The extremely low energy cost of biosynthesis in holometabolous insect larvae

The metabolic cost of growth, which quantifies the amount of energy required to synthesize a unit of biomass, is an important component of an animal's ontogenetic energy budget. Here we investigated this quantity as well as other energy budget variables of the larvae of a holometabolous insect species, Vanessa cardui (painted lady). We found that the high growth rate of this caterpillar cannot be explained by its metabolic rate and the percentage of the metabolic energy allocated to growth; the key to understanding its fast growth is the extremely low cost of growth, 336 Joules/gram of dry mass. The metabolic cost of growth in caterpillars is 15-65 times lower than that of the endothermic and ectothermic species investigated in previous studies. Our results suggest that the low cost cannot be attributed to its body composition, diet composition, or body size. To explain the "cheap price" of growth in caterpillars, we assumed that a high metabolic cost for biosynthesis resulted in a high "quality" of cells, which have fewer errors during biosynthesis and higher resistance to stressors. Considering the life history of the caterpillars, i.e., tissue disintegration during metamorphosis and a short developmental period and lifespan, we hypothesized that an energy budget that allocates a large amount of energy to biosynthesizing high quality cells would be selected against in this species. As a preliminary test of this hypothesis, we estimated the metabolic cost of growth in larvae of Manduca sexta (tobacco hornworm) and nymphs of Blatta lateralis (Turkestan cockroach). The preliminary data supported our hypothesis.

Methyl-substitution of an iminohydantoin spiropiperidine β-secretase (BACE-1) inhibitor has a profound effect on its potency

The IC50 of a beta-secretase (BACE-1) lead compound was improved ∼200-fold from 11 μM to 55 nM through the addition of a single methyl group. Computational chemistry, small molecule NMR, and protein crystallography capabilities were used to compare the solution conformation of the ligand under varying pH conditions to its conformation when bound in the active site. Chemical modification then explored available binding pockets adjacent to the ligand. A strategically placed methyl group not only maintained the required pKa of the piperidine nitrogen and filled a small hydrophobic pocket, but more importantly, stabilized the conformation best suited for optimized binding to the receptor.

Travel-related chikungunya cases in Canada, 2014

Since the spring of 2014, there has been a large increase in travel-related chikungunya cases diagnosed in Canada. As of December 9, 2014, 320 confirmed and 159 probable cases have been diagnosed in Canada, with the majority of provinces identifying at least one imported case. This surge in Canadian infections has been associated with the incursion of chikungunya virus into the Caribbean and the expansion of the virus in the Americas. Ongoing outbreaks in the Asia-Pacific region have also contributed to imported cases among Canadian travellers. Heightened awareness of chikungunya among clinicians is key to diagnosis. This highlights the need to ask for a travel history from anyone who presents with fever or recent onset of polyarthralgia, and to consider testing by provincial laboratories and the National Microbiology Laboratory for chikungunya virus and other diseases as indicated. Also essential is continued communication with travellers regarding the use of preventative measures to decrease the risk of exposure to mosquitoes when travelling to endemic areas.

Irrational use of antibiotics and role of the pharmacist: an insight from a qualitative study in New Delhi, India

WHAT IS KNOWN AND OBJECTIVE

The overall volume of antibiotic consumption in the community is one of the foremost causes of antimicrobial resistance. In developing countries like India, pharmacists often dispense 'prescription-only' drugs, like antibiotics, to patients who do not have a prescription. Not much data is available regarding detailed information on behaviour of antibiotic use by community pharmacists which is of particular significance to develop a suitable and sustainable intervention programme to promote rational use of antibiotics. A qualitative study was conducted to understand the dispensing practices and behaviour of community pharmacists to develop policy interventions that would improve the use of antibiotics at the community level.

METHODS

Focus group discussions (FGDs) were held for five municipal wards of Delhi with retail pharmacists, public sector pharmacists and the office bearers of pharmacists' associations. Data on antibiotic use and resistance were collected earlier from these five wards. FGDs (n = 3 with 40 pharmacists) were analysed through grounded theory.

RESULTS AND DISCUSSION

Four broad themes identified were as follows: prescribing and dispensing behaviour; commercial interests; advisory role; and intervention strategies for rational use of antibiotics. FGDs with pharmacists working in the public sector revealed that, besides the factors listed above, overstock and near-expiry, and under-supply of antibiotics promoted antibiotic misuse. Suggestions for interventions from pharmacists were the following: (i) education to increase awareness of rational use and resistance to antibiotics; (ii) involving pharmacists as partners for creating awareness among communities for rational use and resistance to antibiotics; (iii) developing an easy return policy for near-expiry antibiotics in public sector facilities; and (iv) motivating and showing appreciation for community pharmacists who participate in intervention programmes.

WHAT IS NEW AND CONCLUSIONS

Inappropriate antibiotic dispensing and use owing to commercial interests and lack of knowledge about the rational use of antibiotics and antibiotic resistance were the main findings of this in-depth qualitative study. Community pharmacists were willing to participate in educational programme aimed at improving use of antibiotics. Such programmes should be initiated within a multidisciplinary framework including doctors, pharmacists, social scientists, government agencies and non-profit organizations.

Effect of Oxygen Exposure and Deposition Environment on Thermal Stability of Ta Barriers To Cu Penetration

The effect of deposition pressure and controlled oxygen dosing on the diffusion barrier performance of thin film Ta to Cu penetration was investigated. In-situ resistivity, Auger compositional profiling, scanning electron microscopy and cross-sectional transmission electron microscopy were used to determine the electrical, chemical and structural changes that occur in Cu/Ta bilayers on Si upon heating. A 20 nm Ta barrier allowed the penetration of Cu at temperatures ranging from 320 to 630°C depending on processing conditions. Barrier failure temperature is dependent upon the deposition pressure and oxygen contamination at the Ta/Cu interface. This indicates the importance of understanding how deposition conditions affect diffusion barrier performance.

Blood-brain barrier-specific properties of a human adult brain endothelial cell line

Establishment of a human model of the blood-brain barrier has proven to be a difficult goal. To accomplish this, normal human brain endothelial cells were transduced by lentiviral vectors incorporating human telomerase or SV40 T antigen. Among the many stable immortalized clones obtained by sequential limiting dilution cloning of the transduced cells, one was selected for expression of normal endothelial markers, including CD31, VE cadherin, and von Willebrand factor. This cell line, termed hCMEC/D3, showed a stable normal karyotype, maintained contact-inhibited monolayers in tissue culture, exhibited robust proliferation in response to endothelial growth factors, and formed capillary tubes in matrix but no colonies in soft agar. hCMEC/D3 cells expressed telomerase and grew indefinitely without phenotypic dedifferentiation. These cells expressed chemokine receptors, up-regulated adhesion molecules in response to inflammatory cytokines, and demonstrated blood-brain barrier characteristics, including tight junctional proteins and the capacity to actively exclude drugs. hCMEC/D3 are excellent candidates for studies of blood-brain barrier function, the responses of brain endothelium to inflammatory and infectious stimuli, and the interaction of brain endothelium with lymphocytes or tumor cells. Thus, hCMEC/D3 represents the first stable, fully characterized, well-differentiated human brain endothelial cell line and should serve as a widely usable research tool.

Monoclonal Antibody to Single-Stranded DNA: A Potential Tool for DNA Repair Studies

Growing evidence suggests that DNA repair capacity is an important factor in cancer risk and is therefore essential to assess. Immunochemical assays are amenable to the detection of repair products in complex matrices, such as urine, facilitating noninvasive measurements, although diet and extra-DNA sources of lesion can confound interpretation. The production of single-stranded, lesion-containing DNA oligomers characterises nucleotide excision repair (NER) and hence defines the repair pathway from which a lesion may be derived. Herein we describe the characterisation of a monoclonal antibody which recognises guanine moieties in single-stranded DNA. Application of this antibody in ELISA, demonstrated such oligomers in supernatants from repair-proficient cells post-insult. Testing of urine samples from volunteers demonstrated a relationship between oligomer levels and two urinary DNA damage products, thymine dimers and 8-oxo-2'-deoxyguanosine, supporting our hypothesis that NER gives rise to lesion-containing oligomers which are specific targets for the investigation of DNA repair.

Does breastfeeding protect children from asthma? Analysis of NHANES III survey data

We sought to determine whether breastfeeding (yes/no) or its duration protects against the development of childhood asthma, its severity or age of onset. We conducted a secondary analysis of youth files of the National Health and Nutrition Examination Survey III (1988-94), and reviewed data from 6,783 children age 2 months to 6 years (3,316 breastfed), excluding children with a history of low birth weight or treatment in a neonatal intensive care unit. Study participants were breastfed an average of 157 days. The average age at onset of asthma was 14.3 months. In the logistic regression model, "ever breast-fed" was not a significant protective factor for developing asthma. Significant predictive factors were the mother's age at child's birth (beta = -0.08, p < 0.01), and a parent having asthma or hayfever (beta = 0.46, p < 0.01). In the linear regression model, the duration of breastfeeding was not a predictor for age at onset of asthma (beta = 0.01, p = 0.53). Only maternal smoking during pregnancy was a significant predictor of age at onset of asthma (beta = -7.59, p < 0.01). Breastfeeding does not appear to prevent asthma, delay its onset, or reduce its severity. However, breastfeeding is still recommended for its many other benefits.

The future for nursing education: UKCC review has relevance for New Zealand

The strategic review of undergraduate nursing education recently commissioned by the Nursing Council of New Zealand (NCNZ) will provide a focus for nursing education in Aotearoa/New Zealand in the immediate future. Recently the United Kingdom Central Council for Nursing, Midwifery and Health Visiting (UKCC) completed its own review of undergraduate nursing education. The published report 'Fitness for Practice', has many areas of relevance for New Zealand educators in outlining possible strategies for nursing education. Issues such as recruitment and access to education; retention; clinical assessment and placements; clinical skill acquisition and partnership are valid concerns for educators here also. Internationally the commonalties in issues of concern are remarkable and lend validity to the concept of the global village and the necessity for a global perspective in health care workforce planning, including educational preparation. Discussion of some of the recommendations informs nursing education of the possibilities for forward progress in these times of continual change in health care delivery systems.

Tretinoin-induced sticky skin: a case report and review of the literature

Sticky skin has been reported relatively infrequently in the literature in association with etretinate and doxorubicin/ketoconazole administration. It has a poorly understood pathogenesis, and the associated histologic changes have not been described. We report a case of a patient who experienced sticky skin in areas treated with tretinoin. These reverted to normal after cessation of treatment. In comparison to a biopsy taken while the skin was not sticky, the histologic findings included a thickened, compact stratum corneum and granulosum. The basal epithelial cells showed proliferation with slight crowding and a tall, columnar shape. To our knowledge, this is the first report of sticky skin occurring in response to topical retinoid application. We suggest that the histologic changes observed could represent a modified keratin maturation profile.

Developing an evidence base for teaching nursing practice skills in an undergraduate nursing program

There is international concern over inadequate levels of nursing practice skill acquisition in undergraduate programs. Preparation of student nurses in nursing practice skills prior to clinical placements reduces cognitive dissonance, enhances cognitive flexibility and thus facilitates skill acquisition. This research was a contextually modified replication of the work of Alavi, Loh & Reilly (1991) in determining an evidence basis for selecting content for the clinical skills curriculum in an undergraduate programme. Thirty-three senior nurse clinicians from medical/surgical areas in two large hospitals offering student placements were asked to rate the frequency of performance (frequently, occasionally, rarely and never) of 77 skills for the beginning registered nurse. Those skills frequently used and rated over 65% were considered for inclusion in the undergraduate program--yielding 26 nursing practice skills. The clinicians were also asked to list their ten most important skills and the related expected level of competence for the newly registered nurse in order to aid development of a practical skills curriculum for the undergraduate nursing program at Whitireia Community Polytechnic. The research has provided an illuminating glimpse into the world of practice for a newly registered nurse. Future study of the expectations the new graduates have for themselves compared to those of the clinicians would be useful. Further exploration and dialogue between clinicians and faculty could be enhanced through consideration of faculty expectations of the newly graduated nurse and comparison of the three groups as a whole.

Hostility is associated with a low prolactin response to meta-chlorophenylpiperazine in abstinent alcoholics

The prolactin response to the administration of serotonin agonists is an index of central nervous system serotonin (5HT) activity. This index is blunted in association with hostile aggression in personality-disordered individuals without substance abuse. We tested whether prolactin response to the partial 5HT agonist meta-chlorophenylpiperazine (MCPP) (0.35 mg/kg po) was associated with measures of trait hostility in alcoholics who were completing a 3-week rehabilitation program after medical detoxification. We also tested whether the same 5HT index differed in the group of alcoholics compared with the healthy volunteers. The prolactin response to MCPP was inversely associated with the main index of trait hostility and was similarly inversely associated with an index of depression. There was, however, no difference in neuroendocrine or temperature responses to MCPP between the alcohol-dependent group and the healthy volunteers.

Early identification of communication problems

Questions have been raised about the effectiveness of routine early screening of children's speech development. Mary Gale et al describe an innovative package which can be used by health visitors and parents to ensure they correctly identify those children needing referral for specialist intervention.

Morbidity risk for alcoholism and drug abuse in relatives of cocaine addicts

The morbidity risks for alcoholism in the first-degree relatives of a cohort of male cocaine addicts with or without alcoholism comorbidity were studied. Of the 71 patients who participated in our study, 40 (56.3%) had a history of alcoholism and 37 (59.1%) a history of opioid abuse. Twenty-two patients (30.1%) also met criteria for a lifetime diagnosis of a major psychiatric disorder. Significant increases in morbidity risks for alcoholism were found among male relatives of cocaine addicts with comorbid alcohol dependence when compared with relatives of cocaine addicts with no alcohol comorbidity. Among fathers, risks were .69 vs .32 (z = 2.98, p < .003). Among brothers, risks were .38 vs .15 (z = 2.35, p < .03). Significantly increased risks were also observed in male relatives when probands with a psychiatric diagnosis were excluded from the analyses. Among female relatives, increases in morbidity risks were found but they failed to reach statistical significance. Two interpretations are consistent with these findings. One of these interpretations is that alcoholism is a disorder distinct from other addictions and has its own mode of transmission. The second interpretation is that the transmission of substance use disorders lacks specificity and that the substances selected are influenced by sociocultural or biological factors.

Auditory event-related potentials in HIV-1 infection: a study in the drug-user risk group

Features of event-related potentials (ERPs) may be sensitive and clinically useful markers of central nervous system infection by the human immunodeficiency virus (HIV-1); however, this application has not been studied in the risk group of intravenous drug users. Auditory ERPs generated by an "oddball" paradigm were analyzed for 39 male drug abusers as part of a multimodal assessment. Stage of HIV-1 infection was associated with prolongations of P1, N1, and P3 components of the ERP waveform. Only patients with full acquired immunodeficiency syndrome showed statistically significant increases in waveform prolongations. Specific neuropsychological deficits were not related to waveform latency prolongations.

T-cell activation defect in common variable immunodeficiency: restoration by phorbol myristate acetate (PMA) or allogeneic macrophages

Common variable immunodeficiency (CVI) represents a group of familial and sporadic diseases characterized by a range of B-cell, T-cell, and macrophage defects. A defect in T-cell activation, involving reduced proliferation and IL-2 production after stimulation with OKT3 antibody, has been described previously. In the present study we found that these defects could be corrected in vitro by adding phorbol myristate acetate (PMA) to OKT3-stimulated peripheral blood mononuclear cells (PBMC) of 14 patients with CVI. PBMC of 6 out of 7 patients with CVI studied also exhibited a profound defect in IL-2 receptor expression when incubated with OKT3 antibody. IL-2 receptor expression after stimulation with PMA alone was normal, indicating that the OKT3- but not the PMA-induced pathway of IL-2 receptor expression was defective. On the RNA level, the genes for IL-2 and IL-2 receptor were expressed after stimulation with OKT3 antibody. IL-2 and IL-2 receptor gene expression were normal, indicating a possible post-transcriptional defect. To investigate whether the defect in T-cell activation was at the macrophage or the T-cell level, we prepared adherent cells and monocyte-depleted T cells (E+) from 3 patients with CVI and from normal blood donors. Incubating CVI E+ cells with normal adherent cells resulted in normal proliferation and IL-2 production in the presence of OKT3, whereas incubation of normal E+ cells with adherent cells from patients with CVI under the same conditions showed reduced IL-2 production and proliferation, suggesting the macrophage as the origin of the failure in T-cell activation in the patients with CVI studied. Inhibition by macrophage-secreted prostaglandins was excluded by failure to correct the IL-2 production and proliferation defects in the presence of indomethacin.

Expansion of activated T-lymphocytes in patients treated with recombinant interleukin 2

Recombinant interleukin 2 (rIL 2, Cetus) was administered in escalating doses to 30 patients with advanced malignancy, including 14 patients with the epidemic form of Kaposi's sarcoma, in 2 week treatment cycles as a 6 h i.v. infusion for 10 doses. The maximum tolerated dose was 2 X 10(6) U/m2, with dose-limiting toxicity consisting of fever, diarrhea, and thrombocytopenia. At a well-tolerated dose of 1 X 10(6) U/m2, serum levels of rIL 2 of 30 U/ml were maintained for the duration of the infusion. Such concentrations sustain IL 2-dependent T cell growth in vitro. We observed a significant lymphocytosis in patients receiving 1 X 10(6) U/m2 of rIL 2 following 2 weeks of treatment (p = 0.0035). The expanded T cell pool was polyclonal, as demonstrated by increases in both T4+ and T8+ T cell subsets, and activated, with statistically significant increases in IL 2 receptor (p = 0.043), in the absence of transferrin receptor induction. Proliferating cells were not detected in peripheral blood using flow cytometry. Except for alpha-interferon, no other lymphokines (beta- and gamma-interferon, tumor necrosis factor) were present in serum during treatment. Reversible rises in anti-rIL 2 IgG antibodies occurred, as measured using an enzyme-linked immunosorbent assay. No changes were observed in the T cell mitogenic response to OKT3 and phytohemagglutinin, and no enhancement of cytotoxicity against natural killer-sensitive and resistant targets developed as a consequence of treatment. Except for a partial response in a patient with a myelodysplastic syndrome, no antitumor activity was observed. The in vivo expansion of T cells with the capacity to respond to rIL 2 with enhanced in vitro cytotoxicity against tumor targets provides impetus to ongoing trials exploring different routes and schedules of administration of rIL 2.

Interleukin 2 regulates the expression of Tac antigen on peripheral blood T lymphocytes

We investigated the effect of OKT3 antibody and interleukin 2 (IL-2) on Tac antigen expression and the proliferation of human peripheral blood mononuclear leukocytes. OKT3 monoclonal antibody at low, nonmitogenic concentrations (25 pg/ml) or IL-2 alone at optimal concentrations (20 U/ml) did not induce IL-2 receptor expression, as measured by Tac antibody or by T cell proliferation. However, costimulation with these concentrations of OKT3 antibody and IL-2 led to Tac antigen expression and T cell proliferation. These data suggest that the T cells are activated in two steps: OKT3 antibody at 25 pg/ml does not induce Tac antigen expression, but preactivates T cells to become responsive to IL-2. The addition of exogenous IL-2 then leads to expression of the IL-2 receptor, as recognized by Tac antibody, and to subsequent proliferation.

Expression of Ia-like antigen in lymphatic leukaemias and non-hodgkin lymphomas in correlation with other surface markers

Ia-like antigen, surface Ig, E-rosettes, mouse red blood cell rosettes and further surface markers were investigated in 88 specimens from 69 patients with various lymphocytic leukaemias and non-Hodgkin lymphomas. Ia-like antigen was detectable in all cases of sIg+ leukaemias and lymphomas. E-Ia+sIg-leukaemias, especially CLL and lymphomas were interpreted as B-cell neoplasias, which either did not produce sIg or expressed it in undetectable amounts. E+Ia+sIg+ malignant lymphocytes represented a B-cell population with antibody activity of sIg to SRBC. In the present series 9.5% of all B-cell leukaemias and lymphomas demonstrated this phenotype. Whereas ALL may possess Ia-like antigen, the vast majority of mature T-cell lymphomas are lacking it. In the present series 2 T-cell lymphomas expressed Ia-like antigen and did not contain TdT (E+Ia+sIg-TdT-). These lymphomas are probably derived from a stimulated T-cell clone synthesizing Ia-like antigen.