Mapping general anesthesia states based on electro-encephalogram transition phases.

Cortical electro-encephalography (EEG) served as the clinical reference for monitoring unconsciousness during general anesthesia. The existing EEG-based monitors classified general anesthesia states as underdosed, adequate, or overdosed, lacking predictive power due to the absence of transition phases among these states. In response to this limitation, we undertook an analysis of the EEG signal during isoflurane-induced general anesthesia in mice. Adopting a data-driven approach, we applied signal processing techniques to track θ- and δ-band dynamics, along with iso-electric suppressions. Combining this approach with machine learning, we successfully developed an automated algorithm. The findings of our study revealed that the dampening of the δ-band occurred several minutes before the onset of significant iso-electric suppression episodes. Furthermore, a distinct γ-frequency oscillation was observed, persisting for several minutes during the recovery phase subsequent to isoflurane-induced overdose. As a result of our research, we generated a map summarizing multiple brain states and their transitions, offering a tool for predicting and preventing overdose during general anesthesia. The transition phases identified, along with the developed algorithm, have the potential to be generalized, enabling clinicians to prevent inadequate anesthesia and, consequently, tailor anesthetic regimens to individual patients.

Assembly of particle strings via isotropic potentials.

Assembly of spherical colloidal particles into extended structures, including linear strings, in the absence of directional interparticle bonding interactions or external perturbation could facilitate the design of new functional materials. Here, we use methods of inverse design to discover isotropic pair potentials that promote the formation of single-stranded, polydisperse strings of colloids "colloidomers" as well as size-specific, compact colloidal clusters. Based on the designed potentials, a simple model pair interaction with a short-range attraction and a longer-range repulsion is proposed which stabilizes a variety of different particle morphologies including (i) dispersed fluid of monomers, (ii) ergodic short particle chains as well as porous networks of percolated strings, (iii) compact clusters, and (iv) thick cylindrical structures including trihelical Bernal spirals.

Unsupervised machine learning for detection of phase transitions in off-lattice systems. II. Applications.

We outline how principal component analysis can be applied to particle configuration data to detect a variety of phase transitions in off-lattice systems, both in and out of equilibrium. Specifically, we discuss its application to study (1) the nonequilibrium random organization (RandOrg) model that exhibits a phase transition from quiescent to steady-state behavior as a function of density, (2) orientationally and positionally driven equilibrium phase transitions for hard ellipses, and (3) a compositionally driven demixing transition in the non-additive binary Widom-Rowlinson mixture.

Unsupervised machine learning for detection of phase transitions in off-lattice systems. I. Foundations.

We demonstrate the utility of an unsupervised machine learning tool for the detection of phase transitions in off-lattice systems. We focus on the application of principal component analysis (PCA) to detect the freezing transitions of two-dimensional hard-disk and three-dimensional hard-sphere systems as well as liquid-gas phase separation in a patchy colloid model. As we demonstrate, PCA autonomously discovers order-parameter-like quantities that report on phase transitions, mitigating the need for a priori construction or identification of a suitable order parameter-thus streamlining the routine analysis of phase behavior. In a companion paper, we further develop the method established here to explore the detection of phase transitions in various model systems controlled by compositional demixing, liquid crystalline ordering, and non-equilibrium active forces.

On the formation of equilibrium gels via a macroscopic bond limitation.

Restricting the number of attractive physical "bonds" that can form between particles in a fluid suppresses the usual demixing phase transition to very low particle concentrations, allowing for the formation of open, percolated, and homogeneous states, aptly called equilibrium or "empty" gels. Most demonstrations of this concept have directly limited the microscopic particle valence via anisotropic (patchy) attractions; however, an alternative macroscopic valence limitation would be desirable for greater experimental tunability and responsiveness. One possibility, explored in this paper, is to employ primary particles with attractions mediated via a secondary species of linking particles. In such a system, the linker-to-primary particle ratio serves as a macroscopic control parameter for the average microscopic valence. We show that the phase behavior of such a system predicted by Wertheim's first order perturbation theory is consistent with equilibrium gel formation: the primary particle concentrations corresponding to the two-phase demixing transition are significantly suppressed at both low and high linker-to-primary particle ratios. Extensive molecular dynamics simulations validate these theoretical predictions but also reveal the presence of loops of bonded particles, which are neglected in the theory. Such loops cause densification and inhibit percolation, and hence the range of viable empty gel state conditions is somewhat reduced relative to the Wertheim theory predictions.

Equilibrium cluster fluids: pair interactions via inverse design.

Inverse methods of statistical mechanics are becoming productive tools in the design of materials with specific microstructures or properties. While initial studies have focused on solid-state design targets (e.g., assembly of colloidal superlattices), one can alternatively design fluid states with desired morphologies. This work addresses the latter and demonstrates how a simple iterative Boltzmann inversion strategy can be used to determine the isotropic pair potential that reproduces the radial distribution function of a fluid of amorphous clusters with prescribed size. The inverse designed pair potential of this "ideal" cluster fluid, with its broad attractive well and narrow repulsive barrier at larger separations, is qualitatively different from the so-called SALR form most commonly associated with equilibrium cluster formation in colloids, which features short-range attractive (SA) and long-range repulsive (LR) contributions. These differences reflect alternative mechanisms for promoting cluster formation with an isotropic pair potential, and they in turn produce structured fluids with qualitatively different static and dynamic properties. Specifically, equilibrium simulations show that the amorphous clusters resulting from the inverse designed potentials display more uniformity in size and shape, and they also show greater spatial and temporal resolution than those resulting from SALR interactions.

Adenosine receptor activation is responsible for prolonged depression of synaptic transmission after spreading depolarization in brain slices.

Spreading depolarization (SD) is a slowly propagating, coordinated depolarization of brain tissue, which is followed by a transient (5-10min) depression of synaptic activity. The mechanisms for synaptic depression after SD are incompletely understood. We examined the relative contributions of action potential failure and adenosine receptor activation to the suppression of evoked synaptic activity in murine brain slices. Focal micro-injection of potassium chloride (KCl) was used to induce SD and synaptic potentials were evoked by electrical stimulation of Schaffer collateral inputs to hippocampal area Cornu Ammonis area 1 (CA1). SD was accompanied by loss of both presynaptic action potentials (as assessed from fiber volleys) and field excitatory postsynaptic potentials (fEPSPs). Fiber volleys recovered rapidly upon neutralization of the extracellular direct current (DC) potential, whereas fEPSPs underwent a secondary suppression phase lasting several minutes. Paired-pulse ratio was elevated during the secondary suppression period, consistent with a presynaptic mechanism of synaptic depression. A transient increase in extracellular adenosine concentration was detected during the period of secondary suppression. Antagonists of adenosine A1 receptors (8-cyclopentyl-1,3-dipropylxanthine [DPCPX] or 8-cyclopentyl-1,3-dimethylxanthine [8-CPT]) greatly accelerated fEPSP recovery and abolished increases in paired-pulse ratio normally observed after SD. The duration of fEPSP suppression was correlated with both the duration of the DC shift and the area of tissue depolarized, consistent with the model that adenosine accumulates in proportion to the metabolic burden of SD. These results suggest that in brain slices, the duration of the DC shift approximately defined the period of action potential failure, but the secondary depression of evoked responses was in large part due to endogenous adenosine accumulation after SD.

Elemental versus polymeric enteral nutrition in paediatric Crohn's disease: a multicentre randomized controlled trial.

AIM: To compare the efficacy and safety of an elemental and a polymeric diet as the primary therapy for active Crohn's disease in children. METHODS: In a randomized, non-blind, multicentre, controlled trial in Sweden, 16 children with Crohn's disease received Elemental 028 Extra (E028E) and 17 Nutrison Standard (NuS). Remission rates (Paediatric Crohn's Disease Activity Index (PCDAI) < 10 or a PCDAI decrease of 40% or 15 points of initial level) were compared at 6 wk. RESULTS: There was no significant difference between the two groups in remission rate at 6 wk (intent-to-treat analysis): E028E 11/16 (69%) and NuS 14/17 (82%) (p = 0.438). There was no difference in the decrease in PCDAI and CDAI between patients treated with E028E and those treated with NuS from 0 to 6 wk. Patients treated with NuS gained significantly more weight than patients treated with E028E (+2.5 kg; 95% CI 0.9, 4.1; p = 0.004), this difference remained when adjusting for maximum caloric intake per kilogram bodyweight (+2.9 kg; 95% CI 1.4, 4.5; p = 0.001). Concomitant disease, complications and side effects were seen in 5/33 patients (pyelonephritis, pneumonia, intraabdominal abscess, perianal abscess and borborygmi). CONCLUSION: E028E and NuS did not differ in terms of remission rate. Patients treated with NuS gained more weight than patients with E028E. Polymeric diet may be superior to elemental diet in the treatment of paediatric Crohn's disease where the primary aim is to increase the patient's weight.

Colonization of Streptococcus mutans and Streptococcus sobrinus genotypes and caries development in children to mothers harboring both species.

The major route of early acquisition of mutans streptococci in humans is a vertical transmission from mother to child. The purpose of this longitudinal study was to examine the acquisition, distribution and persistence of Streptococcus mutans and Streptococcus sobrinus in children whose mothers harbored both species and to study the caries incidence in relation to colonization of these bacteria. Fifteen mother-child pairs were followed during the child's first 7 years. Stimulated salivary samples were taken from the mothers and the children. Plaque samples were also collected from the teeth and the tongue of the children. The samples were analyzed by cultivating techniques together with genomic fingerprinting and hybridizing. The caries experience was evaluated on the sampling occasions and retrospectively using the records of caries registrations from the community clinics. During the 7-year period 10 of the 15 children acquired mutans streptococci. Only 4 of them were colonized by both S. mutans and S. sobrinus despite the fact that their mothers harbored both species. In 2 of the children S. sobrinus was found later than S. mutans. A total of 26 genotypes were found in the children and 9 of them were identical to their mothers. New genotypes and a gain-loss pattern were noted especially in the children but also in their mothers. The groups of teeth first positive for the two species were the deciduous molars. The caries experience was low during the study period with 8 children showing no caries.

Health status and functional capacity in a group of successfully ageing 65-85-year-olds.

PURPOSE: To examine health behaviours of older people, comparing people aged 65-74 years with those aged 75-85 years. METHOD: Seventy-five men (45%) and women (55%) aged between 65 and 85 years were recruited from a sample of convenience. Participants completed three questionnaires which documented health status, exercise patterns, levels of physical capacity, independence in daily living and involvement in activities. Tests of physical ability were then conducted related to walking, upper extremity function, ability on tram steps, and grip strength. RESULTS: The sampling method delivered a biased sample with most participants rating their health as excellent or very good for their age. While many participants reported chronic medical conditions, or more than one fall in the last year, the level of physical activity was strikingly high. Men were more active than women, and physical activity declined minimally after the age of 75. Anecdotally, the sample was also active in social and intellectual activities, with women involved in these activities more than physical pursuits. CONCLUSIONS: The role of activity is important in the study of successful ageing. This study reported gender and age group differences in the activities chosen, demonstrating that the inclusion of a cross-section of daily activities is essential in the study of health status and well-being.

Pharmacokinetics of budesonide controlled ileal release capsules in children and adults with active Crohn's disease.

BACKGROUND: Systemic glucocorticosteroid therapy is effective in Crohn's disease, but is associated with side-effects. Budesonide has high topical anti-inflammatory activity, but considerably lower systemic activity than other oral glucocorticosteroids. AIM: To evaluate the systemic exposure to budesonide (controlled ileal release capsules) in children and adults with active Crohn's disease, and to assess the suppression of plasma cortisol. METHODS: In an open label study, patients (eight children and six adults) with active Crohn's disease received 9 mg budesonide (Entocort capsules) orally once daily for 7 days. Plasma concentrations were determined on the seventh day of administration, and pharmacokinetic parameters were calculated. For reference, 0.5 mg budesonide was given intravenously separately. Plasma cortisol levels were compared with the pre-treatment baseline values. RESULTS: Systemic exposure to budesonide (AUC0-24 h) after 1 week of oral administration was 41 +/- 21 nmol/L x h (mean +/- s.d.) in children and 35 +/- 20 nmol/L x h in adults. The estimated systemic availability in children was 9 +/- 5% and in adults 11 +/- 7%. The mean plasma cortisol (AUC0-24 h) decreased by 64 +/- 18% in children and by 50 +/- 27% in adults. CONCLUSIONS: The systemic exposure, systemic availability and cortisol suppression after oral administration of 9 mg budesonide were similar in children and adults with active Crohn's disease. Budesonide was well tolerated and no clinically important safety-related findings were identified.

Small bowel biopsy in Swedish paediatric clinics.

AIM: A correct diagnosis of coeliac disease, one of the most common chronic diseases in Swedish children, demands small bowel biopsy, which can be performed endoscopically or by means of a peroral capsule. Recently there was a debate among Swedish paediatric gastroenterologists, with some advocating the cessation of capsule biopsy in favour of endoscopic biopsies. To gain information on which to base a recommendation for which technique to use, the Swedish Working Group for Childhood Coeliac Disease was commissioned to carry out a national questionnaire study on current small bowel biopsy routines in Swedish paediatric clinics. METHODS: A questionnaire concerning biopsy routines in the year 2000 was sent to all paediatric clinics performing biopsies. A reply was obtained from 39 of 40 clinics, covering 98% of the Swedish population. RESULTS: Some 1400 biopsies were performed, 64% of which were capsule biopsies and 36% endoscopic. Three clinics performed all biopsies endoscopically and 11 clinics all via a capsule. At endoscopy all children were under deep sedation or full anaesthesia, while most children undergoing capsule biopsy were under light or deep sedation. The oxygen saturation was monitored during endoscopy but less often or never during routine capsule biopsy. The presence of the parents during biopsy varied according to the degree of sedation: at 97% of the clinics performing capsule biopsy on children under light sedation, the parents were present during the whole procedure, whereas no parents were present at clinics where the biopsy was performed endoscopically under anaesthesia. CONCLUSION: Compared with the results of a similar questionnaire concerning biopsy routines performed in the early 1990s, children are now more effectively sedated. Furthermore, there is an obvious trend from capsule towards endoscopic biopsy. Both the endoscopic and the capsule biopsy techniques are useful and satisfactory for obtaining small bowel mucosal samples providing that the children are effectively sedated. For practical and economic reasons the capsule biopsy technique will probably continue to be used, although to a lesser extent than today.

Design of filters in a one-dimensional tight-binding system.

We show how to design one-dimensional systems that in the transmission through a finite potential barrier, in a predetermined way, discriminate between monochromatic waves depending on their wave number. These systems, described by the on-site tight-binding equation, act as filters of different types, with adjustable pass and stop bands. The use of these filters for discrimination of linear wave packets depending on their different velocities is illustrated, and we also comment on the influence of an added nonlinearity.

Inflammatory bowel disease in children and adolescents in Sweden, 1984-1995.

BACKGROUND: A prospective study of inflammatory bowel disease (IBD) in Sweden was performed to investigate whether the incidence and morbidity have changed from 1984 through 1995. METHODS: Children 15 years of age or less with IBD were included--i.e., those with a definite diagnosis of ulcerative colitis (UC) and Crohn's disease (CD) and those classified as having indeterminate colitis (IC) and probable Crohn's disease (PCD). The study covered 56.5% of the pediatric population of Sweden. RESULTS: The diagnosis of IBD was made in 639 children, which corresponds to a mean annual incidence of 5.8 per 100,000. The incidence increased from 4.6 per 100,000 per year from 1984 through 1986 to 7.0 from 1993 through 1995. It reflected an increase in UC from 1.4 to 3.2 per 100,000 per year, which is a significant yearly percentage of increase (8%; confidence interval, 2-14%; P < 0.05). In contrast, no change occurred in the incidence of CD (1.2-1.3 per 100,000). The incidence of IC and PCD also remained fairly stable. The percentages of children who underwent surgery decreased from 17.3% in the first 6 years to 4.6% in the last 6 years (P < 0.001). Surgery was performed in 27.7% of CD and 5.3% of UC cases. The median age at diagnosis was 12.2 years for UC, 13.0 years for CD, 11.2 for IC, and 11.2 for PCD. At diagnosis, 48 children (7.5%) were 5 years of age or less, whereas most of the patients were 11 years of age or more (398 children, 62.3%). CONCLUSIONS: In Sweden, the incidence of UC has increased, whereas that of CD remains the same. A significant number of children were classified with IC and PCD. In most children, IBD was diagnosed when they were 11 years old or more, but some cases were detected even in those below 6 years of age. A decrease in the frequency of surgery occurred during the study.

Epidemic of coeliac disease in Swedish children.

Coeliac disease has emerged as a public health problem. The aim of the present study was to analyse trends in the occurrence of symptomatic coeliac disease in Swedish children from 1973 to 1997, and to explore any temporal relationship to changes in infant dietary patterns. We established a population-based prospective incidence register of coeliac disease in 1991, and, in addition, retrospective data from 1973 were collected. A total of 2151 cases fulfilled the diagnostic criteria. Furthermore. We collected national data on a yearly basis on duration of breastfeeding, intake of gluten-containing cereals and recommendations on when and how to introduce gluten into the diet of infants. From 1985 to 1987 the annual incidence rate in children below 2 y of age increased fourfold to 200-240 cases per 100000 person years, followed from 1995 by a sharp decline to the previous level of 50-60 cases per 100000 person years. This epidemic pattern is quite unique for a chronic disease of immunological pathogenesis, suggesting that prevention could be possible. The ecological observations made in this study are compatible with the epidemic being the result, at least in part, of a change in and an interplay among three factors within the area of infant feeding, i.e. amount of gluten given, age at introduction of gluten, and whether breastfeeding was ongoing or not when gluten was introduced. Other factor(s) may also have contributed, and the search for these should be intensified.

Community-based rehabilitation in Moshupa village, Botswana.

This article presents a summary of findings from the 'Moshupa Community Based Rehabilitation (CBR) project', which to date have been the subject of three studies: one initial survey of disabled people and two follow-up studies. Of the 132 disabled people who were identified in the survey, all but three could be accounted for in the first follow-up. Seventy-seven were interviewed about independence of activities of daily living, school/jobs and quality of life. A high percentage of elderly (17% were 65 and over) were alive, and most had maintained high levels of ADL skills. Twenty per cent of the adult disabled were working, 10 out of 14 school-aged children were enrolled in schools, and life satisfaction was high. The second follow-up study indicated that personnel, although acknowledging the benefits of the programme, pointed to several remaining problems such as lack of rehabilitation education for the personnel. The results are discussed with reference to the CBR programme's aims, and implications drawn for industrialized countries.

[Proposed criteria for diagnosis of celiac disease in children]. / Förslag till kriterier för celiakidiagnos hos barn.

At a seminar arranged in September 1997 by the Swedish Paediatric Working Group for Coeliac Disease, a diagnostic protocol proposed by the working group was approved by a majority of the paediatricians present, representing almost all paediatric units in Sweden. Briefly, a small bowel biopsy is called for in all children, both at presentation and as a control during gluten-free dieting. Subsequent gluten challenge and biopsy are mandatory only in cases of atypical presentation or if the diagnosis is questioned at some future date. Serum antigliadin and anti-endomysial antibody tests are complementary tools. Agreement was also reached regarding the institution of a national coeliac disease registry.