Effect of intermittent fasting on prostate cancer tumor growth in a mouse model

Caloric restriction (CR) has been shown to have anti-cancer properties. However, CR may be difficult to apply in humans secondary to compliance and potentially deleterious effects. An alternative is intermittent CR, or in the extreme case intermittent fasting (IF). In a previous small pilot study, we found 2 days per week of IF with ad libitum feeding on the other days resulted in trends toward prolonged survival of mice bearing prostate cancer xenografts. We sought to confirm these findings in a larger study. A total of 100 (7- to 8-week-old) male severe combined immunodeficiency mice were injected subcutaneously with 1 × 10(5) LAPC-4 prostate cancer cells. Mice were randomized to either ad libitum Western Diet (44% carbohydrates, 40% fat and 16% protein) or ad libitum Western Diet with twice-weekly 24 h fasts (IF). Tumor volumes and mouse bodyweights were measured twice weekly. Mice were killed when tumor volumes reached 1000 mm(3). Serum and tumor were collected for analysis of the insulin/insulin-like growth factor 1 (IGF-1) hormonal axis. Overall, there was no difference in mouse survival (P=0.37) or tumor volumes (P ≥ 0.10) between groups. Mouse body weights were similar between arms (P=0.84). IF mice had significantly higher serum IGF-1 levels and IGF-1/IGFBP-3 ratios at killing (P<0.001). However, no difference was observed in serum insulin, IGFBP-3 or tumor phospho-Akt levels (P ≥ 0.39). IF did not improve mouse survival nor did it delay prostate tumor growth. This may be secondary to metabolic adaptations to the 24 h fasting periods. Future studies are required to optimize CR for application in humans.

Childhood onset of Scheie syndrome, the attenuated form of mucopolysaccharidosis I

Scheie syndrome is the most attenuated and rarest form of mucopolysaccharidosis type I (MPS I), an inherited lysosomal storage disorder. Only small patient series have previously been reported. Using natural history data from the uniquely large population of 78 Scheie patients enrolled in the MPS I Registry, we characterized the onset and prevalence of clinical manifestations and explored reasons for delayed diagnosis of the disease. Median patient age was 17.5 years; 46% of the patients were male, and 88% were Caucasian. Of 25 MPS I-related clinical features, cardiac valve abnormalities, joint contractures, and corneal clouding were each reported by >80% and all three by 53% of patients. Carpal tunnel syndrome, hernia, coarse facial features, and hepatomegaly were each reported by >50% of patients. Age at onset of the clinical features varied widely between individuals, but the median age at onset was 3 years for hernia and between 5 and 12 years for most features, including coarse facial features, hepatomegaly, joint contractures, bone deformities, cardiac valve abnormalities, cognitive impairment, and corneal clouding. Carpal tunnel syndrome, cardiomyopathy, and myelopathy arose more commonly during adolescence or adulthood. Delays up to 47 years intervened between symptom onset and disease diagnosis, and the longest delays were associated with later age at symptom onset and symptom onset before 1980. In summary, Scheie syndrome usually emerges during childhood, and recognition of attenuated MPS I requires awareness of the multisystemic disease manifestations and their diverse presentation. Given the availability of etiologic treatment, prompt diagnosis is important.

Succinyl-CoA ligase deficiency: a mitochondrial hepatoencephalomyopathy

This patient presented on the first day of life with pronounced lactic acidosis with an elevated lactate/pyruvate ratio. Urine organic acids showed Krebs cycle metabolites and mildly elevated methylmalonate and methylcitrate. The acylcarnitine profile showed elevated propionylcarnitine and succinylcarnitine. Amino acids showed elevated glutamic acid, glutamine, proline, and alanine. From the age 2 of mo on, she had elevated transaminases and intermittent episodes of liver failure. Liver biopsy showed steatosis and a decrease of mitochondrial DNA to 50% of control. She had bilateral sensorineural hearing loss. Over the course of the first 2 y of life, she developed a progressively severe myopathy with pronounced muscle weakness eventually leading to respiratory failure, Leigh disease, and recurrent hepatic failure. The hepatic symptoms and the metabolic parameters temporarily improved on treatment with aspartate, but neither muscle symptoms nor brain lesions improved. Laboratory testing revealed a deficiency of succinyl-CoA ligase enzyme activity and protein in fibroblasts because of a novel homozygous mutation in the SUCLG1 gene: c.40A>T (p.M14L). Functional analysis suggests that this methionine is more likely to function as the translation initiator methionine, explaining the pathogenic nature of the mutation. Succinyl-CoA ligase deficiency due to an SUCLG1 mutation is a new cause for mitochondrial hepatoencephalomyopathy.

UV inhibits allergic airways disease in mice by reducing effector CD4 T cells

BACKGROUND

In human asthma, and experimental allergic airways disease in mice, antigen-presenting cells and CD4(+) effector cells at the airway mucosa orchestrate, and CD4(+)CD25(+) regulatory T cells attenuate, allergen immunity. UV irradiation of skin before sensitization with ovalbumin (OVA) causes significantly reduced asthma-like responses in respiratory tissues.

OBJECTIVE

To determine whether UV-induced changes in CD11c(+) cells, CD4(+)CD25(+) effector cells or CD4(+)CD25(+) regulatory cells in the trachea and airway draining lymph nodes (ADLNs) were responsible for reduced allergic airways disease.

METHODS

The phenotype and function of CD11c(+) cells and CD4(+)CD25(+) cells in the trachea and ADLNs of UV- and non-irradiated, OVA-sensitized mice was examined 24 h after a single exposure to aerosolized OVA.

RESULTS

No changes in the function of CD11c(+) cells from UV-irradiated mice were observed. CD4(+)CD25(+) cells from UV-irradiated, OVA-sensitized mice harvested 24 h after OVA aerosol proliferated less in response to OVA in vitro and were unable to suppress the proliferation of OVA-sensitized responder cells. This result suggested reduced activation of effector T cells in the airway mucosa of UV-irradiated, OVA-sensitized mice. To exclude regulatory cells of any type, there was similar proliferation in vivo to aerosolized OVA by CFSE-loaded, OVA-TCR-specific CD4(+) cells adoptively transferred into UV- and non-irradiated, OVA-sensitized mice. In addition, there was no difference in the expression of regulatory T cell markers (Foxp3, IL-10, TGF-beta mRNA). To examine effector T cells, ADLN cells from UV-irradiated, OVA-sensitized and -challenged mice were cultured with OVA. There was reduced expression of the early activation marker CD69 by CD4(+)CD25(+) cells, and reduced proliferation in the absence of the regulatory cytokine, IL-10.

CONCLUSION

Reduced allergic airways disease in UV-irradiated mice is due to fewer effector CD4(+)CD25(+) cells in the trachea and ADLNs, and not due to UV-induced regulatory cells.

Acoustical mimicry in a predatory social parasite of ants

Rapid, effective communication between colony members is a key attribute that enables ants to live in dominant, fiercely protected societies. Their signals, however, may be mimicked by other insects that coexist as commensals with ants or interact with them as mutualists or social parasites. We consider the role of acoustics in ant communication and its exploitation by social parasites. Social parasitism has been studied mainly in the butterfly genus Maculinea, the final instar larvae of which are host-specific parasites of Myrmica ants, preying either on ant grubs (predatory Maculinea) or being fed by trophallaxis (cuckoo Maculinea). We found similar significant differences between the stridulations of model queen and worker ant castes in both Myrmica sabuleti and Myrmica scabrinodis to that previously reported for Myrmica schencki. However, the sounds made by queens of all three Myrmica species were indistinguishable, and among workers, stridulations did not differ significantly in two of three species-pairs tested. Sounds recorded from the predatory caterpillars and pupae of Maculinea arion had similar or closer patterns to the acoustics of their host Myrmica sabuleti than those previously reported for the cuckoo Maculinea rebeli and its host Myrmica schencki, even though Maculinea rebeli caterpillars live more intimately with their host. We conclude that chemical mimicry enables Maculinea larvae to be accepted as colony members by worker ants, but that caterpillars and pupae of both predatory and cuckoo butterflies employ acoustical mimicry of queen ant calls to elevate their status towards the highest attainable position within their host's social hierarchy.

Management of a patient with holocarboxylase synthetase deficiency

We investigated in a patient with holocarboxylase synthetase deficiency, the relation between the biochemical and genetic factors of the mutant protein with the pharmacokinetic factors of successful biotin treatment. A girl exhibited abnormal skin at birth, and developed in the first days of life neonatal respiratory distress syndrome and metabolic abnormalities diagnostic of multiple carboxylase deficiency. Enzyme assays showed low carboxylase activities. Fibroblast analysis showed poor incorporation of biotin into the carboxylases, and low transfer of biotin by the holocarboxylase synthetase enzyme. Kinetic studies identified an increased Km but a preserved Vmax. Mutation analysis showed the child to be a compound heterozygote for a new nonsense mutation Q379X and for a novel missense mutation Y663H. This mutation affects a conserved amino acid, which is located the most 3' of all recorded missense mutations thus far described, and extends the region of functional biotin interaction. Treatment with biotin 100mg/day gradually improved the biochemical abnormalities in blood and in cerebrospinal fluid (CSF), corrected the carboxylase enzyme activities, and provided clinical stability and a normal neurodevelopmental outcome. Plasma concentrations of biotin were increased to more than 500 nM, thus exceeding the increased Km of the mutant enzyme. At these pharmacological concentrations, the CSF biotin concentration was half the concentration in blood. Measuring these pharmacokinetic variables can aid in optimizing treatment, as individual tailoring of dosing to the needs of the mutation may be required.

The mitochondrial 13513G>A mutation is associated with Leigh disease phenotypes independent of complex I deficiency in muscle

The mitochondrial 13513G>A (D393N) mutation in the ND5 subunit of the respiratory chain complex I was initially described in association with MELAS syndrome. Recent observations have linked this mutation to Leigh disease. We screened for the 13513G>A mutation in a cohort of 265 patients with Leigh and Leigh-like disease. The mutation was found in a total of 5 patients. An additional patient who had clinical presentation consistent with a Leigh-like phenotype but with a normal brain MRI was added to the cohort. None of an additional 88 patients meeting MELAS disease criteria, nor 56 patients with respiratory chain deficiency screened for the 13513G>A were found positive for the mutation. The most frequent clinical manifestations in our patients were hypotonia, ocular and cerebellar involvement. Low mutation heteroplasmy in the range of 20-40% was observed in all 6 patients. This observation is consistent with the previously reported low heteroplasmy of this mutation in some patients with the 13513G>A mutation and complex I deficiency. However, normal complex I activity was observed in two patients in our cohort. As most patients with Leigh-like disease and the 13513G>A mutation have been described with complex I deficiency, this report adds to the previously reported subset of patients with normal respiratory complex function. We conclude that in any patient with Leigh or Leigh-like disease, testing for the 13513G>A mutation is clinically relevant and low mutant loads in blood or muscle may be considered pathogenic, in the presence of normal respiratory chain enzyme activities.

Infantile cardiomyopathy caused by the T14709C mutation in the mitochondrial tRNA glutamic acid gene

A 6-week-old child presented with hypotonia, myopathy, and a rapidly worsening dilated cardiomyopathy with severe atrial and ventricular arrhythmias and pulmonary hypertension, which proved fatal at age 3 months. Biochemical analysis showed a combined deficiency of the enzymatic activities of complexes I and IV and molecular studies identified a T14709C mutation in the mitochondrial tRNA glutamic acid gene. A review of symptomatology in patients with this mutation shows that it mainly presents in childhood or young adults with mild myopathy and diabetes mellitus. Infants with a high, nearly homoplasmic mutant load can present with more severe symptoms including cardiomyopathy. Families with this mitochondrial DNA mutation should be aware that increased mutant load in a subsequent generation may result in severe and often fatal cardiac symptoms.

Effect of surface wettability on liquid density, structure, and diffusion near a solid surface

Molecular dynamics and Langevin dynamics simulations are used to elucidate the behavior of liquid atoms near a solid boundary. Correlations between the surface wettability and spatial variations in liquid density and structure are identified. The self-diffusion coefficient tensor is predicted, revealing highly anisotropic and spatially varying mass transfer phenomena near the solid boundary. This behavior affects self-diffusion at a range of time scales. Near a more-wetting surface, self-diffusion is impeded by strong solid-liquid interactions that induce sharp liquid density gradients and enhanced liquid structure. Conversely, near a less-wetting surface, where solid-liquid interactions are weaker, the liquid density is low, the atoms are disordered, and diffusion is enhanced. These findings suggest that altering the wettability of a micro- or nanochannel may provide a passive means for controlling the diffusion of select targets towards a functionalized surface and controlling the reaction rate in diffusion-limited reactions.

Increased genetic diversity as a defence against parasites is undermined by social parasites: Microdon mutabilis hoverflies infesting Formica lemani ant colonies

Genetic diversity can benefit social insects by providing variability in immune defences against parasites and pathogens. However, social parasites of ants infest colonies and not individuals, and for them a different relationship between genetic diversity and resistance may exist. Here, we investigate the genetic variation, assessed using up to 12 microsatellite loci, of workers in 91 Formica lemani colonies in relation to their infestation by the specialist social parasite Microdon mutabilis. At the main study site, workers in infested colonies exhibited lower relatedness and higher estimated queen numbers, on average, than uninfested ones. Additionally, estimated queen numbers were negatively correlated with estimated average numbers of mates per queen within infested colonies. At another site, infested colonies also exhibited significantly lower worker relatedness, and estimated queen numbers were comparable in trend. In contrast, in two populations of F. lemani where M. mutabilis was absent, relatedness within colonies was high (40 and 90% with R>0.6). While high genetic variation can benefit social insects by increasing their resistance to pathogens, there may be a cost in the increased likelihood of infiltration by social parasites owing to greater variation in nestmate recognition cues. This study provides the first empirical test of this hypothesis.

Late-onset combined homocystinuria and methylmalonic aciduria (cblC) and neuropsychiatric disturbance

We report on the case of a 36-year-old Hispanic woman with a spinal cord infarct, who was subsequently diagnosed with methylmalonic aciduria and homocystinuria, cblC type (cblC). Mutation analysis revealed c.271dupA and c.482G > A mutations in the MMACHC gene. The patient had a past medical history significant for joint hypermobility, arthritis, bilateral cataracts, unilateral hearing loss, anemia, frequent urinary tract infections, and mental illness. There was no significant past history of mental retardation, failure to thrive, or seizure disorder as reported in classic cases of cblC. Prior to the thrombotic incident, the patient experienced increased paresthesia in the lower extremities, myelopathy, and impaired gait. Given her previous psychiatric history, she was misdiagnosed with malingering until hemiplegia and incontinence became apparent. The authors would like to emphasize the recognition of a neuropsychiatric presentation in late onset cblC. Ten other reported late onset cases with similar presentations are also reviewed.

Outcome after three years of laronidase enzyme replacement therapy in a patient with Hurler syndrome

Enzyme replacement therapy (ERT) with laronidase, recombinant alpha-L-iduronidase, for mucopolysaccharidosis type I (MPS I) has been clinically available since April 2003. Pre-approval studies were performed on patients with the more attenuated forms of MPS I, Hurler-Scheie and Scheie syndromes. The clinical efficacy of laronidase on the severe form of MPS I, Hurler syndrome, is not well known. We present a patient with Hurler syndrome who has been treated with laronidase for 3 years. Clinically, the patient demonstrated improvement in urinary glycosaminoglycan (GAG) levels and hepatomegaly, but continued to experience decline in respiratory status, musculoskeletal and spinal involvement, and developmental skills. Overall, the benefit of ERT with laronidase in advanced Hurler syndrome appeared to be minimal in this patient.

Host propagation permits extreme local adaptation in a social parasite of ants

The Red Data Book hoverfly species Microdon mutabilis is an extreme specialist that parasitises ant societies. The flies are locally adapted to a single host, Formica lemani, more intimately than was thought possible in host-parasite systems. Microdon egg survival plummeted in F. lemani colonies > 3 km away from the natal nest, from c. 96% to 0% to < 50%, depending on the hoverfly population. This is reflected in the life-time dispersal of females, measured at < 2 m, resulting in oviposition back into the same ant nests for generation after generation. To counter destabilizing effects on the host, Microdon manipulates the social dynamics of F. lemani by feeding selectively on ant eggs and small larvae, which causes surviving larvae to switch development into queens. Infested colonies rear double the number of new queens, thus propagating the vulnerable local genotype and compensating for damage to the host colonies. The consequences of such extreme host specificity for insect conservation are discussed.

D-2-hydroxyglutaric aciduria in three patients with proven SSADH deficiency: genetic coincidence or a related biochemical epiphenomenon?

Succinic semialdehyde dehydrogenase (SSADH) deficiency and D-2-hydroxyglutaric aciduria (D-2-HGA) are rare inborn errors of metabolism primarily revealed by urinary organic acid screening. Three patients with proven SSADH deficiency excreted, in addition to GHB considerable amounts of D-2-HG. We examined whether these patients suffered from two inborn errors of metabolism by measuring D-2-HG concentrations in the culture medium of cells from these patients. In addition, mutation analysis of the D-2-hydroxyglutarate dehydrogenase gene was performed. Normal concentrations of D-2-HG were measured in the culture media of fibroblasts or lymphoblasts derived from the three patients. In one patient, we found a heterozygous likely pathogenic mutation in the D-2-hydroxyglutarate dehydrogenase gene. These combined results argue against the hypothesis that the patients are affected with "primary" D-2-HGA in combination with their SSADH deficiency. Moderately increased levels of D-2-HG were also found in urine, plasma, and cerebrospinal fluid samples derived from 12 other patients with SSADH deficiency, revealing that D-2-HG is a common metabolite in this disease. The increase of D-2-HG in SSADH deficiency can be explained by the action of hydroxyacid-oxoacid transhydrogenase, a reversible enzyme that oxidases GHB in the presence of 2-ketoglutarate yielding SSA and D-2-HG.

The Third International Intercomparison on EPR Tooth Dosimetry: part 2, final analysis

The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation.

Clinical and molecular characterization of the first adult congenital disorder of glycosylation (CDG) type Ic patient

Congenital disorder of glycosylation (CDG) type Ic, the second largest subtype of CDG, is caused by mutations in human ALG6 (hALG6). This gene encodes the alpha1,3-glucosyltransferase that catalyzes transfer of the first glucose residue to the lipid-linked oligosaccharide precursor for N-linked glycosylation. In this report, we describe the first adult patient diagnosed with CDG-Ic, carrying two previously unknown mutations. The first is a three base deletion (897-899delAAT) leading to the loss of I299, the second is an intronic mutation (IVS7 + 2T > G) that causes aberrant splicing. Wildtype hALG6, delivered by a lentiviral vector into patient's fibroblasts, clearly improves the biochemical phenotype, which confirms that the mutations are disease-causing. Striking clinical findings include limb deficiencies in the fingers, resembling brachydactyly type B, a deep vein thrombosis, pseudotumor cerebri, and endocrine disturbances with pronounced hyperandrogenism and virilization. However, even in adulthood, this patient shows normal magnetic resonance imaging of the brain.

Monitoring change in the abundance and distribution of insects using butterflies and other indicator groups

Conservative estimates suggest that 50-90% of the existing insect species on Earth have still to be discovered, yet the named insects alone comprise more than half of all known species of organism. With such poor baseline knowledge, monitoring change in insect diversity poses a formidable challenge to scientists and most attempts to generalize involve large extrapolations from a few well-studied taxa. Butterflies are often the only group for which accurate measures of change can be obtained. Four schemes, used successfully to assess change in British butterflies, that are increasingly being applied across the world are described: Red Data Books (RDB) list the best judgements of experts of the conservation status of species in their field of expertise; mapping schemes plot the changing distributions of species at scales of 1-100 km2; transect monitoring schemes generate time series of changes in abundance in sample populations of species on fixed sites across the UK; and occasional surveys measure the number, boundaries and size of all populations of a (usually RDB) species at intervals of 10-30 years. All schemes describe consistent patterns of change, but if they are to be more generally useful, it is important to understand how well butterflies are representative of other taxa. Comparisons with similarly measured changes in native bird and plant species suggest that butterflies have declined more rapidly that these other groups in Britain; it should soon be possible to test whether this pattern exists elsewhere. It is also demonstrated that extinction rates in British butterflies are similar to those in a range of other insect groups over 100 years once recording bias is accounted for, although probably lower than in aquatic or parasitic taxa. It is concluded that butterflies represent adequate indicators of change for many terrestrial insect groups, but recommended that similar schemes be extended to other popular groups, especially dragonflies, bumblebees, hoverflies and ants. Given institutional backing, similar projects could be employed internationally and standardized. Finally, a range of schemes designed to monitor change in communities of aquatic macro-invertebrates is described. Although designed to use invertebrates as a bio-indicator of water quality for human use, these programmes could be extended to monitor the 2010 biodiversity targets of the World Summit on Sustainable Development.

Parameters affecting EPR dose reconstruction in teeth

The aim of this paper is to analyze the lower limit of detection (LLD), linearity of dose response, variation of radiation sensitivity between different tooth enamel samples, and time/temperature stability of EPR biodosimetry in tooth enamel. The theoretical LLD is shown to be 0.46 mGy, which is far lower than the measured value of about 30 mGy. The main issues to lowering LLD are the differentiation of the radiation-induced component against the total EPR spectrum and the complex nature of the dose dependence of the EPR signal. The following questions are also discussed in detail: need for exfoliated or extracted teeth from persons of interest, accounting for background radiation contribution; conversion of tooth enamel absorbed dose to effective dose; accounting for internal exposure specifically from bone-seeking radionuclides. Conclusions on future development of EPR retrospective biodosimetry are made.

Spectrum file size optimization for EPR tooth dosimetry

Spectral acquisition time is one of the limiting factors in electron paramagnetic resonance (EPR) retrospective biodosimetry in teeth. Acquisition times for one sample can be from 2 to 4h. This problem is even more acute for in vivo EPR measurements in L-band. Patients cannot be expected to remain stationary for these lengths of time. In order to overcome this limitation, we investigated the dependence of EPR dose measurements on the number of data points in an EPR spectrum. We have shown that this number could be reduced from 1024 to 256 (factor of 4 reduction in spectral acquisition time) at 5 mT magnetic field sweep without a loss of precision in the dose measurements.

Biopharmaceuticals derived from genetically modified plants

Modern biotechnology has resulted in a resurgence of interest in the production of new therapeutic agents using botanical sources. With nearly 500 biotechnology products approved or in development globally, and with production capacity limited, the need for efficient means of therapeutic protein production is apparent. Through genetic engineering, plants can now be used to produce pharmacologically active proteins, including mammalian antibodies, blood product substitutes, vaccines, hormones, cytokines, and a variety of other therapeutic agents. Efficient biopharmaceutical production in plants involves the proper selection of host plant and gene expression system, including a decision as to whether a food crop or a non-food crop is more appropriate. Product safety issues relevant to patients, pharmaceutical workers, and the general public must be addressed, and proper regulation and regulatory oversight must be in place prior to commercial plant-based biopharmaceutical production. Plant production of pharmaceuticals holds great potential, and may become an important production system for a variety of new biopharmaceutical products.

Changes in chemical signature and host specificity from larval retrieval to full social integration in the myrmecophilous butterfly Maculinea rebeli

The ant social parasite, Maculinea rebeli shows high levels of host specificity at a regional scale. While 68-88% of caterpillars in the field are adopted by nonhost Myrmica ants, 95-100% of the butterflies emerge from the natural host M. schencki the following year. While retrieval of preadoption caterpillars is specific to the genus Myrmica, it does not explain differential survival with different Myrmica species. We present survival data with host and nonhost Myrmica species suggesting that, with nonhosts (M. sabuleti and M. rubra), survival depends on the physiological state of the colony. We also compared the similarities of the epicuticular surface hydrocarbon signatures of caterpillars that were reared by host and nonhost Myrmica for 3 weeks with those from tending workers. Counterintuitively, the hydrocarbons of postadoption caterpillars were more similar (78%, 73%) to the ant colony profiles of the nonhost species than were caterpillars reared in colonies of M. schencki (42% similarity). However, caterpillars from M. schencki nests that were then isolated for 4 additional days showed unchanged chemical profiles, whereas the similarities of those from nonhost colonies fell to 52 and 56%, respectively. Six compounds, presumably newly synthesized, were detected on the isolated caterpillars that could not have been acquired from M. sabuleti and M. rubra (nor occurred on preadoption caterpillars), five of which were found on the natural host M. schencki. These new compounds may relate to the high rank the caterpillars attain within the hierarchy of M. schencki societies. The same compounds would identify the caterpillars as intruders in non-schencki colonies, where their synthesis appeared to be largely suppressed. The ability to synthesize or suppress additional compounds once adopted explains the pattern of mortalities found among fully integrated caterpillars in Myrmica colonies of different species and physiological states.

Comparative losses of British butterflies, birds, and plants and the global extinction crisis

There is growing concern about increased population, regional, and global extinctions of species. A key question is whether extinction rates for one group of organisms are representative of other taxa. We present a comparison at the national scale of population and regional extinctions of birds, butterflies, and vascular plants from Britain in recent decades. Butterflies experienced the greatest net losses, disappearing on average from 13% of their previously occupied 10-kilometer squares. If insects elsewhere in the world are similarly sensitive, the known global extinction rates of vertebrate and plant species have an unrecorded parallel among the invertebrates, strengthening the hypothesis that the natural world is experiencing the sixth major extinction event in its history.

Effect of room illuminance on monitor black level luminance and monitor calibration

In this article we demonstrate the effect of room illuminance and surrounding monitor black level luminance on image quality for soft copy interpretation. Luminance values of a 10% central target and image quality evaluations and observer performance using a contrast-detail mammography (CDMAM) phantom demonstrate these effects. Our results indicate that high room illuminance has a more damaging effect on image quality when the surrounding monitor luminance is 0% to 5% of the maximum monitor luminance. The effect of room illuminance is less obvious when the surrounding monitor luminance is 20% of the maximum.