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1.
Scand J Trauma Resusc Emerg Med ; 30(1): 22, 2022 Mar 24.
Article in English | MEDLINE | ID: mdl-35331311

ABSTRACT

BACKGROUND: There has been in increase in the use of systems for organizing lay responders for suspected out-of-hospital cardiac arrests (OHCAs) dispatch using smartphone-based technology. The purpose is to increase survival rates; however, such systems are dependent on people's commitment to becoming a lay responder. Knowledge about the characteristics of such volunteers and their motivational factors is lacking. Therefore, we explored characteristics and quantified the underlying motivational factors for joining a smartphone-based cardiopulmonary resuscitation (CPR) lay responder system. METHODS: In this descriptive cross-sectional study, 800 consecutively recruited lay responders in a smartphone-based mobile positioning first-responder system (SMS-lifesavers) were surveyed. Data on characteristics and motivational factors were collected, the latter through a modified version of the validated survey "Volunteer Motivation Inventory" (VMI). The statements in the VMI, ranked on a Likert scale (1-5), corresponded to(a) intrinsic (an inner belief of doing good for others) or (b) extrinsic (earning some kind of reward from the act) motivational factors. RESULTS: A total of 461 participants were included in the final analysis. Among respondents, 59% were women, 48% between 25 and 39 years of age, 37% worked within health care, and 66% had undergone post-secondary school. The most common way (44%) to learn about the lay responder system was from a CPR instructor. A majority (77%) had undergone CPR training at their workplace. In terms of motivation, where higher scores reflect greater importance to the participant, intrinsic factors scored highest, represented by the category values (mean 3.97) followed by extrinsic categories reciprocity (mean 3.88) and self-esteem (mean 3.22). CONCLUSION: This study indicates that motivation to join a first responder system mainly depends on intrinsic factors, i.e. an inner belief of doing good, but there are also extrinsic factors, such as earning some kind of reward from the act, to consider. Focusing information campaigns on intrinsic factors may be the most important factor for successful recruitment. When implementing a smartphone-based lay responder system, CPR instructors, as a main information source to potential lay responders, as well as the workplace, are crucial for successful recruitment.


Subject(s)
Cardiopulmonary Resuscitation , Emergency Responders , Out-of-Hospital Cardiac Arrest , Cardiopulmonary Resuscitation/education , Cross-Sectional Studies , Female , Humans , Motivation , Out-of-Hospital Cardiac Arrest/therapy
2.
Perspect Public Health ; 142(3): 175-183, 2022 May.
Article in English | MEDLINE | ID: mdl-33461394

ABSTRACT

AIM: Foodborne illnesses have a significant global burden and can be life-threatening, with higher risk in vulnerable groups such as children. SafeConsume is an EU-funded, transdisciplinary project aiming to improve consumers' food safety behaviour. Developing educational resources on food safety for use in schools has potential to improve teaching of our young consumers. The aim of this study was to explore school educators' attitudes, behaviours and knowledge towards food hygiene, safety and education. METHODS: Focus groups and interviews in England, France, Portugal and Hungary explored educator knowledge, skills, intentions and beliefs around educating young people (11-18 years) about food safety. Data were analysed using NVivo and emerging themes were applied to the Theoretical Domains Framework. RESULTS: A total of 48 educators participated. Knowledge, confidence and skills to teach food safety to young people varied depending on background and training. Educators reported they had a role to teach food safety to young people, were positive about delivering education and optimistic they could improve students' food safety behaviour. Barriers to teaching included lack of national curriculum coverage, limited time and money, and lack of facilities. Educators reported that social influences (family, celebrity chefs, public health campaigns and social media) were important opportunities to improve young peoples' awareness of food safety and consequences of foodborne illness. CONCLUSION: Educator food safety expertise varied; training could help to optimise educator knowledge, confidence and skills. Ministries of Health and Education need encouragement to get food safety incorporated further into school curricula across Europe, so schools will be motivated to prioritise these topics.


Subject(s)
Curriculum , Hygiene , Adolescent , Child , Europe , Food Safety , Humans , Needs Assessment
3.
Child Abuse Negl ; 110(Pt 3): 104438, 2020 12.
Article in English | MEDLINE | ID: mdl-32164944

ABSTRACT

Emotional intelligence (EI) refers to the ability to recognize and appropriately respond to emotions in oneself and others; these competencies include, but are not limited to, empathy, emotion regulation, reflective ability, self-awareness, and psychological flexibility. Such abilities are crucial to meaningful and effective child welfare work. Further, they are part of resilience and healthy coping mechanisms, which are important for those working in child welfare if compassion fatigue and burnout are to be combated. However, little is known about how to cultivate these competencies in child welfare professionals. The present study had two goals: 1) To conduct a systematic scoping review of the literature on interventions purporting to develop and/or enhance EI-related competencies in this population, whether those interventions be at the caseworker, supervisor, or organizational level; 2) To consider future directions for the teaching and enhancement of EI competencies for child welfare professionals. A total of 18 studies met inclusion criteria, with the majority focused on developing mindfulness and/or empathy skills. However, no studies focused on child welfare professionals, and instead focused on social work students or professionals, with a few including other helping professionals. Additionally, none were focused on a supervisory or organizational level. Future directions for research are discussed, including the use of experiential or simulation-based training in order to elicit emotions within a safe and supportive learning context, the use of reflective supervision to help develop self-reflection and emotion regulation skills, and system-wide interventions that enhance the development of emotional intelligence competencies in public child welfare organizations.


Subject(s)
Adaptation, Psychological , Child Welfare/psychology , Emotional Intelligence , Empathy , Mindfulness , Workforce , Adult , Child , Child Protective Services , Emotional Regulation , Humans , Professional Role , Program Evaluation
4.
Science ; 363(6425): 367-374, 2019 01 25.
Article in English | MEDLINE | ID: mdl-30538164

ABSTRACT

In 2018, Kilauea Volcano experienced its largest lower East Rift Zone (LERZ) eruption and caldera collapse in at least 200 years. After collapse of the Pu'u 'O'o vent on 30 April, magma propagated downrift. Eruptive fissures opened in the LERZ on 3 May, eventually extending ~6.8 kilometers. A 4 May earthquake [moment magnitude (M w) 6.9] produced ~5 meters of fault slip. Lava erupted at rates exceeding 100 cubic meters per second, eventually covering 35.5 square kilometers. The summit magma system partially drained, producing minor explosions and near-daily collapses releasing energy equivalent to M w 4.7 to 5.4 earthquakes. Activity declined rapidly on 4 August. Summit collapse and lava flow volume estimates are roughly equivalent-about 0.8 cubic kilometers. Careful historical observation and monitoring of Kilauea enabled successful forecasting of hazardous events.

5.
Acta Anaesthesiol Scand ; 61(10): 1354-1360, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28940249

ABSTRACT

BACKGROUND: The aim of this study was to survey the current equipment used for prevention, treatment and monitoring of accidental hypothermia in Swedish pre-hospital services. METHODS: A questionnaire was sent to all road ambulance services (AS), the helicopter emergency medical services (HEMS), the national helicopter search and rescue service (SAR) and the municipal rescue services (RS) in Sweden to determine the availability of insulation, active warming, fluid heating, and low-reading thermometers. RESULTS: The response rate was 77% (n = 255). All units carried woollen or polyester blankets for basic insulation. Specific windproof insulation materials were common in the HEMS, SAR and RS units but only present in about half of the AS units. Active warming equipment was present in all the SAR units, but only in about two-thirds of the HEMS units and about one-third of the AS units. About half of the RS units had the ability to provide a heated tent or container. Low-reading thermometers were present in less than half of the AS and HEMS units and were non-existent in the SAR units. Pre-warmed intravenous fluids were carried by almost all of the AS units and half of the HEMS units but infusion heaters were absent in most units. CONCLUSION: Basic insulation capabilities are well established in the Swedish pre-hospital services. Specific wind and waterproof insulation materials, active warming devices, low-reading thermometers and IV fluid heating systems are less common. We suggest the development and implementation of national guidelines on accidental hypothermia that include basic recommendations on equipment requirements.


Subject(s)
Emergency Medical Services , Hypothermia/prevention & control , Air Ambulances , Humans
6.
Eur J Clin Microbiol Infect Dis ; 36(3): 509-516, 2017 Mar.
Article in English | MEDLINE | ID: mdl-27812804

ABSTRACT

France has remained among the top five European countries for ambulatory antibiotic consumption since such monitoring began in 1998. Young children are major antibiotic consumers, in spite of the viral origin of most infections in this population. Recommendations were updated in 2011 to limit prescriptions. In order to assess their impact, diagnoses and prescriptions were compared in a population of children attending daycare centres in southeastern France in 2008 and 2012. Trends in the reimbursement of paediatric antibiotic prescriptions by the national health insurance (NHI) for the whole area were also studied. Distribution of diagnoses accounting for antibiotic treatment and type of antibiotic prescribed over the previous 3 months to children below 4 years of age attending daycare centres in the Alpes-Maritimes area in southeastern France were compared between 2008 and 2012 prior to and following the availability of these new recommendations. Trends in reimbursed ambulatory antibiotic prescriptions by general practitioners and paediatricians in the area were studied for this age group from 2008 to 2012 and in 2013. The majority of recorded diagnoses concerned upper respiratory tract infections (URTI). Inappropriate antibiotic prescription persisted for colds and bronchitis in similar proportions during both surveys. Improvement in the choice of antibiotic with fewer prescriptions for third-generation cephalosporins was observed both in daycare centres and according to NHI data; however, this was mainly recorded among paediatricians. The management of paediatric URTI still needs improvement, pointing to the need to investigate and adequately address the reasons for inappropriate antibiotic prescription.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Drug Utilization , Practice Patterns, Physicians' , Primary Health Care/methods , Child, Preschool , Cross-Sectional Studies , Female , France , Humans , Infant , Infant, Newborn , Male , Practice Guidelines as Topic , Prescriptions/statistics & numerical data
7.
BMJ Open ; 6(11): e012872, 2016 11 17.
Article in English | MEDLINE | ID: mdl-27856479

ABSTRACT

OBJECTIVES: To examine differences in growth patterns in preterm infants developing major morbidities including retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), necrotising enterocolitis (NEC) and intraventricular haemorrhage (IVH). STUDY DESIGN: Cohort study of 2521 infants born at a gestational age (GA) of 23-30 weeks from 11 level III neonatal intensive care units in USA and Canada, and 3 Swedish population-based cohorts. OUTCOMES: Birth weight and postnatal weight gain were examined relative to birth GA and ROP, BPD, NEC and IVH development. RESULTS: Among infants with a birth GA of 25-30 weeks, birth weight SD score and postnatal weight were lower in those developing ROP and BPD. Infants developing ROP showed lower growth rates during postnatal weeks 7-9 in the 23-24 weeks GA group, during weeks 4-6 in the 25-26 weeks GA group and during weeks 1-5 in the 27-30 weeks GA group. Infants with BPD born at 27-30 weeks GA showed lower growth rates during postnatal weeks 3-5. Infants with NEC had lower growth rates after postnatal week 6 in all GA groups, with no significant differences in birth weight SD score. IVH was not associated with prenatal or postnatal growth. CONCLUSIONS: In this cohort study of extremely preterm infants, we found that the postnatal growth pattern was associated with morbidities such as ROP, BPD and NEC as well as with gestational age at birth.


Subject(s)
Bronchopulmonary Dysplasia/epidemiology , Cerebral Hemorrhage/epidemiology , Enterocolitis, Necrotizing/epidemiology , Gestational Age , Infant, Extremely Premature/growth & development , Retinopathy of Prematurity/epidemiology , Birth Weight , Canada , Cohort Studies , Female , Humans , Infant , Infant, Newborn , Intensive Care Units, Neonatal , Linear Models , Male , Morbidity , Sweden , United States
8.
PLoS One ; 11(9): e0156950, 2016.
Article in English | MEDLINE | ID: mdl-27658247

ABSTRACT

Biological invasions can induce rapid evolutionary change. As cane toads (Rhinella marina) have spread across tropical Australia over an 80-year period, their rate of invasion has increased from around 15 to 60 km per annum. Toads at the invasion front disperse much faster and further than conspecifics from range-core areas, and their offspring inherit that rapid dispersal rate. We investigated morphological changes that have accompanied this dramatic acceleration, by conducting three-dimensional morphometric analyses of toads from both range-core and invasion-front populations. Morphology of heads, limbs, pectoral girdles and pelvic girdles differed significantly between toads from the two areas, ranging from 0.5% to 16.5% difference in mean bone dimensions between populations, with invasion-front toads exhibiting wider forelimbs, narrower hindlimbs and more compact skulls. Those changes plausibly reflect an increased reliance on bounding (multiple short hops in quick succession) rather than separate large leaps. Within an 80-year period, invasive cane toads have converted the basic anuran body plan - which evolved for occasional large leaps to evade predators - into a morphotype better-suited to sustained long-distance travel.

10.
Mol Ecol ; 22(23): 5821-34, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24112610

ABSTRACT

Understanding connectivity of coral populations among and within reefs over ecologically significant timescales is essential for developing evidence-based management strategies, including the design of marineprotected areas. Here, we present the first assessment of contemporary connectivity among populations of two Molecular Operational Taxonomic Units (MOTUs) of the brooding coral Pocillopora damicornis. We used individual-based genetic assignment methods to identify the proportions of philopatric and migrant larval recruits, settling over 12 months at sites around Lizard Island (northern Great Barrier Reef [GBR]) and over 24 months at sites around the Palms Islands (central GBR). Overall, we found spatially and temporally variable rates of self-recruitment and dispersal, demonstrating the importance of variation in local physical characteristics in driving dispersal processes. Recruitment patterns and inferred dispersal distances differed between the two P. damicornis MOTUs, with type α recruits exhibiting predominantly philopatric recruitment, while the majority of type ß recruits were either migrants from identified putative source populations or assumed migrants based on genetic exclusion from all known populations. While P. damicornis invests much energy into brooding clonal larvae, we found that only 15% and 7% of type α and type ß recruits, respectively, were clones of sampled adult colonies or other recruits, challenging the hypothesis that reproduction is predominantly asexual in this species on the GBR. We explain high rates of self-recruitment and low rates of clonality in these MOTUs by suggesting that locally retained larvae originate predominantly from spawned gametes, while brooded larvae are mainly vagabonds.


Subject(s)
Animal Distribution , Anthozoa/genetics , Genetics, Population/methods , Animals , Australia , Ecosystem , Genotype , Islands , Larva/genetics , Microsatellite Repeats , Population Density , Spatio-Temporal Analysis
11.
Mol Ecol ; 22(23): 5805-20, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24112642

ABSTRACT

Understanding levels of connectivity among scleractinian coral populations over a range of temporal and spatial scales is vital for managing tropical coral reef ecosystems. Here, we use multilocus microsatellite genotypes to assess the spatial genetic structure of two molecular operational taxonomic units (MOTUs, types α and ß) of the widespread coral Pocillopora damicornis on the Great Barrier Reef (GBR) and infer the extent of connectivity on spatial scales spanning from local habitat types to latitudinal sectors of the GBR. We found high genetic similarities over large spatial scales spanning > 1000 km from the northern to the southern GBR, but also strong genetic differentiation at local scales in both MOTUs. The presence of a considerable number of first-generation migrants within the populations sampled (12% and 27% for types α and ß, respectively) suggests that genetic differentiation over small spatial scales is probably a consequence of stochastic recruitment from different genetic pools into recently opened up spaces on the reef, for example, following major disturbance events. We explain high genetic similarity among populations over hundreds of kilometres by long competency periods of brooded zooxanthellate larvae and multiple larval release events each year, combined with strong longshore currents typical along the GBR. The lack of genetic evidence for predominantly clonal reproduction in adult populations of P. damicornis, which broods predominantly asexually produced larvae, further undermines the paradigm that brooded larvae settle close to parent colonies shortly after the release.


Subject(s)
Anthozoa/genetics , Genetics, Population , Animal Distribution , Animals , Australia , Ecosystem , Genotype , Microsatellite Repeats , Multilocus Sequence Typing
12.
Ann Surg Oncol ; 19(10): 3282-8, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22878612

ABSTRACT

BACKGROUND: Skin-sparing mastectomy and prosthetic reconstruction can be complicated by poor surgical outcomes in large-breasted, obese women. This article describes a single surgeon's experience comparing conventional skin-sparing mastectomy (SSM) and skin-reduction mastectomy using an autologous vascularized inferior dermal/cutaneous sling (autoderm). METHODS: From July 2007 to May 2012, patients undergoing skin-sparing mastectomy were evaluated for surgical outcomes. After July 2009, the surgeon performed skin-reduction mastectomies with autoderm (SRM-AD) on all patients with macromastia or grade 3-4 ptosis. Remaining patients in this time period (SSM-cont) underwent conventional skin-sparing mastectomies while all previous patients (historical) also underwent skin-sparing mastectomies (SSM-hist). A predictive model was used to compare the large historical patients (who would have had reduction mastectomy if available) with the smaller historical patients to evaluate the effect of the procedure. RESULTS: Body mass index (BMI) and specimen weight were higher in both the SRM group and large historical group. The hazard ratio for having skin-reduction mastectomy was 0.53 (P = 0.51) compared with the historical group. There was a total of 16 complications for the whole study. Smoking was the only significant risk factor. CONCLUSIONS: This study shows that mastectomy with prosthetic reconstruction using a skin-reduction technique with autoderm can be done safely with a low complication rate and improved cosmetic outcomes in the traditionally "at-risk" group of women with high BMI and large ptotic breasts.


Subject(s)
Breast Neoplasms/surgery , Dermatologic Surgical Procedures , Hypertrophy/surgery , Mammaplasty , Mastectomy/rehabilitation , Plastic Surgery Procedures , Surgical Flaps , Breast/abnormalities , Breast/surgery , Breast Neoplasms/pathology , Choice Behavior , Female , Follow-Up Studies , Humans , Middle Aged , Neoplasm Staging , Postoperative Complications , Prognosis , Retrospective Studies , Skin Transplantation
13.
Nanotechnology ; 19(28): 285204, 2008 Jul 16.
Article in English | MEDLINE | ID: mdl-21828728

ABSTRACT

In this paper, we focus on critical issues directly related to the viability of carbon nanotube-based nanoelectromechanical switches, to perform their intended functionality as logic and memory elements, through assessment of typical performance parameters with reference to complementary metal-oxide-semiconductor devices. A detailed analysis of performance metrics regarding threshold voltage control, static and dynamic power dissipation, speed, and integration density is presented. Apart from packaging and reliability issues, these switches seem to be competitive in low power, particularly low-standby power, logic and memory applications.

14.
Gait Posture ; 28(1): 93-100, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18096389

ABSTRACT

The aim of this work was to use bone anchored external markers to describe the kinematics of the tibia, fibula, talus, calcaneus, navicular, cuboid, medial cuneiform, first and fifth metatarsals during gait. Data were collected from six subjects. There was motion at all the joints studied. Movement between the talus and the tibia showed the expected predominance of sagittal plane motion, but the talocalcaneal joint displayed greater variability than expected in its motion. Movement at the talonavicular joint was greater than at the talocalcaneal joint and motion between the medial cuneiform and navicular was far greater than expected. Motion between the first metatarsal and the medial cuneiform was less than motion between the fifth metatarsal and cuboid. Overall the data demonstrated the complexity of the foot and the importance of the joints distal to the rearfoot in its overall dynamic function.


Subject(s)
Forefoot, Human/physiology , Walking/physiology , Adult , Biomechanical Phenomena , Foot Joints/physiology , Humans , Male , Middle Aged , Movement/physiology
15.
J Biomech ; 40(15): 3412-23, 2007.
Article in English | MEDLINE | ID: mdl-17631298

ABSTRACT

The aim was to compare kinematic data from an experimental foot model comprising four segments ((i) heel, (ii) navicular/cuboid (iii) medial forefoot, (iv) lateral forefoot), to the kinematics of the individual bones comprising each segment. The foot model was represented using two different marker attachment protocols: (a) markers attached directly to the skin; (b) markers attached to rigid plates mounted on the skin. Bone data were collected for the tibia, talus, calcaneus, navicular, cuboid, medial cuneiform and first and fifth metatarsals (n=6). Based on the mean differences between the three data sets during stance, the differences between any two of the three kinematic protocols (i.e. bone vs skin, bone vs plate, skin vs plate) were >3 degrees in only 35% of the data and >5 degrees in only 3.5% of the data. However, the maximum difference between any two of the three protocols during stance was >3 degrees in 100% of the data, >5 degrees in 73% of the data and >8 degrees in 23% of the data. Differences were greatest for motion of the combined navicular/cuboid relative to the calcaneus and the medial forefoot segment relative to the navicular/cuboid. The differences between the data from the skin and plate protocols were consistently smaller than differences between either protocol and the kinematic data for each bone comprising the segment. The pattern of differences between skin and plate protocols and the actual bone motion showed no systematic pattern. It is unlikely that one rigid body foot model and marker attachment approach is always preferable over another.


Subject(s)
Bones of Lower Extremity/physiology , Foot/physiology , Skin , Walking/physiology , Adult , Biomechanical Phenomena , Humans , Male , Middle Aged
16.
J Biomech ; 40(12): 2672-8, 2007.
Article in English | MEDLINE | ID: mdl-17368465

ABSTRACT

An accurate kinematic description of the intrinsic articulations of the foot during running has not previously been presented, primarily due to methodological limitations. An invasive method based upon reflective marker arrays mounted on intracortical pins drilled into the bones was used in this study. Four male volunteers participated as subjects. Pins (1.6mm diameter) were inserted under local anaesthetic in the tibia, fibula, calcaneus, talus, navicular, cuboid, medial cuneiform and metatarsals I and V. A 10 camera motion analysis system was used for kinematic data capture and the ground reaction force was simultaneously measured. Segment motion relative to adjacent proximal segments was determined using helical axes projected into the coordinate system of the proximal segment. Coefficients of multiple correlation calculated to determine the strength of association between running style with and without the pins inserted indicated that the subjects had little restriction due to the inserted pins. Individual and mean results were presented for rotations defined in the planes of the proximal segment's coordinate system and showed frontal plane rotation of the talocrural joint (12.2+/-7.1 degrees ), which exceeded that of the subtalar joint (8.9+/-3.2 degrees ). Considerable mobility of the talonavicular joint was found (6.5+/-2.9 degrees , 13.5+/-4.1 degrees and 8.7+/-1.4 degrees in the sagittal, frontal and transverse planes, respectively). Furthermore, little, but non-negligible motion between the fibula and tibia was found (3.3+/-2.4 degrees in the sagittal plane). The presented data are of interest as input for future biomechanical modelling and clinical decision making in particular, concerning joint fusion.


Subject(s)
Fibula/physiology , Foot Bones/physiology , Foot Joints/physiology , Foot/physiology , Running/physiology , Tibia/physiology , Adult , Biomechanical Phenomena , Humans , Male , Middle Aged , Models, Biological
17.
Neuroscience ; 143(1): 73-81, 2006 Nov 17.
Article in English | MEDLINE | ID: mdl-16938407

ABSTRACT

The neurosteroid allopregnanolone (ALLO) or 3alpha-OH-5alpha-pregnane-20-one interacts with the GABA type A receptor chloride ion channel complex and enhances the effect of GABA. Animal and human studies suggest that ALLO plays an important role in several disorders including premenstrual syndrome, anxiety, and memory impairment. In contrast to ALLO, steroids with a hydroxy group in the 3beta position usually exert a reducing effect and have recently attracted interest due to their suggested role in counteracting the negative action of ALLO. In this study, five different 3beta-steroids were tested for their ability to modulate GABA-mediated chloride ion uptake in the absence and presence of ALLO in rat brain microsacs preparations. In addition, the effects of the 3beta-steroids and their interaction with ALLO were investigated by patch-clamp recordings of spontaneous inhibitory postsynaptic currents (sIPSCs) in rat hypothalamic neurons from the medial preoptic nucleus (MPN). All tested 3beta-steroids reduced the ALLO-enhanced GABA response in cerebral cortex, in hippocampus and in MPN. In cerebellum, only one had this effect. However, in the absence of ALLO, two of the 3beta-steroids potentiated GABA-evoked chloride ion uptake and prolonged the sIPSCs decay time, whereas the others had little or no effect. Therefore, it is possible that at least some 3beta-steroids can act as positive GABA(A) receptor modulators as well as negative modulators depending on whether or not ALLO is present. Finally, these results suggest that the 3beta-steroids could be of interest as pharmacological agents that could counteract the negative effects of ALLO.


Subject(s)
Neurons/drug effects , Pregnanolone/pharmacology , Receptors, GABA-A/metabolism , Steroids/pharmacology , gamma-Aminobutyric Acid/pharmacology , Analysis of Variance , Animals , Brain/cytology , Cells, Cultured , Chloride Channels/drug effects , Chloride Channels/physiology , Chlorides/metabolism , Dose-Response Relationship, Drug , Drug Interactions , Male , Membrane Potentials/drug effects , Membrane Potentials/physiology , Membrane Potentials/radiation effects , Neurons/physiology , Patch-Clamp Techniques/methods , Rats , Rats, Wistar
18.
Eur J Neurosci ; 21(8): 2083-8, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15869504

ABSTRACT

Glucocorticoids and neurosteroids, such as allopregnanolone and tetrahydrodeoxycorticosterone, are released during stress. A non-genomic effect of glucocorticoids has been established but is not yet fully understood. We have studied the effect of glucocorticoid metabolites on the gamma-aminobutyric acid (GABA) system. In these experiments we studied the effects of the glucocorticoid metabolites allotetrahydrocortisol, tetrahydrocortisol, allotetrahydrocortisone and tetrahydrocortisone in rat cortical microsacs. Our results showed that both these cortisol and cortisone metabolites reduce GABA-mediated chloride ion uptake. This reduction was not observed in the presence of allopregnanolone but allotetrahydrocortisol interacts with allopregnanolone, enhancing the allopregnanolone-stimulated potentiation of GABA-mediated chloride ion uptake. This enhanced effect was completely blocked by the addition of 30 microm of the 3beta-isomer of allopregnanolone, isoallopregnanolone. Our findings show that steroids released during stress interact with each other and GABA in the GABA system.


Subject(s)
Cerebral Cortex/cytology , Desoxycorticosterone/analogs & derivatives , Glucocorticoids/metabolism , Glucocorticoids/pharmacology , Neurons/cytology , Receptors, GABA-A/metabolism , Synaptosomes/drug effects , Animals , Chlorides/metabolism , Desoxycorticosterone/pharmacology , Dose-Response Relationship, Drug , Drug Interactions , Male , Neurons/drug effects , Neurons/metabolism , Pregnanolone/pharmacology , Rats , Rats, Wistar , gamma-Aminobutyric Acid/pharmacology
19.
Science ; 294(5546): 1534-7, 2001 Nov 16.
Article in English | MEDLINE | ID: mdl-11711677

ABSTRACT

In the modern ocean, a significant amount of nitrogen fixation is attributed to filamentous, nonheterocystous cyanobacteria of the genus Trichodesmium. In these organisms, nitrogen fixation is confined to the photoperiod and occurs simultaneously with oxygenic photosynthesis. Nitrogenase, the enzyme responsible for biological N2 fixation, is irreversibly inhibited by oxygen in vitro. How nitrogenase is protected from damage by photosynthetically produced O2 was once an enigma. Using fast repetition rate fluorometry and fluorescence kinetic microscopy, we show that there is both temporal and spatial segregation of N2 fixation and photosynthesis within the photoperiod. Linear photosynthetic electron transport protects nitrogenase by reducing photosynthetically evolved O2 in photosystem I (PSI). We postulate that in the early evolutionary phase of oxygenic photosynthesis, nitrogenase served as an electron acceptor for anaerobic heterotrophic metabolism and that PSI was favored by selection because it provided a micro-anaerobic environment for N2 fixation in cyanobacteria.


Subject(s)
Cyanobacteria/metabolism , Nitrogen Fixation , Oxygen/metabolism , Photosynthesis , Photosystem II Protein Complex , Aerobiosis , Anaerobiosis , Biological Evolution , Circadian Rhythm , Cyanobacteria/enzymology , Dibromothymoquinone/pharmacology , Diuron/pharmacology , Electron Transport , Fluorometry , Light , Microscopy, Fluorescence , Nitrogenase/metabolism , Oxidation-Reduction , Oxygen Consumption , Photoperiod , Photosynthetic Reaction Center Complex Proteins/metabolism , Quinones/metabolism , Time Factors
20.
Dig Dis Sci ; 46(4): 765-72, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11330410

ABSTRACT

Ceramide plays an important role in regulating cell proliferation and apoptosis. Recent studies indicate that generation of ceramide in the intestine from sphingomyelin hydrolysis may be implicated in colon cancer development. The enzymes that catalyze the further hydrolysis of ceramide in the intestine have, however, not been well investigated. Our data reveal the existence of a ceramidase (EC 3.5.1.23) in rat intestinal mucosa with an optimal pH of 7.0. One milligram of mucosal protein is able to hydrolyze 44.0+/-9.6 nmol of ceramide in 1 hr. The activity is low in the proximal duodenum and increases to a plateau in the proximal jejunum. The activity is then similar throughout the small intestine, until it declines in the distal part of ileum. Some activity is also detectable in the colon. The activity increases slightly in the presence of monomeric bile salt concentrations and sharply at the critical micellar concentration. Similar patterns were observed for both primary (taurocholate) and secondary (taurodeoxycholate) bile salts. The addition of Triton X-100 enhances the ceramidase activity at optimal bile salt concentration. The reaction is linear with time for the first 20 min and the hydrolytic rate declines slowly thereafter. Finally, the activity shows a considerable resistance against tryptic degradation, as 71% of the ceramidase activity remained when the homogenates were preincubated with high concentrations of trypsin. Intestinal mucosa also has a ceramide synthesis activity, with a distribution pattern generally paralleling ceramide hydrolysis activity. In conclusion, intestinal neutral ceramidase has a distinct distribution pattern and bile salt dependence, which enables it to collaborate with intestinal sphingomyelinase in hydrolysis of sphingomyelin.


Subject(s)
Amidohydrolases/metabolism , Intestines/enzymology , Animals , Ceramidases , Male , Neutral Ceramidase , Octoxynol/pharmacology , Rats , Rats, Sprague-Dawley , Trypsin/metabolism
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