improved production of simple syllables, while treatment of complex syllables also led to improvement on some complex syllables for one of the two patients. CONCLUSIONS: These results suggests that training complex items is more effective than training simple items, at least for some patients. Possible reasons for lack of stronger effects are discussed, as well as directions for future research.

The presynaptic particle web: ultrastructure, composition, dissolution, and reconstitution

We report the purification of a presynaptic "particle web" consisting of approximately 50 nm pyramidally shaped particles interconnected by approximately 100 nm spaced fibrils. This is the "presynaptic grid" described in early EM studies. It is completely soluble above pH 8, but reconstitutes after dialysis against pH 6. Interestingly, reconstituted particles orient and bind PSDs asymmetrically. Mass spectrometry of purified web components reveals major proteins involved in the exocytosis of synaptic vesicles and in membrane retrieval. Our data support the idea that the CNS synaptic junction is organized by transmembrane adhesion molecules interlinked in the synaptic cleft, connected via their intracytoplasmic domains to the presynaptic web on one side and to the postsynaptic density on the other. The CNS synaptic junction may therefore be conceptualized as a complicated macromolecular scaffold that isostatically bridges two closely aligned plasma membranes.

Should celecoxib be contraindicated in patients who are allergic to sulfonamides? Revisiting the meaning of 'sulfa' allergy

Celecoxib, a selective cyclo-oxygenase-2 inhibitor, is a diaryl-substituted pyrazole derivative containing a sulfonamide substituent. Because of this structural component, celecoxib is contraindicated for use in patients who have demonstrated allergic reactions to sulfonamides. However, there is a lack of data demonstrating cross-reactivity among sulfonamide medications. A sulfonamide is any compound with an SO2NH2 moiety. The major difference between sulfonamide antimicrobials and other sulfonamide-containing medications such as furosemide, thiazide diuretics and celecoxib, is that sulfonamide antimicrobials contain an aromatic amine group at the N4 position. This allows for division of the sulfonamides into 2 groups: aromatic amines (i.e., sulfonamide antimicrobials) and nonaromatic amines. In addition, sulfonamide antimicrobials contain a substituted ring at the N1-position; this group is not found with nonaromatic amine-containing sulfonamides. Adverse reactions to sulfonamide antimicrobials include type I, or immunoglobulin (Ig) E-mediated reactions, hypersensitivity syndrome reactions, and severe skin reactions such as toxic epidermal necrolysis. The aromatic amine portion of the sulfonamide antimicrobial is considered to be critical in the development of latter 2 reactions. In susceptible individuals, the hydroxylamine metabolite is unable to be detoxified leading to a cascade of cytotoxic and immunological events that eventually results in the adverse reaction. Since celecoxib does not contain the aromatic amine, adverse reactions such as hypersensitivity syndrome reactions and toxic epidermal necrolysis would not be expected to occur at the same frequency as they do with sulfonamide antimicrobials. Similarly, for IgE-mediated reactions, the N1-substituent and not the sulphonamide moiety is important in determining specificity to antibodies. Celecoxib and other nonaromatic amine-containing sulfonamide medications do not contain the N1-substituent. Cross-reactivity among the various sulfonamide-containing medications has also not been substantiated by published case reports. In fact, conflicting information exists in the literature. Reports showing lack of cross-reactivity balance the few case reports suggesting cross-reactivity. Cross-reactivity between sulfonamide medications should be based on scientific data, including chemistry, metabolism, immune responses and clinical data. Based on the current information, there is no documentation for cross-reactivity between sulfonamide antimicrobials and other sulfonamide medications, such as celecoxib.

Interleukin-18 inhibits human immunodeficiency virus type 1 production in peripheral blood mononuclear cells

Interleukin (IL)-18 is an interferon (IFN)-gamma-inducing factor and contributes to the Th1 immune response. IL-18 added after infection of peripheral blood mononuclear cells (PBMC) with monocyte-tropic human immunodeficiency virus type 1 (HIV-1) inhibited p24 antigen production by a maximum of 72%. IFN-gamma levels in these cultures were increased, and a significant inverse relationship between HIV-1 production and IFN-gamma levels was observed. A neutralizing anti-IFN-gamma antibody reversed the IL-18 inhibitory effect. Preincubation of PBMC with IL-18 before infection inhibited p24 without additional IL-18 (64%). However, compared with the degree of IL-18 inhibition observed after a 4-day culture, no additional IL-18 inhibitory effect was observed during days 5-13. IL-18 also reduced cell surface expression of the HIV-1 receptor CD4. These results demonstrate that IL-18 inhibited HIV-1 production in PBMC through intermediate IFN-gamma. Furthermore, inhibition was present during the early stages of viral infection and was associated with reduced HIV-1 receptor expression.

Conserved promoter motif is required for cell cycle timing of dnaX transcription in Caulobacter

Cells use highly regulated transcriptional networks to control temporally regulated events. In the bacterium Caulobacter crescentus, many cellular processes are temporally regulated with respect to the cell cycle, and the genes required for these processes are expressed immediately before the products are needed. Genes encoding factors required for DNA replication, including dnaX, dnaA, dnaN, gyrB, and dnaK, are induced at the G(1)/S-phase transition. By analyzing mutations in the dnaX promoter, we identified a motif between the -10 and -35 regions that is required for proper timing of gene expression. This motif, named RRF (for repression of replication factors), is conserved in the promoters of other coordinately induced replication factors. Because mutations in the RRF motif result in constitutive gene expression throughout the cell cycle, this sequence is likely to be the binding site for a cell cycle-regulated transcriptional repressor. Consistent with this hypothesis, Caulobacter extracts contain an activity that binds specifically to the RRF in vitro.

G-protein signaling through tubby proteins

Dysfunction of the tubby protein results in maturity-onset obesity in mice. Tubby has been implicated as a transcription regulator, but details of the molecular mechanism underlying its function remain unclear. Here we show that tubby functions in signal transduction from heterotrimeric GTP-binding protein (G protein)-coupled receptors. Tubby localizes to the plasma membrane by binding phosphatidylinositol 4,5-bisphosphate through its carboxyl terminal "tubby domain." X-ray crystallography reveals the atomic-level basis of this interaction and implicates tubby domains as phosphorylated-phosphatidyl- inositol binding factors. Receptor-mediated activation of G protein alphaq (Galphaq) releases tubby from the plasma membrane through the action of phospholipase C-beta, triggering translocation of tubby to the cell nucleus. The localization of tubby-like protein 3 (TULP3) is similarly regulated. These data suggest that tubby proteins function as membrane-bound transcription regulators that translocate to the nucleus in response to phosphoinositide hydrolysis, providing a direct link between G-protein signaling and the regulation of gene expression.

The CcrM DNA methyltransferase of Agrobacterium tumefaciens is essential, and its activity is cell cycle regulated

DNA methylation is now recognized as a regulator of multiple bacterial cellular processes. CcrM is a DNA adenine methyltransferase found in the alpha subdivision of the proteobacteria. Like the Dam enzyme, which is found primarily in Escherichia coli and other gamma proteobacteria, it does not appear to be part of a DNA restriction-modification system. The CcrM homolog of Agrobacterium tumefaciens was found to be essential for viability. Overexpression of CcrM is associated with significant abnormalities of cell morphology and DNA ploidy. Mapping of the transcriptional start site revealed a conserved binding motif for the global response regulator CtrA at the -35 position; this motif was footprinted by purified Caulobacter crescentus CtrA protein in its phosphorylated state. We have succeeded in isolating synchronized populations of Agrobacterium cells and analyzing their progression through the cell cycle. We demonstrate that DNA replication and cell division can be followed in an orderly manner and that flagellin expression is cyclic, consistent with our observation that motility varies during the cell cycle. Using these synchronized populations, we show that CcrM methylation of the chromosome is restricted to the late S phase of the cell cycle. Thus, within the alpha subdivision, there is a conserved cell cycle dependence and regulatory mechanism controlling ccrM expression.

A homolog of the CtrA cell cycle regulator is present and essential in Sinorhizobium meliloti

During development of the symbiotic soil bacterium Sinorhizobium meliloti into nitrogen-fixing bacteroids, DNA replication and cell division cease and the cells undergo profound metabolic and morphological changes. Regulatory genes controlling the early stages of this process have not been identified. As a first step in the search for regulators of these events, we report the isolation and characterization of a ctrA gene from S. meliloti. We show that the S. meliloti CtrA belongs to the CtrA-like family of response regulators found in several alpha-proteobacteria. In Caulobacter crescentus, CtrA is essential and is a global regulator of multiple cell cycle functions. ctrA is also an essential gene in S. meliloti, and it is expressed similarly to the autoregulated C. crescentus ctrA in that both genes have complex promoter regions which bind phosphorylated CtrA.

Dynamic localization of a cytoplasmic signal transduction response regulator controls morphogenesis during the Caulobacter cell cycle

We present evidence that a bacterial signal transduction cascade that couples morphogenesis with cell cycle progression is regulated by dynamic localization of its components. Previous studies have implicated two histidine kinases, DivJ and PleC, and the response regulator, DivK, in the regulation of morphogenesis in the dimorphic bacterium Caulobacter crescentus. Here, we show that the cytoplasmic response regulator, DivK, exhibits a dynamic, cyclical localization that culminates in asymmetric distribution of DivK within the two cell types that are characteristic of the Caulobacter cell cycle; DivK is dispersed throughout the cytoplasm of the progeny swarmer cell and is localized to the pole of the stalked cell. The membrane-bound DivJ and PleC histidine kinases, which are asymmetrically localized at the opposite poles of the predivisional cell, control the temporal and spatial localization of DivK. DivJ mediates DivK targeting to the poles whereas PleC controls its release from one of the poles at times and places that are consistent with the activities and location of DivJ and PleC in the late predivisional cell. Thus, dynamic changes in subcellular location of multiple components of a signal transduction cascade may constitute a novel mode of prokaryotic regulation to generate and maintain cellular asymmetry.

Complete genome sequence of Caulobacter crescentus

The complete genome sequence of Caulobacter crescentus was determined to be 4,016,942 base pairs in a single circular chromosome encoding 3,767 genes. This organism, which grows in a dilute aquatic environment, coordinates the cell division cycle and multiple cell differentiation events. With the annotated genome sequence, a full description of the genetic network that controls bacterial differentiation, cell growth, and cell cycle progression is within reach. Two-component signal transduction proteins are known to play a significant role in cell cycle progression. Genome analysis revealed that the C. crescentus genome encodes a significantly higher number of these signaling proteins (105) than any bacterial genome sequenced thus far. Another regulatory mechanism involved in cell cycle progression is DNA methylation. The occurrence of the recognition sequence for an essential DNA methylating enzyme that is required for cell cycle regulation is severely limited and shows a bias to intergenic regions. The genome contains multiple clusters of genes encoding proteins essential for survival in a nutrient poor habitat. Included are those involved in chemotaxis, outer membrane channel function, degradation of aromatic ring compounds, and the breakdown of plant-derived carbon sources, in addition to many extracytoplasmic function sigma factors, providing the organism with the ability to respond to a wide range of environmental fluctuations. C. crescentus is, to our knowledge, the first free-living alpha-class proteobacterium to be sequenced and will serve as a foundation for exploring the biology of this group of bacteria, which includes the obligate endosymbiont and human pathogen Rickettsia prowazekii, the plant pathogen Agrobacterium tumefaciens, and the bovine and human pathogen Brucella abortus.

Alpha-1-antitrypsin inhibits human immunodeficiency virus type 1

Several observations suggest the existence of potent endogenous suppressors of human immunodeficiency virus type 1 (HIV-1) production, and inhibitors of serine proteases may participate in this effect. Alpha-1-antitrypsin (AAT) is the most abundant circulating serine protease inhibitor. Physiological AAT concentrations inhibited HIV-1 production in chronically infected U1 monocytic cells, reduced virus replication in freshly infected peripheral blood mononuclear cells, and blocked infection of permissive HeLa cells. In U1 cells, AAT suppressed activation of the HIV-1-inducing transcription factor NF-kappaB. Similar results were obtained using CE-2072, a synthetic inhibitor of host serine proteases. HIV-1 did not replicate in blood obtained from healthy volunteers, but marked replication was observed in blood from individuals with hereditary AAT deficiency. These results identify AAT as a candidate circulating HIV-1 inhibitor in vivo. Two different mechanisms of AAT-induced HIV-1 inhibition were identified, including reduced HIV-1 infectivity and blockade of HIV-1 production. A novel host-pathogen interaction is suggested, and an alternative strategy to treat HIV-1-related disease may be possible.

Global analysis of the genetic network controlling a bacterial cell cycle

This report presents full-genome evidence that bacterial cells use discrete transcription patterns to control cell cycle progression. Global transcription analysis of synchronized Caulobacter crescentus cells was used to identify 553 genes (19% of the genome) whose messenger RNA levels varied as a function of the cell cycle. We conclude that in bacteria, as in yeast, (i) genes involved in a given cell function are activated at the time of execution of that function, (ii) genes encoding proteins that function in complexes are coexpressed, and (iii) temporal cascades of gene expression control multiprotein structure biogenesis. A single regulatory factor, the CtrA member of the two-component signal transduction family, is directly or indirectly involved in the control of 26% of the cell cycle-regulated genes.

A multicenter, randomized, double-blind, placebo-controlled trial of recombinant human interleukin-10 in HIV-infected subjects

OBJECTIVE

To determine the effect of multiple subcutaneous doses of recombinant human interleukin (rhuIL)-10 on plasma HIV RNA levels and CD4 T-cell counts, and to evaluate its safety and tolerability in HIV-infected subjects.

DESIGN

Prospective, randomized, double-blind, placebo-controlled, multicenter trial.

SUBJECTS

Thirty-nine HIV-infected subjects with CD4 T-cell counts > 200 x 10(6)/l, plasma HIV RNA concentrations > or = 3.18 log10 copies/ml and on stable antiretroviral therapy were recruited from six centers.

INTERVENTION

Subjects received (subcutaneously) rhuIL-10 1 microg/kg daily, 4 microg/kg daily, 8 microg/kg three times per week, placebo daily or placebo three times per week for 4 weeks.

MAIN OUTCOME MEASURES

Prospectively defined outcomes included safety and tolerability, plasma HIV RNA levels and CD4 T-cell counts. Outcomes were assessed at baseline, weeks 1, 2, 3 and 4 during treatment and weeks 2 and 4 following completion of therapy.

RESULTS

Baseline characteristics were similar in all groups. Compared to baseline, no significant change in plasma HIV RNA concentrations or CD4 T-cell counts was observed in any of the groups. RhuIL-10 was generally well tolerated. Two patients receiving rhuIL-10 4 microg/kg required discontinuation due to thrombocytopenia. One patient receiving rhuIL-10 4 microg/kg who had chronic hepatitis B and C infections discontinued drug because of elevated liver function tests. One patient receiving placebo discontinued study drug because of depression.

CONCLUSION

The lack of a demonstrable virological benefit, as assessed by plasma viral load, with 4 weeks of rhuIL-10 does not support the development of this immune-based therapy for treatment of HIV infection.

Bioengineered cardiac grafts: A new approach to repair the infarcted myocardium?

BACKGROUND

The myocardium is unable to regenerate because cardiomyocytes cannot replicate after injury. The heart is therefore an attractive target for tissue engineering to replace infarcted myocardium and enhance cardiac function. We tested the feasibility of bioengineering cardiac tissue within novel 3-dimensional (3D) scaffolds.

METHODS AND RESULTS

We isolated and grew fetal cardiac cells within 3D porous alginate scaffolds. The cell constructs were cultured for 4 days to evaluate viability and morphology before implantation. Light microscopy revealed that within 2 to 3 days in culture, the dissociated cardiac cells form distinctive, multicellular contracting aggregates within the scaffold pores. Seven days after myocardial infarction, rats were randomized to biograft implantation (n=6) or sham-operation (n=6) into the myocardial scar. Echocardiography study was performed before and 65+/-5 days after implantation to assess left ventricular (LV) remodeling and function. Hearts were harvested 9 weeks after implantation. Visual examination of the biograft revealed intensive neovascularization from the neighboring coronary network. Histological examination revealed the presence of myofibers embedded in collagen fibers and a large number of blood vessels. The specimens showed almost complete disappearance of the scaffold and good integration into the host. Although control animals developed significant LV dilatation accompanied by progressive deterioration in LV contractility, in the biograft-treated rats, attenuation of LV dilatation and no change in LV contractility were observed.

CONCLUSIONS

Alginate scaffolds provide a conducive environment to facilitate the 3D culturing of cardiac cells. After implantation into the infarcted myocardium, the biografts stimulated intense neovascularization and attenuated LV dilatation and failure in experimental rats compared with controls. This strategy can be used for regeneration and healing of the infarcted myocardium.

Making memories stick: cell-adhesion molecules in synaptic plasticity

Synapses are adhesive junctions highly specialized for interneuronal signalling in the central nervous system. The strength of the synaptic signal can be modified (synaptic plasticity), a key feature of the cellular changes thought to underlie learning and memory. Cell-adhesion molecules are important constituents of synapses, with well-recognized roles in building and maintaining synaptic structure during brain development. However, growing evidence indicates that cell-adhesion molecules also play important and diverse roles in regulating synaptic plasticity and learning and memory. This review focuses on recent advances in understanding the molecular mechanisms through which adhesion molecules might regulate synaptic plasticity.

Proteins on the move: dynamic protein localization in prokaryotes

Despite their small size and lack of obvious intracellular structures, bacteria have a complex and dynamic intracellular organization. Recent work has shown that many proteins, and even regions of the chromosome, are localized to specific subcellular regions that can change over time, sometimes extraordinarily fast. Protein function can depend on cellular position, so the analysis of the intracellular location of a protein can be crucial for understanding its activity. Because regulatory proteins are among those that reside at specific cellular sites, it is now necessary to consider three-dimensional organization when describing the genetic networks that control bacterial cells.

Loving openness as a meta-world hypothesis: expanding our vision of mind and medicine

In 1942, Stephen C. Pepper published a seminal book, World Hypothesis, that sought to explain how people create hypotheses about the world. Pepper proposed that there were four basic world hypotheses: (1) formistic (the hypothesis that nature exists as categories); (2) mechanistic (the hypothesis that nature obeys cause-effect relationships); (3) contextual (the hypothesis that processes in nature are relative and context dependent); and (4) organismic (the hypothesis that processes in nature reflect interactive relationships in systems). Most classical and modern theories of science and medicine implicitly adopt one or more of these foundational hypotheses. In 1997, Schwartz and Russek proposed that there were four additional world hypotheses: (5) implicit process (the hypothesis that nature consists of invisible forces and information, such as energy and consciousness); (6) circular causality (the hypothesis that nature consists of circulating interactions that inherently change over time); (7) creative unfolding (the hypothesis that processes in nature reflect flexible designs or plans that have adaptive function); and (8) integrative diversity (the hypothesis that phenomena in nature reflect complex integrations of diverse processes). Theories in postmodern and integrative science implicitly adopt hypotheses 5 through 8. However, underlying the creation of the eight world hypotheses is an implicit meta-world hypothesis which we term loving openness (the hypothesis that phenomena in nature reflect levels of openness and caring). This paper briefly explains the origin and implications of the loving openness meta-world hypothesis for understanding mind-body healing in medicine, the reordering of values in integrative medicine (with a primary focus on caring with humility), and the fostering of a new vision for twenty-first century frontier science, spirituality, and medicine.

The lipopolysaccharide-activated toll-like receptor (TLR)-4 induces synthesis of the closely related receptor TLR-2 in adipocytes

The central regulatory role of the adipocyte in whole body energy homeostasis is well established. However, recent findings suggest that preadipocytes and adipocytes may play an important physiological role in the regulation of both the innate and adaptive immune response. To systematically characterize the molecular machinery of the adipocyte that mediates the recognition of pathogens, we have focused our analysis on the recently identified Toll-like receptors (TLRs). These receptors have been implicated as mediators of the cellular response to bacterial lipopolysacharides (LPSs). Here, we report the cloning and functional characterization of mouse TLR-2 from 3T3-L1 adipocytes. TLR-2 synthesis is strongly induced in the adipocyte by LPS, TNFalpha, and the yeast cell wall extract zymosan. TLR-2 undergoes a lengthy intracellular maturation process with a half-life of exit from the ER of approximately 3 h. Furthermore, LPS treatment of adipocytes results in dramatic changes at the level of gene expression, including the synthesis of a distinct set of secretory proteins such as interleukin-6. Our studies demonstrate the presence of a fully intact pathway of innate immunity in the adipocyte that can be activated by LPS binding to the cell surface and results in the secretion of immunomodulatory molecules.