Usability and feasibility analysis of an mHealth-tool for supporting physical activity in people with heart failure

BACKGROUND

Physical inactivity and a sedentary lifestyle are common among people with heart failure (HF), which may lead to worse prognosis. On an already existing mHealth platform, we developed a novel tool called the Activity coach, aimed at increasing physical activity. The aim of this study was to evaluate the usability of the Activity coach and assess feasibility of outcome measures for a future efficacy trial.

METHODS

A mixed-methods design was used to collect data. People with a HF diagnosis were recruited to use the Activity coach for four weeks. The Activity coach educates the user about physical activity, provides means of registering daily physical activity and helps the user to set goals for the next week. The usability was assessed by analysing system user logs for adherence, reported technical issues and by interviews about user experiences. Outcome measures assessed for feasibility were objective physical activity as measured by an accelerometer, and subjective goal attainment. Progression criteria for the usability assessment and for the proposed outcomes, were described prospectively.

RESULTS

Ten people with HF were recruited, aged 56 to 78 with median age 72. Data from nine of the ten study participants were included in the analyses. Usability: The Activity coach was used 61% of the time and during the first week two study participants called to seek technical support. The Activity coach was found to be intuitive and easy to use by all study participants. An increased motivation to be more physically active was reported by six of the nine study participants. However, in spite of feeling motivated, four reported that their habits or behaviours had not been affected by the Activity coach.

FEASIBILITY

Data was successfully stored in the deployed hardware as intended and the accelerometers were used enough, for the data to be analysable. One finding was that the subjective outcome goal attainment, was challenging to collect. A proposed mitigator for this is to use pre-defined goals in future studies, as opposed to having the study participants be completely free to formulate the goals themselves.

CONCLUSIONS

It was confirmed that the Activity coach was easy to use. Furthermore, it might stimulate increased physical activity in a population of people with HF, who are physically inactive. The outcomes investigated seem feasible to include in a future efficacy trial.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05235763. Date of first registration: 11/02/2022.

Utility of single-item questions to assess physical inactivity in patients with chronic heart failure

Aim

The purpose of this study was to explore the utility of two single‐item self‐report (SR) questions to assess physical inactivity in patients with heart failure (HF).

Methods and results

This is a cross‐sectional study using data from 106 patients with HF equipped with accelerometers for 1 week each. Two SR items relating to physical activity were also collected. Correlations between accelerometer activity counts and the SR items were analysed. Patients were classified as physically active or inactive on the basis of accelerometer counts, and the SR items were used to try to predict that classification. Finally, patients were classified as having high self‐reported physical activity or low self‐reported physical activity, on the basis of the SR items, and the resulting groups were analysed for differences in actual physical activity. There were significant but weak correlations between the SR items and accelerometer counts: ρ = 0.24, P = 0.016 for SR1 and ρ = 0.21, P = 0.033 for SR2. Using SR items to predict whether a patient was physically active or inactive produced an area under the curve of 0.62 for SR1, with a specificity of 92% and a sensitivity of 30%. When dividing patients into groups on the basis of SR1, there was a significant difference of 1583 steps per day, or 49% more steps in the high self‐reported physical activity group (P < 0.001).

Conclusions

There might be utility in the single SR question for high‐specificity screening of large populations to identify physically inactive patients in order to assign therapeutic interventions efficiently where resources are limited.

Atomic diffusion in liquid nickel: First-principles modeling

Self- and impurity diffusion coefficients are assessed in the liquid nickel system by the fundamental ab initio molecular dynamics approach. The impurity diffusion coefficients in the Ni-X systems (X=C, Co, N, Nb, Ta, Ti, W) are mostly not available in the current literature. The simulations are performed at four temperatures, in the range from 1903 to 2303 K, which allows to extract activation energies and frequency factors for the temperature dependent diffusion coefficient assuming an Arrhenius-type behavior in the liquid. In addition to the temperature dependence, the concentration-dependent impurity diffusion was investigated for the Ni-Co system. The data are of relevance for the development of the state-of-the art Ni-based superalloys and alternative binder systems in cemented carbides. The obtained theoretical results are in very good agreement with the limited experimental data for the diffusion in liquid Ni systems.

Effects of AV delay and VV delay on left atrial pressure and waveform in ambulant heart failure patients: insights into CRT optimization

BACKGROUND

We hypothesized that left atrial pressure (LAP) obtained by a permanent implantable sensor is sensitive to changes in cardiac resynchronization therapy (CRT) settings and could guide CRT optimization to improve the response rate. We investigated the effect of CRT optimization on LAP and its waveform parameters in ambulant heart failure (HF) patients.

METHODS

CRT optimization was performed in eight ambulant HF patients, using echocardiography as reference. LAP waveform was acquired at each of eight atrioventricular (AV) intervals and five inter-ventricular (VV) intervals. Selected waveform parameters were also evaluated for their sensitivity to CRT changes and agreement with echocardiography-guided optimal settings.

RESULTS

Optimal AV and VV intervals varied considerably between patients. All patients exhibited significant changes in waveform morphology with AV optimization. Optimal AV delay determined from echocardiography ranged between 140 ms and 225 ms. Mean LAP tended to be lower at optimal setting 14 ± 3 mmHg compared to shorter (<100 ms) or longer (>160 ms) AV settings (P = 0.16). There were clear trends to smaller peak a-wave (P = 0.11) and gentler positive a-slope (P = 0.15) and positive v-slope (P = 0.09) with longer AV delays. Mean LAP and negative v-wave slope correlated well with echo-guided optimal setting, r = 0.91 (P = 0.001) and 0.79 (P = 0.03), respectively. No significant effects on LAP or waveform were seen during VV optimization.

CONCLUSIONS

LAP and its waveform changes considerably with AV optimization. There is good agreement between echo-guided optimal setting and LAP. LAP could provide an objective guide to CRT optimization. (Clinical Trial Registry information: URL: http://www.clinicaltrials.gov. Unique Identifier: NCT00632372).

Proteomic profiling of the hypothalamus in a mouse model of cancer-induced anorexia-cachexia

Background:

Anorexia-cachexia is a common and severe cancer-related complication but the underlying mechanisms are largely unknown. Here, using a mouse model for tumour-induced anorexia-cachexia, we screened for proteins that are differentially expressed in the hypothalamus, the brain's metabolic control centre.

Methods:

The hypothalamus of tumour-bearing mice with implanted methylcholanthrene-induced sarcoma (MCG 101) displaying anorexia and their sham-implanted pair-fed or free-fed littermates was examined using two-dimensional electrophoresis (2-DE)-based comparative proteomics. Differentially expressed proteins were identified by liquid chromatography-tandem mass spectrometry.

Results:

The 2-DE data showed an increased expression of dynamin 1, hexokinase, pyruvate carboxylase, oxoglutarate dehydrogenase, and N-ethylmaleimide-sensitive factor in tumour-bearing mice, whereas heat-shock 70 kDa cognate protein, selenium-binding protein 1, and guanine nucleotide-binding protein Gα₀ were downregulated. The expression of several of the identified proteins was similarly altered also in the caloric-restricted pair-fed mice, suggesting an involvement of these proteins in brain metabolic adaptation to restricted nutrient availability. However, the expression of dynamin 1, which is required for receptor internalisation, and of hexokinase, and pyruvate carboxylase were specifically changed in tumour-bearing mice with anorexia.

Conclusion:

The identified differentially expressed proteins may be new candidate molecules involved in the pathophysiology of tumour-induced anorexia-cachexia.

Minor changes in gene expression in the mouse preoptic hypothalamic region by inflammation-induced prostaglandin E2

We investigated to what extent inflammation-induced prostaglandin E2 (PGE2 ) regulates gene expression in the central nervous system. Wild-type mice and mice with deletion of the gene encoding microsomal prostaglandin E synthase-1 (mPGES-1), which cannot produce inflammation-induced PGE2 , were subjected to peripheral injection of bacterial wall lipopolysaccharide (LPS) and killed after 5 h. The median and medial preoptic nuclei, which are rich in prostaglandin E receptors, were isolated by laser capture microdissection (LCM), and subjected to whole genome microarray analysis. Although the immune stimulus induced robust transcriptional changes in the brain, as seen by a quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on selected genes, only small PGE2 -dependent gene expression changes were observed in the gene array analysis and, for only two genes, a pronounced differential expression between LPS-treated wild-type and mPGES-1 knockout mice could be verified by qRT-PCR. These were Hspa1a and Hspa1b, encoding heat shock proteins, which showed a two- to three-fold higher expression in wild-type mice than in knockout mice after immune challenge. However, the induced expression of these genes was found to be secondary to increased body temperature because they were induced also by cage exchange stress, which did not elicit PGE2 synthesis, and thus were not induced per se by PGE2 -elicited transcriptional events. Our findings suggest that inflammation-induced PGE2 has little effect on gene expression in the preoptic region, and that centrally elicited disease symptoms, although PGE2 -dependent, occur as a result of regulation of neuronal excitability that is a consequence of intracellular, transcriptional-independent signalling cascades. Our findings also imply that the profound changes in gene expression in the brain that are elicited by peripheral inflammation occur independently of PGE2 via a yet unidentified mechanism.

Immune-induced expression of lipocalin-2 in brain endothelial cells: relationship with interleukin-6, cyclooxygenase-2 and the febrile response

Interleukin (IL)-6 is critical for the febrile response to peripheral immune challenge. However, the mechanism by which IL-6 enables fever is still unknown. To characterise the IL-6-dependent fever generating pathway, we used microarray analysis to identify differentially expressed genes in the brain of lipopolysaccharide (LPS)-treated IL-6 wild-type and knockout mice. Mice lacking IL-6 displayed a two-fold lower expression of the lipocalin-2 gene (lcn2), and this difference was confirmed by real-time reverse transcriptase-polymerase chain reaction. Conversely, the induction of lipocalin-2 protein was observed in brain vascular cells following i.p. administration of recombinant IL-6, suggesting a direct relationship between IL-6 and lipocalin-2. Immunohistochemical analysis also revealed that LPS-induced lipocalin-2 is expressed by brain endothelial cells and is partly co-localised with cyclooxygenase-2 (Cox-2), the rate-limiting enzyme for the production of inflammatory induced prostaglandin E(2) (PGE(2) ), which is the key mediator of fever. The direct role of lipocalin-2 in fever was examined in LPS-challenged lipocalin-2 knockout mice. In both male and female mice, normal fever responses were observed at near-thermoneutral conditions (29-30 °C) but when recorded at normal room temperature (19-20 °C), the body temperature of lipocalin-2 knockout female mice displayed an attenuated fever response compared to their wild-type littermates. This difference was reflected in significantly attenuated mRNA expression of Cox-2 in the brain of lipocalin-2 knockout female mice, but not of male mice, following challenge with peripheral LPS. Our findings suggest that IL-6 influences the expression of lipocalin-2, which in turn may be involved in the control of the formation of Cox-2, and hence central PGE(2) -production. We have thus identified lipocalin-2 as a new factor in the pathway of inflammatory IL-6 signalling. However, the effect of lipocalin-2 on fever is small, being sex-dependent and ambient temperature-specific, and thus lipocalin-2 cannot be considered as a major mediator of the IL-6-dependent fever generating pathway.

Theoretical study of C60 as catalyst for dehydrogenation in LiBH4

Complex light metal hydrides possess many properties which make them attractive as a storage medium for hydrogen, but typically catalysts are required to lower the hydrogen desorption temperature and to facilitate hydrogen uptake in the form of a reversible reaction. The overwhelming focus in the search for catalysing agents has been on compounds containing titanium, but the precise mechanism of their actions remains somewhat obscure. A recent experiment has now shown that fullerenes (C(60)) can also act as catalysts for both hydrogen uptake and release in lithium borohydride (LiBH(4)). In an effort to understand the involved mechanism, we have employed density functional theory to carry out a detailed study of the interaction between this complex metal hydride and the carbon nanomaterial. Considering a stepwise reduction of the hydrogen content in LiBH(4), we find that the presence of C(60) can lead to a substantial reduction of the involved H-removal energies. This effect is explained as a consequence of the interaction between the BH(x)( - ) complex and the C(60) entity.

Relativity and the lead-acid battery

The energies of the solid reactants in the lead-acid battery are calculated ab initio using two different basis sets at nonrelativistic, scalar-relativistic, and fully relativistic levels, and using several exchange-correlation potentials. The average calculated standard voltage is 2.13 V, compared with the experimental value of 2.11 V. All calculations agree in that 1.7-1.8 V of this standard voltage arise from relativistic effects, mainly from PbO2 but also from PbSO4.

Significance of self-trapping on hydrogen diffusion

The diffusion rate of hydrogen in Nb was calculated using ab initio molecular dynamics simulations. At low temperatures the hydrogen is strongly trapped in a local strain field which is caused by the elastic response of the lattice. At elevated temperatures, the residence time (τ) of hydrogen in an interstitial site is not sufficient for fully developing the local strain field. This unbinding of the interstitial hydrogen and the strain field increases the hopping rate (1/τ) at elevated temperatures (>400  K). These results call for a revision of the conceptual framework of diffusion of hydrogen in transition metals at elevated temperatures.

Peripheral lipopolysaccharide administration induces cytokine mRNA expression in the viscera and brain of fever-refractory mice lacking microsomal prostaglandin E synthase-1

We examined the expression of interleukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF) alpha in mice lacking microsomal prostaglandin E synthase-1 (mPGES-1), which neither produce prostaglandin E(2), nor mount a febrile response upon immune challenge. Intraperitoneal lipopolysaccharide (LPS) injection resulted in a strongly induced expression of all three cytokines in the brain and viscera, similar to wild-type animals. Several brain regions additionally showed modest induction of receptors for these cytokines in both genotypes. Telemetric recordings of body temperature showed that the mPGES-1 deficient mice remained afebrile upon LPS challenge, in contrast to the prominent fever displayed by the wild-type mice. These data demonstrate that LPS-induced cytokine expression occurs independently of prostaglandin E(2), and imply that endogenously expressed IL-1beta, IL-6, and TNFalpha are not pyrogenic per se, supporting the role of prostaglandin E(2) as the final and obligatory mediator of LPS-induced fever.

Carbon nanomaterials as catalysts for hydrogen uptake and release in NaAlH4

A synergistic approach involving experiment and first-principles theory not only shows that carbon nanostructures can be used as catalysts for hydrogen uptake and release in complex metal hydrides such as sodium alanate, NaAlH(4), but also provides an unambiguous understanding of how the catalysts work. Here we show that the stability of NaAlH(4) originates with the charge transfer from Na to the AlH(4) moiety, resulting in an ionic bond between Na(+) and AlH(4)(-) and a covalent bond between Al and H. Interaction of NaAlH(4) with an electronegative substrate such as carbon fullerene or nanotube affects the ability of Na to donate its charge to AlH(4), consequently weakening the Al-H bond and causing hydrogen to desorb at lower temperatures as well as facilitating the absorption of H(2) to reverse the dehydrogenation reaction. In addition, based on our experimental observations and theoretical calculations it appears the curvature of the carbon nanostructure plays a role in the catalytic process. Ab initio molecular dynamics simulation further reveals the time evolution of the charge transfer process.

Formation of large voids in the amorphous phase-change memory Ge2Sb2Te5 alloy

On the basis of ab initio molecular dynamics simulations, large voids mainly surrounded by Te atoms are observed in molten and amorphous Ge2Sb2Te5, which is due to the clustering of two- and threefold coordinated Te atoms. Furthermore, pressure shows a significant effect on the clustering of the under coordinated Te atoms and hence the formation of large voids. The present results demonstrate that both vacancies and Te play an important role in the fast reversible phase transition process.

Local structure of liquid Ge(1)Sb(2)Te(4) for rewritable data storage use

Phase-change materials based on chalcogenide alloys have been widely used for optical data storage and are promising materials for nonvolatile electrical memory use. However, the mechanism behind the utilization is unclear as yet. Since the rewritable data storage involved an extremely fast laser melt-quenched process for chalcogenide alloys, the liquid structure of which is one key to investigating the mechanism of the fast reversible phase transition and hence rewritable data storage, here by means of ab initio molecular dynamics we have studied the local structure of liquid Ge(1)Sb(2)Te(4). The results show that the liquid structure gives a picture of most Sb atoms being octahedrally coordinated, and the coexistence of tetrahedral and fivefold coordination at octahedral sites for Ge atoms, while Te atoms are essentially fourfold and threefold coordinated at octahedral sites, as characterized by partial pair correlation functions and bond angle distributions. The local structure of liquid Ge(1)Sb(2)Te(4) generally resembles that of the crystalline form, except for the much lower coordination number. It may be this unique liquid structure that results in the fast and reversible phase transition between crystalline and amorphous states.

Usefulness of monitoring congestive heart failure by multiple impedance vectors

INTRODUCTION

We investigated trends in intrathoracic impedance measured between multiple implanted electrodes for monitoring pulmonary edema secondary to congestive heart failure (CHF) in an experimental model.

METHODS

Biventricular ICDs were implanted in 16 dogs and 5 sheep. Continuous RV pacing (230- 250 bpm) was applied over several weeks. Meanwhile, impedance was measured every hour along 4 intrathoracic and 2 intracardiac vectors. Four cardiogenic impedance vectors were also monitored. Cardiac function was assessed biweekly by catheterization and echocardiography. Left atrial (LA) pressure was measured daily by an implanted LA pressure sensor.

RESULTS

All animals developed CHF after 2-4 weeks of pacing as evidenced by changes in function (EF, 52 vs. 34%; LV end-diastolic volume, 65 vs. 97 ml; LV end-diastolic pressure, 7 vs. 16 mmHg; LA volume, 17 vs. 33 ml; LA pressure, 7 vs. 26 mmHg), clinical symptoms, or autopsy. Steady state impedance decreased during CHF: LV-Can, 17+/-9%; LV-RV, 15+/-8%; LV-RA, 13+/-6%; RV-Can, 13+/-8%; RVcoil-Can, 8+/-6%; RA-Can, 6+/-6%. Change in LV-Can impedance was greater than that of RA-Can, RV-Can, and RVcoil-Can (P0.05). LV-Can impedance correlated well with LA pressure (r(2)=0.73), while RV-Can and RVcoil-Can were weakly correlated (r(2)=0.43 and r(2)=0.52, respectively). Changes in LV-RV and LV-RA impedances were also larger than those of RVcoil-Can and RA-Can (P0.05). Meanwhile, all impedances were associated with circadian variability at baseline (5+/-2%) which diminished during CHF (2+/-1%); P=0.02. Furthermore, significant variations were observed in cardiogenic impedances during progression into CHF as evidenced by reduced peak-to-peak amplitude and increased fractionation of the signals.

CONCLUSIONS

All impedance vectors decreased during CHF. Impedance measurement employing left heart sensors correlated well wit- - h LA pressure, and may improve detection of CHF onset compared to sensing by RA or RV leads alone. This approach has important clinical implications for managing heart failure patients in the ambulatory setting.

Li-decorated metal-organic framework 5: a route to achieving a suitable hydrogen storage medium

A significant improvement in molecular hydrogen uptake properties is revealed by our ab initio calculations for Li-decorated metal-organic framework 5. We have found that two Li atoms are strongly adsorbed on the surfaces of the six-carbon rings, one on each side, carrying a charge of +0.9e per Li atom. Each Li can cluster three H(2) molecules around itself with a binding energy of 12 kJ (mol H(2))(-1). Furthermore, we show from ab initio molecular dynamics simulations with a hydrogen loading of 18 H(2) per formula unit that a hydrogen uptake of 2.9 wt % at 200 K and 2.0 wt % at 300 K is achievable. To our knowledge, this is the highest hydrogen storage capacity reported for metal-organic framework 5 under such thermodynamic conditions.

Lipopolysaccharide induces preproenkephalin transcription in hypophysiotropic neurons of the rat paraventricular hypothalamic nucleus suggesting a neuroendocrine role for enkephalins during immune stress

Opioids have impact on stress responses and possess immune modulatory functions. We have previously shown that immune stress elevates the levels of preproenkephalin transcript in a variety of autonomic structures in the rat brain, including the paraventricular hypothalamic nucleus. By using in situ hybridization with an intronic probe recognizing the preproenkephalin heteronuclear RNA combined with retrograde tract tracing, we examined the efferent target of the enkephalinergic neurons in the paraventricular hypothalamic nucleus that display induced transcriptional activity during immune challenge. Rats were first given i.p. injections of the tracer substance Fluoro-Gold, which following this route of administration is taken up only by nerve terminals residing outside the blood-brain barrier, and were then given an i.v. injection of lipopolysaccharide. Neuronal cell bodies retrogradely labeled with Fluoro-Gold were detected by immunohistochemistry, and-using a dual-labeling approach-the same cells were then examined for their expression of preproenkephalin heteronuclear RNA. We found that over 90% of the neurons that expressed preproenkephalin heteronuclear RNA also contained Fluoro-Gold. In addition, approximately 40% of the neurons expressing preproenkephalin heteronuclear RNA co-expressed mRNA for corticotropin-releasing hormone, the main adrenocorticotropic hormone secretagogue. These data show that the paraventricular hypothalamic neurons that display induced preproenkephalin transcription following immune challenge are almost exclusively hypophysiotropic neurons, indicating a role for enkephalin in the hypothalamic control of hormone release during infectious and inflammatory conditions.

Expression of melanocortin-4 receptor by rat parabrachial neurons responsive to immune and aversive stimuli

The pontine parabrachial nucleus is a major relay area for visceral and other interoceptive information, and has been implicated in mechanisms underlying anorexia and food aversion during disease. Thus, physiological studies have shown that peripheral immune stimuli, as well as the administration of aversive substances such as lithium chloride, evoke a prominent Fos-expression in the lateral parabrachial nucleus and behavioral experiments have demonstrated that this structure is critical for the acquisition of conditioned taste aversion. The present study examined in rats the relationship between parabrachial neurons activated by systemic administration of bacterial cell-wall lipopolysaccharide or lithium chloride and the melanocortin system, a major regulator of feeding and energy homeostasis that also has been implicated in aversive behavior. Dual-labeling in situ hybridization showed melanocortin-4 receptor expression on neurons in the external lateral parabrachial subnucleus that displayed lipopolysaccharide- or lithium chloride-induced expression of c-fos mRNA. Melanocortin-4 receptor mRNA was also co-expressed with mRNA for calcitonin gene-related peptide in this subnucleus. Taken together with previous observations showing that calcitonin gene-related peptide expressing neurons in the external lateral parabrachial subnucleus are activated by peripheral immune challenge, that lipopolysaccharide-activated external lateral parabrachial subnucleus neurons project to the amygdala, and that the amygdala-projecting neurons in the external lateral parabrachial subnucleus are calcitonin gene-related peptide-positive, the present findings suggest the presence of a melanocortin-regulated calcitonin gene-related peptide-positive pathway from the external lateral parabrachial subnucleus to the amygdala that relays information of importance to forebrain responses to certain aspects of sickness behavior. These observations may thus help explain how melanocortins can reduce feeding and influence conditioned taste aversion during inflammation and other disease conditions.

Defective Reproductive Organ Morphology and Function in Domestic Rooster Embryonically Exposed to o,p′-DDT or Ethynylestradiol1

Environmental pollutants with estrogenic activity have a potential to disrupt estrogen-dependent developmental processes. The objective of this study was to investigate if embryonic exposure to the environmental estrogens o,p'-DDT (1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2,2-trichloroethane; 37, 75, 150 or 300 microg/g egg) and EE2 (17alpha-ethynyl estradiol; 60 ng/g egg) affects the reproductive system in domestic roosters. Following egg injection on Embryonic Day 4, the newly hatched chicks were sexed by cloacal inspection. A skewed phenotypic sex ratio with overrepresentation of chicks deemed as females was observed in the groups exposed to the three highest doses of o,p'-DDT but not in the EE2-exposed group. Normal sex ratios were observed in all groups at adulthood. However, a cloacal deformation seemed to remain in the adult roosters, causing an abnormal semen flow upon semen collection. Semen yield was significantly reduced in both o,p'-DDT-exposed and EE2- exposed birds, whereas semen quality was unaffected. When killed, deformations of the left testis were found in all treatment groups. Image analysis revealed a reduced seminiferous tubular area in the roosters exposed to the two highest doses of o,p'-DDT. Embryonic exposure to o,p'-DDT caused decreased comb weight and right-spur diameter, while EE2 only affected right-spur diameter. In conclusion, this study shows that embryonic exposure to estrogenic compounds can induce permanent effects in male birds. The effects of the two studied compounds were partly similar but o,p'-DDT also induced alterations not seen in the EE2-treated birds.

Distribution of growth hormone receptor mRNA in the brain stem and spinal cord of the rat

By using in situ hybridization histochemistry the distribution of growth hormone (GH) receptor mRNA was examined in the rat brain stem and spinal cord. Dense labeling was seen in the arcuate nucleus of the hypothalamus, as reported previously, but also in several other areas, including the locus coeruleus, the area postrema, and the commissural part of the nucleus of the solitary tract. Other labeled structures included the superior lateral parabrachial nucleus, the facial, hypoglossal and trigeminal motor nuclei, the nucleus incertus, the dorsal tegmental nucleus, the dorsal raphe nucleus, the nucleus of the trapezoid body, and the superficial layers of the dorsal horn of the spinal cord. These findings provide support for a direct action of GH on brain regions involved in various aspects of homeostatic control. Thus, the distribution of GH receptor mRNA to visceral sensory and motor structures is consonant with a role of GH in the regulation of food intake and energy homeostasis. Its presence in the superficial dorsal horn of the spinal cord indicates a role for GH in the initial processing of fine afferent input, and may help explain the beneficial effects of GH replacement in certain unclear pain conditions.

Embryonic exposure to oestrogen causes eggshell thinning and altered shell gland carbonic anhydrase expression in the domestic hen

Eggshell thinning among wild birds has been an environmental concern for almost half a century. Although the mechanisms for contaminant-induced eggshell thinning are not fully understood, it is generally conceived to originate from exposure of the laying adult female. Here we show that eggshell thinning in the domestic hen is induced by embryonic exposure to the synthetic oestrogen ethynyloestradiol. Previously we reported that exposure of quail embryos to ethynyloestradiol caused histological changes and disrupted localization of carbonic anhydrase in the shell gland in the adult birds, implying a functional disturbance in the shell gland. The objective of this study was to examine whether in ovo exposure to ethynyloestradiol can affect eggshell formation and quality in the domestic hen. When examined at 32 weeks of age, hens exposed to ethynyloestradiol in ovo (20 ng/g egg) produced eggs with thinner eggshells and reduced strength (measured as resistance to deformation) compared with the controls. These changes remained 14 weeks later, confirming a persistent lesion. Ethynyloestradiol also caused a decrease in the number of shell gland capillaries and in the frequency of shell gland capillaries with carbonic anhydrase activity. These data suggested that a disrupted carbonic anhydrase expression was involved in the mechanism for the oestrogen-induced eggshell thinning found in this study. The results support our hypothesis that eggshell thinning in avian wildlife can result from a structural and functional malformation in the shell gland, induced by xeno-oestrogen exposure during embryonic development.

EP3 and EP4 receptor mRNA expression in peptidergic cell groups of the rat parabrachial nucleus

This study examines the distribution of prostaglandin E2 receptors of subtype EP3 and EP4 among brain stem parabrachial neurons that were characterized with respect to their neuropeptide expression. By using a dual-labeling in situ hybridization method, we show that preprodynorphin mRNA expressing neurons in the dorsal and central lateral subnuclei express EP3 receptor mRNA. Such receptors are also expressed in preproenkephalin, calcitonin gene related peptide and preprotachykinin mRNA positive neurons in the external lateral subnucleus, whereas preprodynorphin mRNA expressing neurons in this subnucleus are EP receptor negative. In addition, EP3 receptor expression is seen among some enkephalinergic neurons in the Kölliker-Fuse nucleus. Neurons in the central part of the cholecystokininergic population in the regions of the superior lateral subnucleus express EP4 receptor mRNA, whereas those located more peripherally express EP3 receptors. Taken together with previous findings showing that discrete peptidergic cell groups mediate nociceptive and/or visceral afferent information to distinct brain stem and forebrain regions, the present results suggest that the processing of this information in the parabrachial nucleus is influenced by prostaglandin E2. Recent work has shown that prostaglandin E2 is released into the brain following peripheral immune challenge; hence, the parabrachial nucleus may be a region where humoral signaling of peripheral inflammatory events may interact with neuronal signaling elicited by the same peripheral processes.

Workshop 8 (synthesis): managing urban development and industrial growth from a drainage basin perspective

Urban development and industrial growth give rise to the two problems of insidious and growing pollution, and an over-exploitation of water resources. To solve these problems, various solutions have been promoted, such as multi-stakeholder dialogues, establishment of river basin committees, strong regulation, compensation for water-exporting basins and convincing politicians and the public of the need for change.

Management of acute cholecystitis in the laparoscopic era: results of a prospective, randomized clinical trial

The aim of this prospective, randomized study was to determine whether laparoscopic cholecystectomy should be performed as an early or a delayed operation in patients with acute cholecystitis. After diagnostic workup, patients were randomized to one of two groups: (1) early laparoscopic cholecystectomy (i.e., within 7 days after onset of symptoms) or (2) initial conservative treatment followed by delayed laparoscopic cholecystectomy 6 to 8 weeks later. Seventy-four patients were placed in the early-operation group, and 71 patients were assigned to the delayed-operation strategy. There was no significant difference in conversion rates (early 31% vs. delayed 29%), operating times (early 98 [range 30 to 355] minutes vs. delayed 100 [45 to 280] minutes), or complications. Failure with the conservative treatment strategy was noted in 26% of these patients. The total hospital stay was significantly shorter in the early group (5 [range 3 to 63] days) vs. the delayed group (8 [range 4 to 50] days; P<0.05). Despite a high conversion rate, early laparoscopic cholecystectomy offered significant advantages in the management of acute cholecystitis compared to a conservative strategy. The greatest advantage was a reduced total hospital stay.

Synaptology of trigemino- and spinothalamic lamina I terminations in the posterior ventral medial nucleus of the macaque

We used the electron microscope to examine lamina I trigemino- and spinothalamic (TSTT) terminations in the posterior part of the ventral medial nucleus (VMpo) of the macaque thalamus. Lamina I terminations were identified by anterograde labeling with biotinylated dextran, and 109 boutons on 38 terminal fibers were closely studied in series of ultrathin sections. Five unlabeled terminal boutons of similar appearance were also examined in detail. Three-dimensional, volume-rendered computer models were reconstructed from complete series of serial sections for 29 boutons on 10 labeled terminal fibers and one unlabeled terminal fiber. In addition, postembedding immunogold staining for GABA was obtained in alternate sections through 23 boutons. Lamina I TSTT terminations in VMpo generally have several large boutons (mean length = 2.16 microm, mean width = 1.29 microm) that are densely packed with vesicles and make asymmetric synaptic contacts on low-order dendrites of VMpo neurons (mean diameter 1.45 microm). They are closely associated with GABAergic presynaptic dendrites (PSDs), and nearly all form classic triadic arrangements (28 of 29 reconstructed boutons). Consecutive boutons on individual terminal fibers make multiple contacts with a single postsynaptic dendrite and can show evidence of progressive complexity. Dendritic appendages that enwrap and invaginate the terminal bouton constitute additional anatomic evidence for secure, high-fidelity synaptic transfer. These observations provide direct ultrastructural evidence supporting the hypothesis that VMpo is a lamina I TSTT thalamocortical relay nucleus in primates that subserves pain, temperature, itch, and other sensations related to the physiological condition of the body.

Workshop 2 (synthesis): water pollution abatement within the industrial sector

This workshop aimed at demonstrating and discussing how effective abatement of water pollution can be achieved through introducing cleaner technologies, recycling and reuse of water, and implementing new public policy measures.

Association of spinothalamic lamina I neurons and their ascending axons with calbindin-immunoreactivity in monkey and human

The calbindin-immunoreactivity of spinothalamic (STT) lamina I neurons and their ascending axons was examined in two experiments. In the first experiment, lamina I STT neurons in macaque monkeys were double-labeled for calbindin and for retrogradely transported WGA*HRP following large (n=2) or small (n=1) injections that included the posterior thalamus. Most, but not all (78%) of the contralateral retrogradely labeled lamina I STT cells were positive for calbindin. Calbindin-immunoreactivity was not selectively associated with any particular anatomical type of lamina I STT cell; 82% of the fusiform cells, 78% of the pyramidal cells and 67% of the multipolar cells were double-labeled. In the second experiment, oblique transverse sections from upper cervical spinal segments of three macaque monkeys, one squirrel monkey and five humans were stained for calbindin-immunoreactivity. In each case, a distinct bundle of fibers was densely stained in the middle of the lateral funiculus. This matches the location of anterogradely labeled ascending lamina I axons observed in prior work in cats and monkeys, and it matches the location of the classically described 'lateral spinothalamic tract' in humans. This bundle had variable shape across cases, an observation that might have clinical significance. These findings support the view that lamina I STT neurons are involved in spinal cordotomies that reduce pain, temperature and itch sensations.

Preproenkephalin mRNA expression in rat parabrachial neurons: relation to cells activated by systemic immune challenge

By using a dual-labeling immunohistochemical/in situ hybridization technique we examined if enkephalin-expressing neurons in the pontine parabrachial nucleus, a major brain stem relay for ascending visceral and homeostatic information, were activated by systemic immune challenge. While rats subjected to intravenous injection of bacterial wall lipopolysaccharide expressed dense labeling for the immediate-early gene product FOS in parts of the parabrachial nucleus that also demonstrated dense preproenkephalin expression, only a small proportion of the enkephalin-positive neurons were FOS-positive. These data indicate that enkephalins, although implicated in a variety of autonomic responses, are not primarily involved in the transmission of immune-related information from the parabrachial nucleus to its different forebrain and brain stem targets.

Activation of prostanoid EP(3) and EP(4) receptor mRNA-expressing neurons in the rat parabrachial nucleus by intravenous injection of bacterial wall lipopolysaccharide

Systemic inflammation activates central autonomic circuits, such as neurons in the pontine parabrachial nucleus. This activation may be the result of afferent signaling through the vagus nerve, but it may also depend on central prostaglandin-mediated mechanisms. Recently, we have shown that neurons in the parts of the parabrachial nucleus that are activated by immune challenge express prostaglandin receptors of the EP(3) and EP(4) subtypes, but it remains to be determined if the prostaglandin receptor-expressing neurons are identical to those that respond to immune stimuli. In the present study, bacterial wall lipopolysaccharide was injected intravenously in adult male rats and the expression of c-fos mRNA and of EP(3) and EP(4) receptor mRNA was examined with complementary RNA probes labeled with digoxigenin and radioisotopes, respectively. Large numbers of neurons in the external lateral parabrachial subnucleus, a major target of vagal-solitary tract efferents, expressed c-fos mRNA. Quantitative analysis showed that about 60% (range 40%-79%) of these neurons also expressed EP(3) receptor mRNA. Conversely, slightly more than 50% (range 48%-63%) of the EP(3) receptor-expressing neurons in the same subnucleus coexpressed c-fos mRNA. In contrast, few EP(4) receptor-expressing neurons were c-fos positive, with the exception of a small population located in the superior lateral and dorsal lateral subnuclei. These findings show that immune challenge activates central autonomic neurons that could be the target of centrally produced prostaglandin E(2), suggesting that synaptic signaling and paracrine mechanisms may interact on these neurons.

Feeding-related immune responsive brain stem neurons: association with CGRP

Using dual-labeling in situ hybridization histochemistry, the neurotransmitter expression of immune-responsive neurons in the pontine parabrachial nucleus, a major relay for interoceptive information, was investigated. Intravenous injection of bacterial wall lipopolysaccharide resulted in dense c-fos mRNA expression in the external lateral parabrachial nucleus, and a majority of the c-fos expressing cells also expressed calcitonin gene-related peptide (CGRP) mRNA. In contrast CGRP-positive cells in the adjoining external medial subnucleus were c-fos negative. Taken together with previous hodological and behavioral studies, these data suggest that CGRPergic parabrachial neurons may mediate lipopolysaccharide-induced anorexia by means of their projection to central nucleus of the amygdala.

Neuropeptide expression in rat paraventricular hypothalamic neurons that project to the spinal cord

The paraventricular hypothalamic nucleus (PVH) exerts many of its regulatory functions through projections to spinal cord neurons that control autonomic and sensory functions. By using in situ hybridization histochemistry in combination with retrograde tract tracing, we analyzed the peptide expression among neurons in the rat PVH that send axons to the spinal cord. Projection neurons were labeled by immunohistochemical detection of retrogradely transported cholera toxin subunit B, and radiolabeled long riboprobes were used to identify neurons containing dynorphin, enkephalin, or oxytocin mRNA. Of the spinally projecting neurons in the PVH, approximately 40% expressed dynorphin mRNA, 40% expressed oxytocin mRNA, and 20% expressed enkephalin mRNA. Taken together with our previous findings on the distribution of vasopressin-expressing neurons in the PVH (Hallbeck and Blomqvist [1999] J. Comp. Neurol. 411:201-211), the results demonstrated that the different PVH subdivisions display distinct peptide expression patterns among the spinal cord-projecting neurons. Thus, the lateral parvocellular subdivision contained large numbers of spinal cord-projecting neurons that express any of the four investigated peptides, whereas the ventral part of the medial parvocellular subdivision displayed a strong preponderance for dynorphin- and vasopressin-expressing cells. The dorsal parvocellular subdivision almost exclusively contained dynorphin- and oxytocin-expressing spinal cord-projecting neurons. This parcellation of the peptide-expressing neurons suggested a functional diversity among the spinal cord-projecting subdivisions of the PVH that provide an anatomic basis for its various and distinct influences on autonomic and sensory processing at the spinal level.

[Estrogen receptors can regulate pain sensitivity. Possible explanation of certain chronic pain conditions]

Animal experiments as well as observations in humans have shown that somatosensory perception and pain sensitivity are influenced by gonadal hormones. These effects are likely to be exerted, at least in part, by the binding of estrogen to estrogen receptors present in neurons located in the superficial layers of the spinal dorsal horn. Neurons containing estrogen receptors in these locations have been found to express mRNA for the endogenous opioid enkephalin, and administration of estrogen has been shown to increase enkephalin transcription in the spinal cord. The possible clinical implications of these findings in relation to gender differences in pain sensitivity and chronic pain conditions are discussed.

Impact of complete gastric fundus mobilization on outcome after laparoscopic total fundoplication

With the objective of further optimizing the outcome of antireflux surgery, we have studied the importance of dividing the short gastric vessels when performing a laparoscopic total fundoplication. Ninety-nine consecutive patients with chronic gastroesophageal reflux disease (GERD) were enrolled in the trial. Forty-seven patients (25 men, age 52 +/- 1.6 years [mean +/- standard error]) were randomized to undergo a laparoscopic Nissen-Rossetti total fundic wrap with intact short gastric vessels, whereas 52 patients (29 men, 48 +/- 1.4 years) had complete division of these vessels. Quality of life was assessed by means of the psychological general well-being and gastrointestinal symptom rating scale indices. The 6- and 12-month follow-up data are reported. Two patients were converted to open surgery. Mobilization of the fundus significantly prolonged the operative time (120 vs. 104 minutes, P = 0.05); otherwise the complication rates were similar in the two groups. Both procedures were equally effective in controlling gastroesophageal reflux at 6 and 12 months' postoperatively. Division of the short gastric vessels had no significant impact on the point prevalence of postfundoplication complaints at the given follow-up time points. Quality of life was significantly improved by both operative procedures and remained "normal" throughout the follow-up period. Dividing all short gastric vessels had no impact on the functional outcome during the first year of recovery after a total laparoscopic fundoplication.

Long-term management of gastro-oesophageal reflux disease with omeprazole or open antireflux surgery: results of a prospective, randomized clinical trial. The Nordic GORD Study Group

BACKGROUND AND AIM

The efficacy of antireflux surgery (ARS) and omeprazole treatment in the control of gastrooesophageal reflux disease (GORD) are well established. We have compared these two therapeutic options in a randomized, clinical trial.

PATIENTS AND METHODS

Three hundred and ten patients with erosive oesophagitis were enrolled into the trial. After a run-in period when all patients had < or = 40 mg of omeprazole daily to heal the oesophagitis and relieve symptoms, 155 patients were randomized to continuous omeprazole therapy and 155 to open antireflux surgery, of whom 144 later had an operation. One hundred and thirty-nine and 129 in the omeprazole and antireflux surgery groups, respectively, completed the 3-year follow-up. Symptoms, 24-h pH monitoring and endoscopy were used to document the outcome. Quality of life was evaluated by the psychological general well-being (PGWB) index and the gastrointestinal symptom rating scale (GSRS).

RESULTS

Analysis of time to treatment failure (defined as moderate to severe GORD symptoms for > or = 3 days during the last 7 days, oesophagitis or changed therapy) revealed a significant difference in favour of antireflux surgery (P = 0.0016). Seventeen patients originally submitted to antireflux surgery experienced symptom relapse alone, 14 had oesophagitis at endoscopy and another six had omeprazole for different reasons, leaving 97 patients in clinical remission after 3 years. The corresponding figures in the omeprazole arm were 50 relapses, 18 with oesophagitis, two had surgery, leaving 77 patients in remission. Allowing a dose adjustment in the case of relapse in those on omeprazole therapy to either 40 or 60 mg, the curves describing the failure rates were not significantly different from each other. Quality of life assessment showed a comparable outcome in the two study groups.

CONCLUSION

In this randomized multicentre trial we found antireflux surgery to be very efficacious in controlling GORD, a level of control which could also be achieved by omeprazole provided that advantage was taken of the opportunity of adjusting the dose.