Re-Thinking Dimer Design Principles with Indolonaphthyridine Intramolecular Singlet Fission

Singlet fission is a phenomenon that could significantly improve the efficiency of photovoltaic devices. Indolonaphthyridine thiophene (INDT) is a photostable singlet fission material that could potentially be utilised in singlet fission-based photovoltaic devices. This study investigates the intramolecular singlet fission (i-SF) mechanism of INDT dimers linked via para-phenyl, meta-phenyl and fluorene bridging groups. Using ultra-fast spectroscopy the highest rate of singlet fission is found in the para-phenyl linked dimer. Quantum calculations show the para-phenyl linker encourages enhanced monomer electronic coupling. Increased rates of singlet fission were also observed in the higher polarity o-dichlorobenzene, relative to toluene, indicating that charge-transfer states have a role in mediating the process. The mechanistic picture of polarisable singlet fission materials, such as INDT, extends beyond the traditional mechanistic landscape.

Aza-Cibalackrot: Turning on Singlet Fission Through Crystal Engineering

Singlet fission is a photophysical process that provides a pathway for more efficient harvesting of solar energy in photovoltaic devices. The design of singlet fission candidates is non-trivial and requires careful optimization of two key criteria: (1) correct energetic alignment and (2) appropriate intermolecular coupling. Meanwhile, this optimization must not come at the cost of molecular stability or feasibility for device applications. Cibalackrot is a historic and stable organic dye which, although it has been suggested to have ideal energetics, does not undergo singlet fission due to large interchromophore distances, as suggested by single crystal analysis. Thus, while the energetic alignment is satisfactory, the molecule does not have the desired intermolecular coupling. Herein, we improve this characteristic through molecular engineering with the first synthesis of an aza-cibalackrot and show, using ultrafast transient spectroscopy, that singlet fission is successfully "turned on."

The translating bacterial ribosome at 1.55 Å resolution generated by cryo-EM imaging services

Our understanding of protein synthesis has been conceptualised around the structure and function of the bacterial ribosome. This complex macromolecular machine is the target of important antimicrobial drugs, an integral line of defence against infectious diseases. Here, we describe how open access to cryo-electron microscopy facilities combined with bespoke user support enabled structural determination of the translating ribosome from Escherichia coli at 1.55 Å resolution. The obtained structures allow for direct determination of the rRNA sequence to identify ribosome polymorphism sites in the E. coli strain used in this study and enable interpretation of the ribosomal active and peripheral sites at unprecedented resolution. This includes scarcely populated chimeric hybrid states of the ribosome engaged in several tRNA translocation steps resolved at ~2 Å resolution. The current map not only improves our understanding of protein synthesis but also allows for more precise structure-based drug design of antibiotics to tackle rising bacterial resistance.

Modulating Vascular Hemodynamics With an Alpha Globin Mimetic Peptide (HbαX)

The ability of hemoglobin to scavenge the potent vasodilator nitric oxide (NO) in the blood has been well established as a mechanism of vascular tone homeostasis. In endothelial cells, the alpha chain of hemoglobin (hereafter, alpha globin) and endothelial NO synthase form a macromolecular complex, providing a sink for NO directly adjacent to the production source. We have developed an alpha globin mimetic peptide (named HbαX) that displaces endogenous alpha globin and increases bioavailable NO for vasodilation. Here we show that, in vivo, HbαX administration increases capillary oxygenation and blood flow in arterioles acutely and produces a sustained decrease in systolic blood pressure in normal and angiotensin II-induced hypertensive states. HbαX acts with high specificity and affinity to endothelial NO synthase, without toxicity to liver and kidney and no effect on p50 of O₂ binding in red blood cells. In human vasculature, HbαX blunts vasoconstrictive response to cumulative doses of phenylephrine, a potent constricting agent. By binding to endothelial NO synthase and displacing endogenous alpha globin, HbαX modulates important metrics of vascular function, increasing vasodilation and flow in the resistance vasculature.

Recapitulation of metabolic defects in a model of propionic acidemia using patient-derived primary hepatocytes

BACKGROUND

Propionic acidemia (PA) is a disorder of intermediary metabolism with defects in the alpha or beta subunits of propionyl CoA carboxylase (PCCA and PCCB respectively) enzyme. We previously described a liver culture system that uses liver-derived hemodynamic blood flow and transport parameters to restore and maintain primary human hepatocyte biology and metabolism utilizing physiologically relevant milieu concentrations.

METHODS

In this study, primary hepatocytes isolated from the explanted liver of an 8-year-old PA patient were cultured in the liver system for 10 days and evaluated for retention of differentiated polarized morphology. The expression of PCCA and PCCB was assessed at a gene and protein level relative to healthy donor controls. Ammonia and urea levels were measured in the presence and absence of amino acid supplements to assess the metabolic consequences of branched-chain amino acid metabolism in this disease.

RESULTS

Primary hepatocytes from the PA patient maintained a differentiated polarized morphology (peripheral actin staining) over 10 days of culture in the system. We noted lower levels of PCCA and PCCB relative to normal healthy controls at the mRNA and protein level. Supplementation of branched-chain amino acids, isoleucine (5mM) and valine (5mM) in the medium, resulted in increased ammonia and decreased urea in the PA patient hepatocyte system, but no such response was seen in healthy hepatocytes or patient-derived fibroblasts.

CONCLUSIONS

We demonstrate for the first time the successful culture of PA patient-derived primary hepatocytes in a differentiated state, that stably retain the PCCA and PCCB enzyme defects at a gene and protein level. Phenotypic response of the system to an increased load of branched-chain amino acids, not possible with fibroblasts, underscores the utility of this system in the better understanding of the molecular pathophysiology of PA and examining the effectiveness of potential therapeutic agents in the most relevant tissue.

The second extracellular loop of the adenosine A1 receptor mediates activity of allosteric enhancers

Allosteric enhancers of the adenosine A1 receptor amplify signaling by orthosteric agonists. Allosteric enhancers are appealing drug candidates because their activity requires that the orthosteric site be occupied by an agonist, thereby conferring specificity to stressed or injured tissues that produce adenosine. To explore the mechanism of allosteric enhancer activity, we examined their action on several A1 receptor constructs, including (1) species variants, (2) species chimeras, (3) alanine scanning mutants, and (4) site-specific mutants. These findings were combined with homology modeling of the A1 receptor and in silico screening of an allosteric enhancer library. The binding modes of known docked allosteric enhancers correlated with the known structure-activity relationship, suggesting that these allosteric enhancers bind to a pocket formed by the second extracellular loop, flanked by residues S150 and M162. We propose a model in which this vestibule controls the entry and efflux of agonists from the orthosteric site and agonist binding elicits a conformational change that enables allosteric enhancer binding. This model provides a mechanism for the observations that allosteric enhancers slow the dissociation of orthosteric agonists but not antagonists.

Coordinated evolution of the hepatitis B virus polymerase

The detection of compensatory mutations that abrogate negative fitness effects of drug-resistance and vaccine-escape mutations indicates the important role of epistatic connectivity in evolution of viruses, especially under the strong selection pressures. Mapping of epistatic connectivity in the form of coordinated substitutions should help to characterize molecular mechanisms shaping viral evolution and provides a tool for the development of novel anti-viral drugs and vaccines. We analyzed coordinated variation among amino acid sites in 370 the hepatitis B virus (HBV) polymerase sequences using Bayesian networks. Among the HBV polymerase domains the spacer domain separating terminal protein from the reverse-transcriptase domain, showed the highest network centrality. Coordinated substitutions preserve the hydrophobicity and charge of Spacer. Maximum likelihood estimates of codon selection showed that Spacer contains the highest number of positively selected sites. Identification of 67% of the domain lacking an ordered structure suggests that Spacer belongs to the class of intrinsically disordered domains and proteins whose crucial functional role in the regulation of transcription, translation and cellular signal transduction has only recently been recognized. Spacer plays a central role in the epistatic network associating substitutions across the HBV genome, including those conferring viral virulence, drug resistance and vaccine escape. The data suggest that Spacer is extensively involved in coordination of HBV evolution.

Pathology and temporal onset of visual hallucinations, misperceptions and family misidentification distinguishes dementia with Lewy bodies from Alzheimer's disease

OBJECTIVE

To determine whether the temporal onset of visual phenomena distinguishes Lewy body disease (LBD) from Alzheimer's disease (AD), and to characterize the extent Lewy bodies and neurofibrillary tangles are associated with these clinical features.

METHODS

Consecutive cases of autopsy-confirmed LBD (n = 41), AD (n = 70), and AD with amygdala-predominant Lewy bodies (AD-ALB) (n = 14) with a documented clinical history of dementia were included. We mailed questionnaires to next-of-kin asking about symptoms during life. Lewy pathology and neurofibrillary tangle pathology were assessed.

RESULTS

The occurrence of visual hallucinations, misperceptions and family misidentification did not distinguish LBD from AD or AD-ALB, but the onset was earlier in LBD compared to AD and AD-ALB. When visual hallucinations developed within the first 5 years of dementia, the odds were 4-5 times greater for autopsy-confirmed LBD (or intermediate/high likelihood dementia with Lewy bodies) and not AD or AD-ALB. In LBD, limbic but not cortical Lewy body pathology was related to an earlier onset of visual hallucinations, while limbic and cortical Lewy body pathology were associated with visual misperceptions and misidentification. Cortical neurofibrillary tangle burden was associated with an earlier onset of misidentification and misperceptions in LBD and AD, but only with earlier visual hallucinations in AD/AD-ALB.

CONCLUSION

When visual hallucinations occur within the first 5 years of the dementia, a diagnosis of LBD was more likely than AD. Visual hallucinations in LBD were associated with limbic Lewy body pathology. Visual misperceptions and misidentification delusions were related to cortical Lewy body and neurofibrillary tangle burden in LBD and AD/AD-ALB.

Phase IB study of the combination of docetaxel, gemcitabine, and bevacizumab in patients with advanced or recurrent soft tissue sarcoma: the Axtell regimen

BACKGROUND

To assess the response of patients with soft tissue sarcoma (STS) to the combination of docetaxel, bevacizumab, and gemcitabine. Vascular endothelial growth factor (VEGF)-A levels and expression of VEGF-A and VEGF receptors 1 and 2 were evaluated.

PATIENTS AND METHODS

Thirty-eight chemotherapy-naive patients with STS were enrolled. A dose-finding study for gemcitabine from 1000, 1250, then 1500 mg/m(2) was done in nine patients (three cohorts), followed by an expansion cohort of 27 patients. Dose of docetaxel was 50 mg/m(2), bevacizumab was 5 mg/kg, and gemcitabine was 1500 mg/m(2), every 2 weeks. Serum VEGF-A was measured by enzyme-linked immunosorbent assay and tissue VEGF-A and its receptors by immunohistochemistry.

RESULTS

The median follow-up was 36 months. The overall response rate observed was 31.4%, with 5 complete and 6 partial responses, and 18 stable diseases lasting for a median of 6 months. There was no significant hematologic toxicity. The adverse events with the highest grade were attributed to bevacizumab. There was no correlation of VEGF pathway biomarkers with outcome.

CONCLUSIONS

The combination of gemcitabine, docetaxel, and bevacizumab is safe and effective in patients with STS. The most concerning adverse events were consequences of bevacizumab administration. The benefit of bevacizumab in this patient population remains unclear.

Phase I/II study of docetaxel (D), gemcitabine (G), and bevacizumab (B) in patients (pts) with advanced or recurrent soft tissue sarcoma (STS)

10056

Background: The combination of G and D has shown efficacy against refractory STS (Hensley, JCO 2002). STS have a high content of VEGF, which is associated with poor prognosis. This phase I/II study assesses the safety, tolerability, efficacy, and pharmacodynamics (PD) of B in combination with G+D, given on a two-weekly schedule to minimize adverse events (AEs). We are reporting the phase I results. Methods: Untreated pts with advanced or recurrent STS and ECOG PS =2 were eligible. Some pts were treated in a neoadjuvant setting, when surgically appropriate. Planned doses were G 1,000, 1,250, and 1,500 mg/m2, D 50 mg/m2, and B 5 mg/kg iv, every 2 wks. G doses were escalated in serial pt cohorts to determine the maximum tolerated dose (MTD) of G with fixed doses of D and B. MTD was assessed on the first 2 cycles (1 cycle = 2 wks). Treatment was continued until progression or unacceptable toxicity. For neoadjuvant therapy, B was given only for 4 cycles, followed by 4 cycles without B in anticipation of surgery and pts came off study at that point. PD and antitumor efficacy were also assessed. Results: Nine pts have been treated on the phase I escalation arm, including 3 in the neoadjuvant setting. There were no dose limiting toxicities. After 4 cycles with G at 1,500 mg/m2, there was 1 asymptomatic grade 4 bowel perforation at the site of the tumor in a pt with initially inoperable leiomyosarcoma (LMS). After emergency surgery, the pt is free of disease. Observed grade 1 and 2 AEs include alopecia, diarrhea, fatigue (5 each), rigors (4), nausea, dyspnea, headaches (3 each), chest pain, epistaxis, stomatitis, anemia (2 each), rash, hypertension, neuropathy, leukopenia (1 each). There were 1 CR (angiosarcoma), 2 PR, (myxoid sarcoma, undifferentiated sarcoma), 4 NC (2 LMS, liposarcoma, PNST), and 2 PD (myxoid sarcoma, PNST). Necrosis was observed, including in NC disease. Three pts are free of disease after surgery. Conclusions: The combination of G, D, and B given every 2 weeks is safe and has demonstrated some activity in pts with advanced or recurrent STS. The phase II arm is ongoing at G 1,500 mg/m2 with 4 pts already enrolled. Mature data including PD will be reported at the meeting.

No significant financial relationships to disclose.

Prevalence and screening costs of hepatitis C virus among Ugandan blood donors

BACKGROUND

Screening donated blood for hepatitis C virus (HCV) is important for HCV prevention and is routinely practiced in North America and Europe. However, in many African countries little is known about HCV prevalence or cost-effectiveness of HCV antibody (anti-HCV) screening.

METHODS

We investigated 2592 plasma specimens collected consecutively from blood donors in central Uganda in 1999. Routine screening by the blood bank included human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), and syphilis. To assess HCV prevalence and cost-effectiveness of testing, specimens were additionally tested for anti-HCV IgG by enzyme immunosorbent assay (EIA). Specimens repeatedly reactive (RR) on EIA were tested with a recombinant immunoblot assay (RIBA).

RESULTS

Overall, 107 (4.1%) specimens were HCV EIA RR. Fifteen EIA RR specimens (0.6%, 95% confidence interval = 0.3-0.9%) were RIBA positive and 47 (1.8%) were RIBA indeterminate. Most (80%) RIBA-positive specimens were non-reactive for HIV, HBsAg, and syphilis. RIBA positivity was not associated with donor age, sex, number of donations, HIV, or HBsAg positivity. Costs of screening donors for anti-HCV by using EIA were estimated at US Dollars 782 per potential transfusion-associated HCV infection (exposure to RIBA-positive blood) averted.

CONCLUSIONS

Current screening tests for other infections are ineffective in removing HCV-positive donations. Testing costs are considerable; cost-effectiveness of identifying HCV-infected donors will be critical in decision making about HCV screening in Uganda.

Prevalence of cryoglobulinemia in hepatitis C virus (HCV) positive patients with and without human immunodeficiency virus (HIV) coinfection

BACKGROUND

Coinfection with human immunodeficiency virus (HIV) has been shown to influence the natural history of hepatitis C infection.

OBJECTIVE

Our interest was to determine if HIV coinfection influences the prevalence of cryoglobulinemia in hepatitis C virus (HCV) infected persons.

STUDY DESIGN

A total of 384 HCV RNA positive (234 HIV-infected and 150 HIV-uninfected) participants were tested at two visits, 18 months apart, for HCV and HIV RNA, CD4, and liver enzyme levels. Serum cryoglobulin levels were measured at a subsequent visit for a subset of the sample.

RESULTS

HIV-infected participants had significantly higher HCV RNA levels (P < 0.0001) and aspartate transaminase (AST) levels (P < 0.0001), but not alanine transaminase (ALT) levels (P > 0.05) as compared with HIV-uninfected participants. These findings were consistent at both visits and no significant changes were observed between visits. Fifty (19%) of the 264 participants tested had detectable cryoglobulins. No difference was observed in HIV seropositivity among participants with or without cryoglobulinemia (68% versus 61%; odds ratio = 1.34, P = 0.37). However, among HIV coinfected participants, elevated AST levels (P = 0.04) and lower CD4 levels (P = 0.02) were associated with cryoglobulinemia.

CONCLUSIONS

While previously reported associations were found between HIV and coinfection with HCV in this study, we did not find an association between HIV infection and cryoglobulinemia.

Preliminary crystallographic analysis of the complex of the human GTPase RhoA with the DH/PH tandem of PDZ-RhoGEF

PDZ-containing RhoGEF (PDZ-RhoGEF) is a multidomain protein composed of 1522 amino acids that belongs to the guanine nucleotide exchange factors family (GEF) active on Rho GTPases. It is highly specific for RhoA and is thought to transduce signals from Galpha(12/13)-coupled receptors to the RhoA-dependent regulatory cascades. The protein shows high sequence homology to LARG, p115-RhoGEF and Drosophila DRhoGEF2. The exchange reaction is catalyzed by a DH domain, which is directly downstream of a PH domain in all known Rho-specific GEFs. The DH/PH tandem of PDZ-RhoGEF and C-terminally truncated RhoA were overexpressed in Escherichia coli as TEV protease-cleavable fusion proteins containing GST and a hexahistidine tag at the N-termini, respectively. The nucleotide-free DH/PH-RhoA complex was purified by gel filtration and crystallized. The crystals belong to space group P2(1), with unit-cell parameters a = 88.6, b = 119.0, c = 91.5 A, beta = 114.7 degrees.

Sequence heterogeneity of TT virus and closely related viruses

TT virus (TTV) is a recently discovered infectious agent originally obtained from transfusion-related hepatitis. However, the causative link between the TTV infection and liver disease remains uncertain. Recent studies demonstrated that genome sequences of different TTV strains are significantly divergent. To assess genetic heterogeneity of the TTV genome in more detail, a sequence analysis of PCR fragments (271 bp) amplified from open reading frame 1 (ORF1) was performed. PCR fragments were amplified from 5 to 40% of serum specimens obtained from patients with different forms of hepatitis who reside in different countries (e.g., China, Egypt, Vietnam, and the United States) and from normal human specimens obtained from U.S. residents. A total of 170 PCR fragments were sequenced and compared to sequences derived from the corresponding TTV genome region deposited in GenBank. Genotypes 2 and 3 were found to be significantly more genetically related than any other TTV genotype. Moreover, three sequences were shown to be almost equally related to both genotypes 2 and 3. These observations suggest a merger of genotypes 2 and 3 into one genotype, 2/3. Additionally, five new groups of TTV sequences were identified. One group represents a new genotype, whereas the other four groups were shown to be more evolutionary distant from all known TTV sequences. The evolutionary distances between these four groups were also shown to be greater than between TTV genotypes. The phylogenetic analysis suggested that these four new genetic groups represent closely related yet different viral species. Thus, TTV exists as a "swarm" of at least five closely related but different viruses. These observations suggest a high degree of genetic complexity within the TTV population. The finding of the additional TTV-related species should be taken into consideration when the association between TTV infections and human diseases of unknown etiology is studied.

Expression of the hepatitis E virus ORF1

Hepatitis E virus (HEV) is an unclassified, plus-strand RNA virus whose genome contains three open reading frames (ORFs). ORF1, the 5' proximal ORF of HEV, encodes nonstructural proteins involved in RNA replication which share homology with the products of the corresponding ORF of members of the alphavirus-like superfamily of plus-strand RNA viruses. Among animal virus members of this superfamily (the alphavirus and rubivirus genera of the family Togaviridae), the product of this ORF is a nonstructural polyprotein (NSP) that is cleaved by a papain-like cysteine protease (PCP) within the NSP. To determine if the NSP of HEV is similarly processed, ORF1 was introduced into a plasmid vector which allowed for expression both in vitro using a coupled transcription/translation system and in vivo using a vaccinia virus-driven transient expression system. A recombinant vaccinia virus expressing ORF1 was also constructed. Both in vitro and in vivo expression under standard conditions yielded only the full-length 185 kDa polyprotein. Addition of co-factors in vitro, such as divalent cations and microsomes which have been shown to activate other viral proteases, failed to change this expression pattern. However, in vivo following extended incubations (24-36 hours), two potential processing products of 107 kDa and 78 kDa were observed. N- and C-terminus-specific immunoprecipitation and deletion mutagenesis were used to determine that the order of these products within the NSP is NH2-78 kDa-107 kDa-COOH. However, site-specific mutagenesis of Cys483, predicted by computer alignment to be one member of the catalytic dyad of a PCP within the NSP, failed to abolish this cleavage. Additionally, sequence alignment across HEV strains revealed that the other member of the proposed catalytic dyad of this PCP, His590, was not conserved. Thus, the cleavage of the NSP observed following prolonged in vivo expression was not mediated by this protease and it is doubtful that a functional PCP exists within the NSP. Attempts to detect NSP expression and processing in HEV-infected primary monkey hepatocytes were not successful and therefore this proteolytic cleavage could not be authenticated. Overall, the results of this study indicate that either the HEV NSP is not processed or that it is cleaved at one site by a virally-encoded protease novel among alpha-like superfamily viruses or a cellular protease.

Artificial NS4 mosaic antigen of hepatitis C virus

An artificial antigen composed of 17 small antigenic regions derived from the NS4-protein of hepatitis C virus (HCV) genotypes 1 through 5 was designed and constructed. Eleven antigenic regions were derived from the 5-1-1 region, and 6 others were derived from the C-terminus of the NS4-protein of different genotypes. The gene encoding for this artificial antigen was assembled from synthetic oligonucleotides by a new approach designated as restriction enzyme-assisted ligation (REAL). The full-length synthetic gene was expressed in Escherichia coli as a fusion protein with glutathione S-transferase. By the use of site-specific antibodies raised against synthetic peptides, it was shown that all regions for which sequence-specific antibodies were obtained were accessible to antibody binding. The diagnostic relevance of the NS4 artificial antigen was demonstrated by testing this antigen with 4 HCV seroconversion panels and a panel of previously tested and stored serum specimens. The artificial antigen was found to specifically detect anti-NS4 antibodies in a number of specimens that were previously found to be anti-NS4 negative. Furthermore, this antigen detected anti-NS4 activity earlier in 2 of 4 seroconversion panels than did the antigen used in a commercially available supplemental assay. Equally important is the observation that the artificial NS4 antigen demonstrated equivalent anti-NS4 immunoreactivity with serum specimens obtained from patients infected with different HCV genotypes, whereas the NS4 recombinant protein derived from genotype 1, used in the commercial supplemental test, was less immunoreactive with serum specimens containing HCV genotypes 2, 3, and 4. Collectively, these data support the significant diagnostic potential of the NS4 mosaic antigen. The strategy employed in this study may be applied to the design and construction of other artificial antigens with improved diagnostically pertinent properties. J. Med. Virol. 59:437-450 1999.

The Dysphagia Outcome and Severity Scale

The Dysphagia Outcome and Severity Scale (DOSS) is a simple, easy-to-use, 7-point scale developed to systematically rate the functional severity of dysphagia based on objective assessment and make recommendations for diet level, independence level, and type of nutrition. Intra- and interjudge reliabilities of the DOSS was established by four clinicians on 135 consecutive patients who underwent a modified barium swallow procedure at a large teaching hospital. Patients were assigned a severity level, independence level, and nutritional level based on three areas most associated with final recommendations: oral stage bolus transfer, pharyngeal stage retention, and airway protection. Results indicate high interrater (90%) and intrarater (93%) agreement with this scale. Implications are suggested for use of the DOSS in documenting functional outcomes of swallowing and diet status based on objective assessment.

Humanist ideology and nurse education. I. Humanist educational theory

Nurse education is dominated by the humanist perspective and the educational theory that it generates. Following a brief description of the perspective's phenomenological foundations and definition of humanist ideology, humanist educational theory is illustrated in an outline of the key contributions of John Dewey, Carl Rogers, Malcolm Knowles and Paulo Freire. The article concludes by noting Freire's sociological challenge to the individualism of the humanist perspective. This challenge recognizes the ideological and social control role of education in securing the reproduction of power relations and leads to questioning the function of individualism and the interests that humanist ideology may serve.

Humanist ideology and nurse education. 2. Limitations of humanist educational theory in nurse education

This article questions the viability of humanist educational theory in nurse education and raises the issue of which interests are served by humanist ideology. The limitations of the humanist approach are traced. Self-directed learning is shown to be problematic in nurse education, leading to tensions between independent learning and required course content, and the appropriateness of student-centred learning to the professional education of nurses is queried. The need to produce safe practitioners compromises the humanist model. Lifelong learning, for example, becomes institutionalized, and its self-directed character transformed into a mandatory process of lifelong professional education. The humanist model has become the new orthodoxy in nurse education and operates as a form of social control. Through its individualism the approach supports a competency model, which in turn restricts the potential diversity of 'product'. This individualistic bias denies the social reality of nursing and fails to empower the nurse by emphasizing individual growth at the expense of social learning. The article concludes that humanist ideology serves the needs of a free-market philosophy. If nurse education is to be challenging it must break with individualism and seek to develop a different rationale, that of a collectivist ideology.

The problem of self-assessment in nurse education

Nurse education is expected to fulfil two functions: the facilitation of individual personal development and professional selection. The need to produce competent nurses compromises the facilitation of personal development. This is reflected in the minor role assigned to self-assessment in preregistration nurse education. The problematic nature of self-assessment in nurse education is illustrated through a discussion of three issues: self-assessment and power, self-assessment and stereotyping and self-assessment and context.

Nurse education and the impact of professionalisation

This article asks what kind of educational process nurse education can follow. Educational theory offers two views; the rationalist and the humanist perspectives. Both involve problems for nurse education. Professionalisation is identified as the major force determining the educational process in nurse education. It prevents progressive humanist education and reinforces traditional rationalist education. This process continues with integration into higher education. Professionalisation must be abandoned as an occupational strategy, if an alternative educational process is to be developed in nurse education.

Hepatitis C and E in non-A non-B fulminant hepatic failure: a polymerase chain reaction and serological study

A significant proportion of patients with fulminant hepatic failure have clinical, biochemical and histological features suggestive of acute viral hepatitis, without serological evidence of either hepatitis A or B. The contribution of hepatitis C to such cases of non-A non-B fulminant hepatic failure is presently uncertain while hepatitis E is well recognized as a cause of fulminant hepatic failure in endemic areas. Nested polymerase chain reaction for detection of both hepatitis C and E virus as well as two serological assays for anti-hepatitis C virus and anti-hepatitis E virus western blotting (both IgG and IgM) were performed on acute sera of 42 consecutive cases of non A, non B-fulminant hepatic failure and on convalescent sera of 17 of 20 patients who underwent orthotopic liver transplantation. Fresh liver tissue, obtained at the time of transplantation, was also studied by polymerase chain reaction in eight cases. Evidence of an acute hepatitis E virus infection (hepatitis E virus RNA amplified from serum by polymerase chain reaction or serum IgM positive to western blot) was found in eight patients. One patient had anti-HCV at presentation but assays on later sera proved negative. Convalescent sera and sera obtained after orthotopic liver transplantation were all negative to both anti-HCV assay systems, but HCV RNA was not found in either serum or liver tissue in any case.(ABSTRACT TRUNCATED AT 250 WORDS)

Transplantation of enriched CD34-positive autologous marrow into breast cancer patients following high-dose chemotherapy: influence of CD34-positive peripheral-blood progenitors and growth factors on engraftment

PURPOSE

To evaluate the capacity of enriched CD34-positive (CD34+) progenitor cells to reconstitute hematopoiesis in poor-prognosis breast cancer patients following administration of a high-dose alkylating agent chemotherapy regimen.

PATIENTS AND METHODS

Forty-four breast cancer patients received high-dose chemotherapy followed by autologous bone marrow support (ABMS) with CD34+ hematopoietic progenitor cells in five sequentially treated cohorts. Following infusion of CD34+ marrow, cohort no. 1 received no growth factor, cohort no. 2 received granulocyte colony-stimulating factor (G-CSF), and cohort no. 3 received granulocyte-macrophage colony-stimulating factor (GM-CSF). Cohort no. 4 received the CD34+ fractions of both marrow and peripheral-blood progenitor cells (PBPCs) plus G-CSF. Cohort no. 5 received only the CD34+ PBPCs plus G-CSF. Immunohistochemical staining for breast cancer was performed on all hematopoietic cell products before and after the positive selection procedure, to assess quantitatively the level of tumor-cell contamination.

RESULTS

Cohorts no. 1, 2, 3, 4, and 5 achieved a granulocyte count > or = 500 x 10(9)/L in a median of 23, 10, 16, 11, and 11 days, with a platelet count greater than 20,000 x 10(9)/L documented in a median of 22, 23, 32, 12, and 10 days, respectively. The time to granulocyte reconstitution was significantly shorter for patients who received CD34+ PBPCs alone (cohort no. 5), or in combination with CD34+ marrow (cohort no. 4), when compared with those who received only the CD34+ marrow fraction (P < .01). From 1 to greater than 4 logs of breast cancer cell depletion were documented after CD34-selection, for patients in whom tumor was initially detected.

CONCLUSION

CD34+ marrow and/or PBPCs provide reliable and timely hematopoietic reconstitution in breast cancer patients receiving high-dose chemotherapy. Contamination of both marrow and PBPCs with breast cancer cells was reduced using this positive selection technique.

New strategies in marrow purging for breast cancer patients receiving high-dose chemotherapy with autologous bone marrow transplantation

High-dose chemotherapy and autologous bone marrow transplantation (ABMT) are commonly used to treat selected patients with high-risk breast cancer. A limitation of ABMT is that clonogenic cancer cells could be collected with the bone marrow and produce a relapse of diseases when reinfused into patients. Purging the marrow ex vivo may eliminate the tumor cells, but it can also delay engraftment. We employed two different purging methods whereby breast cancer cells were depleted without delaying engraftment. The addition of WR-2721 (amifostine) to 4-hydroperoxycyclophosphamide (4-HC) reduced the time to engraftment by 10 days compared with marrow purged with 4-HC alone (26 versus 37 days, respectively). The positive selection of CD34+ hematopoietic progenitors produced engraftment within 21 days. The use of granulocyte colony-stimulating factor (G-CSF) accelerated the engraftment time of CD34+ hematopoietic progenitors to 11 days.

Respiratory epithelial cells masquerading as agents of primary amebic meningoencephalitis: distinguishing features

CSF does not normally contain motile cells within flagella or cilia. When motile cells are seen in the CSF, they may be incorrectly assumed to be amebae. We studied a patient with a traumatic mucocele, in whom motile ciliated respiratory epithelial cells were seen in the CSF and within a frontal lobe brain abscess.

Cloning of the bluetongue virus L3 gene

The genes of the bluetongue virus (BTV) serotype 17 have been cloned into pBR322 by tailing both strands of the double-stranded RNA with polyadenylic acid, transcribing them with reverse transcriptase with an oligodeoxythymidylic acid primer, hybridizing the cDNA products, and completing them into duplex structures with the Klenow fragment of Escherichia coli DNA polymerase. After cloning the double-stranded cDNA molecules into pBR322, the complete sequence of the cloned L3 gene was determined. The clone is 2,772 nucleotides long (1.78 X 10(6) daltons), excluding the 3' polyadenylic acid sequence, and has an open reading frame which codes for a protein of some 901 amino acids (103,412 daltons). This clone can hybridize L3 RNA segments of three other U.S. BTV serotypes, BTV-10, -11, and -13 in addition to -17 but not the equivalent RNA segment of epizootic hemorrhagic disease virus of deer, an orbivirus related to BTV.