Signature methods for brain-computer interfaces

Brain-computer interfaces (BCIs) allow direct communication between one's central nervous system and a computer without any muscle movement hence by-passing the peripheral nervous system. They can restore disabled people's ability to interact with their environment, e.g. communication and wheelchair control. However, to this day their performance is still hindered by the non-stationarity of electroencephalography (EEG) signals, as well as their susceptibility to noise from the users' environment and from their own physiological activity. Moreover, a non-negligible amount of users struggle to use BCI systems based on motor imagery. In this paper, a new method based on the path signature is introduced to tackle this problem by using features which are different from the usual power-based ones. The path signature is a series of iterated integrals computed from a multidimensional path. It is invariant under translation and time reparametrization, which makes it a robust feature for multichannel EEG time series. The performance can be further boosted by combining the path signature with the gold standard Riemannian classifier in the BCI field exploiting the geometric structure of symmetric positive definite (SPD) matrices. The results obtained on publicly available datasets show that the signature method is more robust to inter-user variability than classical ones, especially on noisy and low-quality data. Hence, this study paves the way towards the use of mathematical tools that until now have been neglected, in order to tackle the EEG-based BCI variability issue. It also sheds light on the lead-lag relationship captured by path signature which seems relevant to assess the underlying neural mechanisms.

The double task-switching protocol: An investigation into the effects of similarity and conflict on cognitive flexibility in the context of mental fatigue

Considerable fundamental studies have focused on the mechanisms governing cognitive flexibility and the associated costs of switching between tasks. Task-switching costs refer to the phenomenon that reaction times and accuracy decrease briefly following the switch from one task to another. However, cognitive flexibility also impacts day-to-day life in many complex work environments where operators have to perform several different tasks. One major difference between typical tasks examined in fundamental studies and real-world applications is that fundamental studies often rely on much more similar tasks, which is not the case for real-world applications. In the latter, operators may switch between vastly dissimilar tasks. Therefore, this behavioural study aims to test if task-switching costs are different for switches between similar and dissimilar tasks. The proposed protocol has participants switch between 2 pairs of two tasks each. Between pairs, there is more dissimilarity, while the two tasks within each pair are more similar. In addition, this study examines the impact of mental fatigue and interference in form of confounding information on cognitive flexibility. To induce mental fatigue the participants' breaks between blocks will be limited. We expect that dissimilarity between tasks will result in greater task-switching costs.

Cognitive effects of prolonged continuous human-machine interaction: The case for mental state-based adaptive interfaces

Operators of complex systems across multiple domains (e.g., aviation, automotive, and nuclear power industry) are required to perform their tasks over prolonged and continuous periods of time. Mental fatigue as well as reduced cognitive flexibility, attention, and situational awareness all result from prolonged continuous use, putting at risk the safety and efficiency of complex operations. Mental state-based adaptive systems may be a solution to this problem. These systems infer the current mental state of an operator based on a selection of metrics ranging from operator independent measures (e.g., weather and time of day), to behavioral (e.g., reaction time and lane deviation) as well as physiological markers (e.g., electroencephalography and cardiac activity). The interaction between operator and system may then be adapted in one of many ways to mitigate any detected degraded cognitive state, thereby ensuring continued safety and efficiency. Depending on the task at hand and its specific problems, possible adaptations -usually based on machine learning estimations- e.g., include modifications of information, presentation modality or stimuli salience, as well as task scheduling. Research on adaptive systems is at the interface of several domains, including neuroergonomics, human factors, and human-computer interaction in an applied and ecological context, necessitating careful consideration of each of the aforementioned aspects. This article provides an overview of some of the key questions and aspects to be considered by researchers for the design of mental state-based adaptive systems, while also promoting their application during prolonged continuous use to pave the way toward safer and more efficient human-machine interaction.

Retrospective on the First Passive Brain-Computer Interface Competition on Cross-Session Workload Estimation

As is the case in several research domains, data sharing is still scarce in the field of Brain-Computer Interfaces (BCI), and particularly in that of passive BCIs-i.e., systems that enable implicit interaction or task adaptation based on a user's mental state(s) estimated from brain measures. Moreover, research in this field is currently hindered by a major challenge, which is tackling brain signal variability such as cross-session variability. Hence, with a view to develop good research practices in this field and to enable the whole community to join forces in working on cross-session estimation, we created the first passive brain-computer interface competition on cross-session workload estimation. This competition was part of the 3rd International Neuroergonomics conference. The data were electroencephalographic recordings acquired from 15 volunteers (6 females; average 25 y.o.) who performed 3 sessions-separated by 7 days-of the Multi-Attribute Task Battery-II (MATB-II) with 3 levels of difficulty per session (pseudo-randomized order). The data -training and testing sets-were made publicly available on Zenodo along with Matlab and Python toy code (https://doi.org/10.5281/zenodo.5055046). To this day, the database was downloaded more than 900 times (unique downloads of all version on the 10th of December 2021: 911). Eleven teams from 3 continents (31 participants) submitted their work. The best achieving processing pipelines included a Riemannian geometry-based method. Although better than the adjusted chance level (38% with an α at 0.05 for a 3-class classification problem), the results still remained under 60% of accuracy. These results clearly underline the real challenge that is cross-session estimation. Moreover, they confirmed once more the robustness and effectiveness of Riemannian methods for BCI. On the contrary, chance level results were obtained by one third of the methods-4 teams- based on Deep Learning. These methods have not demonstrated superior results in this contest compared to traditional methods, which may be due to severe overfitting. Yet this competition is the first step toward a joint effort to tackle BCI variability and to promote good research practices including reproducibility.

Topological Data Analysis as a New Tool for EEG Processing

Electroencephalography (EEG) is a widely used cerebral activity measuring device for both clinical and everyday life applications. In addition to denoising and potential classification, a crucial step in EEG processing is to extract relevant features. Topological data analysis (TDA) as an emerging tool enables to analyse and understand data from a different angle than traditionally used methods. As a higher dimensional analogy of graph analysis, TDA can model rich interactions beyond pairwise relations. It also distinguishes different dynamics of EEG time series. TDA remains largely unknown to the EEG processing community while it fits well the heterogeneous nature of EEG signals. This short review aims to give a quick introduction to TDA and how it can be applied to EEG analysis in various applications including brain-computer interfaces (BCIs). After introducing the objective of the article, the main concepts and ideas of TDA are explained. Next, how to implement it for EEG processing is detailed, and lastly the article discusses the benefits and limitations of the method.

Mental Workload Estimation Based on Physiological Features for Pilot-UAV Teaming Applications

Manned-Unmanned Teaming (MUM-T) can be defined as the teaming of aerial robots (artificial agents) along with a human pilot (natural agent), in which the human agent is not an authoritative controller but rather a cooperative team player. To our knowledge, no study has yet evaluated the impact of MUM-T scenarios on operators' mental workload (MW) using a neuroergonomic approach (i.e., using physiological measures), nor provided a MW estimation through classification applied on those measures. Moreover, the impact of the non-stationarity of the physiological signal is seldom taken into account in classification pipelines, particularly regarding the validation design. Therefore this study was designed with two goals: (i) to characterize and estimate MW in a MUM-T setting based on physiological signals; (ii) to assess the impact of the validation procedure on classification accuracy. In this context, a search and rescue (S&R) scenario was developed in which 14 participants played the role of a pilot cooperating with three UAVs (Unmanned Aerial Vehicles). Missions were designed to induce high and low MW levels, which were evaluated using self-reported, behavioral and physiological measures (i.e., cerebral, cardiac, and oculomotor features). Supervised classification pipelines based on various combinations of these physiological features were benchmarked, and two validation procedures were compared (i.e., a traditional one that does not take time into account vs. an ecological one that does). The main results are: (i) a significant impact of MW on all measures, (ii) a higher intra-subject classification accuracy (75%) reached using ECG features alone or in combination with EEG and ET ones with the Adaboost, Linear Discriminant Analysis or the Support Vector Machine classifiers. However this was only true with the traditional validation. There was a significant drop in classification accuracy using the ecological one. Interestingly, inter-subject classification with ecological validation (59.8%) surpassed both intra-subject with ecological and inter-subject with traditional validation. These results highlight the need for further developments to perform MW monitoring in such operational contexts.

Scheduling and Rescheduling Operations Using Decision Support Systems: Insights From Emotional Influences on Decision-Making

For many years, manufacturers have focused on improving their productivity. Production scheduling operations are critical for this objective. However, in modern manufacturing systems, the original schedule must be regularly updated as it takes places in a dynamic and uncertain environment. The modern manufacturing environment is therefore very stressful for the managers in charge of the production process because they have to cope with many disruptions and uncertainties. To help them in their decision-making process, several decision support systems (DSSs) have been developed. A recent and enormous challenge is the implementation of DSSs to efficiently manage the aforementioned issues. Nowadays, these DSSs are assumed to reduce the users' stress and workload because they automatically (re)schedule the production by applying algorithms. However, to the best of our knowledge, the reciprocal influence of users' mental state (i.e., cognitive and affective states) and the use of these DSSs have received limited attention in the literature. Particularly, the influence of users' unrelated emotions has received even less attention. However, these influences are of particular interest because they can account for explaining the efficiency of DSSs, especially in modulating DSS feedback processing. As a result, we assumed that investigating the reciprocal influences of DSSs and users' mental states could provide useful avenues of investigation. The intention of this article is then to provide recommendations for future research on scheduling and rescheduling operations by suggesting the investigation of users' mental state and encouraging to conduct such research within the neuroergonomic approach.

Monitoring Pilot's Mental Workload Using ERPs and Spectral Power with a Six-Dry-Electrode EEG System in Real Flight Conditions

Recent technological progress has allowed the development of low-cost and highly portable brain sensors such as pre-amplified dry-electrodes to measure cognitive activity out of the laboratory. This technology opens promising perspectives to monitor the "brain at work" in complex real-life situations such as while operating aircraft. However, there is a need to benchmark these sensors in real operational conditions. We therefore designed a scenario in which twenty-two pilots equipped with a six-dry-electrode EEG system had to perform one low load and one high load traffic pattern along with a passive auditory oddball. In the low load condition, the participants were monitoring the flight handled by a flight instructor, whereas they were flying the aircraft in the high load condition. At the group level, statistical analyses disclosed higher P300 amplitude for the auditory target (Pz, P4 and Oz electrodes) along with higher alpha band power (Pz electrode), and higher theta band power (Oz electrode) in the low load condition as compared to the high load one. Single trial classification accuracy using both event-related potentials and event-related frequency features at the same time did not exceed chance level to discriminate the two load conditions. However, when considering only the frequency features computed over the continuous signal, classification accuracy reached around 70% on average. This study demonstrates the potential of dry-EEG to monitor cognition in a highly ecological and noisy environment, but also reveals that hardware improvement is still needed before it can be used for everyday flight operations.

Temporal Dynamics of Natural Static Emotional Facial Expressions Decoding: A Study Using Event- and Eye Fixation-Related Potentials

This study aims at examining the precise temporal dynamics of the emotional facial decoding as it unfolds in the brain, according to the emotions displayed. To characterize this processing as it occurs in ecological settings, we focused on unconstrained visual explorations of natural emotional faces (i.e., free eye movements). The General Linear Model (GLM; Smith and Kutas, 2015a,b; Kristensen et al., 2017a) enables such a depiction. It allows deconvolving adjacent overlapping responses of the eye fixation-related potentials (EFRPs) elicited by the subsequent fixations and the event-related potentials (ERPs) elicited at the stimuli onset. Nineteen participants were displayed with spontaneous static facial expressions of emotions (Neutral, Disgust, Surprise, and Happiness) from the DynEmo database (Tcherkassof et al., 2013). Behavioral results on participants' eye movements show that the usual diagnostic features in emotional decoding (eyes for negative facial displays and mouth for positive ones) are consistent with the literature. The impact of emotional category on both the ERPs and the EFRPs elicited by the free exploration of the emotional faces is observed upon the temporal dynamics of the emotional facial expression processing. Regarding the ERP at stimulus onset, there is a significant emotion-dependent modulation of the P2-P3 complex and LPP components' amplitude at the left frontal site for the ERPs computed by averaging. Yet, the GLM reveals the impact of subsequent fixations on the ERPs time-locked on stimulus onset. Results are also in line with the valence hypothesis. The observed differences between the two estimation methods (Average vs. GLM) suggest the predominance of the right hemisphere at the stimulus onset and the implication of the left hemisphere in the processing of the information encoded by subsequent fixations. Concerning the first EFRP, the Lambda response and the P2 component are modulated by the emotion of surprise compared to the neutral emotion, suggesting an impact of high-level factors, in parieto-occipital sites. Moreover, no difference is observed on the second and subsequent EFRP. Taken together, the results stress the significant gain obtained in analyzing the EFRPs using the GLM method and pave the way toward efficient ecological emotional dynamic stimuli analyses.

Detecting Pilot's Engagement Using fNIRS Connectivity Features in an Automated vs. Manual Landing Scenario

Monitoring pilot's mental states is a relevant approach to mitigate human error and enhance human machine interaction. A promising brain imaging technique to perform such a continuous measure of human mental state under ecological settings is Functional Near-InfraRed Spectroscopy (fNIRS). However, to our knowledge no study has yet assessed the potential of fNIRS connectivity metrics as long as passive Brain Computer Interfaces (BCI) are concerned. Therefore, we designed an experimental scenario in a realistic simulator in which 12 pilots had to perform landings under two contrasted levels of engagement (manual vs. automated). The collected data were used to benchmark the performance of classical oxygenation features (i.e., Average, Peak, Variance, Skewness, Kurtosis, Area Under the Curve, and Slope) and connectivity features (i.e., Covariance, Pearson's, and Spearman's Correlation, Spectral Coherence, and Wavelet Coherence) to discriminate these two landing conditions. Classification performance was obtained by using a shrinkage Linear Discriminant Analysis (sLDA) and a stratified cross validation using each feature alone or by combining them. Our findings disclosed that the connectivity features performed significantly better than the classical concentration metrics with a higher accuracy for the wavelet coherence (average: 65.3/59.9 %, min: 45.3/45.0, max: 80.5/74.7 computed for HbO/HbR signals respectively). A maximum classification performance was obtained by combining the area under the curve with the wavelet coherence (average: 66.9/61.6 %, min: 57.3/44.8, max: 80.0/81.3 computed for HbO/HbR signals respectively). In a general manner all connectivity measures allowed an efficient classification when computed over HbO signals. Those promising results provide methodological cues for further implementation of fNIRS-based passive BCIs.

Efficient Workload Classification based on Ignored Auditory Probes: A Proof of Concept

Mental workload is a mental state that is currently one of the main research focuses in neuroergonomics. It can notably be estimated using measurements in electroencephalography (EEG), a method that allows for direct mental state assessment. Auditory probes can be used to elicit event-related potentials (ERPs) that are modulated by workload. Although, some papers do report ERP modulations due to workload using attended or ignored probes, to our knowledge there is no literature regarding effective workload classification based on ignored auditory probes. In this paper, in order to efficiently estimate workload, we advocate for the use of such ignored auditory probes in a single-stimulus paradigm and a signal processing chain that includes a spatial filtering step. The effectiveness of this approach is demonstrated on data acquired from participants that performed the Multi-Attribute Task Battery - II. They carried out this task during two 10-min blocks. Each block corresponded to a workload condition that was pseudorandomly assigned. The easy condition consisted of two monitoring tasks performed in parallel, and the difficult one consisted of those two tasks with an additional plane driving task. Infrequent auditory probes were presented during the tasks and the participants were asked to ignore them. The EEG data were denoised and the probes' ERPs were extracted and spatially filtered using a canonical correlation analysis. Next, binary classification was performed using a Fisher LDA and a fivefold cross-validation procedure. Our method allowed for a very high estimation performance with a classification accuracy above 80% for every participant, and minimal intrusiveness thanks to the use of a single-stimulus paradigm. Therefore, this study paves the way to the efficient use of ERPs for mental state monitoring in close to real-life settings and contributes toward the development of adaptive user interfaces.

Dibutyl phthalate, the bioactive compound produced by Streptomyces albidoflavus 321.2

It was found that the bioactive compound, dibutyl phthalate, was produced by a new soil isolate Streptomyces albidoflavus 321.2. Once this active compound was recovered by ethyl acetate from the fermented broth, being possible to isolate 13.4 mg/l, it was purified by paper, silica gel column, thin layer and gas chromatography. Structure was determined by analysing UV, IR and GC-MS spectra. During analysis, such active compound showed strong activity against gram-positive and gram-negative bacteria, as well as unicellular and filamentous fungi. The antimicrobial activity of the compound was reversed by the amino acid proline. No acute toxicity was observed.

Who's got what? A benchmarking exercise for tertiary neonatal units

OBJECTIVES

To determine the current facilities available in level-3 neonatal units (NNU) in Australia and New Zealand to assist with establishment of standards for new NNU design.

BACKGROUND

Many current NNU in Australia and New Zealand are planning new or redesigning existing facilities. There are no adequate local standards for NNU design available which reflect changing neonatal practices.

METHODS

All level-3 neonatal units belonging to the Australia and New Zealand Neonatal Network (ANZNN) were invited to respond to a survey on NNU facilities. Questions were based around obtaining information on whether the NNU were planning to build or redesign the space and clinical facilities available in their existing facilities and what support and family spaces were provided.

RESULTS

Twenty-six (six in New Zealand and 20 in Australia) of the 29 tertiary NNU in the ANZNN responded the survey. The oldest facility was built in 1960, with the most recent NNU being commissioned in 2003. Of the 26 responders, 18 indicated that they were planning to rebuild or renovate, with 13 anticipating completion within 6 years. The median floor area for existing level-3 cots was 11.1 m(2) (range 5.5-18.0 m(2)) and 5.8 m(2) (range 2.3-15.6 m(2)) for level-2 cots, respectively. Most units responded that storage space was insufficient (median 1.5 m(2) per cot, range 0.4-3.3 m(2) per cot). Most units had facilities for parents including a family lounge and parent overnight rooms, although 16 units indicated that they needed more overnight rooming in facilities. Noise levels in level-3 areas were described as being 'generally' or 'mostly noisy' in 14 of 25 responses, but noise levels in level-2 areas were less in the majority of responses. Privacy was cited as an issue for 80% of responding NNU with comments directed at either the layout or space constraints interfering with confidentiality or interactions with families.

CONCLUSIONS

The majority of NNU have inadequate space and environmental control. The lack of space particularly impacts on infection control aspects, parental privacy and participation and staff satisfaction. Level-2 areas, where parent participation in the care of infants is often greater, should receive as much attention as higher technology level-3 areas. Furthermore, work should be undertaken to develop appropriate local recommendations for NNU design which are acknowledged by local government agencies and professional bodies and take into account the changes in neonatal care practices, integration of family in the care of infants and the needs of the staff.

Utilisation pattern of blood in a teaching hospital of Kolkata

An annual utilisation of blood transfusion services at several depts. of R.G. Kar Medical College and Hospital, Kolkata were assessed among a sample of 3122 patients selected by Systematic Random Sampling Technique from the register made available in the blood bank there. Record analysis revealed that overall 79.4% of supplied blood units were actually transfused, wastage of 21.6%. Wastage was maximum in the Department of Gynae & Obstetrics (33.11%) and Surgery (32.87%). Only single unit of blood was requisitioned and transfused for 5.44% & 30.90% of the patients respectively. Most common indications of blood transfusion were for surgical cases (37.92%), followed by anaemia (34.80%) and haemorrhage (26.92%). The use of blood and blood products merit attention, appraisal and instructional guiding accordingly.

Status of maternal and new born care at first referral units in the state of West Bengal

A study was conducted in 12 First Referral Units (FRUs), selected through multistage sampling, from 6 districts of West Bengal. Infrastructure facilities, record keeping, referral system and MCH indicators related to newborn care were documented. Data was collected by review of records, interview and observation using a pre-designed proforma. Inadequate infrastructure facilities (e.g. no sanctioned posts of specialists, no blood bank at rural hospitals declared as First Referral Units etc.); poor utilization of equipment like neonatal resuscitation sets, radiant warmer etc, lack of training of the service providers were evident. Records/registers were available but incomplete. Referral system was found to be almost nonexistent. Most of the deliveries (86.1%) were normal delivery. Deliveries (87.71%) and immediate neonatal resuscitation (94.9%) were done mostly by nursing personnel. Institution based maternal, perinatal and early neonatal mortality rates were found to be 5.6, 62.4 and 25.2 per 1000 live births respectively. Eclampsia (48.9%), hemorrhage (17.7%), puerperal sepsis (7.1%) were reported to be major causes of maternal mortality. Common causes of early neonatal mortality were birth asphyxia (54.3%), sepsis (14.6%) and prematurity/LBW (12.4%).

Survey of antimicrobial streptomycetes from soils of West Bengal: characterization and identification of potent broad spectrum antibiotic producing Streptomyces albidoflavus 321.2

Survey of 611 streptomycetes isolates from 330 soil samples from various parts of West Bengal were done for their antimicrobial activity against Gram positive, Gram negative bacteria, unicellular and filamentous fungi. The strain 321.2 showed inhibition against all the test organisms used and found as potent. The morphological, cultural, physiological and biochemical characters were studied, compared with known species and identified as Streptomyces albidoflavus. This strain produces an antibiotic.

Development and evaluation of a monoclonal antibody based competitive enzyme-linked immunosorbent assay for the detection of rinderpest virus antibodies

A competitive enzyme-linked immunosorbent assay has been standardised for the detection of antibodies to rinderpest virus in sera from cattle, sheep and goats. The test uses a neutralising monoclonal antibody (MAb) directed against the haemagglutinin protein of rinderpest virus. The test is specific for rinderpest, as it failed to detect antibodies to peste des petits ruminants virus in convalescent goat sera. A 45% inhibition of the binding of the MAb to the antigen was used as the cut-off point for deciding the rinderpest status of the test samples. The specificity and sensitivity of the test and the stability of the test reagents were determined and compared to the results obtained using a commercial kit with approximately 1,200 serum samples from cattle, sheep and goats in India. The current test compared very well with the commercial kit. The test is expected to be extremely useful for sero-monitoring and sero-surveillance of rinderpest in countries which are actively pursuing a rinderpest eradication programme.

Effect of tamoxifen treatment on the endometrial expression of human insulin-like growth factors and their receptor mRNAs

The effect of tamoxifen (Tam) treatment on the endometrial expression of IGF-I and II/IGF-IR and IIR mRNAs was assessed by measuring the levels of expression of these mRNAs in the endometrial samples of Tam-treated postmenopausal breast cancer patients by RT-PCR assays. The levels of these mRNAs were compared with those in normal endometrium and in Type I and Type II endometrial carcinomas (EC). The promoter-specific transcript profiles of IGF-I and II were also elucidated. The levels of IGF/IGF-R mRNAs in the endometrium from Tam-treated patients were found to be comparable with the high levels of these mRNAs observed in the proliferative and early secretory phase endometrium and in the samples of Type I EC. These results indicate that Tam acts as an estrogen agonist in inducing the endometrial expression of these genes. Tam stimulated transcription from the multiple promoters of IGF-I and II, with the exception of IGF-II P2 promoter, in which case the transcription across exon 4 appeared to be inhibited. The profiles of IGF-I and II transcripts of endometrium from Tam-treated patients were similar to Type I EC but differed considerably from those of Type II EC. These results suggest that the Tam-associated ECs are likely to be similar to type I EC and will therefore have a more favorable prognosis.

Transcriptional induction of the conserved alternative sigma factor RpoS in Escherichia coli is dependent on BarA, a probable two-component regulator

The stationary phase expression of many conserved, adaptive bacterial proteins is dependent on RpoS, a second vegetative sigma factor. The regulation of RpoS itself, however, is complex and not fully understood, particularly at the level of transcription. In this report, we show that the observed hydrogen peroxide sensitivity of a mutant defective in expression of barA, a bacterial virulence factor, can be explained by a reduction in catalase activity, an RpoS-controlled function. Levels of katE mRNA, encoding the major catalase of Escherichia coli, were much lower in the barA mutant, suggesting that BarA is required for the expression of this RpoS-regulated gene. Expression of another RpoS-regulated gene, osmY, was also found to be severely reduced in the barA mutant. Employing Western analyses with anti-RpoS antisera and Northern analyses using probes specific for rpoS, we found that BarA is required for the exponential phase induction of RpoS itself. Operon lacZ fusion expression studies and Northern analyses indicate that BarA itself is maximally expressed in early exponential phase cultures immediately preceding the transcriptional induction of RpoS. Results of primer extension studies indicate that exponential phase expression from the rpoSp1 promoter is reduced by more than 85% in a barA mutant but could be efficiently complemented by a plasmid-borne copy of barA in trans. These results suggest that regulatory signals that are operant in exponentially growing cultures play an important role in effecting stationary phase gene expression.

Loss of IGF-II imprinting in endometrial tumors: overexpression in carcinosarcoma

The genomic imprinting of the maternal allele defines the monoallelic expression of the IGF-II gene in most human tissues. The loss of imprinting (LOI) leading to biallelic overexpression of IGF-II has been reported in several human malignancies, including uterine leiomyosarcoma. To ascertain if LOI occurs in endometrial malignancies, the allelic expression of the IGF-II gene was examined in samples of normal human endometrium (n=22) and endometrial tumors (n=12) by assessing the ApaI polymorphism in cDNA segments amplified by RT-PCR. The biallelic overexpression of IGF-II mRNA, involving activation of all four (P1-P4) promoters, was detected in one normal endometrium and in one endometrial carcinosarcoma. Low level biallelic expression of IGF-II was also detected in two samples of hormone-unresponsive/Type II endometrial carcinomas. The level of IGF-I mRNA in these four samples was low. The IGF-IR mRNA was overexpressed in all endometrial cancers including the carcinosarcoma sample, but not in normal endometrium. These data suggest that LOI associated with overexpression of IGF-II and concomitant overexpression of IGF-IR may play a role in the rare carcinosarcoma of the endometrium.

Discordant expression of insulin-like growth factors and their receptor messenger ribonucleic acids in endometrial carcinomas relative to normal endometrium

The inappropriate expressions of insulin-like growth factors (IGF-I and II) and IGF-I receptor (IGF-IR) are implicated in the malignant growth of many cancers. To determine changes, if any, in the levels of expression of IGFs and IGF receptor genes in neoplastic endometrium, relative to normal endometrium, the mRNA levels of IGF-I and II and of IGF-IR and IIR were measured in samples of endometrial carcinomas (EC) and normal endometrium, through all phases of the menstrual cycle, by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) assays. In normal endometrium, the mRNA levels of IGF-I were elevated in the proliferative and early secretory phases. The IGF-II mRNAs were relatively high in the proliferative phase, but unaltered through early and late secretory phases. Significantly elevated levels of IGF-II transcripts were observed during the menstrual phase, suggesting a possible role of IGF-II in endometrial regeneration. A positive correlation between the levels of IGF-I and IGF-IR mRNAs, apparent in the samples of normal endometrium, was not observed in endometrial carcinomas. The IGF-IR and IIR mRNA levels were elevated in endometrial carcinoma samples. On the other hand, the IGF-I and II mRNA levels were conspicuously low in many carcinoma samples, which were not associated with hyperplasia (type II EC), but relatively elevated in two other carcinoma samples, associated with adenomatous hyperplasia (type I EC). These results albeit with few samples suggest the possibility that the overexpressed receptor, IGF-IR, could be activated differently in two types of endometrial carcinomas, namely ligand-dependently in type I ECs and ligand-independently in type II ECs.

Endometrial transcripts of human insulin-like growth factors arise by differential promoter usage

By the application of RT-PCR, we have demonstrated that in the human endometrium mRNAs for insulin-like growth factors, IGF-I and II, and their receptors are expressed not only in the intact endometrium, but also in the freshly isolated stromal and epithelial cells. The expression of multiple transcript forms of the IGF-I and II at various phases of the menstrual cycle, occurs by differential use of all four IGF-I transcriptional start sites, and two of the four known promoter sites of the IGF-II gene. The complete spectrum of transcripts is displayed by the proliferative phase and the menstrual phase endometrium. During the secretory phase, the exon 1 upstream start site of the IGF-I gene and the P2 promoter of the IGF-II gene are not used. Irrespective of the phase of the menstrual cycle, the stromal cells always display the same transcriptional patterns of both growth factor genes as those of the intact endometrium. In contrast, the epithelial cells do not express IGF-I transcript originating from the exon 2 upstream initiation site. These results indicate that the expressions of the IGF-I and II genes in the intact endometrium and stromal and epithelial cells are modulated at the transcriptional level during the menstrual cycle by differential usage of promoters and start sites.

Control of temperature during newborn transport: an old problem with new difficulties

OBJECTIVE

To explore any changes in temperature control during neonatal emergency inter-hospital transport between 1977 and 1996.

METHODS

Records were reviewed of all infants undergoing emergency transfer by the statewide Victorian Newborn Emergency Transport Service (NETS). Per axillary temperatures were recorded prospectively on arrival of transport team and at conclusion of transfer for all infants.

RESULTS

The rate of hypothermia (< 36.0 degrees C) when NETS reached the infant has decreased overall (22% in 1977-79 to 7% in 1995-96) and for all weight groups; although in 1995-96 hypothermia was present in 36% of infants less than 1000 g when NETS arrived. The rate of hypothermia (< 36.0 degrees C) at the end of the transfer has remained at 3% overall for many years. The rate of hyperthermia at both times has increased significantly overall (12% in 1977-79 to 24% in 1995-96 on NETS arrival, 4%-19%, respectively at end of transfer) and for all weight groups except infants less than 1000 g. The range of abnormal temperatures has not substantially changed over time.

CONCLUSION

There has been significant improvement in avoidance of hypothermia and cold stress amongst infants requiring emergency neonatal transport from 1977 to 1996. However, in order to improve the number of infants transferred who achieve a temperature in the normal range the need to avoid hyperthermia is highlighted. Infants who require incubator care for optimal medical management require continual monitoring of temperature and review of environmental conditions to optimise the conditions both prior to and during transport.

Minimal haemolysis in blood co-infused with amino acid and dextrose solutions in vitro

OBJECTIVE

To examine the haemolytic effects of amino acid and dextrose solutions on co-infused packed red blood cells.

METHODOLOGY

An in vitro study of packed cells co-infused at various rates with dextrose 5%, 10%, 15% and intravenous amino acid solution (Vamin; Kabi-Pharmacia, Baxter Healthcare Pty Ltd) in dextrose 5%, 10% and 15%. The degree of haemolysis was measured as free oxyhaemoglobin by spectrophotometer. Co-infused 0.9% saline and water were used as 0% and 100% haemolysis controls.

RESULTS

Only minimal haemolysis was observed with the solutions tested. The greatest observed amount of haemolysis was 0.14%.

CONCLUSIONS

Co-infusion of packed red blood cells with dextrose and amino acid solutions at the concentrations and infusion rates commonly used in neonatal care, does not cause clinically important haemolysis.

Gene expression of A- and B-type natriuretic peptides in response to acute ethanol ingestion

Given that ethanol ingestion is associated with a disruption of water and electrolyte balance in addition to being a significant risk factor for cardiovascular disease, we have investigated the gene expression of ANP and BNP in response to acute doses of ethanol. Wistar rats were administered either a 5 g/kg dose of ethanol or an equivalent volume of water, and atrial and ventricular tissue samples were removed at 30, 60, and 120 min for analyses. Although no differences in ANP mRNA were observed between ethanol and water-treated rats during the time course, BNP mRNA levels in ethanol-treated rats were 43% of those present in water-treated animals in atrial tissue at 120 min. In ventricular tissue, BNP mRNA levels were reduced similarly to 38% of control. These results suggest a possible differential regulation of A- and B-type natriuretic peptides under the influence of ethanol ingestion.

Isolation and sequencing of gene fusions carried by lambda placMu specialized transducing phage

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Genomic sequence, structural organization and evolutionary conservation of the 13.2-kDa subunit of rat NADH:ubiquinone oxidoreductase

The 13.2-kDa subunit of NADH:ubiquinone oxidoreductase has been shown to be an integral part of the bovine iron-sulfur (IP) part of the protein. This subunit has been shown to interact with at least two other protein subunits of the IP fragment. The amino acid (aa) sequence of this subunit, determined from an acid extract of rat heart was used to generate an oligodeoxyribonucleotide probe which allowed isolation of a cDNA coding for the rat homologue of 13.2-kDa IP. The cDNA was used as a probe of a rat genomic DNA library and two clones were isolated, one of which contained the entire coding region for 13.2-kDa IP. Southern analysis indicates that the IP13 sequence exists as a single copy gene. The sequence of the genomic clone contains one intron and promoter elements including a TATAAA region. The 5' flank region has several potential regulatory sites, most notably regions similar to the nuclear respiratory factor 1 (NRF-1) motif, found in other genes which code for mitochondrial proteins [Evans and Scarpulla, Genes Dev. 4 (1990) 1023-1034]. The core domain of the deduced rat aa sequence has a high degree of identity with the mouse and cow homologues of this protein. The high degree of conservation of this protein indicates that the protein is essential for the function of complex I.

Chronic ethanol ingestion modifies the renin-aldosterone axis independent of alterations in the regulation of atrial natriuretic peptide

Using an animal model, we have investigated the effects of chronic ethanol ingestion on the regulation of atrial natriuretic peptide (ANP) synthesis and release. Male Sprague-Dawley rats were maintained for 6 weeks on a liquid diet of ethanol (up to 20% v/v) as part of a 2% solution of calf milk replacer. Weight-matched controls received an equal volume of ethanol-free solution, and normal animals drank ad libitum. All animals received rat chow throughout the experiment. This model produced physiologically relevant levels of blood ethanol, as concentrations at the time of sacrifice were 171.98 +/- 39.26 mg/dl. Plasma renin activity was significantly elevated in response to ethanol treatment, whereas circulating aldosterone concentration was reduced. No alterations in the plasma or atrial tissue levels of ANP were evident, although we did observe a significant increase in the ventricular tissue levels of ANP from 45.1 to 71.8 ng/g as a consequence of ethanol treatment. Levels of both atrial and ventricular ANP mRNA were not different between alcohol-treated and liquid-restricted control animals, although both groups showed significant increases in the amount of transcript in comparison with rats drinking ad libitum. No significant increases in either arterial blood pressure or heart/body weight ratio were observed for ethanol-treated rats. These results suggest that modifications in the renin-aldosterone axis can occur independently of alterations in the regulation of ANP under the influence of chronic ethanol ingestion.

Crohn's disease & aflatoxins

An investigation to examine the relationship between Crohn's disease and aflatoxins, a group of structurally related toxic and carcinogenic metabolites, was carried out on 24 patients. Extracts of serum and urine from the patients were assayed qualitatively by thin layer chromatography and the Aflatest method, and quantitatively by fluorimetry. There was evidence that some patients suffering from Crohn's Disease, together with some having coeliac disease and ulcerative colitis, did have varying amounts of aflatoxins in their serum and urine. The presence of aflatoxins may have been due to exposure to food containing these toxins or inability of the patient to excrete aflatoxins on account of some gastro-intestinal derangement. Only long-term investigation would establish the link between dietary history and the presence of aflatoxins in these patients.

Expression of natriuretic peptide genes in cardiac tissues of hypertensive rats

A quantitative assay using a reverse transcriptase-linked polymerase chain reaction has been developed for measuring the levels of rANP and iso-rANP mRNA. A linear correlation between total RNA template and amplified cDNA was obtained for the amplification of cDNA from both iso-rANP and rANP mRNAs even when both cDNAs were amplified in the same assay. Application of the assay showed that in contrast to rANP levels of iso-rANP transcript in hypertensive rats remained approximately the same in atrium but were increased 10-fold in ventricle compared to normal rats. Given the relative size of the ventricle the increase of iso-rANP in this tissue in SHR may be a major response to the hypertensive state.

Organization of the gene for iso-rANP, a rat B-type natriuretic peptide

Using the polymerase chain reaction and oligonucleotide primers constructed from knowledge of the cDNA sequence we have sequenced the gene for iso-rANP, a peptide of the B-type of atrial natriuretic peptides. The overall organization of the rat iso-ANP gene is the same as that of ANP and BNP consisting of three exons and two introns at relatively similar positions. Iso-rANP and it's gene are more closely related to BNPs than ANP and yet there are significant differences at both the protein and DNA levels. Our results suggest that iso-rANP and BNP are distinct members of the same sub-family (B-type natriuretic peptides) within the family of natriuretic peptide genes.

The Melbourne Chart--a logical guide to neonatal resuscitation

Resuscitation of the asphyxiated infant is one of the great emergencies in medical practice. Properly done, it can save many lives and greatly reduce the morbidity resulting from hypoxic-ischaemic encephalopathy, but if it is ineptly performed, the effects of hypoxic-ischaemic encephalopathy may be accentuated, with resultant increased morbidity and even mortality. Other than paediatricians, few practitioners have regular experience in neonatal resuscitation: indeed many, including obstetricians, anaesthetists, general practitioners and midwives may only rarely face the problem of severe asphyxia. It is therefore essential for the occasional practitioner to have ready reference to a logical guide to resuscitation. We have designed such a guide which is widely distributed in delivery suites and operating theatres in Victoria. Its basic form has been in use for over a decade and it has recently been revised. Use of the chart assists the resuscitator to judge the level of resuscitation required. It is our experience that much unnecessary intervention occurs at resuscitation, and we believe the methods outlined in this schematic chart represent a more conservative but logical approach to neonatal resuscitation. The chart is based on the pathophysiological changes that occur in perinatal asphyxia, directing the user to the appropriate manoeuvres required to correct those changes, depending on the degree of asphyxia which is determined by clinical signs and by use of the Apgar score.

Methods of delivery and resuscitation of very-low-birthweight infants in Victoria: 1982-1985

This article describes the patterns of delivery and resuscitation for very-low-birthweight infants who were born in Victoria from 1982 to 1985. Caesarean delivery rates increased from 15% to 30% for infants of birthweights of 500-999 g, and from 39% to 52% for infants of birthweights of 1000-1499 g. In level-III hospitals, the proportion of live-born infants who did not receive active resuscitation fell from 32% to 18% for those who weighed 500-999 g, and from 28% to 15% for those who weighed 1000-1499 g. Time trends over the four years showed the management of very-low-birthweight infants to be in a state of rapid transition in all birth settings. At the same time there was a fall in the still-birth rate of infants of birthweights of 500-999 g. Still-births rates for infants of birthweights of 1000-1499 g remained unchanged, as did neonatal mortality rates in both weight groups.

Developmental regulation of specific protein interactions with an enhancerlike binding site far upstream from the avian very-low-density apolipoprotein II gene

Expression of the avian very-low-density apolipoprotein II (apoVLDLII) gene is completely dependent on estrogen and restricted to the liver. We have identified binding sites for nonhistone nuclear proteins located between -1.96 and -2.61 kilobases. One of these sites, located at -2.6 kilobases (designated site 1), was found to span an MspI site that becomes demethylated between days 7 and 9 of embryogenesis, the stage of development at which competence to express the apoVLDLII gene begins to be acquired. Levels of the factor(s) involved were high at day 7 of embryogenesis, decreased two- to threefold by days 9 to 11, and continued to decline more slowly until hatching. Furthermore, the mobility of the complex formed underwent a well-defined shift between days 11 to 13 embryogenesis. Methylation interference studies showed that modification of the outer guanosines of the MspI site resulted in marked inhibition of the formation of the protein-DNA complex. Competition studies, fractionation of nuclear extracts, and tissue distribution indicated that the factor was not the avian homolog of hepatocyte nuclear factor 1, nuclear factor 1, or CCAAT/enhancer-binding protein (C/EBP). However, site 1 could complete for binding to an oligonucleotide, previously shown to be recognized by C/EBP, in a nonreciprocal fashion. These studies demonstrate that the sequence recognized by the protein includes a C/EBP consensus sequence but that elements in addition to the core enhancer motif are essential for binding.

Observations on spinal dysraphism

An attempt has been made to look into the age at presentation, incidence and clinical presentation of 40 patients with spinal dysraphism. Thirteen cases of myelomeningocele and 11 cases of meningocele constituted the 'aperta' group and there were 16 'occulta' cases. Though among the 'aperta' cases male is to female ratio was 1:1, a marked male preponderance of 2.2:1 was seen among 'occulta' cases. First born child was found to be most frequently (44.50%) affected in the present series. Myelography remained a mainstay in deciding operation in 'occulta' cases. All 'aperta' cases and 11 out of 16 'occulta' cases were treated by operation. Regarding results of treatment, all cases with meningocele were fully cured, cases with myelomeningocele showed no improvement but further deterioration of the neurological status could be arrested. Hydrocephalus was associated in 8 out of 13 cases with myelomeningocele and ventriculoperitoneal (VP) shunt were instituted in all of them. Prognostic significance of presence of hydrocephalus was profoundly grave as was evident from the mortality rate (10%) in this series.

Increased mortality of preterm infants transferred between tertiary perinatal centres

Over 18 months almost one quarter of infants born before 30 weeks' gestation in a tertiary perinatal centre who required intensive care had to be transferred to other tertiary centres because intensive care facilities were fully occupied. When infants with lethal congenital malformations were excluded half of the 34 infants who were transferred died; this was twice the mortality (24%) in the 111 infants remaining. The difference between the groups was significant (relative odds = 3.1) and remained so after adjustment for any discrepancies in gestational age (relative odds = 4.0). After adjustment for potential confounding variables by logistic function regression the risk of dying for those transferred remained significantly higher than that for infants who remained (relative odds = 4.6, 95% confidence interval 1.8 to 12.1). As the requirement for neonatal intensive care is episodic and unpredictable more flexibility has to be built into the perinatal health care system to enable preterm infants delivered in tertiary perinatal centres to be cared for where they are born.

The survival of extremely-low-birthweight infants in Victoria: 1982-1985

A population-based survey of mortality in extremely-low-birthweight (500- to 999-g) infants was carried out in Victoria for the years 1982 to 1985. No increase in the number of extremely-preterm births occurred during that time. The still-birth rate fell from 498 still births per 1000 births in 1982-1983 to 403 still births per 1000 births in 1984-1985. The neonatal mortality in 1982-1985 was 638 deaths per 1000 live births, with no significant decline from that of the 1978-1981 cohort. The small increase in neonatal survivors was not associated with any change in the postneonatal death rate. Delivery in a level-3 unit was associated with a significantly better outcome. Multiple births made a major contribution to the extremely-low-birthweight group of infants.

A novel insertion sequence in the cryptic plasmid of Neisseria gonorrhoeae may alter the B protein at the translational level

A variant of the cryptic plasmid of Neisseria gonorrhoeae, 4.4 kb in size, was isolated and characterized at the molecular level. This variant harbored a 156-bp insertion which was located between coordinates 3134 and 3135 within the putative cppB gene using the 4.2-kb cryptic plasmid, pJD1, as a reference. The insertion contained a novel EcoRI site and several elements of symmetry (both direct and inverted repeats). Stop codons present in the insertion interrupted the coding capacity of the cppB gene. Although the insertion was within one of two previously characterized 44-bp repeats purportedly involved in site-specific recombination, it was distinct from a 54-bp segment deleted in some cryptic plasmids. The presence of the insertion suggests a mechanism of modulating the expression of the cppB gene at the translational level through DNA rearrangement.

Cranial ultrasound screening of preterm and term neonates

A cranial ultrasound examination was performed between 48 and 96 h of age on 580 neonates of 25-42 weeks gestation. The incidence of cerebroventricular haemorrhage (CVH) in infants less than 32 weeks gestation was 37%, compared with an incidence of 2.7% in infants of 32 weeks or more. The incidence of CVH unselected healthy term infants (between 37 and 42 weeks) was only 1.1%. Of the 13 infants of 32 weeks or more who were found to have a haemorrhage, nine had a small (Grade I) haemorrhage (69%) and none of these infants had abnormal neurological signs in the neonatal period. The remaining four infants with Grade II, III or IV haemorrhage developed either seizures or episodes of apnoea. Two of the 13 infants of 32 weeks or more with a haemorrhage died, one during the newborn period and the other at 5.5 months of age. CVH in asymptomatic infants of 32 weeks or more gestation is uncommon and does not justify routine cranial ultrasound scanning.

Standard electromotive force of the H2-AgCl;Ag cell in 30, 40, and 50 mass% glycerol/water from -20 to 25 degrees C: pK2 and pH values for a standard "mops" buffer in 50 mass% glycerol/water

Data are presented regarding the establishment of the pH (designated pH*) of a standard buffer solution suitable as a pH reference in 50 mass% glycerol/water mixtures at temperatures ranging from -20 to 25 degrees C. The buffer material selected was the ampholyte Mops [(3-N-morpholino)-propane sulfonic acid], and the reference standard consists of equal molal amounts of Mops and its sodium salt. The assignment of pH* values is based on measurements of the electromotive force (emf) of cells without liquid junction of the type: Pt;H2(g, 1 atm) / Mops, Na Mopsate, NaCl / AgCl;Ag and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Mops) +/- in equilibrium with (Mopsate)- + H+. The standard emf of the silver-silver chloride electrode in 30, 40, and 50 mass% glycerol/water mixtures was determined from emf measurements of the cell at subzero temperatures with HCl solutions replacing the buffer-chloride mixtures.

Acid dissociation constants and pH values for standard "bes" and "tricine" buffer solutions in 30, 40, and 50 mass% dimethyl sulfoxide/water between 25 and -25 degrees C

Information is given concerning two standard buffer solutions suitable as pH references in 30, 40, and 50 mass% dimethyl sulfoxide (DMSO)/H2O mixed solvents at subzero temperatures from -20 to 0 degrees C, with the intention of establishing a pH (designated pH*) scale. The two buffers selected were the ampholytes N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid ("bes") and N-tris(hydroxymethyl)methylglycine ("tricine"), and the reference standard consisted of equal molal quantities of the buffer and its respective sodium salt. The assignment of pH* values was based on measurements of the emf of cells without liquid junction of the type: Pt;H2(g,l atm) /Bes, Na Besate, NaCl / AgCl;Ag and Pt;H2(g,l atm) /Tricine, Na Tricinate, NaCl /AgCl;Ag and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Buffer)+/- in equilibrium with(Buffer)- + H+.

Perinatal factors, periventricular haemorrhage and mortality in very low birthweight infants

In a population of 225 very low birthweight infants born over a 21 month period the cerebroventricular system was scanned by ultrasound. One third of the infants developed a periventricular haemorrhage; in 41% of infants the haemorrhage was detected before an hour of age and 66% of all haemorrhages occurred within the first 24 hours. Statistically significant associations with periventricular haemorrhage included vaginal delivery, endotracheal intubation and intravenous sodium bicarbonate when this was administered in the first 24 hours. In a stepwise regression analysis, however, these and other potentially significant variables added little to the total accountable variance. A similar analysis of perinatal factors and mortality revealed that decreasing gestation was the major association with death.

Standard electromotive force of the H2-AgCl;Ag cell in 30, 40, and 50 mass% dimethyl sulfoxide/water from -20 to 25 degrees C: pK2 and pH values for a standard "Bicine" buffer solution at subzero temperatures

The establishment of the pH (designated pH*) of a standard buffer solution suitable as a pH reference in 30, 40, and 50 mass% dimethyl sulfoxide (DMSO)/H2O mixtures at temperatures in the range -20 to 0 degrees C is reported. The buffer material selected was the ampholyte Bicine (N,N-bis(2-hydroxyethyl)glycine), and the reference standard consists of equal molal quantities of Bicine and its sodium salt. The assignment of pH* values rests on measurements of the emf of cells without liquid junction, Pt;H2(g, 1 atm) [Bicine, Na Bicinate, NaCl [AgCl;Ag, and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Bicine) +/- in equilibrium (Bicinate)- + H+. The standard emf in the DMSO/H2O solvents at subzero temperatures was determined from emf measurements of the cell with solutions of HCl replacing the buffer-chloride mixture.