Polychlorinated biphenyl and polybrominated diphenyl ether profiles vary with feeding ecology and marine rearing distribution among 10 Chinook salmon (Oncorhynchus tshawytscha) stocks in the North Pacific Ocean

Chinook salmon (Oncorhynchus tshawytscha) along the west coast of North America have experienced significant declines in abundance and body size over recent decades due to several anthropogenic stressors. Understanding the reasons underlying the relatively high levels of persistent organic pollutants (POPs) in Chinook stocks is an important need, as it informs recovery planning for this foundation species, as well for the Chinook-dependent Resident killer whales (Orcinus orca, RKW) of British Columbia (Canada) and Washington State (USA). We evaluated the influence of stock-related differences in feeding ecology, using stable isotopes, and marine rearing ground on the concentrations and patterns of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Chinook salmon. A principal components analysis (PCA) revealed a clear divergence of PCB and PBDE congener patterns between Chinook with a nearshore rearing distribution ('shelf resident') versus a more offshore distribution. Shelf resident Chinook had 12-fold higher PCB concentrations and 46-fold higher PBDE concentrations relative to offshore stocks. Shelf resident Chinook had PCB and PBDE profiles that were heavier and dominated by more bioaccumulative congeners, respectively. The higher δ13C and δ15N in shelf resident Chinook compared to the offshore rearing stocks, and their different marine distributions explain the large divergence in contaminant levels and profiles, with shelf resident stocks being heavily influenced by land-based sources of industrial contamination. Results provide compelling new insight into the drivers of contaminant accumulation in Chinook salmon, raise important questions about the consequences for their health, and explain a major pathway to the heavily POP-contaminated Resident killer whales that consume them.

Regulation of mouse exploratory behaviour by irradiance and cone-opponent signals

BACKGROUND

Animal survival depends on the ability to adjust behaviour according to environmental conditions. The circadian system plays a key role in this capability, with diel changes in the quantity (irradiance) and spectral content ('colour') of ambient illumination providing signals of time-of-day that regulate the timing of rest and activity. Light also exerts much more immediate effects on behaviour, however, that are equally important in shaping daily activity patterns. Hence, nocturnal mammals will actively avoid light and dramatically reduce their activity when light cannot be avoided. The sensory mechanisms underlying these acute effects of light are incompletely understood, particularly the importance of colour.

RESULTS

To define sensory mechanisms controlling mouse behaviour, we used photoreceptor-isolating stimuli and mice with altered cone spectral sensitivity (Opn1mwR), lacking melanopsin (Opn1mwR; Opn4-/-) or cone phototransduction (Cnga3-/-) in assays of light-avoidance and activity suppression. In addition to roles for melanopsin-dependent irradiance signals, we find a major influence of spectral content in both cases. Hence, remarkably, selective increases in S-cone irradiance (producing a blue-shift in spectrum replicating twilight) drive light-seeking behaviour and promote activity. These effects are opposed by signals from longer-wavelength sensitive cones, indicating a true spectrally-opponent mechanism. Using c-Fos-mapping and multielectrode electrophysiology, we further show these effects are associated with a selective cone-opponent modulation of neural activity in the key brain site implicated in acute effects of light on behaviour, the subparaventricular zone.

CONCLUSIONS

Collectively, these data reveal a mechanism whereby blue-shifts in the spectrum of environmental illumination, such as during twilight, promote mouse exploratory behaviour.

Colour opponency is widespread across the mouse subcortical visual system and differentially targets GABAergic and non-GABAergic neurons

Colour vision plays many important roles in animal behaviour but the brain pathways processing colour remain surprisingly poorly understood, including in the most commonly used laboratory mammal, mice. Indeed, particular features of mouse retinal organisation present challenges in defining the mechanisms underlying colour vision in mice and have led to suggestions that this may substantially rely on 'non-classical' rod-cone opponency. By contrast, studies using mice with altered cone spectral sensitivity, to facilitate application of photoreceptor-selective stimuli, have revealed widespread cone-opponency across the subcortical visual system. To determine the extent to which such findings are truly reflective of wildtype mouse colour vision, and facilitate neural circuit mapping of colour-processing pathways using intersectional genetic approaches, we here establish and validate stimuli for selectively manipulating excitation of the native mouse S- and M-cone opsin classes. We then use these to confirm the widespread appearance of cone-opponency (> 25% of neurons) across the mouse visual thalamus and pretectum. We further extend these approaches to map the occurrence of colour-opponency across optogenetically identified GABAergic (GAD2-expressing) cells in key non-image forming visual centres (pretectum and intergeniculate leaflet/ventral lateral geniculate; IGL/vLGN). Strikingly, throughout, we find S-ON/M-OFF opponency is specifically enriched in non-GABAergic cells, with identified GABAergic cells in the IGL/VLGN entirely lacking this property. Collectively, therefore, we establish an important new approach for studying cone function in mice, confirming a surprisingly extensive appearance of cone-opponent processing in the mouse visual system and providing new insight into functional specialisation of the pathways processing such signals.

Recurrent atherosclerotic cardiovascular disease events preventable with guideline recommended lipid-lowering treatment following myocardial infarction

Background

The 2018 American Heart Association/American College of Cardiology (AHA/ACC) cholesterol guideline provides recommendations for lipid-lowering therapy (LLT) including statins, ezetimibe and proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) to prevent recurrent atherosclerotic cardiovascular disease (ASCVD) events in adults with established ASCVD. Many adults with ASCVD who are recommended to take statins, ezetimibe and/or PCSK9i do not receive these medications.

Purpose

To estimate the number of recurrent ASCVD events potentially prevented by population-wide use of guideline recommended LLT following a myocardial infarction (MI).

Methods

We simulated the population-wide impact of receipt of 2018 AHA/ACC cholesterol guideline recommended LLT over 3 and 5 years among US adults with government health insurance through Medicare or commercial health insurance following hospital discharge for MI. We used data from patients with an MI hospitalization in 2018–2019 to estimate the percentage receiving guideline recommended LLT defined by having the medications available to take in the 30 days after their discharge date. We used data from patients with an MI hospitalization in 2013–2016 to estimate the 3 and 5-year cumulative incidence of recurrent ASCVD events (i.e., MI, coronary revascularization or ischemic stroke). The reduction in ASCVD events associated with guideline recommended LLT was estimated from a meta-analysis by the Cholesterol-Lowering Treatment Trialists Collaboration. We conducted a sensitivity analysis estimating the number and percentage of ASCVD events prevented if LLT recommendations from the 2019 European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) cholesterol guideline were followed. We repeated all analyses with recurrent coronary heart disease (i.e., MI or coronary revascularization) and ischemic stroke events as separate outcomes.

Results

Among 279,395 adults with an MI hospitalization in 2018–2019 (mean age 75 years, 54% men, mean low-density lipoprotein cholesterol 92 mg/dL), 27% were receiving guideline recommended LLT. With current lipid-lowering medication use, we estimated that 70,698 (95% CI: 70,311–71,077) and 89,255 (95% CI: 88,841–89,730) ASCVD events would occur in 3 and 5 years, respectively, after MI hospital discharge (Table, top panel). If all patients were to receive 2018 AHA/ACC guideline recommended LLT, the number of ASCVD events was estimated to be reduced by 21.6%, representing 15,264 (95% CI: 14,451–16,679) events prevented over 3 years and 19,271 (95% CI: 18,245–21,055) events prevented over 5 years. A higher number of recurrent ASCVD events were estimated to be averted following the LLT recommendations of the 2019 ESC/EAS cholesterol guideline (Table, bottom panel).

Conclusions

Population-wide implementation of guideline recommended LLT in adults with an MI hospitalization could prevent a substantial number of recurrent ASCVD events.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Amgen Inc.

Factors associated with time to initiation of a PCSK9 inhibitor after hospital discharge for acute myocardial infarction

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) lower atherosclerotic cardiovascular disease (ASCVD) event risk.

OBJECTIVE

Analyze patient characteristics associated with time to PCSK9i initiation following an acute myocardial infarction (AMI).

METHODS

We analyzed characteristics of patients ≥21 years of age in the Marketscan or Medicare databases who initiated a PCSK9i 0-89 days, 90-179 days, or 180-365 days after an AMI between July 2015 and December 2018 (n=1,705). We estimated the cumulative incidence of recurrent ASCVD events before PCSK9i initiation.

RESULTS

Overall, 42%, 25%, and 33% of patients who initiated a PCSK9i did so 0-89 days, 90-179 days, and 180-365 days following AMI hospital discharge, respectively. Taking ezetimibe prior to AMI hospitalization and initiating ezetimibe within 30 days after AMI hospital discharge were each associated with a higher likelihood of PCSK9i initiation in the 0-89 days versus 180-365 days post-discharge (adjusted odds ratio [OR] 1.83, 95% confidence interval [95%CI] 1.35-2.49 and 1.76, 95%CI 1.11-2.80, respectively). Statin use before and statin initiation within 30 days after AMI hospitalization were associated with a lower likelihood of PCSK9i initiation 0-89 days versus 180-365 days post-discharge (adjusted OR 0.64, 95%CI 0.49-0.84 and 0.39, 95%CI 0.28-0.54, respectively). Overall, 8.0%, 10.5%, and 12.5% of patients had an ASCVD event at 90, 180, and 365 days following AMI hospital discharge and before initiating a PCSK9i, respectively.

CONCLUSION

Among patients initiating a PCSK9i after AMI, a low proportion did so within 89 days of hospital discharge. Many patients had a recurrent ASCVD event before treatment initiation.

P3422Contrasting the risk for atherosclerotic cardiovascular disease events among individuals with lower extremity peripheral artery disease, coronary heart disease and cerebrovascular disease

Background

Having more vascular conditions, including coronary heart disease (CHD), cerebrovascular disease and lower extremity artery disease (LEAD), may increase the risk for atherosclerosis cardiovascular disease (ASCVD) events. Specific vascular conditions may increase the ASCVD event rate more than others.

Purpose

To compare the risk for future ASCVD events associated with the number and type of vascular conditions among adults with a history of CHD, cerebrovascular disease and/or LEAD.

Methods

We analyzed data from US adults ≥19 years of age with commercial or Medicare health insurance who had a history of CHD, cerebrovascular disease and/or LEAD as of December 31, 2014 (N=901,391). Individuals were followed through December 31, 2016 (median follow-up: 2 years) for ASCVD events, including myocardial infarction, coronary revascularization, stroke, carotid revascularization and lower extremity amputation or revascularization.

Results

Among individuals included in the current analysis (mean age 63 years, 45% female), 70%, 23% and 7% had 1, 2 and 3 vascular conditions, respectively. After adjustment for sociodemographic and cardiovascular risk factors, the hazard ratio for ASCVD among individuals with 2 and 3 versus 1 vascular conditions was 1.88 (1.85, 1.92) and 2.93 (2.86, 3.00), respectively. Among individuals with 1 vascular condition, the rate of ASCVD events per 1,000 person-years was 46.5 (95% CI 44.1, 49.0), 29.6 (95% CI 29.0, 30.1) and 19.9 (95% CI 19.2, 20.8) for those with LEAD, CHD and cerebrovascular disease, respectively. The multivariable-adjusted hazard ratio (95% CI) for ASCVD events comparing individuals with LEAD only and CHD only versus those with cerebrovascular disease only was 1.84 (1.77, 1.92) and 1.12 (1.08, 1.16), respectively. Among individuals with 2 vascular conditions, the ASCVD event rate per 1,000 person-years was higher in those with LEAD and CHD (122.0, 95% CI 112.5, 132.2) and with LEAD and cerebrovascular disease (92.4, 95% CI 79.9, 106.4), versus those with CHD and cerebrovascular disease (59.1, 95% CI 54.8, 63.6). The multivariable-adjusted hazard ratio (95% CI) comparing individuals with LEAD and CHD and those with LEAD and cerebrovascular disease versus those with CHD and cerebrovascular disease was 1.48 (1.44, 1.53) and 1.49 (1.41, 1.58), respectively.

Conclusion

Among adults with vascular disease, having LEAD confers a higher risk for future ASCVD events than CHD or cerebrovascular disease and this group may benefit from more intensive risk reduction treatment.

Acknowledgement/Funding

Amgen Inc.

P652Lower use of statins among patients with peripheral artery disease compared with those with coronary heart disease

Background

Adults with atherosclerotic cardiovascular disease are recommended to take a statin to reduce their risk for future cardiovascular events. Prior studies suggest that statins are being taken by most adults with coronary heart disease (CHD). However, there are few data on the use of statins among adults with peripheral artery disease (PAD).

Purpose

To compare the use of statins among US adults with a history of PAD versus those with a history of CHD.

Methods

We conducted a retrospective cohort study among US adults ≥19 years of age with commercial or government health insurance who had a history of CHD or PAD as of December 31, 2014 (n=1,006,451, mean age 63 years, 47% male). We used pharmacy claims between January 1 and December 31, 2014 to identify use of any statin and of a high-intensity statin (i.e., atorvastatin 40–80 mg, rosuvastatin 20–40 mg, simvastatin 80 mg). Patients with a history of CHD without PAD (CHD only), both CHD and PAD, and PAD without CHD (PAD only) were analysed. Prevalence ratios for use of any statin and a high-intensity statin among those taking a statin were calculated after multivariable adjustment for sociodemographics and cardiovascular risk factors.

Results

Overall, 69.1% of patients included in the current analysis had CHD only, 21.4% had both CHD and PAD, and 9.5% had PAD only. Overall, 66.0%, 68.2% and 47.5% of patients with CHD only, CHD and PAD, and PAD only were taking a statin. After multivariable adjustment and compared to patients with CHD only, the prevalence ratio for statin use was 1.02 (95% CI 1.01, 1.02) for those with both CHD and PAD and 0.82 (95% CI 0.82, 0.83) for those with PAD only. Among patients taking a statin, 29.4% of those with CHD only, 28.6% of those with both CHD and PAD, and 17.3% of those with PAD only were taking a high-intensity dosage. Compared to patients with CHD only, the multivariable adjusted prevalence ratio for taking a high-intensity dosage was 1.05 (95% CI 1.04, 1.06) for those with both CHD and PAD and 0.71 (95% CI 0.70, 0.73) for those with PAD only.

Conclusion

Adults with PAD receive less intensive statin therapy compared with their counterparts who have CHD. Interventions aimed to increase statin use among patients with PAD are warranted.

Acknowledgement/Funding

This study was supported through a research grant from Amgen, Inc. (Thousand Oaks, CA, USA).

Commissural communication allows mouse intergeniculate leaflet and ventral lateral geniculate neurons to encode interocular differences in irradiance

Key points

Unlike other visual thalamic regions, the intergeniculate leaflet and ventral lateral geniculate nucleus (IGL/vLGN) possess extensive reciprocal commissural connections, the functions of which are unknown.

Using electrophysiological approaches, it is shown that commissural projecting IGL/vLGN cells are primarily activated by light increments to the contralateral eye while cells receiving commissural input typically exhibit antagonistic binocular responses.

Across antagonistic cells, the nature of the commissural input (excitatory or inhibitory) corresponds to the presence of ipsilateral ON or OFF visual responses and in both cases antagonistic responses disappear following inactivation of the contralateral thalamus.

The steady state firing rates of antagonistic cells uniquely encode interocular differences in irradiance.

There is a pivotal role for IGL/vLGN commissural signalling in generating new sensory properties that are potentially useful for the proposed contributions of these nuclei to visuomotor/vestibular and circadian control.

Abstract

The intergeniculate leaflet and ventral lateral geniculate nucleus (IGL/vLGN) are portions of the visual thalamus implicated in circadian and visuomotor/vestibular control. A defining feature of IGL/vLGN organisation is the presence of extensive reciprocal commissural connections, the functions of which are at present unknown. Here we use a combination of multielectrode recording, electrical microstimulation, thalamic inactivation and a range of visual stimuli in mice to address this deficit. Our data indicate that, like most IGL/vLGN cells, those that project commissurally primarily convey contralateral ON visual signals while most IGL/vLGN neurons that receive this input exhibit antagonistic binocular responses (i.e. excitatory responses driven by one eye and inhibitory responses driven by the other), enabling them to encode interocular differences in irradiance. We also confirm that this property derives from commissural input since, following inactivation of the contralateral visual thalamus, these cells instead display monocular contralateral‐driven ON responses. Our data thereby reveal a fundamental role for commissural signalling in generating new visual response properties at the level of the visual thalamus.

Unlike other visual thalamic regions, the intergeniculate leaflet and ventral lateral geniculate nucleus (IGL/vLGN) possess extensive reciprocal commissural connections, the functions of which are unknown.

Using electrophysiological approaches, it is shown that commissural projecting IGL/vLGN cells are primarily activated by light increments to the contralateral eye while cells receiving commissural input typically exhibit antagonistic binocular responses.

Across antagonistic cells, the nature of the commissural input (excitatory or inhibitory) corresponds to the presence of ipsilateral ON or OFF visual responses and in both cases antagonistic responses disappear following inactivation of the contralateral thalamus.

The steady state firing rates of antagonistic cells uniquely encode interocular differences in irradiance.

There is a pivotal role for IGL/vLGN commissural signalling in generating new sensory properties that are potentially useful for the proposed contributions of these nuclei to visuomotor/vestibular and circadian control.

Spatial and temporal trends of alternative flame retardants and polybrominated diphenyl ethers in ringed seals (Phoca hispida) across the Canadian Arctic

Concentrations of alternative flame retardants and polybrominated diphenyl ethers (PBDEs) were analyzed in ringed seal (Phoca hispida) blubber collected across the Canadian Arctic during subsistence hunts between 1998 and 2013. More than 80% of sampled animals were females and juvenile males. The highest mean ΣPBDE concentrations (sum of 13 congeners) were found in seals from Nain (Nunatsiavut) as well as Inukjuaq and Arviat (Hudson Bay) and the lowest mean levels were found in seals from Lancaster Sound. BDE-47 and -99 were the predominant PBDE congeners quantified in ringed seals. The most frequently detected non-PBDE flame retardants were polybrominated biphenyl 101 (BB-101, 57% of samples analyzed for this chemical), hexabromocyclododecane (HBCDD; 38%), hexabromobenzene (HBB, 30%), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTeBB, 23%). The relative trophic position of seals, estimated using stable isotopes, did not vary over time and did not influence flame retardant blubber concentrations. The relative carbon source increased over time at Arviat and Resolute Bay and weak relationships were observed with ΣPBDEs in blubber of seals. ΣPBDEs increased significantly from 1998 to 2008 in ringed seals from East Baffin and subsequently decreased in recent years. PBDE levels at other sites fluctuated slightly over time. HBCDD concentrations increased at several sites over the past decade. The presence of flame retardants in ringed seals suggests their persistence and their continuous inputs in the Canadian Arctic environment. Monitoring and research on the effects of these contaminants in seals are warranted given the importance of this species in Arctic marine food webs and for local communities.

Return to sender: the need to re-address patient antibiotic allergy labels in Australia and New Zealand

BACKGROUND/AIM

Antibiotic allergies are frequently reported and have significant impacts upon appropriate prescribing and clinical outcomes. We surveyed infectious diseases physicians, allergists, clinical immunologists and hospital pharmacists to evaluate antibiotic allergy knowledge and service delivery in Australia and New Zealand.

METHODS

An online multi-choice questionnaire was developed and endorsed by representatives of the Australasian Society of Clinical Immunology and Allergy (ASCIA) and the Australasian Society of Infectious Diseases (ASID). The 37-item survey was distributed in April 2015 to members of ASCIA, ASID, the Society of Hospital Pharmacists of Australia and the Royal Australasian College of Physicians.

RESULTS

Of 277 respondents, 94% currently use or would utilise antibiotic allergy testing (AAT) and reported seeing up to 10 patients/week labelled as antibiotic-allergic. Forty-two per cent were not aware of or did not have AAT available. Most felt that AAT would aid antibiotic selection, antibiotic appropriateness and antimicrobial stewardship (79, 69 and 61% respectively). Patients with the histories of immediate hypersensitivity were more likely to be referred than those with delayed hypersensitivities (76 vs 41%, P = 0.0001). Lack of specialist physicians (20%) and personal experience (17%) were barriers to service delivery. A multidisciplinary approach was a preferred AAT model (53%). Knowledge gaps were identified, with the majority overestimating rates of penicillin/cephalosporin (78%), penicillin/carbapenem (57%) and penicillin/monobactam (39%) cross-reactivity.

CONCLUSIONS

A high burden of antibiotic allergy labelling and demand for AAT is complicated by a relative lack availability or awareness of AAT services in Australia and New Zealand. Antibiotic allergy education and deployment of AAT, accessible to community and hospital-based clinicians, may improve clinical decisions and reduce antibiotic allergy impacts. A collaborative approach involving infectious diseases physicians, pharmacists and allergists/immunologists is required.

Transplacental Transfer of Polychlorinated Biphenyls, Polybrominated Diphenylethers, and Organochlorine Pesticides in Ringed Seals (Pusa hispida)

The transplacental transfer of persistent organic pollutants in marine mammals takes place at a formative developmental period, thereby exposing the fetus to endocrine-disrupting compounds. We evaluated the transplacental transfer of polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), and organochlorine pesticides (OCPs) in five pregnant ringed seals in Northern Labrador, Canada. PCBs, PBDEs, and OCPs were transferred from the mother to the fetus with average concentrations in the fetuses ranging from 0.3 ng/g lipid weight (lw) of mirex to 94 ng/g lw of PCBs. The average percent transferred to the blubber in the fetus was very low with <0.02 % for each of the compounds studied. Based on relationships observed, transfer for full-term fetuses is estimated to range from 0.03 to 0.27 %. Log K(ow) explained the transfer of PCBs (r (2) = 0.67, p < 0.001) and OCPs (r (2) = 0.62, p < 0.001) with those PCB congeners and OCP compounds having a log K(ow) of <6.0 and 4.6, respectively, because they are preferentially transferred to the fetus. Adult females transferred a contaminant mixture to their fetuses, which correlated with estimated fetal age (p < 0.001; r (2) = 0.697), with younger fetuses showing a greater proportion of compounds with low K(ow) compared with later-term fetuses. The implications for the prenatal exposure to these developmental toxicants remains unknown because current toxicity thresholds in marine mammals have only been derived from juveniles or adults.

Solid-state solar modules based on mesoscopic organometal halide perovskite: a route towards the up-scaling process

We fabricated the first solid state modules based on organometal halide perovskite CH3NH3PbI3-xClx using Spiro-OMeTAD and poly(3-hexylthiophene) as hole transport materials. Device up-scaling was performed using innovative procedures to realize large-area cells and the integrated series-interconnections. The perovskite-based modules show a maximum conversion efficiency of 5.1% using both poly(3-hexylthiophene) and Spiro-OMeTAD. A long-term stability test was performed (in air, under AM1.5G, 1 Sun illumination conditions) using both materials showing different behaviour under continuous light stress. Whilst the poly(3-hexylthiophene)-based module efficiency drops by about 80% with respect to the initial value after 170 hours, the Spiro-based module shows a promising long-term stability maintaining more than 60% of its initial efficiency after 335 hours.

Distinguishing between mechanisms of cell aggregation using pair-correlation functions

Many cell types form clumps or aggregates when cultured in vitro through a variety of mechanisms including rapid cell proliferation, chemotaxis, or direct cell-to-cell contact. In this paper we develop an agent-based model to explore the formation of aggregates in cultures where cells are initially distributed uniformly, at random, on a two-dimensional substrate. Our model includes unbiased random cell motion, together with two mechanisms which can produce cell aggregates: (i) rapid cell proliferation and (ii) a biased cell motility mechanism where cells can sense other cells within a finite range, and will tend to move towards areas with higher numbers of cells. We then introduce a pair-correlation function which allows us to quantify aspects of the spatial patterns produced by our agent-based model. In particular, these pair-correlation functions are able to detect differences between domains populated uniformly at random (i.e. at the exclusion complete spatial randomness (ECSR) state) and those where the proliferation and biased motion rules have been employed - even when such differences are not obvious to the naked eye. The pair-correlation function can also detect the emergence of a characteristic inter-aggregate distance which occurs when the biased motion mechanism is dominant, and is not observed when cell proliferation is the main mechanism of aggregate formation. This suggests that applying the pair-correlation function to experimental images of cell aggregates may provide information about the mechanism associated with observed aggregates. As a proof of concept, we perform such analysis for images of cancer cell aggregates, which are known to be associated with rapid proliferation. The results of our analysis are consistent with the predictions of the proliferation-based simulations, which supports the potential usefulness of pair correlation functions for providing insight into the mechanisms of aggregate formation.

Evaluation of a modified pH-shift process to reduce 2-methylisoborneol and geosmin in spiked catfish and produce a consumer acceptable fried catfish nugget-like product

Muddy and/or musty off-flavors in farmed-raised catfish occur as a result of the absorption of geosmin (GEO) and 2-methylisoborneol (MIB), compounds produced by algae. Previous research suggests the acid pH-shift method may be able to reduce off-flavors to produce a consumer acceptable product. The objective of this research was to evaluate application of the acid pH-shift method using a shaker sieve for protein recovery and to evaluate consumer acceptability of a resultant batter-coated fried nugget-like catfish product. Farm-raised catfish were either allowed to depurate (control) or treated with 1 ppb GEO or MIB. Fillets from each replicate were collected and ground and treated by the acid pH-shift process. Samples from all treatments and replicates were evaluated for residual GEO and MIB. In addition, batter-coated fried catfish samples were prepared for a consumer sensory evaluation. Results demonstrated that the pH-shift process decreased moisture, ash, and collagen content of catfish fillet tissue (P < 0.05). Flavor of control samples was preferred (P < 0.05). Texture of catfish samples treated by the pH-shift process was preferred (P < 0.05). Results demonstrate the pH-shift process can be utilized to reduce off-flavors and increase the acceptability of a processed catfish product.

PRACTICAL APPLICATION

Use of a sieve as an economic alternative for the pH-shift process was evaluated for removing off-flavors from catfish. Difficulties were encountered with regard to protein recovery using the sieve and suggestions are made to, perhaps, make the process more applicable for a sieve-based recovery step. The process as described reduced off-flavors, but only 2-fold suggesting the process would work best on catfish near or just over off-flavor thresholds. Results also indicated the pH-shift process could be used to improve texture of a fried catfish product designed to be similar to chicken nuggets.

Health-related quality of life and productivity impact in haemophilia patients with inhibitors

To measure health-related quality of life (HRQL), its determinants, and its association with patient and caregiver productivity among a sample of haemophilia patients with inhibitors in the United States (US). Data on demographical and clinical characteristics, treatment patterns, HRQL (SF-12v2), and productivity outcomes were reported for 53 patients. Mean SF-12v2 domain and mental (MCS) and physical (PCS) component summary scores were assessed and compared with US norms. Regression analyses explored the association of patient and treatment factors with HRQL and productivity. Patients' mean age was 20.7 years (SD = 18.8), 88.5% were type A, and 39.6% received on-demand therapy as their only mode of treatment. Mean PCS was significantly lower than the US norm (PCS, 39.9, P < 0.01) and mean MCS showed no significant difference (MCS, 49.9, P = ns). On-demand treatment (B = -0.336, P < 0.05) and number of haemorrhages (B = -0.366, P < 0.05) were negatively associated with PCS; and PCS was associated with patients' missed work or school days [incidence rate ratio (IRR) = 0.93, P < 0.001] and perceived impact on daily activities (OR = 0.72, P < 0.05). Younger age (IRR = 0.91, P < 0.01), lower PCS (IRR = 0.94, P < 0.01), more haemorrhages (IRR = 1.05, P < 0.05), and surgery (IRR = 2.74, P < 0.05) were associated with fewer patients' productive days. Physical functioning among inhibitor patients in the US is compromised and is negatively associated with their daily activities and productivity. These data suggest a positive association of prophylactic and immunotolerance therapy with HRQL, specifically physical impairment.

Angiotensin II regulates the activity of mouse suprachiasmatic nuclei neurons

Neuropeptide signaling plays key roles in coordinating cellular activity within the suprachiasmatic nuclei (SCN), site of the master circadian oscillator in mammals. The neuropeptide angiotensin II (ANGII) and its cognate receptor AT1, are both expressed by SCN cells, but unlike other SCN neurochemicals, very little is known about the cellular actions of ANGII within this circadian clock. We used multi-electrode, multiunit, extracellular electrophysiology, coupled with whole-cell voltage and current clamp techniques to investigate the actions of ANGII in mouse SCN slices. ANGII (0.001-10 microM) dose dependently stimulated and inhibited extracellularly recorded neuronal discharge in many SCN neurons ( approximately 60%). Both actions were blocked by pre-treatment with the AT1 receptor antagonist ZD7155 (0.03 microM), while suppressions but not activations were prevented by pre-treatment with the GABA A receptor antagonist bicuculline (20 microM). AT1 receptor blockade itself suppressed discharge in a subset ( approximately 30%) of SCN neurons, and this action was not blocked by bicuculline. In voltage-clamped SCN neurons (-70 mV), AT1 receptor activation dose-dependently enhanced the frequency of action potential-driven, GABA A receptor-mediated currents, but did not alter their responses to exogenously applied GABA. In current-clamped SCN neurons perfused with tetrodotoxin, ANGII induced a membrane depolarization with a concomitant decrease in input resistance. In conclusion we show that AT1 receptor activation by ANGII depolarizes SCN neurons and stimulates action potential firing, leading to increased GABA release in the mouse SCN. Additionally we provide the first evidence that endogenous AT1 receptor signaling tonically regulates the activities of some SCN neurons.

Disrupted neuronal activity rhythms in the suprachiasmatic nuclei of vasoactive intestinal polypeptide-deficient mice

Vasoactive intestinal polypeptide (VIP), acting via the VPAC(2) receptor, is a key signaling pathway in the suprachiasmatic nuclei (SCN), the master clock controlling daily rhythms in mammals. Most mice lacking functional VPAC(2) receptors are unable to sustain behavioral rhythms and lack detectable SCN electrical rhythms in vitro. Adult mice that do not produce VIP (VIP/PHI(-/-)) exhibit less severe alterations in wheel-running rhythms, but the effects of this deficiency on the amplitude, phasing, or periodicity of their SCN cellular rhythms are unknown. To investigate this, we used suction electrodes to extracellularly record multiple- and single-unit electrical activity in SCN brain slices from mice with varying degrees of VIP deficiency, ranging from wild-type (VIP/PHI(+/+)) to heterozygous (VIP/PHI(+/-)) and VIP/PHI(-/-) animals. We found decreasing proportions of rhythmic cells in SCN slices from VIP/PHI(+/+) ( approximately 91%, n = 23) through VIP/PHI(-/+) ( approximately 71%, n = 28) to VIP/PHI(-/-) mice (62%; n = 37) and a parallel trend toward decreasing amplitude in the remaining rhythmic cells. SCN neurons from VIP/PHI(-/-) mice exhibited a broad range in the period and phasing of electrical rhythms, concordant with the known alterations in their behavioral rhythms. Further, treatment of VIP/PHI(-/-) slices with a VPAC(2) receptor antagonist significantly reduced the proportion of oscillating neurons, suggesting that VPAC(2) receptors still become activated in the SCN of these mice. The results establish that VIP is important for appropriate periodicity and phasing of SCN neuronal rhythms and suggest that residual VPAC(2) receptor signaling promotes rhythmicity in adult VIP/PHI(-/-) mice.

IDENTIFICATION OF MYCOPLASMATACEAE BY THE FLUORESCENT ANTIBODY METHOD

Clark, Harold W. (The George Washington University, Washington, D.C.), Jack S. Bailey, Richard C. Fowler, and Thomas McP. Brown. Identification of Mycoplasmataceae by the fluorescent antibody method. J. Bacteriol. 85:111-118. 1963.-The conditions of the fluorescent antibody reactions were studied in relation to their application to Mycoplasmataceae or pleuropneumonia-like organisms (PPLO). Mycoplasma hominis type 1 and 2 antigens and their homologous antisera were used to determine the activity and specificity of these and other strains. Fluorescein isothiocyanate conjugated antiserum globulin preparations were used in both the direct and indirect fluorescent antibody methods. A direct tube technique was used for the detection and measurement of growth in broth cultures by the addition of conjugated antiserum. The specific fluorescent staining and recognition of hot water fixed M. hominis colonies was presented as a suitable identification standard. The antigenic activity was found to remain in the insoluble residue after exposure of M. hominis strains to sonic vibration (9 kc) for 30 min and centrifugation. Brief 2-min exposures of tissue cells to vibration (9 kc) caused the disruption of tissues, with the release of viable and "bound" nonwashable strains that reacted specifically with fluorescent antibody. It is proposed to apply both the sonic vibration and the fluorescent antibody techniques for the identification of Mycoplasmataceae in human tissues.

Effects of vasoactive intestinal polypeptide on neurones of the rat suprachiasmatic nuclei in vitro

The suprachiasmatic nuclei (SCN) of the hypothalamus house the main circadian pacemaker in mammals. Vasoactive intestinal polypeptide (VIP) is the most abundant neuropeptide in the SCN and has been shown to phase-shift the electrical activity rhythm of SCN cells in vitro. However, the effects of VIP on the cellular activity of rat SCN neurones are unknown. In this study, we examined the acute effects of VIP on the extracellularly recorded spontaneous firing rate of SCN neurones in an in-vitro hypothalamic slice preparation. Furthermore, with the use of receptor-selective agonists and antagonists, we determined which receptors might mediate the effects of VIP in the SCN. Approximately 50% of cells responded to VIP; the main type of response was suppression in firing rate, although a few cells were activated. Suppression responses to VIP were mimicked by the VPAC(2) receptor agonist Ro 25-1553 and blocked by the selective VPAC(2) receptor antagonist PG 99-465. The PAC(1) receptor agonist maxadilan evoked responses from 40% of SCN cells, and activations to this agonist were not altered by PG 99-465. Responses to VIP were not blocked by antagonists to ionotropic glutamate receptors, but the duration of suppression was modulated by the GABA(A) receptor antagonist bicuculline. Our data indicate that VIP alters the electrical activity of rat SCN neurones in vitro, via both VPAC(2) and PAC(1) receptors.

Typing of Chlamydia trachomatis strains from urine samples by amplification and sequencing the major outer membrane protein gene (omp1)

OBJECTIVES

To develop a novel protocol for the extraction, amplification, and sequencing of Chlamydia trachomatis MOMP gene (omp1) from urine, a non-invasive source, and apply it to an epidemiological study on the distribution of C trachomatis strains in a population of pregnant women in Thailand.

METHODS

The C trachomatis DNA was extracted from culture stocks and urine using a slightly modified commercially available kit, the High Pure PCR Template Preparation Kit (Roche Molecular Biochemicals, IN, USA). The PCR and sequencing primers used for the amplification and sequencing of the omp1 were designed based on the nucleotide sequence of multiple C trachomatis strains found in GenBank. The protocol for the extraction, amplification, and sequencing was tested on laboratory culture stocks of reference strains of all C trachomatis serovars and on urine samples collected in a cross sectional study designed to assess the prevalence of C trachomatis infections in the cities of Bangkok and Chiang Rai, Thailand.

RESULTS

The omp1 gene was successfully amplified and sequenced from 18 laboratory C trachomatis reference strains and from 45 C trachomatis positive urine clinical samples collected from asymptomatic pregnant women. Among clinical samples, we found nine different C trachomatis genotypes: F (11, 25%), D (10, 22.6%), H (5, 11.7%), K (5, 11.7%), E (4, 9.3%), Ia (3, 7%), B (3, 7%), Ja (2, 4.5%), and G (1, 2.3%). One specimen generated an omp1 DNA sequence pattern indicating the presence of a mixed infection with at least two different serovars.

CONCLUSIONS

Urine is a convenient and reliable source for genotyping C trachomatis strains. A clear advantage of urine over traditional samples, such as cervical swabs, is that urine is a non-invasive source which makes collection easier and thus facilitates the enrolment of patients in clinical and epidemiological studies. In addition to typing, urine is increasingly used for diagnosis of C trachomatis infection by several commercially available nucleic acid amplification assays which represents a distinct advantage for collecting, transport, storage, and laboratory handling of samples.

Detection of eastern equine encephalitis virus in infected mosquitoes using a monoclonal antibody-based antigen-capture enzyme-linked immunosorbent assay

Surveillance of mosquito populations for virus activity is not often performed by small, vector-control districts because they do not have the financial resources to use virus isolation, or newer methods such as the polymerase chain reaction. Consequently, development and refinements of rapid, sensitive, and simple enzyme-linked immunosorbent assays (ELISAs) applicable to a wide variety of public health settings are justified. We have developed an antigen-capture ELISA for the detection of eastern equine encephalitis (EEE) virus in mosquitoes that uses both monoclonal capture and detector antibodies. The sensitivity of this assay is 4.0-5.0 log10 plaque-forming units/ml, which is comparable to previously published EEE antigen-capture assays developed with polyclonal antibody reagents. This test identifies only North American strains of EEE virus and does not react with either western equine encephalitis or Highlands J viruses. Test sensitivity was enhanced by sonicating mosquito pools, treating them with Triton X-100, and increasing the time and temperature of antigen incubation. The conversion of this ELISA to a monoclonal antibody-based format should result in a readily standardizable and transferable assay that will permit laboratories lacking virus isolation facilities to conduct EEE virus surveillance.

Preemptive biopreparedness: can we learn anything from history?

The treat of bioterrorism is in the public eye again, and major public health agencies are urging preparedness efforts and special federal funding. In a sense, we have seen this all before. The Centers for Disease Control and Prevention grew substantially during the Cold War era in large part because Alexander Langmuir, Chief Epidemiologist of the CDC, used an earlier generation's anxieties to revitalize the CDC, create an Epidemic Intelligence Service, and promote epidemiologic "surveillance" as part of the nation's defense. Retrospective investigation suggests that, while Langmuir contributed to efforts promoted by the Department of Defense and the Federal Civil Defense Administration, the United States did not have real cause to fear Communist biological warfare aggression. Given clear historical parallels, it is appropriate to ask, What was gained and what was lost by Langmuir's central role in that first instance of American biopreparedness? Among the conclusions drawn is that biopreparedness efforts fed the Cold War climate, narrowed the scope of public health activities, and failed to achieve sustained benefits for public health programs across the country.