The spiking output of the mouse olfactory bulb encodes large-scale temporal features of natural odor environments

Spatiotemporal dynamics of natural odor environment have informative features for animals navigating to an odor source. Population activity in the olfactory bulb (OB) has been shown to follow plume dynamics to a moderate degree (Lewis et al., 2021), but it is unknown whether the ability to follow plume dynamics is driven by individual cells or whether it emerges at the population level. Previous research has explored the responses of individual OB cells to isolated features of plumes, but it is difficult to adequately sample these features as it is still undetermined which features navigating mice employ during olfactory guided search. Here we released odor from an upwind odor source and simultaneously recorded both odor concentration dynamics and cellular response dynamics in awake, head-fixed mice. We found that longer timescale features of odor concentration dynamics were encoded at both the cellular and population level. At the cellular level, plume onset was encoded across all trials and plume offset was encoded for high concentration odors, but not low concentration odors. Although cellular level tracking of plume dynamics was observed to be weak, we found that at the population level, OB activity distinguished whiffs and blanks (accurately detected odor presence versus absence) throughout the duration of a plume. Even ~20 OB cells were enough to accurately encode these features. Our findings indicate that the full range of odor concentration dynamics and high frequency fluctuations are not encoded by OB spiking activity. Instead, relatively lower-frequency dynamics of plumes, such as plume onset, plume offset, whiffs, and blanks, are represented in the OB.

Sex differences in conditioned orienting and the role of estradiol in addiction-related behaviors

Conditioned orienting response (OR) is a form of cue-directed behavior thought to indicate increased attentional and/or motivational processing of reward-associated stimuli. OR as a phenotype has been shown to predict both direct drug proclivity in female rats and behaviors indirectly related to drug proclivity in male rats, but no extant research has compared males and females in terms of their OR behavior or its notable substrates. As females are at increased risk for substance abuse, and the ovarian hormone estradiol is often cited as a driving factor for this predilection, it is important to characterize sex differences between males and females and explore what, if any, contribution estradiol has in behaviors which predict substance abuse. In these experiments, male and female rats [intact or ovariectomized (OVX) with/without estradiol replacement] were compared on a battery of behavioral tasks, including OR, novelty-seeking, attentional set-shifting, and ultrasonic vocalizations (USVs) to amphetamine treatment. Female rats, regardless of estradiol replacement, had higher OR scores than males. OR score was a predictor of attention impairments, and estradiol availability contributed to this relationship in females. Sex differences were not observed in novelty-seeking, attentional set-shifting, or USV response to amphetamine; however, estradiol replacement did alter the presentation of these behaviors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Plume Dynamics Structure the Spatiotemporal Activity of Mitral/Tufted Cell Networks in the Mouse Olfactory Bulb

Although mice locate resources using turbulent airborne odor plumes, the stochasticity and intermittency of fluctuating plumes create challenges for interpreting odor cues in natural environments. Population activity within the olfactory bulb (OB) is thought to process this complex spatial and temporal information, but how plume dynamics impact odor representation in this early stage of the mouse olfactory system is unknown. Limitations in odor detection technology have made it difficult to measure plume fluctuations while simultaneously recording from the mouse's brain. Thus, previous studies have measured OB activity following controlled odor pulses of varying profiles or frequencies, but this approach only captures a subset of features found within olfactory plumes. Adequately sampling this feature space is difficult given a lack of knowledge regarding which features the brain extracts during exposure to natural olfactory scenes. Here we measured OB responses to naturally fluctuating odor plumes using a miniature, adapted odor sensor combined with wide-field GCaMP6f signaling from the dendrites of mitral and tufted (MT) cells imaged in olfactory glomeruli of head-fixed mice. We precisely tracked plume dynamics and imaged glomerular responses to this fluctuating input, while varying flow conditions across a range of ethologically-relevant values. We found that a consistent portion of MT activity in glomeruli follows odor concentration dynamics, and the strongest responding glomeruli are the best at following fluctuations within odor plumes. Further, the reliability and average response magnitude of glomerular populations of MT cells are affected by the flow condition in which the animal samples the plume, with the fidelity of plume following by MT cells increasing in conditions of higher flow velocity where odor dynamics result in intermittent whiffs of stronger concentration. Thus, the flow environment in which an animal encounters an odor has a large-scale impact on the temporal representation of an odor plume in the OB. Additionally, across flow conditions odor dynamics are a major driver of activity in many glomerular networks. Taken together, these data demonstrate that plume dynamics structure olfactory representations in the first stage of odor processing in the mouse olfactory system.

Abstract P6-14-02: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Esser MR, Rowe JJ, McCann ML, Nicholas-Alexander M, Helck EP, Lewis SM. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-14-02.

Abstract P6-14-05: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Esser MR, Rowe JJ, McCann ML, Nicholas-Alexander M, Helck EP, Lewis SM. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-14-05.

Extinction to amphetamine-associated context in female rats is dependent upon conditioned orienting

RATIONALE

Females are considered more susceptible to the reinforcing effects of drugs and subsequently at increased risk for drug abuse and relapse after treatment. Estrogen is known to facilitate drug effects in females. However, other factors which contribute to the incidence of drug abuse are important to identify in order to recognize early risk factors and develop effective prevention and treatment schemes. Cue-directed behavior (aka sign tracking) has been implicated as a behavioral phenotype which identifies populations susceptible to drug abuse, partly due to its association with impulsivity and heightened dopamine function.

OBJECTIVES AND METHODS

In this study, we investigate the viability of conditioned orienting (a form of cue-directed behavior) as a potential phenotype which predicts drug proclivity in female rats. In addition, we examine any influence endogenous female hormones across the estrous cycle may have on conditioned orienting and drug proclivity.

RESULTS AND CONCLUSIONS

Utilizing an amphetamine-conditioned place preference task, results suggest that the orienting phenotype is an effective predictor of drug proclivity in females. Rats exhibiting enhanced orienting behavior show more robust preference for an amphetamine-associated context and are more resistant to extinction of this preference than nonorienting counterparts. Furthermore, both conditioned orienting behavior and conditioned place preference are minimally influenced by the estrous cycle.

Reliability and Clinical Impact of the Normalization of the Prothrombin Times in Oral Anticoagulant Control

In 1983, the World Health Organization (WHO) published recommendations for normalization, in oral anticoagulant control, of the prothrombin time (PT). The common denominator is the International Sensitivity Index (ISI) of a thromboplastin, obtained by means of thromboplastin calibration. The common scale is that of the International Normalized Ratio (INR). The INR is the PT ratio Patient PT/normal PT which would have been found normal PT with the WHO primary international reference preparation (IRP) 67/40. The reliability of the INR depends on the extent of calibration precision, patient-specific influences, as well as interlaboratory variation in the PT determination. Under well-controlled conditions the overall coefficient of variation (CV) of the INR is 11-13.5%, if thromboplastins of ISI ≃ 1 are used. For so-called low-sensitivity thromboplastins (ISI ≃ 2-2.5), the overall variation is larger due to a large between-laboratory variation of the measured PT-ratios

The user of thromboplastin will be provided with a chart or graph enabling him to convert the conventional terms used for expressing PTs into INRs. For quality assurance, and to prepare his own calibration chart if necessary, he should check normalization by means of control plasmas to which INRs have been assigned.

There is sufficient clinical evidence to express optimal therapeutic ranges in terms of INR. Manufacturers should revise and adapt their inserts where necessary in order to conform to these requirements.

Mean Platelet Volume and Size Distribution and Their Sensitivity to Agonists in Patients with Coronary Artery Disease and Congestive Heart Failure

Mean platelet volume was related to platelet count in patients with myocardial infarction (n = 55) and patients with congestive heart failure (n = 9). 18 patients with acute myocardial infarction were tested at admission and 4-7 days later, together with 13 patients with chronic stable angina and 10 patients with chest pain which was not related to coronary artery disease. In citrated blood a relative reduced frequency of large platelets (>13 fl) occured in patients with acute myocardial infarction at admission but was not seen during recovery or in patients with chronic stable angina. This suggests consumption of large platelets at time of thrombus formation. No relation was found between plasma catecholamine levels and mean platelet volumes. Effects of serotonine, adrenaline and CGP 28392, a calcium agonist, on platelet volume distributions were determined. Sensitivity of platelets to adrenaline was increased in patients with acute myocardial infarction on admission and reduced 4-7 days later, while in patients with congestive heart failure reactivity to both serotonine and adrenaline were reduced. This indicates a fast down-regulation during the early recovery phase of myocardial infarction and chronically in congestive heart failure.

First Results from a Microwave Cavity Axion Search at 24 μeV

We report on the first results from a new microwave cavity search for dark matter axions with masses above 20  μeV. We exclude axion models with two-photon coupling g_{aγγ}≳2×10^{-14}  GeV^{-1} over the range 23.55<m_{a}<24.0  μeV. These results represent two important achievements. First, we have reached cosmologically relevant sensitivity an order of magnitude higher in mass than any existing limits. Second, by incorporating a dilution refrigerator and Josephson parametric amplifier, we have demonstrated total noise approaching the standard quantum limit for the first time in an axion search.

Postretrieval Extinction Attenuates Alcohol Cue Reactivity in Rats

BACKGROUND

Conditioned responses to alcohol-associated cues can hinder recovery from alcohol use disorder (AUD). Cue exposure (extinction) therapy (CET) can reduce reactivity to alcohol cues, but its efficacy is limited by phenomena such as spontaneous recovery and reinstatement that can cause a return of conditioned responding after extinction. Using a preclinical model of alcohol cue reactivity in rats, we evaluated whether the efficacy of alcohol CET could be improved by conducting CET during the memory reconsolidation window after retrieval of cue-alcohol associations.

METHODS

Rats were provided with intermittent access to unsweetened alcohol. Rats were then trained to predict alcohol access based on a visual cue. Next, rats were treated with either standard extinction (n = 14) or postretrieval extinction (n = 13). Rats were then tested for long-term memory of extinction and susceptibility to spontaneous recovery and reinstatement.

RESULTS

Despite equivalent extinction, rats treated with postretrieval extinction exhibited reduced spontaneous recovery and reinstatement relative to rats treated with standard extinction.

CONCLUSIONS

Postretrieval CET shows promise for persistently attenuating the risk to relapse posed by alcohol cues in individuals with AUD.

Postmating transcriptional changes in the female reproductive tract of the European corn borer moth

Mating triggers a cascade of physiological and behavioural responses in females that persist after copulation. In insects, seminal fluid proteins contained within male ejaculates are known to initiate some responses, but our understanding of how females mediate these reactions remains limited. Few studies have examined postmating transcriptional changes within ejaculate-receiving organs within females or how these changes might depend on the identity of the male. Furthermore, whereas males of many insects transfer packaged ejaculates, transcriptional dynamics have mainly been examined in dipterans, in which males transfer a free ejaculate. To identify genes that may be important in mediating female physiological responses in a spermatophore-producing species, we sequenced the transcriptomes of the ejaculate-receiving organs and examined postmating gene expression within and between pheromone strains of the European corn borer (ECB) moth, Ostrinia nubilalis. After within-strain mating, significant differential expression of 978 transcripts occurred in the female bursa or its associated bursal gland, including peptidases, transmembrane transporters, and hormone processing genes; such genes may potentially play a role in postmating male-female interactions. We also identified 14 transcripts from the bursal gland that were differentially expressed after females mated with cross-strain males, representing candidates for previously observed postmating reproductive isolation between ECB strains.

Expression of CD11c and EMR2 on neutrophils: potential diagnostic biomarkers for sepsis and systemic inflammation

There is a need for cellular biomarkers to differentiate patients with sepsis from those with the non-infectious systemic inflammatory response syndrome (SIRS). In this double-blind study we determined whether the expression of known (CD11a/b/c, CD62L) and putative adhesion molecules [CD64, CD97 and epidermal growth factor (EGF)-like molecule containing mucin-like hormone receptor (EMR2)] on blood neutrophils could serve as useful biomarkers of infection and of non-infectious SIRS in critically ill patients. We studied 103 patients with SIRS, 83 of whom had sepsis, and 50 healthy normal subjects, using flow cytometry to characterize neutrophils phenotypically in whole blood samples. Patients with SIRS had an increased prevalence of neutrophils expressing CD11c, CD64 and EMR2 in comparison with healthy subjects (P < 0.001), but normal expression of CD11a, CD11b, CD62L and CD97. An increase in the percentage of neutrophils bearing CD11c was associated with sepsis, EMR2 with SIRS and CD64 with sepsis and SIRS. Neutrophils expressing CD11c had the highest sensitivity (81%) and specificity (80%) for the detection of sepsis, and there was an association between the percentage of neutrophils expressing EMR2 and the extent of organ failure (P < 0.05). Contrary to other reports, we did not observe an abnormal expression of CD11b or CD62L on neutrophils from patients with SIRS, and suggest that this discrepancy is due to differences in cell processing protocols. We propose that blood neutrophils expressing CD11c and EMR2 be considered as potential biomarkers for sepsis and SIRS, respectively.

Photonic-band-gap traveling-wave gyrotron amplifier

We report the experimental demonstration of a gyrotron traveling-wave-tube amplifier at 250 GHz that uses a photonic band gap (PBG) interaction circuit. The gyrotron amplifier achieved a peak small signal gain of 38 dB and 45 W output power at 247.7 GHz with an instantaneous -3  dB bandwidth of 0.4 GHz. The amplifier can be tuned for operation from 245-256 GHz. The widest instantaneous -3  dB bandwidth of 4.5 GHz centered at 253.25 GHz was observed with a gain of 24 dB. The PBG circuit provides stability from oscillations by supporting the propagation of transverse electric (TE) modes in a narrow range of frequencies, allowing for the confinement of the operating TE03-like mode while rejecting the excitation of oscillations at nearby frequencies. This experiment achieved the highest frequency of operation for a gyrotron amplifier; at present, there are no other amplifiers in this frequency range that are capable of producing either high gain or high output power. This result represents the highest gain observed above 94 GHz and the highest output power achieved above 140 GHz by any conventional-voltage vacuum electron device based amplifier.

Determinants of reproductive success across sequential episodes of sexual selection in a firefly

Because females often mate with multiple males, it is critical to expand our view of sexual selection to encompass pre-, peri- and post-copulatory episodes to understand how selection drives trait evolution. In Photinus fireflies, females preferentially respond to males based on their bioluminescent courtship signals, but previous work has shown that male paternity success is negatively correlated with flash attractiveness. Here, we experimentally manipulated both the attractiveness of the courtship signal visible to female Photinus greeni fireflies before mating and male nuptial gift size to determine how these traits might each influence mate acceptance and paternity share. We also measured pericopulatory behaviours to examine their influence on male reproductive success. Firefly males with larger spermatophores experienced dual benefits in terms of both higher mate acceptance and increased paternity share. We found no effect of courtship signal attractiveness or pericopulatory behaviour on male reproductive success. Taken together with previous results, this suggests a possible trade-off for males between producing an attractive courtship signal and investing in nuptial gifts. By integrating multiple episodes of sexual selection, this study extends our understanding of sexual selection in Photinus fireflies and provides insight into the evolution of male traits in other polyandrous species.

The use of the white cell count and haemoglobin in combination as an effective screen to predict the normality of the full blood count

INTRODUCTION

The utility of the full blood count (FBC) is vast with each parameter serving as a tool to aid diagnosis and monitor disease progression. However, the effectiveness of the test is hampered because of increased workload and lack of interpretation. In the effort to redress this issue, the combined use of the white blood cell count (WBC) and haemoglobin in predicting the normality of the FBC is evaluated.

METHOD

FBC data were collated from 2191 patients and classified into two groups depending on whether the WBC and the haemoglobin were within the reference range. Blood films were examined on the abnormal FBC samples in each group and graded on morphology.

RESULTS

The FBC was normal in 89.6% of cases in the presence of a normal WBC and haemoglobin with subtle abnormalities in the remainder; 1+ grading of abnormal morphology in 93%. However, when the WBC and/or haemoglobin was abnormal, the remaining FBC was significantly abnormal (P < 0.05) and the corresponding blood films were grossly abnormal; 2+/3+ grading in 96% of cases.

CONCLUSION

We concluded that in the presence of a normal WBC and haemoglobin, the FBC is normal in almost all cases and measuring these two parameters could be used as an effective screen to predict FBC normality.

Identification of predicted seminal fluid proteins in Tribolium castaneum

In several insect species, seminal fluid proteins (SFPs) have been demonstrated to be key regulators of male and female fitness through their ability to alter female physiology and behaviour. Tribolium castaneum is an economically important pest species and a model system for sexual selection research, but little is known about SFPs in this insect. To create a foundation for the study of T. castaneum SFPs, we used mass spectrometry to identify putative SFPs by comparing proteins detected in the male reproductive glands with those found in the reproductive tracts of virgin and mated females. Fourteen putative SFPs, thirteen with male biased expression, were identified through this approach. We also used reverse transcription PCR (RT-PCR) to examine expression levels across different tissue types. We found strongly male-biased expression in 13 genes, nine of which were expressed only in male accessory gland tissue. This represents the first proteomic-based method of identifying putative SFPs in any coleopteran species, and is the first study in this species to identify putative SFPs that are likely transferred to the female. This work could lead to functional analyses of the role of SFPs in sexual selection, sexual conflict and potential control of a pest species.

True associations between resting fMRI time series based on innovations

We calculated voxel-by-voxel pairwise crosscorrelations between prewhitened resting-state BOLD fMRI time series recorded from 60 cortical areas (30 per hemisphere) in 18 human subjects (nine women and nine men). Altogether, more than a billion-and-a-quarter pairs of BOLD time series were analyzed. For each pair, a crosscorrelogram was computed by calculating 21 crosscorrelations, namely at zero lag ± 10 lags of 2 s duration each. For each crosscorrelogram, in turn, the crosscorrelation with the highest absolute value was found and its sign, value, and lag were retained for further analysis. In addition, the crosscorrelations at zero lag (irrespective of the location of the peak) were also analyzed as a special case. Based on known varying density of anatomical connectivity, we distinguished four general brain groups for which we derived summary statistics of crosscorrelations between voxels within an area (group I), between voxels of paired homotopic areas across the two hemispheres (group II), between voxels of an area and all other voxels in the same (ipsilateral) hemisphere (group III), and voxels of an area and all voxels in the opposite (contralateral) hemisphere (except those in the homotopic area) (group IV). We found the following. (a) Most of the crosscorrelogram peaks occurred at zero lag, followed by ± 1 lag; (b) over all groups, positive crosscorrelations were much more frequent than negative ones; (c) average crosscorrelation was highest for group I, and decreased progressively for groups II-IV; (d) the ratio of positive over negative crosscorrelations was highest for group I and progressively smaller for groups II-IV; (e) the highest proportion of positive crosscorrelations (with respect to all positive ones) was observed at zero lag; and (f) the highest proportion of negative crosscorrelations (with respect to all negative ones) was observed at lag = 2. These findings reveal a systematic pattern of crosscorrelations with respect to their sign, magnitude, lag and brain group, as defined above. Given that these groups were defined along a qualitative gradient of known overall anatomical connectivity, our results suggest that functional interactions between two voxels may simply reflect the density of such anatomical connectivity between the areas to which the voxels belong.

Attitudes toward genetic research review: results from a survey of human genetics researchers

BACKGROUND

Researchers often relate personal experiences of difficulties and challenges with Institutional Review Board (IRB) review of their human genetic research protocols. However, there have been no studies that document the range and frequency of these concerns among researchers conducting human genetic/genomic studies.

METHODS

An online anonymous survey was used to collect information from human genetic researchers regarding views about IRB review of genetic protocols. Logistic regression was used to test specific hypotheses. Results from the national online survey of 351 human genomic researchers are summarized in this report.

RESULTS

Issues involving considerable discussion with IRBs included reconsent of subjects (51%), protection of participants' personal information (39%) and return of results to participants (34%). Over half of the participants had experienced one or more negative consequences of the IRB review process and approximately 25% had experienced one or more positive consequences. Respondents who had served on an IRB were about 80% more likely to report positive consequences of IRB review than their colleagues who had never served on an IRB (p = 0.03). Survey responses were mixed on the need for reconsent before data sharing and risks related to participant reidentification from genomic data.

CONCLUSION

The results from this study provide important perspectives of researchers regarding genetic research review and show lack of consensus on key research ethics issues in genomic research.

ICSH review of the measurement of the erythocyte sedimentation rate

In recognition of the need for a standardization of the measurement of the erythrocyte sedimentation rate (ESR), the International Council for Standardization in Haematology makes the following recommendations: (i) The reference method for measurement of the ESR should be based on the Westergren method, which is a specific test for the ESR, with modifications, (ii) The reference method for measurement of the ESR should use either whole blood anticoagulated with EDTA and later diluted with sodium citrate or saline (4 : 1) or whole blood anticoagulated with sodium citrate (4 : 1) in Westergren pipettes, (iii) The ESR pipettes can be of glass or plastic (with specific characteristics). It must be colourless; a minimum sedimentation scale of 200 mm, a minimum bore of 2.55 mm, which should be constant within 5%. A protocol for the evaluation of alternative methodologies against the reference method is outlined: The new technologies must be tested over a range of ESR values of 2-120 mm. In this comparison, 95% of the differences should be 5 mm or less, with larger differences associated with higher ESR values. A minimum of 40 samples should be tested in 3 different groups of values: 1-20, 21-60 and more than 60 mm. The statistical methods recommended for ESR evaluations are the coefficient of correlation, the Passing-Bablock regression and the Bland-Altman statistical method. This reference method replaces all earlier standardized and reference methods.

Direct and correlated responses to artificial selection on sexual size dimorphism in the flour beetle, Tribolium castaneum

Sexual size dimorphism (SSD) is a conspicuous yet poorly understood pattern across many organisms. Although artificial selection is an important tool for studying the evolution of SSD, previous studies have applied selection to only a single sex or to both sexes in the same direction. In nature, however, SSD likely arises through sex-specific selection on body size. Here, we use Tribolium castaneum flour beetles to investigate the evolution of SSD by subjecting males and females to sexually antagonistic selection on body size (sexes selected in opposite directions). Additionally, we examined correlated responses to body size selection in larval growth rates and development time. After seven generations, SSD remained unchanged in all selected lines; this observed lack of response to short-term selection may be attributed to evolutionary constraints arising from between-sex body size correlations. Developmental traits showed complex correlated responses under different selection treatments. These results suggest that sex-specific larval development patterns may facilitate the evolution of SSD.

Post-traumatic stress disorder: a right temporal lobe syndrome?

In a recent paper (Georgopoulos et al 2010 J. Neural Eng. 7 016011) we reported on the power of the magnetoencephalography (MEG)-based synchronous neural interactions (SNI) test to differentiate post-traumatic stress disorder (PTSD) subjects from healthy control subjects and to classify them with a high degree of accuracy. Here we show that the main differences in cortical communication circuitry between these two groups lie in the miscommunication of temporal and parietal and/or parieto-occipital right hemispheric areas with other brain areas. This lateralized temporal-posterior pattern of miscommunication was very similar but was attenuated in patients with PTSD in remission. These findings are consistent with observations (Penfield 1958 Proc. Natl Acad. Sci. USA 44 51-66, Penfield and Perot 1963 Brain 86 595-696, Gloor 1990 Brain 113 1673-94, Banceaud et al 1994 Brain 117 71-90, Fried 1997 J. Neuropsychiatry Clin. Neurosci. 9 420-8) that electrical stimulation of the temporal cortex in awake human subjects, mostly in the right hemisphere, can elicit the re-enactment and re-living of past experiences. Based on these facts, we attribute our findings to the re-experiencing component of PTSD and hypothesize that it reflects an involuntarily persistent activation of interacting neural networks involved in experiential consolidation.

The synchronous neural interactions test as a functional neuromarker for post-traumatic stress disorder (PTSD): a robust classification method based on the bootstrap

Traumatic experiences can produce post-traumatic stress disorder (PTSD) which is a debilitating condition and for which no biomarker currently exists (Institute of Medicine (US) 2006 Posttraumatic Stress Disorder: Diagnosis and Assessment (Washington, DC: National Academies)). Here we show that the synchronous neural interactions (SNI) test which assesses the functional interactions among neural populations derived from magnetoencephalographic (MEG) recordings (Georgopoulos A P et al 2007 J. Neural Eng. 4 349-55) can successfully differentiate PTSD patients from healthy control subjects. Externally cross-validated, bootstrap-based analyses yielded >90% overall accuracy of classification. In addition, all but one of 18 patients who were not receiving medications for their disease were correctly classified. Altogether, these findings document robust differences in brain function between the PTSD and control groups that can be used for differential diagnosis and which possess the potential for assessing and monitoring disease progression and effects of therapy.

Point-of-care method for total white cell count: an evaluation of the HemoCue WBC device

Point-of-care testing (POCT) is becoming an important adjunct to haematology laboratory practice. An important component of the blood count is the total white cell count (WBC). Previously, this required laborious microscopic cell counting, but it can now be performed by means of automation; however, in many under-resourced countries, costly automated counters are only available in very few central hospitals. Moreover, neither method is practical in most POCT situations. The HemoCue WBC has been developed as a simplified alternative method, consisting of a reagent pre-loaded disposable cuvette together with basic image analysis technology. This report describes an assessment of its utility. The WBC of 500 routine blood samples from the hospital were tested in parallel by the HemoCue WBC and by a reference analyser to assess accuracy and utility of the former. The tests included precision, linearity, type of blood sample and anticoagulant and potential interfering substances in blood specimens. In the tests for accuracy, 192 of the 200 showed percentage difference from the NEQAS reference of <10% whilst the remaining eight samples differed by <12%, thus meeting the requirements of Clinical laboratory improvement amendments (CLIA)-88 regulations. Of the samples tested with potential interfering substances only those with >2% normoblasts or reticulocytosis showed significant differences from the reference measurements. The HemoCue WBC is reliable for WBC counts within the analytical range of 0.4-30.0 x 10(9)/l, except in samples where there are significant numbers of normoblasts or reticulocytes. It is simple to use and provides a valuable advance in the facilities available for POCT in haematology.

Standardization and harmonization of the blood count: the role of International Committee for Standardization in Haematology (ICSH)

Scientific principles of standardization were first applied in haematology in 1963 when the International Committee for Standardization in Haematology was established with a primary objective to improve the measurement of haemoglobin. Subsequently, ICSH has established Expert Panels on a wide range of haematological topics, including especially a Panel on Cytometry. The purpose of haematological standardization is to obtain precision, accuracy, specificity and harmonization of results between different laboratories in all countries and also between different instruments or methods in the same laboratory. To achieve these objectives ICSH sponsors collaborative studies by scientists from academic centres and from industry and uses a consensus procedure for establishing standards on the basis of the scientific data, followed by an educational programme to ensure that the standards are adopted worldwide. ICSH defines material standards and standardized methods. Material standards are classified as primary international standards, certified reference materials, secondary standards and calibrators. These must be distinguished from control preparations which are intended exclusively for quality control. Standardization of methods must also be considered at four levels: definitive, reference, selected and routine. Each has a place in practice but their roles must be clearly defined. ICSH has an established protocol for evaluation of automated blood cell counters. This defines the levels of precision and accuracy of instrument performance. It is also necessary to assess "clinical utility". The main requirement of the practising haematologist is clinical reliability and harmonization of results for comparability. One of the major functions of ICSH is to provide an interface for collaboration between the manufacturers who develop the instruments and the users in order to achieve this goal.

The selection of laboratory equipment

The last few years have seen dramatic changes in laboratory haematology. Technological developments with increasing levels of automation have resulted in a plethora of new instruments. The choice of which to buy, often confused by conflicting advice and persuasive salesmanship, must be balanced by the need for cost containment. This calls for an understanding of the principles of selection to ensure that the system that is chosen will provide reliable results in the most efficient manner at the lowest possible cost. Most of the instruments which are currently available perform their intended tasks reasonably well albeit with some inter-instrument differences, usually due to different operating procedures and different methods of calibration. The task is to find a system that performs the required tests correctly and reliably, fits into the work requirements of the laboratory and is accepted by the staff who will operate it, whilst its cost both capital and recurrent, should be within the department's financial constraints. The selection of laboratory equipment is thus a complex and time consuming task.

Platelet counting-development of a reference method and a reference preparation

A reference method has been defined for platelet counting by counting chamber haemocytometry, and a procedure has been developed, using platelet rich plasma (PRP) and a Coulter ZBI counter which provides a reliable, rapid and relatively simple method for platelet counting which is closely comparable to the reference method and can thus be used both as a secondary reference method and a routine method. The optimal method for obtaining PRP from EDTA blood was by augmented sedimentation with Boyum's methyl cellulose-metrizoate mixture at sp. gr. 1.08. This was shown to yield a platelet suspension which reflects closely the platelet content of the original blood. Calibration of electronic counters for platelet counting requires material which is stable and which parallels natural human platelets in size, distribution and other physical characteristics. A suspension of glutaraldehyde-fixed human platelets in glycerol appears to be suitable as a reference preparation. Its method of production is described.

Protocol for evaluation of automated blood cell counters. International Committee for Standardization in Haematology (ICSH)

This protocol is proposed for the evaluation of automated blood cell counters to assess the performance, advantages and limitations of such instruments. It is based on the International Committee for Standardization in Haematology (ICSH) 'Protocol for type testing equipment and apparatus used for haematological analysis' (1978a) and the British Committee for Standardization in Haematology 'Guidelines for the evaluation of instruments used in haematology' (Shinton, England & Kennedy, 1982). The document has been prepared by the ICSH Panel on Cytometry after discussion with colleagues. This tentative protocol will be reviewed 1 year after publication, in accordance with the ICSH rules, before it is adopted as a definitive standard.

Detection and functional assessment of accessory splenic tissue (splenunculi) with radiolabelled heat damaged autologous erythrocytes

Eight patients (six with idiopathic thrombocytopenic purpura, one with immune pancytopenia, and one with autoimmune haemolytic anaemia), who had previously been splenectomized, were found to have splenunculi using radioactively labelled heat damaged autologous erythrocytes. In all patients the splenunculi were found to have significant 'splenic function'. However, there was a poor correlation between the size and the function of the splenunculi. Splenunculectomies were carried out in two patients. This led to a complete haematological remission in one patient and partial remission in the other. In three patients, where splenunculectomies could not be undertaken, the patients had to remain on significant doses of immunosuppressive therapy. In one patient complete remission was achieved using a course of immunosuppressive therapy alone and in the remaining two there was insufficient information to draw valid conclusions. Blood clearance kinetic studies of heat damaged erythrocytes were found to provide an accurate functional assessment of the splenunculi in all patients. However, the presence of a functional splenunculus was found to be the cause of disease relapse in only some patients. Therefore, the management of similar patients should perhaps be along the same lines as that at their initial presentation, that is, immunosuppressive therapy should be tried if they are not on any at the time of relapse, if they are already on it, then splenunculectomy should be done.

Lauryl sulphate haemoglobin: a non-hazardous substitute for HiCN in haemoglobinometry

The haemiglobincyanide (HiCN) method for measuring haemoglobin is used extensively worldwide; its advantage is the ready availability of a stable and internationally accepted reference standard/calibrator. However, its use may create a problem, especially in automated analysers, as the waste disposal of large volumes of reagent containing cyanide may constitute a potential toxic hazard. As an alternative, conversion of haemoglobin to a sulphate derivative by nontoxic sodium lauryl sulphate has been proposed and is available as a commercial product from Toa Medical Electronics Co. Ltd., Japan. This evaluation has shown it to be as reliable and reproducible as HiCN for measuring haemoglobin at all concentrations, by both spectrophotometry and automated analyser. Maximum absorbance is at 534 nm. Total conversion occurs almost instantaneously, and includes methaemoglobin but not sulphaemoglobin. HbF is also measured. The only disadvantage is that solutions of haemoglobin-sulphate are stable for only a few hours at room temperature and up to three weeks at 4 degrees C. Thus, for standardization and calibration of instruments it is necessary to use a sample of blood or lysate the haemoglobin value of which has been assigned initially by the HiCN method.

Draft protocol for testing calibration and quality control material used with automatic blood-counting apparatus

A large number of commercial preparations are now available for calibrating or checking the stability of automatic blood counters. Most of these preparations are supplied with 'stated' values though the methods for assigning these values are not described in sufficient detail to allow for an adequate assessment of the validity. The Haemocytometry Panel of the British Committee for Standards in Haematology are therefore proposing a draft protocol for testing calibration and quality control materials. Comments on the draft protocol are invited, either as letters to the Editor of Clinical and Laboratory Haematology or in confidence to the Chairman of the Haemocytometry Panel.

Evaluation of the utility of the HemoCue 301 haemoglobinometer for blood donor screening

BACKGROUND AND OBJECTIVES

Reliable blood donor screening requires more accurate measure of haemoglobin (Hb) than by either copper sulphate or the haemoglobin colour scale. The HemoCue haemoglobinometer has established a method for this, but it is considerably more expensive; a modified version (HemoCue 301) has now been developed with a cheaper reagent-free cuvette for use in budget-restricted situations. This report describes evaluation of the performance, the assessment of reproducibility and accuracy of this modified analyser against the reference technique for Hb measurement.

MATERIALS AND METHODS

Over 300 routine blood samples from specimens received routinely in a hospital laboratory were tested in accordance with the International Committee for Standardization in Haematology (ICSH) protocol. Accuracy and linearity were confirmed by the reference method with the WHO international haemoglobincyanide reference standard. Tests were also performed on selected samples for checking interference by biochemical abnormalities and leucocytosis. The effects of various sample storage conditions prior to testing were also tested.

RESULTS

Ninety per cent of results were within 4% of true values, 96% within 6% and in only three cases was the deviation > 10%, due to interference by bilirubinaemia and/or C-reactive protein. At an Hb value of 120 g/l for donor selection, there were no cases where the method would have been misleading.

CONCLUSION

HemoCue 301 provides a simple and reliable anaemia screen method, conforming to the requirements of CLIA'88 regulations; it is reliable for discriminating Hb values for donor acceptance. The main advantage is that the cuvettes are significantly cheaper than the previous models, and will not deteriorate in adverse climatic conditions.

Effect of Tribolium castaneum (Coleoptera: Tenebrionidae) nutritional environment, sex, and mating status on response to commercial pheromone traps

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), the red flour beetle, is an important cosmopolitan pest of stored grains. Commercial traps baited with the synthetic aggregation pheromone 4,8-dimethyldecanal (DMD) are used to monitor T. castaneum population densities in storage facilities. However, trap catches may depend on several intrinsic and extrinsic factors. In this study, we explored the effects of beetle nutritional environment, sex, and mating status on the response of T. castaneum to commercial Storgard Dome traps. Beetles raised on a low-nutrition diet were 1.7 times more likely to enter DMD-baited traps compared with beetles that were raised on a high-nutrition diet. Although no sex difference in trap response was found, unmated beetles of both sexes were more responsive to DMD than were mated beetles, and this effect was especially pronounced for beetles reared on a low-nutrition diet. These results suggest that estimating T. castaneum population densities based on trap catches might be improved by incorporating information about the nutritional quality of infested stored products.

Female mate choice across mating stages and between sequential mates in flour beetles

Few studies have examined how female premating choice correlates with the outcome of copulatory and post-copulatory processes. It has been shown that polyandrous Tribolium castaneum females discriminate among males before mating based on olfactory cues, and also exert cryptic choice during mating through several mechanisms. This study tested whether a male's relative attractiveness predicted his insemination success during copulation. Bioassays with male olfactory cues were used to rank two males as more and less attractive to females; each female was then mated to either her more attractive male followed by less attractive male, or vice versa. Dissections immediately after second copulations revealed a significantly higher percent of successful inseminations for females that remated with more attractive males compared with those that remated with less attractive males. These results indicate that cryptic female choice during copulation reinforces precopulatory female choice in T. castaneum, and suggest that females could use cryptic choice to trade up to more attractive males, possibly gaining better phenotypic or genetic quality of sires.

ESR or CRP? A comparison of their clinical utility

OBJECTIVE

To review the normal reference values for erythrocyte sedimentation rate (ESR) and the significance of high values in the elderly, to re-examine the correlation, if any, between ESR and C-reactive protein (CRP) and to compare their utility and limitations for both health screening and clinical management of patients.

METHODS

CRP and ESR were measured in 295 blood samples from male and female subjects in whom their family doctors had found no clinically significant symptoms nor abnormal physical sign and in whom all other pathology tests gave normal results. None had been hospitalised during at least a six-week period prior to the study.

RESULTS

The results showed a mean ESR of 10 mm/1 h (range 0-25) in both males and females below the age of 40 yrs; this increased with age, to a mean of 18 mm (range 0-35) by 60 yrs in both men and women. In the CRP test, 95% of the samples in the >40 yrs group had CRP range of 0-18 mg/l compared with 0-10 mg/l in the younger subjects. The distribution plot of CRP results showed a left skew with mode at about 2 mg/l, whereas the equivalent ESR distribution shows a broad plateau with less skew. Thus, there was more overlapping of the numerical values for ESR and CRP in subjects younger than 40 yrs, as compared with those over 40 yrs old in whom the two sets of measurements were well separated. The relative utility of the two tests in clinical management of patients was also discussed. Different rates of increase and subsequent fall in the test results were shown over several weeks on a patient with an acute infection. Initially, both tests were increased, but after antibiotic therapy the CRP returned to normal indicating that remission had occurred, whereas the ESR remained high, indicating persistence of the infection. A subsequent dramatic increase in CRP to 180 mg/l confirmed the re-infection that had been indicated earlier by the ESR. After further antibiotic therapy CRP fell to normal, followed later by a slower reduction in ESR to a normal value for the patient's age.

CONCLUSION

This study confirms that after the age of 40, there is an age-related elevation of ESR, increasing steadily, especially after age 60 yrs. CRP is also affected by age, but to a much less extent. ESR and CRP appear to be equally useful and reliable as a screening test. Accordingly, in deciding which test should be carried out account must be taken of their relative convenience and cost. However, when required as a clinical test in the management of patients with specific diseases both tests should be carried out in tandem.

For IRES trans-acting factors, it is all about location

The translation of many proteins involved in transcription, cell cycle progression, apoptosis and cell survival is mediated by internal ribosome entry sites (IRESs) present within the 5'-untranslated regions (5'-UTRs) of their messenger RNA molecules (mRNAs). Several recent reports now demonstrate that the proteins controlling IRES-dependent translation initiation are regulated by their subcellular localization.

Neutrophils in development of multiple organ failure in sepsis

Multiple organ failure is a major threat to the survival of patients with sepsis and systemic inflammation. In the UK and in the USA, mortality rates are currently comparable with and projected to exceed those from myocardial infarction. The immune system combats microbial infections but, in severe sepsis, its untoward activity seems to contribute to organ dysfunction. In this Review we propose that an inappropriate activation and positioning of neutrophils within the microvasculature contributes to the pathological manifestations of multiple organ failure. We further suggest that targeting neutrophils and their interactions with blood vessel walls could be a worthwhile therapeutic strategy for sepsis.

Measurement of haemoglobin as a screening test in general practice

OBJECTIVE

To assess the validity of using the measurement of haemoglobin as a primary screen test at point-of-care in general practice.

METHODS

1100 consecutive full blood counts carried out at Hammersmith Hospital haematology laboratory on blood samples sent by the general practitioners in the area were reviewed. Where haemoglobin was in the normal range all the parameters of a full blood count were checked and a blood film was screened in order to identify any abnormal features occurring in the absence of anaemia.

RESULTS

Haemoglobin was normal in 81% of the samples, and in 81% of this set none of the blood count components showed any abnormal features (i.e. outside two standard deviations of normal reference range). The remaining 19% of cases included 32 with iron deficiency, 26 with high MCV, 84 with leucocyte abnormalities (neutrophilia, neutropenia, lymphocytosis, eosinophilia, monocytosis) and 19 with platelet counts either too high or too low. The predictive value of a normal full blood count from a normal haemoglobin was 0.81. However, when the limits of normal reference values were set at three standard deviations only 7% of the cases showed abnormal features and the predictive value of normality from a normal haemoglobin increased to 0.92.

CONCLUSION

There are now simple and suitable devices available for measuring haemoglobin at point-of-care, away from a laboratory. This provides a useful screening test in general practice as a full blood count would, as a rule, be required only in the small proportion of cases where anaemia is detected or the patient's history and/or clinical signs specifically indicate the need for this further investigation. This approach should contribute to more efficient, convenient and economical practice without compromising clinical management.