The gut microbiome: what the oncologist ought to know.

The gut microbiome (GM) has been implicated in a vast number of human pathologies and has become a focus of oncology research over the past 5 years. The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation and protection against pathogens. Strong evidence is emerging to support the effects of the GM on the development of some malignancies but also on responses to cancer therapies, most notably, immune checkpoint inhibition. Tools for manipulating the GM including dietary modification, probiotics and faecal microbiota transfer (FMT) are in development. Current understandings of the many complex interrelationships between the GM, cancer, the immune system, nutrition and medication are ultimately based on a combination of short-term clinical trials and observational studies, paired with an ever-evolving understanding of cancer biology. The next generation of personalised cancer therapies focusses on molecular and phenotypic heterogeneity, tumour evolution and immune status; it is distinctly possible that the GM will become an increasingly central focus amongst them. The aim of this review is to provide clinicians with an overview of microbiome science and our current understanding of the role the GM plays in cancer.

Antibiotic-exposed patients with non-small-cell lung cancer preserve efficacy outcomes following first-line chemo-immunotherapy.

BACKGROUND: Prior antibiotic therapy (pATB) is known to impair efficacy of single-agent immune checkpoint inhibitors (ICIs), potentially through the induction of gut dysbiosis. Whether ATB also affects outcomes to chemo-immunotherapy combinations is still unknown. PATIENTS AND METHODS: In this international multicentre study, we evaluated the association between pATB, concurrent ATB (cATB) and overall survival (OS), progression-free survival (PFS) and objective response rate (ORR) in patients with non-small-cell lung cancer (NSCLC) treated with first-line chemo-immunotherapy at eight referral institutions. RESULTS: Among 302 patients with stage IV NSCLC, 216 (71.5%) and 61 (20.2%) patients were former and current smokers, respectively. Programmed death-ligand 1 tumour expression in assessable patients (274, 90.7%) was ≥50% in 76 (25.2%), 1%-49% in 84 (27.9%) and <1% in 113 (37.5%). Multivariable analysis showed pATB-exposed patients to have similar OS {hazard ratio (HR) = 1.42 [95% confidence interval (CI): 0.91-2.22]; P = 0.1207} and PFS [HR = 1.12 (95% CI: 0.76-1.63); P = 0.5552], compared to unexposed patients, regardless of performance status. Similarly, no difference with respect to ORR was found across pATB exposure groups (42.6% versus 57.4%, P = 0.1794). No differential effect was found depending on pATB exposure duration (≥7 versus <7 days) and route of administration (intravenous versus oral). Similarly, cATB was not associated with OS [HR = 1.29 (95% CI: 0.91-1.84); P = 0.149] and PFS [HR = 1.20 (95% CI: 0.89-1.63); P = 0.222] when evaluated as time-varying covariate in multivariable analysis. CONCLUSIONS: In contrast to what has been reported in patients receiving single-agent ICIs, pATB does not impair clinical outcomes to first-line chemo-immunotherapy of patients with NSCLC. pATB status should integrate currently available clinico-pathologic factors for guiding first-line treatment decisions, whilst there should be no concern in offering cATB during chemo-immunotherapy when needed.

Declining levels of serum chemokine (C-X-C motif) ligand 10 over time are associated with new onset of psoriatic arthritis in patients with psoriasis: a new biomarker?

BACKGROUND: We previously found that serum levels of chemokine (C-X-C motif) ligand 10 (CXCL10) decreased after the onset of psoriatic arthritis (PsA). OBJECTIVES: We measured CXCL10 levels over time in patients with psoriasis who developed PsA to determine whether the drop in CXCL10 was specific to these patients and further assess its association with PsA development. METHODS: Prospectively followed patients with psoriasis without arthritis [cutaneous psoriasis (PsC)] were assessed yearly by rheumatologists for the presence of PsA. Patients with PsC who developed PsA (converters) were matched to those that did not develop PsA (nonconverters) based on psoriasis duration and the interval between follow-up visits. The duration between baseline and the first visit postconversion in converters was used to assign a pseudoconversion date in nonconverters. Linear mixed-effects models were used to model the expression of CXCL10 over time. RESULTS: CXCL10 significantly declined over time in converters prior to PsA development with a significant difference in the trend over time between converters (n = 29) and nonconverters (n = 52; P < 0·001). CXCL10 continued to decline after PsA onset in a subset of converters. There was a significant difference in the trend of CXCL10 levels between converters (n = 24) and nonconverters (n = 16; P = 0·01) preconversion/pseudoconversion. This difference remained postconversion (P = 0·006) and was not different from the preconversion period (P = 0·75). CONCLUSIONS: A large difference in CXCL10 was identified in patients with PsC that are destined to develop PsA over time. This exploratory analysis supports the association of CXCL10 with PsA development in patients with PsC and warrants further study of the predictive ability of this chemokine. What is already known about this topic? Chemokine (C-X-C motif) ligand 10 (CXCL10) is elevated in psoriatic affected tissues and serum and/or plasma. Patients with psoriasis that develop psoriatic arthritis (PsA) have elevated CXCL10 levels at baseline and these levels drop after arthritis onset. What does this study add? By monitoring levels of CXCL10 in serum over multiple visits in patients with psoriasis that develop PsA as well as those that do not develop PsA, an association was identified between CXCL10 and PsA development. What is the translational message? CXCL10 is a strong candidate for use by physicians for the detection of patients with psoriasis that are at risk of developing PsA. Linked Comment: Kirby and Fitzgerald. Br J Dermatol 2020; 183:805-806.

Vaginal compared with intramuscular progestogen for preventing preterm birth in high-risk pregnant women (VICTORIA study): a multicentre, open-label randomised trial and meta-analysis.

OBJECTIVE: To compare the efficacy of two types of progestogen therapy for preventing preterm birth (PTB) and to review the relevant literature. DESIGN: A multicentre, randomised, open-label, equivalence trial and a meta-analysis. SETTING: Tertiary referral hospitals in South Korea. POPULATION: Pregnant women with a history of spontaneous PTB or short cervical length (<25 mm). METHODS: Eligible women were screened and randomised at 16-22 weeks of gestation to receive either 200 mg of vaginal micronised progesterone daily (vaginal group) or an intramuscular injection of 250 mg 17α-hydroxyprogesterone caproate weekly (IM group). Stratified randomisation was carried out according to participating centres and indications for progestogen therapy. This trial was registered at ClinicalTrials.gov (NCT02304237). MAIN OUTCOME MEASURE: Preterm birth (PTB) before 37 weeks of gestation. RESULTS: A total of 266 women were randomly assigned and a total of 247 women (119 and 128 women in the vaginal and IM groups, respectively) were available for the intention-to-treat analysis. Risks of PTB before 37 weeks of gestation did not significantly differ between the two groups (22.7 versus 25.8%, P = 0.571). The difference in PTB risk between the two groups was 3.1% (95% CI -7.6 to 13.8%), which was within the equivalence margin of 15%. The meta-analysis results showed no significant differences in the risk of PTB between the vaginal and IM progestogen treatments. CONCLUSION: Compared with vaginal progesterone, treatment with intramuscular progestin might increase the risk of PTB before 37 weeks of gestation by as much as 13.8%, or reduce the risk by as much as 7.6%, in women with a history of spontaneous PTB or with short cervical length. TWEETABLE ABSTRACT: Vaginal and intramuscular progestogen showed equivalent efficacy for preventing preterm birth before 37 weeks of gestation.

Diagnostic value of ultrasound in calcium pyrophosphate deposition disease of the knee joint.

OBJECTIVE: To assess the diagnostic performance of ultrasound (US) for calcium pyrophosphate deposition (CPPD) at the level of menisci, hyaline cartilage (HC), tendons, and synovial fluid (SF) of the knee, and to examine inter- and intra-observer reliability. DESIGN: We consecutively included patients with knee effusion over a 2-year period (43 patients with CPPD and 131 controls). All patients underwent SF analysis, conventional radiography (CR), and US examination using the Outcome Measures in Rheumatology (OMERACT) definition of the US characteristics of CPPD. Two independent operators performed the US, and inter-observer agreement was calculated. Intra-observer agreement was examined with static images obtained for all enrolled patients. RESULTS: US revealed calcium pyrophosphate (CPP) deposits in menisci, HC, and tendon more frequently in patients with CPPD than in control patients. The presence of US CPP deposits in SF was not significantly different between the two groups. Combined US evaluation of the three components (menisci, HC, and tendon) showed the best diagnostic performance. The sensitivity and specificity for US evaluation of the three components were 74.4% and 77.1%, respectively, while for CR evaluation, the sensitivity and specificity were 44.2% and 96.9%, respectively. Inter- and intra-observer agreement were excellent for medial (κ = 0.930, 0.972) and lateral menisci (κ = 0.905, 0.942), HC (κ = 0.844, 0.957), and SF (κ = 0.817, 0.925). Tendon showed fair inter-observer (κ = 0.532) and good intra-observer reliability (κ = 0.788). CONCLUSIONS: Based on the OMERACT definition, US demonstrated better diagnostic capacity than CR to diagnose CPPD, with excellent reliability. Combined evaluation of menisci, HC, and tendon showed the best diagnostic accuracy.

(ICORG 05-03): prospective randomized non-inferiority phase III trial comparing two radiation schedules in malignant spinal cord compression (not proceeding with surgical decompression); the quality of life analysis.

BACKGROUND: The optimal primary external beam radiation therapy (EBRT) radiation schedule for malignant epidural spinal cord compression (MSCC) remains to be determined. The ICORG 05-03 trial assessed if a 10 Gy single fraction radiation schedule was not inferior to one with 20 Gray (Gy) in five daily fractions, in terms of functional motor outcome, for the treatment of MSCC in patients not proceeding with surgical decompression. This article reports on two of the secondary endpoints, Quality of life (QoL), assessed according to the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) version 3.0 (EORTC Data Center, Brussels, Belgium) and pain control assessed using a visual analog scale. METHODS: A randomized, parallel group, multicenter phase III trial was conducted by Cancer Trials Ireland (formerly All-Ireland Cooperative Oncology Research Group, ICORG), across five hospital sites in Ireland and Northern Ireland. Patients were randomized to 10 Gy single fraction of EBRT or 20 Gy in five fractions in a 1:1 ratio. Patients with baseline and 5-week follow up QoL data are included in this analysis. FINDINGS: From 2006 to 2014, 112 eligible patients were enrolled for whom 57 were evaluated for this secondary analysis. After adjusting for pre-intervention scores, there was no statistically significant difference in post-treatment Summary scores (excl. FI and QL), or pain scores between the two RT schedules at 5 weeks and 3 months following EBRT. There was a statistically significant relationship between the pretreatment and post-treatment Summary scores (p = .002) but not between the pre-treatment and post-treatment pain scores. INTERPRETATION: Primary radiotherapy for the treatment of MSCC significantly improves QoL in patients not proceeding with surgical decompression. After adjusting for pre-intervention scores, there was no statistically significant difference between a 10 Gy single fraction radiation schedule and one with 20 Gy in five daily fractions on post-treatment QoL Summary scores. For most patients, an effective treatment with low burden would be desirable. A single fraction schedule should be considered for this group of patients.

THE INFLUENCE OF TOTAL OR SUB-TOTAL GASTRECTOMY ON GLUCOSE CONTROL IN DIABETIC AND NON-DIABETIC PATIENTS.

OBJECTIVE: Although bariatric surgery including gastrectomy has recently emerged as a useful treatment for type 2 DM with obesity, it is not clear whether gastrectomy itself can have beneficial effects on glucose metabolism. Therefore, in this study, we investigated changes in blood glucose in patients with and without diabetes who underwent gastrectomy. METHODS: From Jan 2010 to May 2014, 77 patients with diabetes and 77 patients without diabetes who underwent gastrectomy at Chonbuk National University Hospital, South Korea, were included. We compared fasting plasma glucose levels and HbA1c value before and after gastric surgery. RESULTS: After gastrectomy, 59 patients (38.3%) showed reduced fasting plasma glucose levels at the 1 year point, and 80 patients (51.9%) exhibited reduced fasting plasma glucose at 3 years, irrespective of their diabetes status. Among 77 patients with diabetes, decreased fasting plasma glucose was observed in 22 (28.6%) and 46 patients (59.7%) 1 and 3 years after gastrectomy, respectively. In patients who exhibited reduced fasting plasma glucose after gastrectomy, the degree of reduced glucose was as follows: 56.4±48.5 vs 23.2±16.1 mg/dL after 1 year, 58.3±52.3 vs 18.4±13.7 mg/dL after 3 years, in DM and non-DM patient respectively. CONCLUSIONS: Although there was a significant drop in mean fasting glucose after gastrectomy, not all patients experienced a drop in fasting glucose. Gastrectomy did not show a consistent association with glucose reduction in patients with and without diabetes, and in about half of the patients, fasting plasma glucose levels increased after gastrectomy. Therefore, bariatric surgery including gastrectomy needs to be performed with care in diabetes, and glucose monitoring including oral glucose tolerance tests should be done for assessing or prediction of the glucose state after gastric surgery in non-DM patients.

Systemic LPS and inflammatory response during consecutive days of exercise in heat.

This investigation studied circulating LPS activity, potential intestinal damage, and the systemic inflammatory response (SIR) during the exercise heat acclimation process. 8 healthy males (Age=24±3 years) ran in a hot environment on 5 consecutive days until core temperature (Tc) was elevated 2°C above rest. Plasma was obtained pre-, post-, 1 h post-, and 3 h post-exercise on the 1(st), 3(rd), and 5(th) day of exercise and analyzed for TNF-α, IL-6, IL-10, IL-1ra, LPS, and intestinal fatty acid-binding protein (I-FABP). Plasma LPS (1.1 EU·ml(-1)±0.1 vs. 0.7 EU·ml(-1)±0.03; P<0.01) and I-FABP (930.7 pg·ml(-1)±149.0 vs. 640.2 pg·ml(-1)±125.0; P<0.001) were significantly increased post-exercise each. The SIR remained largely unchanged during the study except for TNF-α. Plasma TNF-α was significantly lower on Day 5 at 1 h (3.2 pg·ml(-1)±0.6 vs. 4.5 pg·ml(-1)±0.8; P=0.01) and 3 h (3.6 pg·ml(-1)±0.8 vs. 4.8 pg·ml(-1)±0.9; P=0.05) post-exercise as compared to Day 1. Findings indicate that adaptations to exercise in the heat resulting in reductions of intestinal damage and plasma LPS activity require longer time periods in moderately trained males.

Correlation between genotype and phenotype in patients with bi-allelic SLC26A4 mutations.

Mutation of SLC26A4 is the most common cause of prelingual hearing loss in East Asia. Patients with SLC26A4 mutations have variable phenotypes ranging from non-syndromic hearing loss to Pendred syndrome. Here, we analyzed the correlation between genotype and various inner ear phenotypes and found a possible underlying mechanism. This study included 111 patients with bi-allelic SLC26A4 mutations who had bilateral enlarged vestibular aqueduct (EVA) and hearing loss. p.H723R (61%), c.919-2A>G (24%), and p.T410M (4%) were the most common mutations in Korean patients with EVAs. Residual hearing in patients with c.919-2A>G or p.T410M mutations was better than that of patients with p.H723R homozygous mutations. Interestingly, quantitative polymerase chain reaction showed normal pendrin transcript (6-17% of normal levels) was produced from patients with c.919-2A>G homozygous mutations. Surface expression ratio of pendrin and residual anion exchange activity were higher in cells transfected with p.T410M in comparison to cells transfected with p.H723R. These results suggest that there is a correlation between degree of residual hearing and the SLC26A4 genotype commonly found in the East Asian population.

Short communication: antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk.

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an "antiviral food." At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.

Construction play frequency and relations with spatial ability and mathematics performance.

The nature of the home mathematics environment (which includes numerical and spatial activities at home) is related to children's spatial and mathematics performance. The current study investigated concrete and digital construction play frequency and relations with spatial and mathematical skills. Participants aged 7-9 years (N = 634) reported their frequency of construction play (concrete and digital) and completed direct measures of spatial ability and mathematics performance. Correlations between measures revealed no association between construction play frequency and outcome measures. This suggests that quantity of construction play is not pertinent for spatial and mathematics skills, however future research should explore whether quality of play is an important factor.

Molecular genetic, cardiac and neurodevelopmental findings in cases of prenatally diagnosed rhabdomyoma associated with tuberous sclerosis complex.

OBJECTIVE: Rhabdomyoma is the most common type of cardiac tumor in fetuses and is often associated with tuberous sclerosis complex (TSC) with neurologic sequelae. The purpose of this study was to investigate the cardiac and neurodevelopmental outcomes of fetal rhabdomyoma. METHODS: We reviewed the clinical characteristics of 23 cases of cardiac rhabdomyoma diagnosed prenatally by fetal echocardiography at the Asan Medical Center between January 1998 and December 2009. We also reviewed postnatal results of brain magnetic resonance imaging, echocardiography, renal ultrasound examination and molecular genetic analysis to confirm the presence of cardiac rhabdomyoma with or without TSC. RESULTS: Among 23 cases, outcome data were available for 17 (73.9%) and six cases (26.1%) were lost to follow-up. The survival rate was 100.0% (17/17). Among the 17 cases with outcome data, spontaneous tumor regression occurred in eight (47.1%), and no change in tumor size and number was observed in the remaining nine cases (52.9%). There was no evidence of long-term cardiac dysfunction caused by persisting rhabdomyomas, regardless of tumor size. TSC was found in nine patients (52.9%), of whom five (55.6%) showed neurodevelopmental morbidity. We identified mutations in one of the TSC1 or TSC2 genes in four of nine TSC infants whose parents allowed us to perform molecular genetic analysis. Three of these (75.0%) were found to have neurologic impairment. Seven (77.8%) of nine TSC cases were non-familial. CONCLUSIONS: The overall outcome of isolated cardiac rhabdomyoma appears to be favorable. We suggest that systematic postnatal evaluation of TSC be performed even in cases of cardiac rhabdomyoma without a family history of TSC. Molecular characterization of TSC1 and TSC2 might be helpful in predicting short- and long-term neurodevelopmental outcomes.

Population-specific spectrum of the F11 mutations in Koreans: evidence for a founder effect.

The aim of this study was to investigate a mutation spectrum of F11 among Korean patients with factor XI (FXI) deficiency and to determine the haplotypes of mutations frequently found in Koreans. Thirteen unrelated patients from non-consanguineous families with FXI deficiency were included in the study. In the mutation analysis, the most frequently found mutations were Q263X (four cases; 31%) and Q226X (three cases; 23%). The frequency of Q263X-bearing haplotype was significantly different between normal and patient groups (p = 0.001), which is consistent with a founder effect of Q263X mutation. Testing for the presence of these two mutations should be the first genetic screening in Korean patients with FXI deficiency.

Transcriptional regulation by cAMP.

Cyclic AMP regulates a myriad of cellular processes through the cAMP-dependent protein kinase A. In many cases, activation of protein kinase A leads to altered patterns of gene transcription. Identification of the cAMP-response-element-binding-protein as a major nuclear substrate for protein kinase A accounts for many recent advances in understanding the signal transduction pathway. This review will focus on the role of cAMP-response-element-binding protein in coupling protein kinase A to the transcriptional machinery and the mechanisms that control cAMP signalling during mammalian development.

Pharmacokinetics of veterinary drugs in laying hens and residues in eggs: a review of the literature.

Poultry treated with pharmaceutical products can produce eggs contaminated with drug residues. Such residues could pose a risk to consumer health. The following is a review of the information available in the literature regarding drug pharmacokinetics in laying hens, and the deposition of drugs into eggs of poultry species, primarily chickens. The available data suggest that, when administered to laying hens, a wide variety of drugs leave detectable residues in eggs laid days to weeks after the cessation of treatment.

A novel approach for tuberculosis diagnosis using exosomal DNA and droplet digital PCR.

OBJECTIVES: The rapid diagnosis of tuberculosis (TB) is important for patient treatment and infection control. Current molecular diagnostic techniques for TB have insufficient sensitivity to detect samples with low bacterial loads. The sensitivity of molecular testing depends on not only the performance of the assay technique but also the nucleic acid extraction method. Here, we present a novel approach using exosomal DNA (exoDNA) and droplet digital PCR (ddPCR) platforms to detect Mycobacterium tuberculosis DNA in clinical samples. METHODS: The ddPCR platform targeting IS6110 was evaluated in parallel using total DNA and exoDNA. The clinical performance of ddPCR method was assessed with 190 respiratory samples from patients with suspected pulmonary TB. RESULTS: Compared with mycobacterial culture, sensitivity and specificity of ddPCR were 61.5% (95% CI 44.6-76.6%) and 98.0% (95% CI 94.3-99.6%) using total DNA, and 76.9% (95% CI 60.7-88.9%) and 98.0% (95% CI 94.3-99.6%) using exoDNA, respectively. Among 15 culture-positive specimens with low concentrations of target molecules (2~99 positive droplets with exoDNA), only 53.3% (8/15), 46.7% (7/15), and 26.7% (4/15) of cases were detected using ddPCR with total DNA, real-time PCR with exoDNA, and real-time PCR with total DNA, respectively. DISCUSSION: Our platform using ddPCR and exoDNA has the potential to provide sensitive and accurate methodology for TB diagnosis.

PTPN11 analysis for the prenatal diagnosis of Noonan syndrome in fetuses with abnormal ultrasound findings.

Noonan syndrome (NS) is an autosomal dominant disorder characterized by short stature, congenital heart defects and distinctive facies. The disorder is genetically heterogeneous with approximately 50% of patients having PTPN11 mutations. Prenatally, the diagnosis of NS has been suspected following certain ultrasound findings, such as cystic hygroma, increased nuchal translucency (NT) and hydrops fetalis. Studies of fetuses with cystic hygroma have suggested an NS prevalence of 1-3%. A retrospective review was performed to assess the utility of PTPN11 testing based on prenatal sonographic findings (n = 134). The most commonly reported indications for testing were increased NT and cystic hygroma. Analysis showed heterozygous missense mutations in 12 fetuses, corresponding to a positive test rate of 9%. PTPN11 mutations were identified in 16% and 2% of fetuses with cystic hygroma and increased NT, respectively. Among fetuses with isolated cystic hygroma, PTPN11 mutation prevalence was 11%. The mutations observed in the three fetuses with hydrops fetalis had previously been reported as somatic cancer mutations. Prenatal PTPN11 testing has diagnostic and possible prognostic properties that can aid in risk assessment and genetic counseling. As NS is genetically heterogeneous, negative PTPN11 testing cannot exclude the diagnosis and further study is warranted regarding the other NS genes.

Differentiated Thyroid Cancer in Children: A UK Multicentre Review and Review of the Literature.

AIMS: To obtain an overview of the management and outcomes of children aged 18 years or younger diagnosed with differentiated thyroid carcinoma of follicular cell origin across the UK, by collecting and analysing data from the limited number of centres treating these patients. This multicentre data might provide a more realistic perspective than single-institution series. MATERIALS AND METHODS: Six centres submitted data extracted from historical records on patients aged 18 years or younger, diagnosed between 1964 and 2017. The univariate and multivariable Cox proportional hazard model was used to identify potential predictors of progression-free survival, using national data as a control. RESULTS: Data on 166 patients were available for analysis. Females (74%) were predominant, and the age ranged from 3 to 19 years at diagnosis, mean 14.1 years. Nodal metastases were present in 51%; 12% had distant metastases. After surgery, 95% received radioactive iodine (39% on more than one occasion) and 4% received external beam radiotherapy. With a median follow-up duration of 5 years, 69% are alive with no evidence of disease; 20% are alive with a raised thyroglobulin level as the only evidence of residual disease; 6% have residual structural disease detectable on imaging; 2% have died, from cerebral metastases. CONCLUSION: Despite most patients having advanced disease at presentation, outcomes are very good. A national prospective registry should allow systematic collection of good-quality data and may facilitate research to further improve outcomes.

Multiple phosphorylation of rhodopsin and the in vivo chemistry underlying rod photoreceptor dark adaptation.

Dark adaptation requires timely deactivation of phototransduction and efficient regeneration of visual pigment. No previous study has directly compared the kinetics of dark adaptation with rates of the various chemical reactions that influence it. To accomplish this, we developed a novel rapid-quench/mass spectrometry-based method to establish the initial kinetics and site specificity of light-stimulated rhodopsin phosphorylation in mouse retinas. We also measured phosphorylation and dephosphorylation, regeneration of rhodopsin, and reduction of all-trans retinal all under identical in vivo conditions. Dark adaptation was monitored by electroretinography. We found that rhodopsin is multiply phosphorylated and then dephosphorylated in an ordered fashion following exposure to light. Initially during dark adaptation, transduction activity wanes as multiple phosphates accumulate. Thereafter, full recovery of photosensitivity coincides with regeneration and dephosphorylation of rhodopsin.

Constitutive immune defences correlate with life-history variables in tropical birds.

1. It has been suggested that immune defences are shaped by life history and ecology, but few general patterns have been described across species. We hypothesized that 'fast' life-history traits (e.g. short development times, large clutch sizes) would be associated with developmentally inexpensive immune defences, minimizing the resource demands of young animals' immune systems during periods of rapid growth. Conversely, 'slow' life histories should be associated with well developed antibody-mediated defences, which are developmentally costly. 2. We therefore predicted that 'fast-living' species would exhibit higher levels of complement proteins, a component of non-specific innate defence, but lower levels of constitutive ('natural') antibodies. Additionally, we predicted that constitutive immune defences in general would be higher in species with ecological characteristics that might increase exposure to pathogens, such as open nests, omnivorous diets, gregariousness, and closed forested habitat. 3. Across 70 Neotropical bird species, we found a strongly positive relationship between incubation period and natural antibody levels in adult birds, suggesting that longer developmental times might allow the production of a more diverse and/or more reactive adaptive immune system. Complement activity was positively, although weakly, correlated with clutch size, providing some support for the hypothesis that faster-living species rely more on innate defences, such as complement. Unexpectedly, solitary species had higher natural antibody titres than species that frequently join flocks. 4. Our results suggest that, despite probably widespread differences in the intensity and diversity of pathogen exposure, species-level variation in constitutive immune defences is understandable within the context of life-history theory.