Increased genetic diversity and immigration after West Nile virus emergence in American crows: No evidence for a genetic bottleneck

Infectious diseases can cause steep declines in wildlife populations, leading to changes in genetic diversity that may affect the susceptibility of individuals to infection and the overall resilience of populations to pathogen outbreaks. Here, we examine evidence for a genetic bottleneck in a population of American crows (Corvus brachyrhynchos) before and after the emergence of West Nile virus (WNV). More than 50% of marked birds in this population were lost over the 2-year period of the epizootic, representing a 10-fold increase in adult mortality. Using analyses of single-nucleotide polymorphisms (SNPs) and microsatellite markers, we tested for evidence of a genetic bottleneck and compared levels of inbreeding and immigration in the pre- and post-WNV populations. Counter to expectations, genetic diversity (allelic diversity and the number of new alleles) increased after WNV emergence. This was likely due to increases in immigration, as the estimated membership coefficients were lower in the post-WNV population. Simultaneously, however, the frequency of inbreeding appeared to increase: Mean inbreeding coefficients were higher among SNP markers, and heterozygosity-heterozygosity correlations were stronger among microsatellite markers, in the post-WNV population. These results indicate that loss of genetic diversity at the population level is not an inevitable consequence of a population decline, particularly in the presence of gene flow. The changes observed in post-WNV crows could have very different implications for their response to future pathogen risks, potentially making the population as a whole more resilient to a changing pathogen community, while increasing the frequency of inbred individuals with elevated susceptibility to disease.

Adjuvant statin therapy for oesophageal adenocarcinoma: the STAT-ROC feasibility study

Background

Statins inhibit proliferative signalling in oesophageal adenocarcinoma (OAC) and their use is associated with better survival in observational studies. The present study was undertaken to examine the feasibility of assessing adjuvant statin therapy in patients with operable OAC in a phase III RCT.

Methods

For this multicentre, double‐blind, parallel‐group, randomized, placebo‐controlled feasibility trial, adults with OAC (including Siewert I–II lesions) who had undergone oesophagectomy were centrally allocated (1 : 1) to simvastatin 40 mg or matching placebo by block randomization, stratified by centre. Participants, clinicians and investigators were blinded to treatment allocation. Patients received treatment for up to 1 year. Feasibility outcomes were recruitment, retention, drug absorption, adherence, safety, quality of life, generalizability and survival.

Results

A total of 120 patients were assessed for eligibility at four centres, of whom 32 (26·7 per cent) were randomized, 16 in each group. Seven patients withdrew. Participants allocated to simvastatin had lower low‐density lipoprotein cholesterol levels by 3 months (adjusted mean difference −0·83 (95 per cent c.i. −1·4 to −0·22) mmol/l; P = 0·009). Median adherence to medication was greater than 90 per cent between 3 and 12 months' follow‐up. Adverse events were similar between the groups. Quality‐of‐life data were complete for 98·3 per cent of questionnaire items. Cardiovascular disease, diabetes and aspirin use were more prevalent in the non‐randomized group, whereas tumour site, stage and grade were similar between groups. Survival estimates were imprecise.

Conclusion

This RCT supports the conduct and informs the design considerations for a future phase III trial of adjuvant statin therapy in patients with OAC. Registration number: ISRCTN98060456 (http://www.isrctn/com).

Modeling the effects of standardized ileal digestible isoleucine to lysine ratio on growth performance of nursery pigs. Transl Anim Sci 2017;1:437-447. [PMID: 32704667 PMCID: PMC7204974 DOI: 10.2527/tas2017.0048]

Two experiments evaluated the effects of increasing standardized ileal digestible (SID) Ile:Lys ratio on growth performance of nursery pigs. In both experiments, dietary treatments consisted of 40, 44, 48, 52, 54, 58, or 63% SID Ile:Lys ratio. Diets were formulated using analyzed ingredient AA values and NRC (2012) SID coefficients. A combination of field peas and spray dried blood cells were used to ensure a low enough Ile diet concentration while minimizing the excess of Leu. The experiments consisted of 8 pens per dietary treatment with 5 pigs per pen for a total of 280 nursery pigs per experiment (Exp. 1: PIC 327 × 1,050, initially 6.7 ± 1.0 kg BW; Exp. 2: DNA 600 × 241, initially 6.0 ± 0.97 kg BW). Data were analyzed using mixed models with heterogeneous variance, where appropriate. The dose response was further characterized using quadratic polynomial (QP), broken-line linear (BLL), or broken-line quadratic (BLQ) functional forms. For Exp. 1, diets were initiated 6-d post-weaning and fed for 12-d followed by a common diet from d 12 to 28. From d 0 to 12, increasing dietary SID Ile:Lys ratio increased ADG (linear, P < 0.005) and ADFI (quadratic, P < 0.017) but G:F decreased (quadratic, P < 0.043). For ADG, the QP, BLL, and BLQ models resulted in maximum ADG at 64.7, 52.0, and 52.0 SID Ile:Lys ratios, respectively. For ADFI, the BLL breakpoint occurred at 50.6 and the QP predicted maximum ADFI at 56.2 SID Ile:Lys ratio. In Exp. 2, diets were initiated 6-d post-weaning for 7 pens and 3-d post-weaning for one heavier block and fed for 18-d followed by a common diet from d 18 to 32. From d 0 to 18, ADG and ADFI increased (quadratic, P < 0.016) with no evidence for difference in G:F as SID Ile:Lys ratio increased. For ADG, the QP and BLL had similar fit with breakpoints or maximums occurring at 58.3 and 51.8% SID Ile:Lys ratio, respectively. For ADFI, the BLQ breakpoint occurred at 52.0 SID Ile:Lys and the QP maximum ADFI at 57.2% SID Ile:Lys ratio. In conclusion, broken-line models reported maxima of 52.0% Ile:Lys ratio while quadratic models were as high as 64% of Lys to maximize ADG and ADFI of 6- to 11-kg nursery pigs. However, for the QP models 99% of the maximum response was achieved with a dose comparable to that from the broken line models. Therefore, these results are similar to the NRC (2012) requirement estimate of 51.1 Ile:Lys ratio.

Modeling the effects of standardized ileal digestible valine to lysine ratio on growth performance of nursery pigs. Transl Anim Sci 2017;1:448-457. [PMID: 32704668 PMCID: PMC7204984 DOI: 10.2527/tas2017.0049]

Two experiments evaluated the effects of increasing Lys and Val on growth performance of nursery pigs. In Exp. 1,300 nursery pigs (PIC 327 × 1,050, initially 6.7 ± 1.4 kg BW) were randomly allotted to 1 of 6 diets containing 1.10, 1.20, 1.30, 1.40, 1.50, or 1.60% standardized ileal digestible (SID) Lys, with 10 pens per dietary treatment and 5 pigs per pen. Linear and nonlinear mixed models were fitted to estimate dose responses. From d 0 to 14, and for the overall 28 d period, ADG and G:F increased (linear, P < 0.001) as SID Lys increased, with no evidence of differences in ADFI. Dose response modeling indicated the SID Lys requirement for ADG and G:F was at 1.45% using a broken line linear (BLL) and greater than 1.60% using a quadratic polynomial (QP) model. In Exp. 2, 280 nursery pigs (PIC 327 × 1,050, initially 6.5 ± 1.3 kg BW) were allotted to 1 of 7 diets containing SID Val:Lys ratios of 50, 57, 63, 68, 73, 78, or 85%. The dietary SID Lys concentration 1.24% SID Lys which was below the estimated requirement from Exp. 1 and ensured the Val:Lys ratio was not underestimated. From d 0 to 14, ADG, ADFI, and G:F increased (quadratic, P < 0.039) with increasing SID Val:Lys. For ADG, the best fitting model was a BLL, with a breakpoint estimate of 62.9% SID Val:Lys [52.2, 73.7] ratio while for G:F the best fit model was a quadratic polynomial with a maximum G:F at 71.7% SID Val:Lys (95%CI:[58, > 85]). Average daily feed intake was also modeled with a quadratic polynomial and maximized at 73.7% Val:Lys (95% CI: [61, > 85]). In conclusion, the Val requirement ranged from approximately 63 to 74% of Lys depending on the response criteria modeled.

Plasmid-mediated resistance to cephalosporins and quinolones in Escherichia coli from American crows in the USA

American crow (Corvus brachyrhynchos) faeces were tested for Escherichia coli with plasmid-mediated quinolone resistance (PMQR), extended-spectrum beta-lactamases (ESBL) and AmpC beta-lactamases. A total of 590 faecal samples were collected at four roosting sites in the USA and cultivated on selective media. Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were performed to assess clonality. Transferability of resistance genes was studied using conjugation and transformation bioassays. In total, 78 (13%, n = 590) cefotaxime-resistant isolates were obtained, of which 66 and 12 displayed AmpC and ESBL phenotypes, respectively. Fifty-four AmpC-producing isolates carried bla_CMY-2 . Isolates producing ESBLs contained genes bla_CTX-M-27 (5 isolates), bla_CTX-M-15 (4), bla_CTX-M-14 (2) and bla_CTX-M-1 (1). Ninety isolates (15%, n = 590) with reduced susceptibility to ciprofloxacin were obtained, among which 14 harboured PMQR genes aac(6')-Ib-cr (4 isolates), qnrB19 (3), qnrS1 (2), qnrA1 (2), qnrB2 (1), qnrB6 (1) and qnrD3 (1). High genetic diversity was revealed by PFGE and MLST. Epidemiologically important E. coli clones (e.g., ST131, ST405) were identified. Plasmids carrying bla_CMY-2 were assigned predominantly to IncA/C (8 plasmids), IncI1/ST23 (5) and IncI1/ST12 (3). The study demonstrates a widespread occurrence of E. coli with ESBL, AmpC and PMQR genes associated with clinically important multidrug-resistant clones and epidemic plasmids, in American crows.

Self-Rehabilitation of a Captive American Crow at Binghamton Zoo

The behavioral transition from an entirely unflighted-to-flighted, female yearling American crow (Corvus brachyrhynchos) in captivity in a specially designed exhibit was documented at the Binghamton Zoo at Ross Park in Binghamton, NY. Upon arrival, the focal crow had no complete primary feathers or retrices and had been in captivity since fledging. She apparently had never flown successfully and was using her legs and an abnormal body orientation to cushion her landing on the ground. In a social and physical environment with 3 flying companion crows and staggered perches, she developed and appeared to "practice" routines that ultimately resulted in her recovering normal body posture and flight ability. The crow's practice routine was recorded during daily observations using an ethogram of social and locomotor behaviors. Both enclosure design and the social environment may have provided an ideal setting for the self-motivation of practice and this recovery. Attention to the potential for such practice could facilitate rehabilitation in individuals for whom rehabilitation was not thought possible.

Age but not ABCD(2) score predicts any level of carotid stenosis in either symptomatic or asymptomatic side in transient ischaemic attack

BACKGROUND

The ABCD(2) score is routinely used in assessment of transient ischaemic attack (TIA) to assess the risk of developing stroke. There remains uncertainty regarding whether the ABCD(2) score could be used to help predict extent of carotid artery stenosis (CAS).

OBJECTIVES

We aimed to (i) collate and analyse all available published literature on this topic and (ii) compare the data from our local population to the existing evidence base.

MATERIALS AND METHODS

We conducted a retrospective-observational study over a 6-month period using our East of England hospital-based TIA clinic data with a catchment population of ~750,000. We also searched the literature on studies reporting the association between ABCD(2) score and CAS.

RESULTS

We included 341 patients in our observational study. The mean age in our cohort was 72.86 years (SD 10.91) with 52% male participants. ABCD(2) score was not significantly associated with CAS (p = 0.78). Only age > 60 years was significantly associated with ipsilateral (> 50%) and contralateral CAS (> 50% and > 70%) (p < 0.01) after controlling for other confounders. The systematic review identified four studies for inclusion and no significant association between ABCD(2) score and CAS was reported, confirming our findings.

CONCLUSION

Our systematic review and observational study confirm that the ABCD(2) score does not predict CAS. However, our observational study has examined a larger number of possible predictors and demonstrates that age appears to be the single best predictor of CAS in patients presenting with a TIA. Selection of urgent carotid ultrasound scan thus should be based on individual patient's age and potential benefit of carotid intervention rather than ABCD(2) score.

The SOAR stroke score predicts hospital length of stay in acute stroke: an external validation study

AIMS

The objective of this study is to externally validate the SOAR stroke score (Stroke subtype, Oxfordshire Community Stroke Project Classification, Age and prestroke modified Rankin score) in predicting hospital length of stay (LOS) following an admission for acute stroke.

METHODS

We conducted a multi-centre observational study in eight National Health Service hospital trusts in the Anglia Stroke & Heart Clinical Network between September 2008 and April 2011. The usefulness of the SOAR stroke score in predicting hospital LOS in the acute settings was examined for all stroke and then stratified by discharge status (discharged alive or died during the admission).

RESULTS

A total of 3596 patients (mean age 77 years) with first-ever or recurrent stroke (92% ischaemic) were included. Increasing LOS was observed with increasing SOAR stroke score (p < 0.001 for both mean and median) and the SOAR stroke score of 0 had the shortest mean LOS (12 ± 20 days) while the SOAR stroke score of 6 had the longest mean LOS (26 ± 28 days). Among patients who were discharged alive, increasing SOAR stroke score had a significantly higher mean and median LOS (p < 0.001 for both mean and median) and the LOS peaked among patients with score value of 6 [mean (SD) 35 ± 31 days, median (IQR) 23 (14-48) days]. For patients who died as in-patient, there was no significant difference in mean or median LOS with increasing SOAR stroke score (p = 0.68 and p = 0.79, respectively).

CONCLUSION

This external validation study confirms the usefulness of the SOAR stroke score in predicting LOS in patients with acute stroke especially in those who are likely to survive to discharge. This provides a simple prognostic score useful for clinicians, patients and service providers.

Acoustic profiling in a complexly social species, the American crow: caws encode information on caller sex, identity, and behavioural context

Previous research on inter-individual variation in the calls of corvids has largely been restricted to single call types, such as alarm or contact calls, and has rarely considered the effects of age on call structure. This study explores structural variation in a contextually diverse set of "caw" calls of the American crow (Corvus brachyrhynchos), including alarm, foraging recruitment and territorial calls, and searches for structural features that may be associated with behavioural context and caller sex, age, and identity. Automated pitch detection algorithms are used to generate 23 pitch-related and spectral parameters for a collection of caws from 18 wild, marked crows. Using principal component analysis and mixed models, we identify independent axes of acoustic variation associated with behavioural context and with caller sex, respectively. We also have moderate success predicting caller sex and identity from call structure. However, we do not find significant acoustic variation with respect to caller age.

Adherence therapy improves medication adherence and quality of life in people with Parkinson's disease: a randomised controlled trial

BACKGROUND

Many factors are associated with medication non-adherence in Parkinson's disease (PD), including complex treatment regimens, mood disorders and impaired cognition. However, interventions to improve adherence which acknowledge such factors are lacking. A phase II randomised controlled trial was conducted investigating whether Adherence Therapy (AT) improves medication adherence and quality of life (QoL) compared with routine care (RC) in PD.

METHODS

Eligible PD patients and their spouse/carers were randomised to intervention (RC plus AT) or control (RC alone). Primary outcomes were change in adherence (Morisky Medication Adherence Scale) and QoL (Parkinson's Disease Questionnaire-39) from baseline to week-12 follow up. Secondary outcomes were MDS-UPDRS (part I, II, IV), Beliefs about Medication Questionnaire (BMQ), EuroQol (EQ-5D) and the Caregiving Distress Scale. Blinded data were analysed using logistic and linear regression models based on the intention-to-treat principle.

RESULTS

Seventy-six patients and 46 spouse/carers completed the study (intervention: n = 38 patients, n = 24 spouse/carers). At week-12 AT significantly improved adherence compared with RC (OR 8.2; 95% CI: 2.8, 24.3). Numbers needed to treat (NNT) were 2.2 (CI: 1.6, 3.9). Compared with RC, AT significantly improved PDQ-39 (-9.0 CI: -12.2, -5.8), BMQ general harm (-1.0 CI: -1.9, -0.2) and MDS-UPDRS part II (-4.8 CI: -8.1, -1.4). No significant interaction was observed between the presence of a spouse/carer and the effect of AT.

CONCLUSION

Adherence Therapy improved self-reported adherence and QoL in a PD sample. The small NNT suggests AT may be cost-effective. A larger pragmatic trial to test the efficacy and cost-effectiveness of AT by multiple therapists is required.

Scent marks as social signals inGalago crassicaudatus II. Discrimination between individuals by scent

Thick-tailed galagos,Galago crassicaudatus argentatus, which had been habituated to the scent marks of a conspecific through repeated presentations, increased their sniffing when presented with scent marks from a second conspecific of the same sex. Thus, they discriminated between the scents of individual conspecifics. This result was obtained using naturally scent-marked perches and perches carrying only chest gland scent-the latter even two weeks after the marking. When urine, the prevalent scent signal among most other galago species, was tested, it elicited little interest and discriminations were not clearly made. It is suggested that the use of more specialized scents is related to the social characteristics ofGalago crassicaudatus.

American crows as carriers of vancomycin-resistant enterococci with vanA gene

We studied the vanA-carrying vancomycin-resistant enterococci (VRE) isolated from American crows in the United States during the winter 2011/2012. Faecal samples from crows were cultured selectively for VRE and characterized. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to examine epidemiological relationships of vanA-containing VRE. Isolates were tested in vitro for their ability to horizontally transfer the vancomycin resistance trait. VRE with the vanA gene were found in 15 (2.5%) of 590 crows samples, from which we obtained 22 different isolates. Enterococcal species were Enterococcus faecium (14) and E. faecalis (8). One, two and 19 isolates originated from Kansas, New York State and Massachusetts, respectively. Based on MLST analysis, E. faecium isolates were grouped as ST18 (6 isolates), ST555 (2), and novel types ST749 (1), ST750 (3), ST751 (1), ST752 (1). Enterococcus faecalis isolates belonged to ST6 (1), ST16 (3) and ST179 (4). All isolates were able to transfer the vancomycin resistance trait via filter mating with very high transfer range. Clinically important enterococci with the vanA gene occur in faeces of wild American crows throughout the United States. These migrating birds may contribute to the dissemination of VRE in environment over large distances. [Correction added after first online publication on 06 August 2013: The number of E. faecium ST752 isolate is now amended to '1', consistent with that shown in the 'Results' section and Figure 2.].

Shyness and boldness in humans and other animals

The shy-bold continuum is a fundamental axis of behavioral variation in humans and at least some other species, but its taxonomic distribution and evolutionary implications are unknown. Models of optimal risk, density- or frequency-dependent selection, and phenotypic plasticity can provide a theoretical framework for understanding shyness and boldness as a product of natural selection. We sketch this framework and review the few empirical studies of shyness and boldness in natural populations. The study of shyness and boldness adds an interesting new dimension to behavioral ecology by focusing on the nature of continuous behavioral variation that exists within the familiar categories of age, sex and size.

Systematic review: potential preventive effects of statins against oesophageal adenocarcinoma

BACKGROUND

The incidence of oesophageal adenocarcinoma (OAC) has risen dramatically in recent decades, and its prognosis remains extremely poor. There is emerging evidence that statins may prevent OAC.

AIM

To systematically review both the experimental and epidemiological evidence to determine whether statins reduce the risk of developing OAC.

METHODS

Relevant laboratory and epidemiological studies were identified by systematically searching the PUBMED and EMBASE electronic databases for data on statins and oesophageal cancer (OC). The evidence was assessed according to the nine Bradford Hill criteria (BHC) of causality. Pooled effect sizes (ES) were calculated for the risk of OC with prior statin use.

RESULTS

Many of the BHC were supported including: 'plausible biological mechanisms', 'coherence', 'strong associations', 'consistency', 'biological gradient', 'analogy' and 'temporality'. Three experimental studies reported that statins inhibited proliferation, induced apoptosis and may limit metastatic potential in OAC cell lines. Fixed effects meta-analysis of two prospective studies in Barrett's oesophagus cohorts, involving 1382 participants, showed an ES of 0.53 (95% CI = 0.36-0.78, P = 0.001, I(2)  = 0%) for risk of OAC with prior statin use. Meta-analysis of three prospective studies in general population cohorts, involving 35 214 participants, showed an ES of 0.86 (95% CI = 0.78-0.94, P = 0.001, I(2)  = 0%) for risk of OC with prior statin use. The most important criterion, 'experiment', is as yet unfulfilled as to date there are no clinical trials which investigate this hypothesis.

CONCLUSION

There is some evidence that statins may protect against the development of OAC, although to be conclusive, data from randomised clinical trials are required.

Auditory disturbances promote temporal clustering of yawning and stretching in small groups of budgerigars (Melopsittacus undulatus)

Yawning may serve both social and nonsocial functions. When budgerigars (Melopsittacus undulatus) are briefly held, simulating capture by a predator, the temporal pattern of yawning changes. When this species is observed in a naturalistic setting (undisturbed flock), yawning and also stretching, a related behavior, are mildly contagious. On the basis of these findings, we hypothesized that a stressful event would be followed by the clustering of these behaviors in a group of birds, which may be facilitated both by a standard pattern of responding to a startling stressor and also contagion. In this study, we measured yawning and stretching in 4-bird groups following a nonspecific stressor (loud white noise) for a period of 1 hr, determining whether auditory disturbances alter the timing and frequency of these behaviors. Our results show that stretching, and to a lesser degree yawning, were nonrandomly clumped in time following the auditory disturbances, indicating that the temporal clustering is sensitive to, and enhanced by, environmental stressors while in small groups. No decrease in yawning such as found after handling stress was observed immediately after the loud noise but a similar increase in yawning 20 min after was observed. Future research is required to tease apart the roles of behavioral contagion and a time-setting effect following a startle in this species. This research is of interest because of the potential role that temporal clumping of yawning and stretching could play in both the collective detection of, and response to, local disturbances or predation threats.

CHANGES IN AMBIENT TEMPERATURE TRIGGER YAWNING BUT NOT STRETCHING IN RATS

Yawning appears to be involved in arousal, state change, and activity across vertebrates. Recent research suggests that yawning may support effective changes in mental state or vigilance through cerebral cooling. To further investigate the relationship between yawning, state change, and thermoregulation, 12 Sprague-Dawley rats (Rattus norvegicus) were exposed to a total of two hours of ambient temperature manipulation over a period of 48 hours. Using a repeated measures design, each rat experienced a range of increasing (22→32°C), decreasing (32→22°C), and constant temperatures (22°C; 32°C). Yawning and locomotor activity occurred most frequently during initial changes in temperature, irrespective of direction, compared to more extended periods of temperature manipulation. The rate of yawning also diminished during constant high temperatures (32°C) compared to low temperatures (22°C). Unlike yawning, however, stretching was unaffected by ambient temperature variation. These findings are compared to recent work on budgerigars (Melopsittacus undulatus), and the ecological selective pressures for yawning in challenging thermal environments are discussed. The results support previous comparative research connecting yawning with arousal and state change, and contribute to refining the predictions of the thermoregulatory hypothesis across vertebrates.

The direction and range of ambient temperature change influences yawning in budgerigars (Melopsittacus undulatus)

Comparative research suggests that yawning is a thermoregulatory behavior in homeotherms. Our previous experiments revealed that yawning increased in budgerigars (Melopsittacus undulatus) as ambient temperature was raised toward body temperature (22-->34 degrees C). In this study, we identify the range of temperatures that triggers yawning to rule out the possible effect of changing temperature in any range. To corroborate its thermoregulatory function, we also related the incidence of yawning to other avian thermoregulatory behaviors in budgerigars (e.g., panting, wing venting). In a repeated measures design, 16 budgerigars were exposed to 4 separate 10-min periods of changing temperatures: (a) low-increasing (23-->27 degrees C), (b) high-increasing (27-->33 degrees C), (c) high-decreasing (34-->28 degrees C), and (d) low-decreasing (28-->24 degrees C). Birds yawned significantly more during the high-increasing temperature range, and yawning was positively correlated with ambient temperature across trials. Yawning was also positively correlated with other thermoregulatory behaviors. This research clarifies the previously demonstrated relationship between yawning rate and temperature by providing evidence that the physiological trigger for yawning is related to increasing body temperatures rather than the detection of changing external temperatures.

Factors associated with the risk of West Nile virus among crows in New York State

West Nile virus (WNV) is transmitted between avian hosts in enzootic cycles by a mosquito vector. The virus has significant disease effects on humans and equines when it bridges into an epizootic cycle. As the initial epidemic of WNV in 1999, perennial outbreaks in New York State suggest the local establishment of natural foci with perpetuation of the virus among susceptible hosts rather than reintroduction of the virus. The factors that play a role in the perpetuation of the virus are not fully understood. American crows (Corvus brachyrhynchos) are known to be highly susceptible to infection with the virus. We investigate the factors that put crows at risk of infection in Tompkins County, New York during the period of 2000-2008 in a case-control study. Cases were crow carcasses that were found dead and tested positive for WNV using real time reverse transcription or VecTest. Data on putative risk factors were collected and assessed for significance of association with the presence of WNV using logistic regression analysis to evaluate the significance of each factor while simultaneously controlling for the effect of others. The risk of a crow carcass testing WNV positive varied with age, season of the year and ecological area where the carcass was found. Crows that were more than 1-year-old were four times more likely to be WNV positive in comparison to birds that were less than 1 year of age. It was three times more likely to find WNV positive carcasses in residential areas in comparison to rural areas. The risk of testing WNV positive did not vary by sex of the crow carcasses.

VISUAL ADAPTATION AND CHEMISTRY OF THE RODS

1. The reality of a chemical cycle proposed to describe the rhodopsin system is tested with dark adaptation measurements. 2. The first few minutes of rod dark adaptation are rapid following short, slower following long irradiation. As dark adaptation proceeds, the slow process grows more prominent, and occupies completely the final stages of adaptation. 3. Light adaptation displays similar duality. As the exposure to light of constant intensity lengthens, the visual threshold rises, and independently the speed of dark adaptation decreases. 4. These results conform with predictions from the chemical equations.

Condition, innate immunity and disease mortality of inbred crows

Cooperatively breeding American crows (Corvus brachyrhynchos) suffer a severe disease-mediated survival cost from inbreeding, but the proximate mechanisms linking inbreeding to disease are unknown. Here, we examine indices of nestling body condition and innate immunocompetence in relationship to inbreeding and disease mortality. Using an estimate of microsatellite heterozygosity that predicts inbreeding in this population, we show that inbred crows were in relatively poor condition as nestlings, and that body condition index measured in the first 2-33 days after hatching, in addition to inbreeding index, predicted disease probability in the first 34 months of life. Inbred nestlings also mounted a weaker response along one axis of innate immunity: the proportion of bacteria killed in a microbiocidal assay increased as heterozygosity index increased. Relatively poor body condition and low innate immunocompetence are two mechanisms that might predispose inbred crows to ultimate disease mortality. A better understanding of condition-mediated inbreeding depression can guide efforts to minimize disease costs of inbreeding in small populations.

Non-West Nile virus-associated mortality in a population of American crows (Corvus brachyrhynchos): a gross and histopathologic study

The American crow (Corvus brachyrhynchos) is a common urban and rural inhabitant of the Northeast and Midwest United States that is commonly infected with West Nile virus (WNV). The current study was initiated to determine non-WNV-associated causes of mortality in the American crow. All animals (40/40) tested negative for WNV infection via polymerase chain reaction and had no evidence of infection based on immunohistochemistry. Common gross necropsy findings included external trauma (6/40), hepatosplenomegaly (6/40), poxviral dermatitis (5/40), and pneumonia (3/40). Common histologic findings included endoparasitism (32/40), multifocal hepatic and splenic necrosis (7/40), pigment accumulation in the spleen (5/40), and disseminated bacterial infection (3/40). The most significant and debilitating diseases included fungal pneumonia and poxvirus-associated lesions. The present report increases the knowledge of diseases present in the American crow population.

Growth and nutritional state of American Crow nestlings vary between urban and rural habitats

In urbanized areas, many adult birds find sufficient foods to survive, but the anthropogenic foods that are abundant there may be detrimental to nestling growth. In fact, American Crow (Corvus brachyrhynchos) nestlings are smaller in suburban than rural areas, possibly because of nutrient limitation. Here, we seek to identify possible causes of size differences by comparing both size and blood chemistry measures in rural and suburban crow nestlings. We quantified land use in known crow territories and distinguished three distinct environments: suburban-residential, suburban-managed (e.g., golf courses), and rural. We measured nestlings near fledging age in each environment and bled them for determination of unbound plasma calcium, total protein, and corticosterone. We supplemented a subset of broods in suburban-residential and rural areas with a food high in protein and calcium. Rural nestlings were significantly larger than suburban-residential crows and had higher total serum protein. Nestlings in suburban-managed areas were intermediate in size and serum protein but had the lowest plasma calcium levels. Nestling corticosterone levels did not differ significantly among habitats, indicating that, although suburban nestlings may be food-limited, they were not starving. Supplemented nestlings in suburban-residential areas were significantly larger in some growth measures than their unsupplemented counterparts. Unexpectedly, supplemented rural nestlings were significantly smaller than unsupplemented rural ones, suggesting that parents use easily accessible food even when it is nutritionally suboptimal. Our results indicate that nestlings in suburban areas are nutrient restricted, rather than calorie restricted.

Disease-mediated inbreeding depression in a large, open population of cooperative crows

Disease-mediated inbreeding depression is a potential cost of living in groups with kin, but its general magnitude in wild populations is unclear. We examined the relationships between inbreeding, survival and disease for 312 offspring, produced by 35 parental pairs, in a large, open population of cooperatively breeding American crows (Corvus brachyrhynchos). Genetic analyses of parentage, parental relatedness coefficients and pedigree information suggested that 23 per cent of parental dyads were first- or second-order kin. Heterozygosity-heterozygosity correlations suggested that a microsatellite-based index of individual heterozygosity predicted individual genome-wide heterozygosity in this population. After excluding birds that died traumatically, survival probability was lower for relatively inbred birds during the 2-50 months after banding: the hazard rate for the most inbred birds was 170 per cent higher than that for the least inbred birds across the range of inbreeding index values. Birds that died with disease symptoms had higher inbreeding indices than birds with other fates. Our results suggest that avoidance of close inbreeding and the absence of inbreeding depression in large, open populations should not be assumed in taxa with kin-based social systems, and that microsatellite-based indices of individual heterozygosity can be an appropriate tool for examining the inbreeding depression in populations where incest and close inbreeding occur.

Reproductive partitioning and the assumptions of reproductive skew models in the cooperatively breeding American crow

Understanding the benefits of cooperative breeding for group members of different social and demographic classes requires knowledge of their reproductive partitioning and genetic relatedness. From 2004-2007, we examined parentage as a function of relatedness and social interactions among members of 21 American crow (Corvus brachyrhynchos) family groups. Paired female breeders monopolized maternity of all offspring in their broods, whereas paired male breeders sired 82.7% of offspring, within-group auxiliary males sired 6.9% of offspring, and extragroup males sired 10.4% of offspring. Although adult females had fewer opportunities for direct reproduction as auxiliaries than males, they appeared to have earlier opportunities for independent breeding. These different opportunities for direct reproduction probably contributed to the male biased adult auxiliary sex ratio. Patterns of reproductive partitioning and conflict among males were most consistent with a synthetic reproductive skew model, in which auxiliaries struggled with breeders for a limited reproductive share, beyond which breeders could evict them. Counter to a frequent assumption of reproductive skew models, female breeders appeared to influence paternity, although their interests might have agreed with the interests of their paired males. Unusual among cooperative breeders, close inbreeding and incest occurred in this population. Incest avoidance between potential breeders did not significantly affect reproductive skew.

Meta-analysis of the timing of haemorrhage after tonsillectomy: an important factor in determining the safety of performing tonsillectomy as a day case procedure

OBJECTIVES

To perform a meta-analysis of studies of the timing of primary tonsillectomy haemorrhage. In particular to compare the difference in risk between 0-8 and 8-24 h; that is whether overnight inpatient tonsillectomy is required.

DESIGN

Medline search of all tonsillectomy studies to perform a meta-analysis of the timing of primary haemorrhages.

SETTING

Literature-based study.

PARTICIPANTS

All adult and paediatric tonsillectomy studies giving the absolute number and timing of all primary haemorrhages.

MAIN OUTCOME MEASURES

The overall incidence of haemorrhage occurring between 0-8 and 8-24 h. The overall incidence of haemorrhage for each of the first 24 h after operation. Compare risk of a bleed occurring 0-8, 8-24 and >24 h where data were available.

RESULTS

From a 1.4% overall risk of a primary haemorrhage only one in 14 occur after 8 h, i.e. 0.1% (95% CI=0.08-0.16%). A total of 833 patients would require to be kept overnight in order to identify one case of bleeding after 8 h.

CONCLUSIONS

Little benefit was conferred from overnight admission from the point of view of monitoring for primary haemorrhage. A case can be made for either day-case tonsillectomy (hospital stay over the period in which 93% of primary haemorrhages would occur) or the 'belt-and-braces' approach of a 1-week stay (during which all haemorrhages would occur) but current 24-h admission appears illogical.

Functional analysis of the mismatch repair system in bladder cancer

In bladder cancer the observed microsatellite instability indicates that mismatch repair deficiency could be a frequently involved factor in bladder cancer progression. To investigate this hypothesis we analysed extracts of seven bladder cancer cell lines and, as a novel approach, five clinical cancer samples for mismatch repair activity. We found that one cell line (T24) and three of the clinical samples had a reduced repair capacity, measured to approximately 20% or less. The T24 cell extract was unable to repair a G-G mismatch and showed reduced repair of a 2-base loop, consistent with diminished function of the MSH2-MSH6 heterodimer. The functional assay was combined with measurement for mutation frequency, microsatellite analysis, sequencing, MTT assay, immunohistochemical analysis and RT-PCR analysis of the mismatch repair genes MSH2, MSH3, MSH6, PMS1, PMS2 and MLH1. A >7-fold relative increase in mutation frequency was observed for T24 compared to a bladder cancer cell line with a fully functional mismatch repair system. Neither microsatellite instability, loss of repair nor mismatch repair gene mutations were detected. However, RT-PCR analysis of mRNA levels did detect changes in the ratio of expression of the Mut S and Mut L homologues. The T24 cell line had the lowest MSH6 expression level of the cell lines tested. Identical RT-PCR analysis of seventeen clinical samples (normal urothelium, 7; pTa low stage, 5; and pT1-4 high stage, 5) indicated a significant change in the expression ratio between MSH3/MSH6 (P< 0.004), MSH2/MSH3 (P< 0.012) and PMS2/MLH1 P< 0.005, in high stage bladder tumours compared to normal urothelium and low stage tumours. Collectively, the data suggest that imbalanced expression of mismatch repair genes could lead to partial loss of mismatch repair activity that is associated with invasive bladder cancer.

Functional interaction of proliferating cell nuclear antigen with MSH2-MSH6 and MSH2-MSH3 complexes

Eukaryotic DNA mismatch repair requires the concerted action of several proteins, including proliferating cell nuclear antigen (PCNA) and heterodimers of MSH2 complexed with either MSH3 or MSH6. Here we report that MSH3 and MSH6, but not MSH2, contain N-terminal sequence motifs characteristic of proteins that bind to PCNA. MSH3 and MSH6 peptides containing these motifs bound PCNA, as did the intact Msh2-Msh6 complex. This binding was strongly reduced when alanine was substituted for conserved residues in the motif. Yeast strains containing alanine substitutions in the PCNA binding motif of Msh6 or Msh3 had elevated mutation rates, indicating that these interactions are important for genome stability. When human MSH3 or MSH6 peptides containing the PCNA binding motif were added to a human cell extract, mismatch repair activity was inhibited at a step preceding DNA resynthesis. Thus, MSH3 and MSH6 interactions with PCNA may facilitate early steps in DNA mismatch repair and may also be important for other roles of these eukaryotic MutS homologs.

Mutator phenotypes of common polymorphisms and missense mutations in MSH2

Hereditary non-polyposis colorectal cancer (HNPCC) is associated with germline mutations in the DNA mismatch repair gene hMSH2 [1], the human homologue of the Escherichia coli MutS gene. These are mostly nonsense, frameshift or deletion mutations that result in loss of intact protein and complete inactivation of DNA mismatch repair. However, cancer is also associated with hMSH2 missense mutations that are merely inferred to be deleterious because they result in non-conservative substitutions of amino acids that are highly conserved among MutS family proteins. Moreover, sequence polymorphisms exist in hMSH2 that also change conserved amino acids but whose functional consequences and relationship to cancer are uncertain. Here, we show that yeast strains harboring putative equivalents of three hMSH2 polymorphisms have elevated mutation rates. Mutator effects were also observed for yeast equivalents of hMSH2 missense mutations found in HNPCC families and in an early onset colon tumor. Several distinct phenotypes were observed, indicating that these missense mutations have differential effects on MSH2 function(s). The results suggest that cancer may be associated with even partial loss of hMSH2 function and they are consistent with the hypothesis that polymorphisms in hMSH2 might predispose humans to disease.

Mutator phenotypes of yeast strains heterozygous for mutations in the MSH2 gene

Heterozygosity for germ-line mutations in the DNA mismatch repair gene MSH2 predisposes humans to cancer. Here we use a highly sensitive reporter to describe a spontaneous mutator phenotype in diploid yeast cells containing a deletion of only one MSH2 allele. We also identify five MSH2 missense mutations that have dominant mutator effects in heterozygous cells when expressed at normal levels from the natural MSH2 promoter. For example, a 230-fold mutator effect is observed in an MSH2/msh2 diploid strain in which Gly693, which is invariant in MutS homologs and involved in ATP hydrolysis, is changed to alanine. DNA binding data suggest that mismatch repair is suppressed by binding of a mutant Msh2-Msh6 heterodimer to a mismatch with subsequent inability to dissociate from the mismatch in the presence of ATP. A dominant mutator effect also is observed in yeast when Gly693 is changed to serine. An early onset colorectal tumor is heterozygous for the analogous Gly --> Ser mutation in hMSH2, and a second hMSH2 mutation was not found, suggesting that this missense mutation may predispose to cancer via a dominant mutator effect. The mutator effects of the deletion mutant and the Gly --> Ala missense mutant in yeast MSH2 are enhanced by heterozygosity for a missense mutation in DNA polymerase delta that reduces its proofreading activity but is not a mutator in the heterozygous state. The synergistic effects of heterozygosity for mutations in two different genes that act in series to correct replication errors may be relevant to cancer predisposition.

Functional analysis of human MutSalpha and MutSbeta complexes in yeast

Mismatch repair (MMR) is initiated when a heterodimer of hMSH2*hMSH6 or hMSH2*hMSH3 binds to mismatches. Here we perform functional analyses of these human protein complexes in yeast. We use a sensitive genetic system wherein the rate of single-base deletions in a homopolymeric run in the LYS2 gene is 10 000-fold higher in an msh2 mutant than in a wild-type strain. Expression of the human proteins alone or in combination does not reduce the mutation rate of the msh2 strain, and expression of the individual human proteins does not increase the low mutation rate of a wild-type strain. However, co-expression of hMSH2 and hMSH6 in wild-type yeast increases the mutation rate 4000-fold, while co-expression of hMSH2 and hMSH3 elevates the rate 5-fold. Analysis of cell extracts indicates that the proteins are expressed and bind to mismatched DNA. The results suggest that hMutSalpha and hMutSbeta complexes form, bind to and prevent correction of replication slippage errors in yeast. Expression of hMSH6 with hMSH2 containing a proline substituted for a conserved Arg524 eliminates the mutator effect and reduces mismatch binding. The analogous mutation in humans is associated with microsatellite instability, defective MMR and cancer, illustrating the utility of the yeast system for studying human disease alleles.

Red-winged blackbird females fail to increase feeding in response to begging call playbacks

The begging behaviour of nestling birds appears to be the main signal telling parents how much food is needed by the brood. Not only may the accuracy of that information be reduced through exaggeration due to competition, but it may also vary with the age of the nestling. Younger nestlings may vary more in how frequently they call than older nestlings because they cannot discriminate stimuli as well. Thus, even if 'honest', begging from younger nestlings could be a less reliable hunger signal than that from older nestlings. We tested the prediction that parents should respond less to the increased frequency of begging from very young versus older nestlings by playing back begging calls at the nests of both younger (</=5 day) and older (>/=6 days) red-winged blackbirds, Agelaius phoeniceus. In neither case did parents respond with consistent increases in feeding, nor did young gain more weight during playbacks. This lack of response is discussed in relation to two other recent studies of blackbirds that did demonstrate increased feeding with playbacks of begging calls. Copyright 1998 The Association for the Study of Animal Behaviour.

Identifying and managing patients with hyperlipidemia

Cardiovascular disease related to hyperlipidemia is a significant cause of morbidity and mortality in the United States. The benefit of lowering lipid levels in patients with and without cardiovascular disease has been demonstrated in numerous clinical trials. The results of these trials prompted the National Heart, Blood, and Lung Institute to form the Nation Cholesterol Education Panel (NCEP). This panel developed guidelines for identifying and treating lipid disorders. Before starting antilipemic therapy, patients should be evaluated for secondary causes of hyperlipidemia, including disease states and medications. Risk factors for cardiovascular disease should be identified and used to determine the patient's goal low-density lipoprotein level. Regardless of the drug therapy used, the cornerstone treatment for hyperlipidemia is dietary changes. The NCEP recommendation for dietary modification follows a two-step plan to reduce intake of cholesterol and dietary fats. Other nonpharmacologic treatments for hyperlipidemia include exercise, weight reduction for obese patients, reduction of excessive alcohol use, and smoking cessation . Drug therapy should be considered in patients who do not respond to an adequate trial of dietary modifications and lifestyle changes. The principal lipid-lowering agents currently used are the bile acid sequestrants, nicotinic acid, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors, and fibric acid derivatives. Estrogen, fish oil, and alcohol also can decrease the risk of developing heart disease. In pharmacoeconomic studies, lipid-lowering drug therapy has been shown to decrease the number of procedures, hospitalizations, and other medical interventions required by patients with cardiovascular disease.

Fluconazole and amphotericin B for cryptococcal meningitis

OBJECTIVE

To describe a patient with cryptococcal meningitis treated with the combination of amphotericin B and fluconazole.

CASE SUMMARY

A 41-year-old woman with cryptococcal meningitis who was not infected with HIV was treated with a combination of amphotericin B and fluconazole because she did not respond to amphotericin B alone and could not tolerate amphotericin B with flucytosine. She improved clinically, but it is unclear whether the combination was beneficial.

DISCUSSION

Standard therapy for cryptococcal meningitis is amphotericin B with or without flucytosine. Fluconazole is an alternative therapy, but its efficacy has not been documented in the patient population not infected with HIV. Theoretically, the combination of amphotericin B and fluconazole is antagonistic, but in vitro and in vivo data suggest that antagonism may not occur. The combination of amphotericin B and fluconazole in cryptococcal meningitis has not been evaluated in clinical trials, and its use is not recommended.

CONCLUSIONS

A patient with cryptococcal meningitis was treated with the combination of amphotericin B and fluconazole because of a poor response to amphotericin B monotherapy and intolerance to flucytosine. It is unclear whether her clinical response was a result of the combination.

Requirement for PCNA in DNA mismatch repair at a step preceding DNA resynthesis

A two-hybrid system was used to screen yeast and human expression libraries for proteins that interact with mismatch repair proteins. PCNA was recovered from both libraries and shown in the case of yeast to interact with both MLH1 and MSH2. A yeast strain containing a mutation in the PCNA gene had a strongly elevated mutation rate in a dinucleotide repeat, and the rate was not further elevated in a strain also containing a mutation in MLH1. Mismatch repair activity was examined in human cell extracts using an assay that does not require DNA repair synthesis. Activity was inhibited by p21WAF1 or a p21 peptide, both of which bind to PCNA, and activity was restored to inhibited reactions by addition of PCNA. The data suggest a PCNA requirement in mismatch repair at a step preceding DNA resynthesis. The ability of PCNA to bind to MLH1 and MSH2 may reflect linkage between mismatch repair and replication and may be relevant to the roles of mismatch repair proteins in other DNA transactions.