The Excited-State Lifetime of Poly(NDI2OD-T2) Is Intrinsically Short

Conjugated polymers composed of alternating electron donor and acceptor segments have come to dominate the materials being considered for organic photoelectrodes and solar cells, in large part because of their favorable near-infrared absorption. The prototypical electron-transporting push-pull polymer poly(NDI2OD-T2) (N2200) is one such material. While reasonably efficient organic solar cells can be fabricated with N2200 as the acceptor, it generally fails to contribute as much photocurrent from its absorption bands as the donor with which it is paired. Moreover, transient absorption studies have shown N2200 to have a consistently short excited-state lifetime (∼100 ps) that is dominated by a ground-state recovery. In this paper, we investigate whether these characteristics are intrinsic to the backbone structure of this polymer or if these are extrinsic effects from ubiquitous solution-phase and thin-film aggregates. We compare the solution-phase photophysics of N2200 with those of a pair of model compounds composed of alternating bithiophene (T2) donor and naphthalene diimide (NDI) acceptor units, NDI-T2-NDI and T2-NDI-T2, in a dilute solution. We find that the model compounds have even faster ground-state recovery dynamics (τ = 45, 27 ps) than the polymer (τ = 133 ps), despite remaining molecularly isolated in solution. In these molecules, as in the case of the N2200 polymer, the lowest excited state has a T2 to NDI charge-transfer (CT) character. Electronic-structure calculations indicate that the short lifetime of this state is due to fast nonradiative decay to the ground state (GS) promoted by strong CT-GS electronic coupling and strong electron-vibrational coupling with high-frequency (quantum) normal modes.

Zika virus infection of retinal cells and the developing mouse eye induces host responses that contrasts to the brain and dengue virus infection

Zika virus (ZIKV) infection causes ocular and neurological pathologies with ZIKV-induction of developmental abnormalities following in utero infection a major concern. The study here has compared ZIKV and the related dengue virus (DENV) infection in the eye and brain. In vitro, both ZIKV and DENV could infect cell lines representing the retinal pigmented epithelium, endothelial cells, and Mueller cells, with distinct innate responses in each cell type. In a 1-day old mouse challenge model, both ZIKV and DENV infected the brain and eye by day 6 post-infection (pi). ZIKV was present at comparable levels in both tissues, with RNA increasing with time post-infection. DENV infected the brain, but RNA was detected in the eye of less than half of the mice challenged. NanoString analysis demonstrated comparable host responses in the brain for both viruses, including induction of mRNA for myosin light chain-2 (Mly2), and numerous antiviral and inflammatory genes. Notably, mRNA for multiple complement proteins were induced, but C2 and C4a were uniquely induced by ZIKV but not DENV. Consistent with the viral infection in the eye, DENV induced few responses while ZIKV induced substantial inflammatory and antiviral responses. Compared to the brain, ZIKV in the eye did not induce mRNAs such as C3, downregulated Retnla, and upregulated CSF-1. Morphologically, the ZIKV-infected retina demonstrated reduced formation of specific retinal layers. Thus, although ZIKV and DENV can both infect the eye and brain, there are distinct differences in host cell and tissue inflammatory responses that may be relevant to ZIKV replication and disease.

Short and long-range electron transfer compete to determine free-charge yield in organic semiconductors

Understanding how Frenkel excitons efficiently split to form free-charges in low-dielectric constant organic semiconductors has proven challenging, with many different models proposed in recent years to explain this phenomenon. Here, we present evidence that a simple model invoking a modest amount of charge delocalization, a sum over the available microstates, and the Marcus rate constant for electron transfer can explain many seemingly contradictory phenomena reported in the literature. We use an electron-accepting fullerene host matrix dilutely sensitized with a series of electron donor molecules to test this hypothesis. The donor series enables us to tune the driving force for photoinduced electron transfer over a range of 0.7 eV, mapping out normal, optimal, and inverted regimes for free-charge generation efficiency, as measured by time-resolved microwave conductivity. However, the photoluminescence of the donor is rapidly quenched as the driving force increases, with no evidence for inverted behavior, nor the linear relationship between photoluminescence quenching and charge-generation efficiency one would expect in the absence of additional competing loss pathways. This behavior is self-consistently explained by competitive formation of bound charge-transfer states and long-range or delocalized free-charge states, where both rate constants are described by the Marcus rate equation. Moreover, the model predicts a suppression of the inverted regime for high-concentration blends and efficient ultrafast free-charge generation, providing a mechanistic explanation for why Marcus-inverted-behavior is rarely observed in device studies.

Abstract P3-07-04: Intrinsic subtype and therapeutic response among early stage HER2-positive breast tumors from the North Central cancer treatment group (Alliance) N9831 trial

Importance: 20-25% of patients with early stage HER2-positive breast cancer develop tumor relapse after adjuvant trastuzumab. Identification of such patients is a key goal for clinical management decisions.

Objective: To assess molecular heterogeneity among early stage HER2-positive patients using the Prosigna™ algorithm, to define intrinsic subtypes, and to determine the clinical significance of such heterogeneity.

Design: The NanoString® platform was used to measure the abundance of the PAM50 subtype signature transcripts. Samples from the NCCTG (Alliance) N9831 trial were analyzed using the Prosigna™ algorithm to define intrinsic subtype and risk scores. Subtypes were evaluated for recurrence-free survival following chemotherapy with or without trastuzumab.

Setting: Samples were obtained from a multi-center randomized phase III trial of chemotherapy versus chemotherapy plus trastuzumab.

Participants: All tumors were centrally evaluated for HER2 positivity, defined as IHC 3+ and/or FISH >2.0; 1392 patients were evaluated for molecular subtype.

Intervention(s): Patients received adjuvant chemotherapy (doxorubicin plus cyclophosphamide followed by paclitaxel) (n=484) or chemotherapy plus trastuzumab (n=908).

Main Outcome Measure(s): The primary outcome was recurrence-free survival as a function of subtype and treatment.

Results: Patients with HER2-positive tumors with HER2-enriched features comprised about 70% of the sample cohort, and these individuals received significant benefit from adjuvant trastuzumab (HR=0.68, 95%CI: 0.52, 0.89, p=0.005), as did the relatively fewer patients (291/1392) with Luminal-type tumors (HR=0.52, 95%CI: 0.32, 0.85, p=0.01). The sample cohort contained a small number of patients with tumors having Basal-like features (97/1392), and the data suggest that these individuals may have received less benefit from trastuzumab, beyond that received from chemotherapy alone (HR=1.06, 95%CI:0.53,2.13, p=0.87).

Conclusions: The majority of HER2-positive tumors are classified as HER2-enriched or Luminal using the Prosigna algorithm, and patients with such tumors benefit from adjuvant trastuzumab. About 10% of HER2-positive tumors exhibit Basal-like genomic features, and such tumors appear to recur at fairly similar frequency irrespective of treatment with chemotherapy or chemotherapy plus trastuzumab. Patients with HER2-positive/Basal-like tumors may represent a cohort that should be considered for enrollment in trials to evaluate emerging novel HER2-targeted agents, other targeted therapies, or combinations of both approaches.

Support provided in part by CA129949 and CA15083.

Citation Format: Perez EA, Ballman KV, Mashadi-Hossein A, Tenner KS, Kachergus JM, Norton N, Necela BM, Carr JM, Ferree S, Perou CM, Cheang MCU, Thompson EA. Intrinsic subtype and therapeutic response among early stage HER2-positive breast tumors from the North Central cancer treatment group (Alliance) N9831 trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-04.

Reduced sphingosine kinase 1 activity in dengue virus type-2 infected cells can be mediated by the 3' untranslated region of dengue virus type-2 RNA

Sphingosine kinase 1 (SphK1) is a lipid kinase with important roles including regulation of cell survival. We have previously shown reduced SphK1 activity in cells with an established dengue virus type-2 (DENV-2) infection. In this study, we examined the effect of alterations in SphK1 activity on DENV-2 replication and cell death and determined the mechanisms of the reduction in SphK1 activity. Chemical inhibition or overexpression of SphK1 after established DENV-2 infection had no effect on infectious DENV-2 production, although inhibition of SphK1 resulted in enhanced DENV-2-induced cell death. Reduced SphK1 activity was observed in multiple cell types, regardless of the ability of DENV-2 infection to be cytopathic, and was mediated by a post-translational mechanism. Unlike bovine viral diarrhea virus, where SphK1 activity is decreased by the NS3 protein, SphK1 activity was not affected by DENV-2 NS3 but, instead, was reduced by expression of the terminal 396 bases of the 3' UTR of DENV-2 RNA. We have previously shown that eukaryotic elongation factor 1A (eEF1A) is a direct activator of SphK1 and here DENV-2 RNA co-localized and co-precipitated with eEF1A from infected cells. We propose that the reduction in SphK1 activity late in DENV-2-infected cells is a consequence of DENV-2 out-competing SphK1 for eEF1A binding and hijacking cellular eEF1A for its own replication strategy, rather than a specific host or virus-induced change in SphK1 to modulate viral replication. Nonetheless, reduced SphK1 activity may have important consequences for survival or death of the infected cell.

Development of methods for coordinate measurement of total cell-associated and integrated human immunodeficiency virus type 1 (HIV-1) DNA forms in routine clinical samples: levels are not associated with clinical parameters, but low levels of integrated HIV-1 DNA may be prognostic for continued successful therapy

We have adapted our established Alu PCR assay for proviral DNA and PCR for total cellular DNA to a real-time PCR format and applied these to human immunodeficiency virus (HIV)-positive specimens collected for routine determination of the plasma viral load (pVL). In a cohort of five patients, measurements of integrated viral load (iVL) and cell-associated viral load (cVL) in CD4(+) cells isolated by a single positive selection step were not indicative of HIV DNA levels in the circulation, and further analysis was performed on peripheral blood mononuclear cells (PBMC). In a cohort of 46 samples total cVL was quantitated in most samples, but iVL could be quantitated in only 47.8%, since in 26% iVL was undetectable and in 21.7% the results were invalid due to high levels of unintegrated HIV DNA. There was no correlation of cVL or iVL with pVL, CD4 count, or duration of successful antiretroviral treatment. Out of 26 patients with undetectable pVL, 4 patients failed therapy within the subsequent 12 months and had higher than average iVL, but this was not the case for cVL. Among nine patients with long-term undetectable pVL, no consistent decline in cVL or iVL was seen with time, and changes in cVL and iVL within a patient could be concordant or discordant. These results show that cVL and iVL can be coordinately measured in PBMC from clinical samples but do not correlate with pVL, CD4 counts, or length of suppressive antiretroviral therapy. Interestingly, a high iVL (but not a high cVL) in patients with undetectable pVL was associated with subsequent treatment failure.

Cellular interactions of virion infectivity factor (Vif) as potential therapeutic targets: APOBEC3G and more?

Vif is an HIV accessory protein whose primary function is to negate the action of APOBEC3G, a naturally occurring cellular inhibitor of HIV replication. Vif acts by binding to APOBEC3G, inducing its protein degradation within infected cells and reducing its levels in progeny virions. Interventions that interfere with the Vif-APOBEC3G interaction, raise intracellular or virion associated levels of APOBEC3G, or reduce intracellular levels of Vif, all could hold promise as potential therapeutic approaches aimed at enhancing the cells innate antiviral activity. Levels of APOBEC3G might be increased or Vif levels decreased, by strategies targeting protein synthesis, protein degradation or cellular localisation and function, and properties of APOBEC3G and Vif relevant to these strategies are discussed. Recent data have suggested that Vif may have other mechanisms of action apart from the above activities against APOBEC3G, including effects against other anti-viral mechanisms independent of APOBEC3G cytidine deaminase activity. In addition to interaction with APOBEC3G, Vif may have other accessory functions, which are discussed in relation to potential therapies that may affect multiple stages of the HIV life cycle. Future development of strategies that combine enhancement of APBOEC3G functional with inhibition of multiple Vif functions may become useful tools for HIV therapy.

Vif-deficient HIV reverse transcription complexes (RTCs) are subject to structural changes and mutation of RTC-associated reverse transcription products

Reverse transcription (RTn) in HIV-infected cells occurs in a nucleoprotein complex termed the reverse transcription complex (RTC). RTCs containing RT activity and integrase (IN) were shown to be heterogeneous in size and density on sucrose velocity and equilibrium gradients. WT and Vif-deficient (Deltavif) RTCs produced by infection with virus from permissive cells displayed similar sedimentation characteristics, while RTCs from Deltavif virus produced in non-permissive cells demonstrated a reduction in the major RTC form and more of the RTn products in rapidly sedimenting structures. APOBEC3G derived from virions did not co-sediment with RTCs, but RTCs from Deltavif infections showed elevated levels of mutations in RTn products, consistent with APOBEC3G and other mutational mechanisms. The most mutated transcripts were present within rapidly sedimenting RTCs. Thus, virus without functional vif, produced from non-permissive cells, forms abnormal RTCs that contain increased mutation of RTC-associated RTn products in newly infected target cells.

Effect of deletion and the site of insertion in double copy anti-tat retroviral vectors: viral titres and production of anti-tat mRNA

In attempts to further develop murine leukemia virus (MLV) based retroviral vectors for gene therapy, we investigated vector production and antisense expression from retroviral constructs with U3 deletions or insertions. Promoter elements in the U3 region of the 3' LTR of the vector pLXSN were deleted and replaced with DNA encoding the HIV anti-tat gene under control of the tRNAmet promoter to produce a double copy self inactivating vector (DC-SIN). DC-SIN constructs were compared to vectors containing the anti-tat cassette inserted at 5 different sites of the U3 region (DC-insertions). Titres of DC-SIN and DC-insertion vectors were similar but approximately 10 fold lower than parental pLXSN. Cells transduced with DC-SIN and DC-insertion vectors all expressed anti-tat mRNA. Transcripts from the MLV-LTR were detected in cells transduced with DC-insertion but not DC-SIN vectors or a vector with the anti-tat cassette between CAAT and TATA boxes of the promoter, indicating inactivation of the viral promoter in the latter vectors. Cells transduced with constructs of either design showed comparable efficacy of protection against HIV challenge. Thus, no U3 insertion site was preferred for virus production. Insertion of a tRNA promoter between CAAT and TATA boxes and the DC-SIN design which would not introduce an active RNA pol II promoter into the genome are attractive for further development of safe gene therapy agents.

Replication of dengue virus type 2 in human monocyte-derived macrophages: comparisons of isolates and recombinant viruses with substitutions at amino acid 390 in the envelope glycoprotein

The severity of dengue virus infection ranges from mild fever to dengue hemorrhagic fever and shock syndrome. The association of disease severity with virus replication in monocyte-derived macrophages (MDMs) was examined for dengue virus type 2 (DEN-2) isolates from Asia or America. Additionally, we constructed DEN-2 recombinant viruses with substitutions at residue 390 in the envelope glycoprotein (E390) because this residue is linked with the region of virus origin. Comparisons of virus yields of 3 isolates failed to show a correlation with clinical disease. However, the American strain did not replicate as well as the 2 Asian strains. For the recombinant viruses, substitution of Asn (Asian) at E390 with Asp (American) resulted in decreased ability to replicate in MDMs. These results are consistent with the proposal that the lack of association of native American DEN-2 strains with severe disease is linked to reduced ability to replicate in MDMs, and that Asp at E390 may contribute to this reduction.

High vesicular monoamine transporter binding in asymptomatic bipolar I disorder: sex differences and cognitive correlates

OBJECTIVE

It has been hypothesized that anomalies in monoaminergic function underlie some of the manifestations of bipolar disorder. In this study the authors examined the possibility that trait-related abnormalities in the concentration of monoaminergic synaptic terminals may be present in patients with asymptomatic bipolar disorder type I.

METHOD

The concentration of a stable presynaptic marker, the vesicular monoamine transporter protein (VMAT2), was quantified with (+)[(11)C]dihydrotetrabenazine (DTBZ) and positron emission tomography. Sixteen asymptomatic patients with bipolar I disorder who had a prior history of mania with psychosis (nine men and seven women) and individually matched healthy subjects were studied. Correlational analyses were conducted to examine the relationship between regional VMAT2 binding, cognitive function, and clinical variables.

RESULTS

VMAT2 binding in the thalamus and ventral brainstem of the bipolar patients was higher than that in the comparison subjects. VMAT2 concentrations in these regions correlated with performance on measures of frontal, executive function. In addition, sex differences in VMAT2 binding were detected in the thalamus of the bipolar patients; the male patients had higher binding than the women. No sex differences in binding were observed in the healthy comparison group.

CONCLUSIONS

These initial results suggest that higher than normal VMAT2 expression and, by extension, concentration of monoaminergic synaptic terminals, may represent a trait-related abnormality in patients with bipolar I disorder and that male and female patients show different patterns. Also, VMAT2 concentrations may be associated with some of the cognitive deficits encountered in euthymic bipolar disorder.

Rapid and efficient cell-to-cell transmission of human immunodeficiency virus infection from monocyte-derived macrophages to peripheral blood lymphocytes

Macrophages are considered of central importance in cell-to-cell transmission of human immunodeficiency virus (HIV) infection in vivo. In this report, we describe a novel cell-to-cell transmission model using HIV-infected monocyte-derived macrophages (MDMs) as donor cells and peripheral blood lymphocytes (PBLs) as recipients. Virus was transmitted during a 2-h coincubation period from intracellular or tightly cell-associated viral stores in adherent infected MDMs to nonadherent CD3(+) PBLs. Transmission required cell contact, but syncytia formation was not observed. HIV cell-to-cell transmission occurred in both allogeneic and autologous systems, and replication was higher in phytohemagglutinin (PHA)-stimulated than unstimulated recipient PBLs. In contrast, transmission of infection by cell-free virus was barely detectable without PHA stimulation of recipients, suggesting the cell-cell interaction may have provided stimuli to recipient cells in the cell-to-cell system. Viral DNA levels increased 5-24 h postmixing, and this increase was inhibited by pretreatment of cells with the reverse transcription inhibitor azidothymidine, indicating de novo reverse transcription was involved. Cell-to-cell transmission was more efficient than infection with cell-free virus released from donor MDMs, or 0.1 TCID(50)/cell cell-free viral challenge. This model provides a system to further investigate the mechanisms and characteristics of HIV cell-to-cell transmission between relevant primary cells that may be analogous to this important mode of virus spread in vivo.

Integrating patterns of knowing in an undergraduate nursing course

A complex and changing contemporary healthcare system and holistic consideration of patients create a need for nurses who have a sophisticated, broad knowledge base. Empirical, ethical, personal, and aesthetic patterns of knowing provide a meaningful background for course development and offer students the opportunity to understand themselves and their patients through multiple modes of awareness. In this article, the author describes the integration of patterns of knowing into an undergraduate nursing course. Course objectives, content, assignments, and evaluation are discussed. A course such as this one that incorporates scientific knowledge of humans in health and illness, aesthetic perception of human experiences, personal understanding of self and others, and the capacity to make ethical choices enriches student learning about the art and science of nursing.

Families at the bedside: an ethnographic study of vigilance

BACKGROUND

Vigilance, the close protective involvement of family members with hospitalized relatives, is a relatively recent phenomenon in the hospital setting. Before the 1960s, hospital visiting policies restricted the presence of family members at the bedside. Policies changed during the 1960s and 1970s when health care professionals recognized that parents' staying with their hospitalized children was beneficial for both the parents and the children. Vigilance later became a phenomenon that included family members staying with adult patients.

METHODS

Two ethnographic studies were conducted to examine the meanings, patterns, and day-to-day experience of vigilance. Sixteen family members, described by the nursing staff as staying with the patient, participated in informal semistructured interviews. Participant observation was also used in data collection.

RESULTS

Data analysis yielded 5 categories of meaning that describe the experience of vigilance: commitment to care, emotional upheaval, dynamic nexus, transition, and resilience.

CONCLUSIONS

Managed care, shortened hospital stays, and cost containment make early involvement of the family in the patient's care imperative. An understanding of the family's needs and experiences is prerequisite to that involvement. The categories of meaning discovered in this research can help health care providers understand family members' experience of vigilance. The implications for the family physician include sensitization and awareness of family members' experiences and the developing of specific actions and interactions fostering a commitment to family-centered care that extends to the hospital setting.

Vigilance as a caring expression and Leininger's theory of cultural care diversity and universality

Vigilance, or the close, protective involvement of families caring for hospitalized relatives, was explored in this study using holistic ethnography. Leininger's theory of cultural care diversity and universality provided direction for the researcher to generate substantive data about the meanings, patterns, and day-to-day experience of vigilance. Five categories of meaning were derived from the data: commitment to care, emotional upheaval, dynamic nexus, transition, and resilience. The research findings expand understanding of vigilance as a caring expression, suggest direction for nursing practice, and contribute to Leininger's theory of cultural care diversity and universality and the development of nursing science.

Secretion in Escherichia coli and phage-display of recombinant insulin-like growth factor binding protein-2

Insulin-like growth factors (IGFs) promote cell growth and differentiation. Their actions are regulated by six different, but related, binding proteins (IGFBPs). To investigate the molecular interactions between IGFs and IGFBPs, an Escherichia coli based production method and a phage display system has been developed. The cDNA for bovine IGFBP-2 was inserted between regions coding for the pelB signal sequence and geneIII product, g3p, of bacteriophage fd in a phagemid vector to generate pGF14. The coding sequences of IGFBP-2 and g3p were separated by an amber stop codon and a flexible linker containing the cleavage recognition site for H64A subtilisin. Using this system in BL21, a non-supE strain lacking ompT, most product, approximately 4 mg 1(-1) of IGFBP-2, was obtained in the growth medium. The bacterially derived IGFBP-2 had a correct N-terminal sequence, molecular mass on SDS-PAGE and the same affinity for IGF-1 and IGF-II as IGFBP-2 from mammalian cells. In a supE strain of E. coli, IGFBP-2 was produced as an IGF-binding fusion to g3p. Procedures for display and approximately 10000 fold enrichment of IGFBP-2 bearing phage using adsorption to IGF-II coated microtitre plates were developed. Thus IGFBP-2 can be secreted in E. coli and displayed on filamentous phage. These can be selectively enriched by binding to immobilised IGF-II.

CD34+ cells and their derivatives contain mRNA for CD4 and human immunodeficiency virus (HIV) co-receptors and are susceptible to infection with M- and T-tropic HIV

Highly purified (>98%) CD34+ cells directly after isolation (D0) or 2 weeks in culture (D14) were CD4+ and contained mRNA for the T-tropic HIV co-receptor, CXCR-4, and minor co-receptor, CCR-2B. D14 but not D0 cells were RT-PCR positive for mRNA for the major M-tropic human immunodeficiency virus (HIV) co-receptor, CCR-5, and potential co-receptor, CCR-1. D14 and D0 cells were susceptible to T- (HXB2) and M-tropic HIV (Bal), showing greater virus production with Bal than HXB2, and with higher virus production levels in D14 compared to D0 cells. Seven days post-infection of D0 cells Bal DNA was present in CD14bright and CD14- fractions, suggesting D0 infection of diverse progenitor types. HXB2 DNA was detected in CD14bright cells alone indicating D0 infection of monocyte progenitors only. It is concluded that CD34+ cells and cultured derivatives are susceptible to M- and T-tropic HIV and this correlates in part with co-receptor expression at the mRNA level.

The family's experience of vigilance: challenges for nursing

The article reports a qualitative study examining vigilance, or the close, protective involvement of families who stay with their hospitalized relatives. Participants described the meanings, patterns, and day-to-day experience of vigilance through five categories of meaning: commitment to care, emotional upheaval, dynamic nexus, transition, and resilience. These categories of meaning sensitize nurses to the family's experience of vigilance and have significant implications for nursing practice.

Who cares for the mentally ill? Theory and practice hours with a 'mental illness' focus in nursing curricula in Australian universities

Should we be concerned about the amount of undergraduate and postgraduate theory and practice hours nurses undertake caring for people with mental illness? Information on mental health curricula was sought from all university schools of nursing in Australia. There was an 84% response rate. For undergraduate courses the findings indicated great variability among schools. In one school students had 30 hours theory and no practice hours, compared with another school's 128 hours of theory and 200 practice hours. Few courses were available at the postgraduate level and the content of these courses did not appear to reflect students' previous experience in mental health/psychiatric nursing. This implies that students could graduate with limited practical experience. Without a clearly articulated career pathway, based on nationally agreed practice and educational requirements, it is difficult to see how mental health/psychiatric nurses can continue to claim they belong to a professional specialist discipline.

Significance of D-dimer concentrations during and after cardiopulmonary bypass

OBJECTIVE

To determine whether D-dimer fragments predictably increase during cardiopulmonary bypass (CPB), and if so, whether increases correlate with postoperative blood loss or predict postoperative coagulopathy.

DESIGN

Prospective observational study of 65 consecutive patients undergoing first-time coronary artery bypass graft (CABG) or first-time valve replacement.

SETTING

Single center University teaching hospital.

PARTICIPANTS

Male and female patients between the ages of 30 and 90 years undergoing first-time CABG or valve replacement surgery using CPB. Patients were excluded from study for prolonged preoperative bleeding time, preoperative warfarin therapy, perioperative intra-aortic balloon pump support, thrombolytic therapy in the week preceding operation, reoperation, and emergency operation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Blood sampling for platelet count, prothrombin time, partial thromboplastin time, thrombin time, fibrinogen, activated coagulation time (ACT) and D-dimer concentrations was obtained at four times during each case; (1) preoperatively, after insertion of the internal jugular introducer, before insertion of pulmonary artery catheter; (2) during CPB at 28 degrees C, immediately before rewarming; (3) after heparin neutralization (20 minutes after initial protamine dose); (4) 12 to 24 hours postoperatively. Blood loss in the intensive care unit was calculated by measuring total mediastinal drainage output at 1 and 4 hours after arrival from the operating room. An initial decrease in fibrinogen was noted during bypass, but no increase in D-dimer was identified. A few patients developed a modest increase in D-dimer after heparin neutralization, but none greater than 2.0 ug/mL. Postoperatively, fibrinogen concentration increased toward baseline levels. However, this is when six patients developed significant (> 2.0 ug/mL) D-dimer formation. Results suggest appropriate physiologic response-normalization of fibrinogen with new synthesis and remodeling of clot in the operative site causing D-dimer formation. Patients with highest D-dimer levels at 12 to 24 hours postoperatively had the highest blood loss at 4 hours postoperatively, suggesting that early postoperative excess bleeding predisposed to increased clot formation and subsequent clot remodeling causing elevated D-dimer concentrations.

CONCLUSIONS

D-dimer concentration is not usually elevated in patients undergoing CPB when adequately anticoagulated as monitored using the ACT. When mild elevation of D-dimer occurs, it is most often after heparin neutralization and/or in the postoperative period and is not predictive of increased postoperative blood loss. Elevations of D-dimer concentrations in the postoperative period without corresponding decreases in fibrinogen concentrations may occur and do not signify coagulopathy.

Analysis of insulin-like growth factor binding proteins in the tammar wallaby, Macropus eugenii

The insulin-like growth factors (IGFs) are important regulators of growth and development in eutherian mammals. In this study we have analyzed circulating insulin-like growth factor binding proteins (IGFBPs) by Western ligand blotting (WLB) and neutral gel filtration, and hepatic IGFBP mRNA transcripts in the wallaby, Macropus eugenii, a marsupial in which the fetus is born at an immature stage compared to eutherian mammals. Plasma from male and female adults, lactating mothers, and pouch young contains an IGF binding species consisting of a 42- to 50-kDa doublet, 30, 28, 24, and approximately 200 kDa, as shown by WLB. This pattern of IGFBPs is very similar to that observed in human and sheep. Neutral gel filtration revealed IGF binding activity of molecular size 70-160 kDa. When electrophoresed under nonreducing, denaturing conditions, the 70- to 160-kDa IGF binding activity appeared as a 42- to 50-kDa doublet, indicating the presence of a high-molecular-weight circulating IGF binding complex. These properties are again analogous to those observed for eutherian IGFBPs. Northern analysis of total wallaby liver RNA detected transcripts of 1.8 kb for IGFBP-1 and 1.6 kb for IGFBP-2, the same as those observed in the sheep and rat. Transcripts of 3.2 kb were detected for IGFBP-4, larger than the major band of 2.6 kb observed for the sheep and rat. Transcripts representing wallaby IGFBP-3 mRNA were not detected using a rat IGFBP-3 cDNA probe. Circulating IGFBPs were analyzed in plasma from wallaby mothers and their pouch young. There were no changes in circulating IGFBPs in the wallaby mothers throughout lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs) and tissue mRNA levels of IGFBP-2 and IGFBP-4 in the ovine fetus

The IGF-binding proteins (IGFBPs) are a family of at least six structurally related proteins, which bind the IGFs and modulate their actions, including the regulation of pre- and postnatal growth. In this study we have examined the relationship between circulating and tissue mRNA levels of IGFBPs and related this to circulating IGFs in the fetal sheep over the gestational period when rapid growth and development occurs. Circulating IGFBP-2, as measured by Western ligand blot (WLB), increases between early and mid gestation, remains high, then declines throughout late gestation (P = 0.0002). Circulating IGFBP-3 increases throughout gestation, as measured by WLB or RIA (P = 0.04 and P = 0.0001 respectively), as does circulating IGFBP-4 (P = 0.004). These ontogenic changes in circulating IGFBPs-2 and -4 are paralleled by changes in liver mRNA for these proteins and, for IGFBP-2, by those in kidney IGFBP-2 mRNA also. This suggests that liver and kidney may be the primary contributors to circulating IGFBP-2 and the liver to circulating IGFBP-4, IGFBP-2 mRNA is present in the heart and lung in early gestation but barely detectable in these tissues after approximately 60 days gestation. IGFBP-4 mRNA is also present in the heart in early but not late gestation, but is abundant in the lung throughout gestation. These results demonstrate tissue specific and developmental regulation of IGFBPs-2 and -4 at the mRNA level. To assess any role the circulating IGFs may play in mediating these changes in IGFBPs, or vice versa, both plasma IGF-I and IGF-II were measured by RIA. Circulating IGF-I increases as gestation progresses (P = 0.0001), while circulating IGF-II increases between early and mid gestation, remains high (P = 0.01), then declines. Circulating IGF-I is positively correlated with fetal weight (r = 0.66, P = 0.03), circulating IGFBP-3 (r = 0.54, P = 0.01) and IGFBP-4 (r = 0.52, P = 0.01). Circulating IGF-II positively correlates with circulating IGFBP-2 (r = 0.48, P = 0.02) throughout gestation and at 1 day postnatally. These relationships are consistent with circulating IGF-I influencing IGFBPs-3 and -4, and similarly, IGF-II determining IGFBP-2, or vice versa. Alternatively, these correlations may reflect coordinate regulation of IGF and IGFBP by a common factor.

A feasibility study for removing tissue contamination from porous implants

Porous implants that are unpackaged in the operating room but not implanted are discarded because they must be considered potentially contaminated with tissue. To reduce this waste, a method was developed to decontaminate these implants so that they can be resterilized and implanted. This method consists of ultrasonic scrubbing, sequentially, in aqueous solutions of dishwashing detergent, 7% nitric acid, and 5.25% sodium hypochlorite. The effectiveness of the method was tested by contaminating samples of porous implants with tissue, subjecting them to the decontamination method, and then using the following techniques to determine whether any tissue remained. The weights of samples after decontamination were compared with their weights before contamination. The rate of removal of labeled protein contamination from samples was measured. The capacity of decontaminated samples to activate immune system cells was assayed. Bioburden evaluations were performed on decontaminated samples. Within the measurement capabilities of each technique, no tissue was detected in any sample after decontamination.

Isolation and characterization of ovine IGFBP-4: protein purification and cDNA sequence

Three different molecular mass forms of IGF-binding proteins (IGFBPs) were purified from ovine plasma by IGF-I affinity chromatography and reverse-phase HPLC: a 46 kDa doublet and 29 kDa and 24 kDa forms. Amino-terminal sequence analysis confirmed that these proteins were ovine (o)IGFBP-3 (46 kDa) and two molecular size variants of oIGFBP-4. oIGFBP-3 and the 29 kDa form of oIGFBP-4 were shown to be N-glycosylated. Isoelectric points were determined to be at approximately pH 6 for oIGFBP-3 and at pH 7 and pH 7.5 for the 29 and 24 kDa forms of oIGFBP-4 respectively. The two different molecular mass variants of oIGFBP-4 had similar IGF-binding properties. Compared with human IGFBP-3 and oIGFBP-3, the two variants of oIGFBP-4 exhibited lower relative binding to amino-terminally modified IGF-I analogues in a competitive IGF-binding assay. The full protein sequence of oIGFBP-4, as deduced from the cDNA sequence, showed a high degree of identity with rat (90%), human (96%) and bovine (98%) IGFBP-4. The cDNA sequence also showed homology over regions of the 3' non-coding sequence, particularly in comparison with bovine IGFBP-4 (96%). Northern analysis of mRNA for oIGFBP-4 indicated a 2.6 kb major transcript and two minor transcripts of approximately 2.1 and 1.8 kb. oIGFBP-4 mRNA transcripts were detected in adult ewe liver > kidney > lung >> heart and also in several fetal tissues, thus suggesting tissue-specific and developmental regulation. The availability of purified oIGFBP-4 and oIGFBP-3 as well as DNA probes for oIGFBP-4 will enable further study of the properties and functions of these proteins, as well as the establishment of specific assays for these IGFBPs.

Babesiosis. Diagnostic pitfalls

A case of babesiosis complicated by quinine-induced hemolysis is described. A splenectomized woman contracted babesiosis after visiting an endemic area. The patient presented with high fevers and minimal hemolysis. While she was on treatment, the hemolysis increased. The increased hemolysis was initially attributed to babesiosis, but after additional evaluation quinine therapy was found to be the cause. In the setting of this brisk hemolysis, there was an increase in red blood cell inclusions. At first, the inclusions were thought to be Babesia, but iron stain demonstrated that many of the inclusions were hemolysis-induced Pappenheimer bodies. The role of the clinical laboratory in sorting out this confusing picture is presented.

Alteration of aliphatic lipid proton NMR linewidths by malignant tumors in guinea pigs

Water-suppressed proton nuclear magnetic resonance spectroscopy was used to observe plasma lipoprotein lipid methyl and methylene resonances from guinea pigs which had been injected with viable or heat-killed line 1 or line 10 tumor cells or sterile oil. It was shown that the widths of these resonances became significantly sharper as the number of tumor cells grew. Plasma from tumor-free control animals showed no change in the NMR linewidths. It is concluded that the changes observed reflect a specific host response to viable tumor cells, and in these models there is a reciprocal relationship between the number of viable tumor cells and the linewidths of plasma lipoprotein methyl and methylene resonances.

Diagnosis of disseminated intravascular coagulation. Role of D-dimer

Detection of the cross-linked fibrin degradation fragment, D-dimer, in patients at risk for disseminated intravascular coagulation (DIC) is strong evidence for the diagnosis. D-dimer confirms that both thrombin generation and plasmin generation have occurred. Patients at risk for DIC (58) and normal controls (7) were studied. Thirty-three patients had DIC--with fragment D-dimer identified in their serum by immunoblotting. Latex agglutination measurements of fibrin(ogen) degradation products (FDPs) and D-dimer were compared with immunoblotting in the detection of D-dimer. FDP measurement was extremely sensitive but not specific. D-dimer measurement was less sensitive but highly specific. Used in tandem, screening with FDP and confirming with D-dimer, sensitivity and specificity were maximized, rendering a predictive value of a confirmed FDP of 100% in this cohort. D-dimer is a valuable adjunct for the laboratory diagnosis of DIC but is most appropriately used as a confirmatory test for the very sensitive FDP test.

Detection of malignant tumors. Water-suppressed proton nuclear magnetic resonance spectroscopy of plasma

A sensitive and specific blood test for cancer has long been sought. The water-suppressed proton nuclear magnetic resonance (NMR) spectrum of plasma is dominated by the resonances of plasma lipoprotein lipids. We measured the mean line widths of the methyl and methylene resonances, which were found to be correlated with the presence or absence of malignant tumors. Values for the average line width were lower in patients with cancer. We analyzed plasma from 331 people (normal controls, patients with malignant and benign tumors, patients without tumors, and pregnant patients); NMR analysis and measurement of line widths were blinded to diagnosis or patient group. The mean line width for 44 normal controls (+/- SD) was 39.5 +/- 1.6 Hz. For 81 patients with untreated cancer, demonstrated by biopsy, the line width was 29.9 +/- 2.5 Hz. Patients with malignant tumors were reliably distinguished from normal controls by this method (P less than 0.0001), and differed from patients with diseases that did not involve tumors (line width, 36.1 +/- 2.6 Hz; P less than 0.0001). Patients with benign tumors (e.g., those of the breast, ovary, uterus, and colon) had line widths of 36.7 +/- 2.0 Hz and were different from those with malignant tumors (P less than 0.0001). However, pregnant patients and those with benign prostatic hyperplasia had line widths consistent with the presence of malignant tumors. The narrowing of lipoprotein-lipid resonances with cancer is consistent with the response of a host to tumor growth. We conclude that these preliminary results demonstrate that water-suppressed proton NMR spectroscopy is a potentially valuable approach to the detection of cancer and the monitoring of therapy.

Efficacy of platelet transfusions in immune thrombocytopenia

Records of 11 patients with immune thrombocytopenia (idiopathic and quinidine-induced) were evaluated retrospectively for response to platelet transfusion. Good post-transfusion platelet count increments occurred on one or more occasions in seven of the 11 patients, with 13 of 31 platelet transfusions (42 percent) resulting in immediate post-transfusion increments of 20,000/mm3 or more. Next-day platelet counts remained elevated in association with five of these 13 transfusions. This study demonstrates that, contrary to common opinion, platelet transfusions can raise the platelet count in many patients with immune thrombocytopenia, and therefore may be beneficial in actively bleeding or high-risk patients with this disorder.

Analysis of elevated fibrin(ogen) degradation product levels in patients with liver disease

Plasma and serum from patients with liver disease and elevated fibrin(ogen) degradation product (FDP) levels as measured by latex agglutination were analyzed by immunoblotting to characterize the FDP in these patients. An antihuman fibrinogen antibody was used that recognizes fibrinogen, fibrin monomer, soluble high molecular weight fibrinogen and fibrin polymers, as well as high molecular weight cross-linked degradation fragments, and the smaller fragments X, Y, D-dimer, D, and E. The analytic procedures were validated with plasma and serum from patients known to have intravascular fibrinolysis associated either with disseminated intravascular coagulation (DIC) or with thrombolytic therapy. The samples demonstrated a spectrum of plasmin degradation fragments on the immunoblots. Twenty-eight of 35 patients with liver disease (80%) had no evidence of plasmin degradation fragments in their plasma or serum. The cause of the elevated FDP levels as measured by latex agglutination was thought to be fibrin monomer or unclottable fibrinogen that was retained in the sera of some of these patients. Seven patients (20%) were found to have circulating plasmin degradation fragments. In addition to liver disease, however, these patients all had an illness (sepsis, shock, and pancreatic carcinoma) independently associated with intravascular coagulation and fibrinolysis. Three patients who lacked plasmin fragments also had pancreatic carcinoma or sepsis. The two groups of liver disease patients could not be clearly differentiated on the basis of clinical or laboratory evidence, but the blotting procedure proved to be a useful discriminator.

Circulating membrane vesicles in leukemic blood

Ultramicroscopic membrane vesicles were found in the plasma of 17 patients with certain types of leukemia (acute promyelocytic leukemia, acute monocytic leukemia, acute myelomonocytic leukemia, and chronic myelogenous leukemia) and in guinea pigs with the L2C leukemia. Labeled vesicles were cleared from normal guinea pig plasma according to a two exponential function with a half-life for the second exponent of greater than 11 h. By immunofluorescence, vesicles shared antigens with the L2C leukemic cells. Attempts to elucidate the cellular origin of the circulating vesicles in human leukemias were less definitive. However, vesicles did not react with the platelet membrane antigen GP IIb/IIIa nor did the presence of circulating vesicles or vesicle-associated procoagulant activity correlate with the platelet count. In three patients studied serially, circulating vesicles paralleled disease activity. Vesicles were not detected in 16 other patients with leukemias including acute myelogenous leukemia and most lymphoid leukemias. Similarly, vesicles were not present in 29 normal plasmas or in 10 plasmas from patients with solid tumors or nonmalignant hematological disorders. In contrast to vesicles of similar appearance shed by a variety of solid and ascites tumor cells in vitro and in vivo, the vesicles circulating in leukemia patients and guinea pigs expressed variable and generally weak procoagulant activity and no tissue factor activity. Thus, although many of the patients with circulating vesicles expressed abnormal coagulation, we were not able to establish a close pathogenetic relationship between the procoagulant activity of circulating vesicles and clinical coagulopathies.

Soft tissue attenuation of acoustic emission pulses

The soft tissue attenuation of acoustic emission signals was measured by transmitting pulses through volunteers and measuring the decay of the waveform characteristics of the pulse as a function of the thickness of the interposed tissue. Waveform characteristics of the received signal (signal duration, number of counts, peak amplitude, energy, and rise time) demonstrated an exponential decrease with increasing tissue thickness. The decrease appeared insensitive to the frequency of the pulse within the range of 50 to 600 KHz.

Clonal distribution of resistance plasmid-carrying Salmonella typhimurium, mainly in the Middle East

Strains of Salmonella typhimurium of predominantly Middle Eastern origin, but distributed from England to India, were found to carry at least three types of resistance plasmid. The most important was initially identified as an F(I) plasmid by compatibility tests, but differs from the F factor on the one hand and the F(I) factors R162 and ColV on the other. The three groups of F(I) plasmids can be distinguished by their compatibility reactions with the MP10 plasmid of S. typhimurium (Smith, Humphreys, Grindley, Grindley & Anderson, 1973) and group H(1) factors: the F factor is unilaterally incompatible with group H(1) (Smith, Grindley, Humphreys & Anderson, 1973; Anderson, 1975b); the F(I) factors are compatible with MP10 and group H(1); and F(I)me factors are incompatible with MP10 but compatible with H(1). The majority of S. typhimurium cultures belonged to phage type 208; most of those that did not, belonged to types related to 208. Only a minority of their F(I)me plasmids were autotransferring. The remainder were mobilizable by F-like plasmids, and by group H(1) and H(2) factors, but not by the fi(-) I(1) factor Delta, or by plasmids of the I(2), B, P, W, N and com 7 groups. The compatibility reactions of the autotransferring F(I)me plasmids were identical with those of the non-transferring members of the group, and both were large, single-copy plasmids.The S. typhimurium strains of this series carried A or AK, and SSu resistance determinants: small, probably multicopy, non-transferring plasmids similar to those originally described in phage type 29 of S. typhimurium (Anderson & Lewis, 1965b).These S. typhimurium cultures probably represent a clone of wide geographical distribution. The accurate epidemiological study of such clonal outbreaks requires, in addition to phage typing, precise identification of the plasmids harboured by the epidemic strains, and may have to be carried to the molecular level.F(I)me plasmids were identified in other drug-resistant salmonellas, notably in a strain of S. wien which caused large outbreaks of mainly paediatric infection in Algeria, and also spread to Britain. An F(I)me plasmid was found in S. typhi phage type 44 from Algeria, in which the phage-restricting properties of the plasmid are responsible for the specificity of the type.

Bacteriophage restriction in Salmonella typhimurium by R factors and transfer factors

A total of 2716 R factors and transfer factors isolated from Escherichia coli and salmonellas of human and animal origin were studied for their phage-restrictive effects in Salmonella typhimurium phage type 36. All of 1402 wild fi(+) factors were non-restricting. The F factor of E. coli K12 was unique among the F-like factors tested in that it inhibited lysis of type 36 by one typing phage. In contrast, eleven distinct changes in the phage type of 36 were produced by fi(-) I-like factors. I-like plasmids can thus be subdivided by this method.I-like R factors and transfer factors from human and animal enterobacteria were categorized by their phage-restrictive effects in type 36. Factors resembling Delta in this respect predominated among fi(-) I-like factor from human E. coli and S. typhimurium and from porcine E. coli. Delta-like and ColI-like fi(-) factors were equally distributed in bovine S. typhimurium. ColI-like factors were commonest in bovine and avian E. coli.