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PubMed1986

Natural campylobacter colonization in chickens raised under different environmental conditions.

A cross-sectional study of 447 laying hens (age range 0-65 weeks) and a longitudinal study of 164 similar birds showed that Campylobacter jejuni was not present in the faeces of newly hatched chicks, but that colonization arose after 5-9 weeks. A survey of 250 broilers obtained from four breeders showed that all were negative for C. jejuni before and after slaughter at the age of 5 weeks. Once C. jejuni had appeared in a flock, it rapidly spread to virtually all birds, but at the age of 42 weeks only 20-46% of birds remained colonized, possibly as a result of having developed immunity. Birds housed in the protective environment of a laboratory still became colonized (after 9 weeks). The mode of infection is unknown, but water and food were bacteriologically negative and were deemed to be unlikely sources. Transmission via attendants, flies or other insects remain possibilities. It is concluded that prevention of colonization might be possible within the life-span of broiler chickens (5-7 weeks), but that it would be difficult to extend this period. There is a need to define how colonization arises so that the feasibility and cost of possible preventive measures can be assessed.

Age Factors↗
PubMed2001

Influence of extrinsic factors on electron transfer in a mixed-valence Fe(2+)/Fe(3+) complex: experimental results and theoretical considerations.

The crystal structure of the mixed-valence complex (NEt(4))[Fe(2)(salmp)(2)].xMeCN(crystal) (x = 2,3) [1].xMeCN(crystal) was determined at temperatures between 153 and 293 K. The complex shows distinct Fe(2+) and Fe(3+) sites over this temperature interval. Variable temperature Mössbauer spectra confirm the valence-localized character of the complex. In contrast, spectroscopic investigation of powder samples generated from [1].xMeCN(crystal) indicate the presence of a valence-averaged component at temperatures above 150 K. To elucidate this apparent contradiction we have conducted a variable-temperature Mössbauer investigation of different forms of 1, including [1].xMeCN(crystal), [1].2DMF(crystal), [1].yMeCN(powder), and solution samples of 1 in acetonitrile. The low-temperature Mössbauer spectra of all forms are virtually identical and confirm the valence-localized nature of the S = (9)/(2) ground state. The high-temperature spectra reveal a subtle control of electron hopping by the environment of the complexes. Thus, [1].xMeCN(crystal) has valence-localized spectra at all explored temperatures, [1].2DMF(crystal) exhibits a complete collapse into a valence-averaged spectrum over a narrow temperature range, the powder exhibits partial valence averaging over a broad temperature interval, and the solution sample shows at 210 K the presence of a valence-averaged component in a minor proportion. The spectral transformations are characterized by a coexistence of valence-localized and valence-averaged spectral components. This phenomenon cannot be explained by intramolecular electron hopping between the valence-localized states Fe(A)(2+)Fe(B)(3+) and Fe(A)(3+)Fe(B)(2+) in a homogeneous ensemble of complexes, but requires relaxation processes involving at least three distinguishable states of the molecular anion. Hopping rates for [1].2DMF(crystal) and [1].yMeCN(powder) have been determined from spectral simulations, based on stochastic line shape theory. Analysis of the temperature dependences of the transfer rates reveals the existence of thermally activated processes between (quasi) degenerate excited states in both forms. The preexponential factors in the rate law for the hopping processes in the [1].yMeCN(powder) and [1].2DMF(crystal) differ dramatically and suggest an important influence of the asymmetry of the complex environment (crystal) on intramolecular electron hopping. The differences between the spectra for the crystalline sample [1].xMeCN and those for powders generated under vacuum from these crystals indicate that solvate depletion has a profound effect on the dynamic behavior. Finally, two interpretations for the three states involved in the relaxation processes in 1 are given and critically discussed (salmp = bis(salicyledeneamino)-2-methylphenolate(3-)).

Crystallography, X-Ray↗
PubMed1999

Germicidal ultraviolet irradiation in air conditioning systems: effect on office worker health and wellbeing: a pilot study.

OBJECTIVES: The indoor environment of modern office buildings represents a new ecosystem that has been created totally by humans. Bacteria and fungi may contaminate this indoor environment, including the ventilation systems themselves, which in turn may result in adverse health effects. The objectives of this study were to test whether installation and operation of germicidal ultraviolet (GUV) lights in central ventilation systems would be feasible, without adverse effects, undetected by building occupants, and effective in eliminating microbial contamination. METHODS: GUV lights were installed in the ventilation systems serving three floors of an office building, and were turned on and off during a total of four alternating 3 week blocks. Workers reported their environmental satisfaction, symptoms, as well as sickness absence, without knowledge of whether GUV lights were on or off. The indoor environment was measured in detail including airborne and surface bacteria and fungi. RESULTS: Airborne bacteria and fungi were not significantly different whether GUV lights were on or off, but were virtually eliminated from the surfaces of the ventilation system after 3 weeks of operation of GUV light. Of the other environmental variables measured, only total airborne particulates were significantly different under the two experimental conditions--higher with GUV lights on than off. Of 113 eligible workers, 104 (87%) participated; their environmental satisfaction ratings were not different whether GUV lights were on or off. Headache, difficulty concentrating, and eye irritation occurred less often with GUV lights on whereas skin rash or irritation was more common. Overall, the average number of work related symptoms reported was 1.1 with GUV lights off compared with 0.9 with GUV lights on. CONCLUSION: Installation and operation of GUV lights in central heating, ventilation and air conditioning systems of office buildings is feasible, cannot be detected by workers, and does not seem to result in any adverse effects.

Adult↗
PubMedDate not supplied

Males as sexual assault victims: multiple levels of trauma.

The definite and persistent phenomenon of sexual assault upon males is virtually ignored in the literature, although incidence data reported here suggest the greater scope of the problem. The avoidance of the subject of sexual assault on males creates a negative environment for victims. While the motivation of assailants is briefly discussed, the article focuses on the psychological aftermath for sexual assault victims. A paradigm is offered, consisting of "Set-up," "Attack," and "Aftermath" phases. Male victims suffer "Rape Trauma Syndrome" as described for females, as well as various forms of stigmatization and secondary trauma. Differences and similarities between male and female victims are identified. Victim responses are discussed as they proceed through several stages, with implications for appropriate interventions on both the clinical and community levels. The article concludes with an extensive bibliography.

Adolescent↗
PubMed2000

The Internet: another facet to the paradigm shift in healthcare.

The Internet is an extremely powerful innovation that has and will continue to shape the healthcare industry in the years to come. Albeit a little too slowly, doctors are starting to catch onto this new wave of digital empowerment and creating niches that will enhance their ability to care for their patients and ultimately add value to their practices. The challenge is to encourage every doctor to come on board. The paradigm shift in healthcare delivery is that the Internet brings about the power of information to the patient. This balances the power in the doctor patient relationship. Taken positively, the doctor too can benefit from Internet technology. The biggest contribution of the Internet in the area of electronic medical records is the web-based display environment that is operating-system independent. The Internet can therefore be exploited to provide a supra system that can draw personal medical information together from anywhere to create a virtual electronic medical record. The Internet can also be used to shape up an Internet-based healthcare delivery system. The healthcare delivery paradigm shift brought about by the Internet calls for an eHealth strategy.

Delivery of Health Care↗
PubMed1994

Environmental and behavioural risk factors for prolonged diarrhoea in Nigerian children.

Prolonged diarrhoea is a particular health concern because it contributes significantly to diarrhoea-related deaths. Studies of risk factors for prolonged or persistent diarrhoea are virtually nonexistent in Africa. In the present study conducted in a semi-urban area of Lagos, we used a case-control design to evaluate the roles of household environment, mothers' food hygiene behaviour, and child-care practices as possible risk factors for prolonged diarrhoea in children 6-36 months old. A total of 628 children were studied. During the 3 1/2 months surveillance period, 166 children became ill with diarrhoea and 20 of the 166 (12.0%) had prolonged episodes (> 7 days). Persistent diarrhoea (> 14 days) accounted for only 2.4% (6 of 251) of all episodes. This analysis of risk factors is focussed on the 20 cases of prolonged diarrhoea and 206 randomly selected controls who experienced no diarrhoea during the surveillance period. A significantly high risk of prolonged diarrhoea was found among children who were given ogi, a maize pap, as the main diet (odds ratio = 4.13). Children who were fed mainly with foods bought from street vendors also had a significantly higher risk (odds ratio = 2.91) of prolonged diarrhoea. No association was found between domestic, environmental, and personal hygiene practices and prolonged diarrhoea. Foods from street vendors may serve as one source of diarrhoeal illnesses in Lagos and such episodes could be prolonged following repeated exposure, especially in children who are fed mainly with a low-energy and low-nutrient-density diet such as ogi.

Child, Preschool↗
PubMed2005

Oral ivermectin for the treatment and prophylaxis of scabies in prison.

INTRODUCTION: Oral ivermectin has been widely used to treat various human diseases, such as filariasis, myiasis, larva migrans, strongyloidiasis and scabies (both the common and crusted forms). However, there are only a small number of papers on the effects of this drug for the control of scabies in infested environments. The current study shows the results obtained with the collective treatment of inmates of a public jail. MATERIALS AND METHODS: A total of 123 inmates living in a restricted and contaminated environment were evaluated clinically by experienced dermatologists for the assessment of the degree of infestation by Sarcoptes scabiei, and were then treated with oral ivermectin (200-300 micorg/kg single dose repeated after 7 days). Both clothing and environment were disinfected. Patients were re-evaluated after 15 days. RESULTS: In all, 78% of the inmates were infected upon initial evaluation. Re-evaluation 15 days after repeat treatment revealed a cure rate of 91.05%. Prophylaxis was also highly effective, where 93.2% of the non-infected inmates and virtually all the house staff remained disease-free throughout the study period. Two of the 29 inmates (6.8%) who showed no apparent lesions upon initial examination were found to be infected upon re-evaluation. These patients responded well to a third dose of ivermectin. CONCLUSIONS: Oral ivermectin at a dose of 300 microg/kg single dose repeated after 7 days proved effective for the treatment and prophylaxis of scabies in an infected institutional environment.

Administration, Oral↗
PubMed2000

Evaluation of an integrated curriculum using problem-based learning in a clinical environment: the Manchester experience.

DESCRIPTION OF COURSE: In 1994, a new problem-based leaning (PBL) curriculum for year 1 medical students was introduced at the University of Manchester. The use of PBL has continued into the clinical clerkships. Year 3 of the curriculum is based entirely in a clinical environment with PBL groups meeting in three teaching hospitals. During this year, all students undertake two integrated 14-week modules with overarching themes. Each week, groups of eight students discuss a trigger problem connected to the relevant theme. The steps the groups use in the PBL process have been amended to encourage students to link their discussion with clinical experience. EVALUATION: At the end of each module, all 309 students were requested to complete an evaluation questionnaire. The response rates were 80% (n=247) and 89% (n=275) for the two core modules. RESULTS: The students have remained 'happy with the way the course is going' (83% at the end of module 2). They were also asked to rate a number of statements on a 5-point Likert scale (5=strongly agree). Concerning PBL, the students remained confident about working in a group (median 4), producing a set of learning objectives (median 4) and linking clinical experience with other knowledge (median 4). However, there were changes over the year. Fewer students agreed at the end of module 2 that 'the working problems were stimulating' (P=0.002) or 'motivated them to learn' (P < 0.001), but the clinical firms were seen as providing more appropriate experience (P=0.01) and being aware of the new curriculum and responding to it (P=0.018). We also surveyed the PBL tutors and had 65 returns from 78 people involved in the 38 PBL groups in year 3. The great majority of these are doctors employed by the National Health service. Virtually all the responders were happy to continue being a tutor (97%) and would recommend it to a colleague (93%). CONCLUSIONS: The evaluation has been positive with PBL having been successfully implemented in a clinical environment. We have identified significant changes over the year, which we need to address as we consolidate the curriculum.

Clinical Clerkship↗
PubMed1993

Astacins, serralysins, snake venom and matrix metalloproteinases exhibit identical zinc-binding environments (HEXXHXXGXXH and Met-turn) and topologies and should be grouped into a common family, the 'metzincins'.

The X-ray crystal structures of two zinc endopeptidases, astacin from crayfish, and adamalysin II from snake venom, reveal a strong overall topological equivalence and virtually identical extended HEXXHXXGXXH zinc-binding segments, but in addition a methionine-containing turn of similar conformation (the 'Met-turn'), which forms a hydrophobic basis for the zinc ion and the three liganding histidine residues. These two features are also present in a similar arrangement in the matrix metalloproteinases (matrixins) and in the large bacterial Serratia proteinase-like peptidases (serralysins). We suggest that these four proteinases represent members of distinct subfamilies which can be grouped together in a family, for which we propose the designation, metzincins.

Amino Acid Sequence↗
PubMed2000

Human orientation and movement control in weightless and artificial gravity environments.

Our goal is to summarize what has been learned from studies of human movement and orientation control in weightless conditions. An understanding of the physics of weightlessness is essential to appreciate the dramatic consequences of the absence of continuous contact forces on orientation and posture. Eye, head, arm, leg, and whole body movements are discussed, but only experiments whose results seem relatively incontrovertible are included. Emphasis is placed on distinguishing between virtually immediate adaptive compensations to weightlessness and those with longer time courses. The limitations and difficulties of performing experiments in weightless conditions are highlighted. We stress that when astronauts and cosmonauts return from extended space flight they do so with both physical "plant" and neural "controller" structurally and functionally altered. Recent developments in adapting humans to artificial gravity conditions are discussed as a way of maintaining sensory-motor and structural integrity in extended missions involving transitions between different force environments.

Humans↗
PubMed1979

Influence of magnesium depletion on matrix-induced endochondral bone formation.

The effect of magnesium deficiency on bone cell differentiation and bone formation was investigated using in vivo matrix-induced endochondral ossification as a test system. Demineralized bone matrix was implanted subcutaneously in young (35-day-old) male Long-Evans rats that had been fed a semisynthetic Mg-deficient diet (50 ppm Mg) for 7 days. Plasma Mg levels were reduced to 25-30% of control values at that time. Control rats were paired the same diet, supplemented to contain 1000 ppm Mg. The implants were harvested 7, 9, 11, 15, and 20 days after implantation and analyzed for Mg and Ca content, 45Ca incorporation, and alkaline phosphatase levels. At each stage, plaques (implants) removed from Mg-deficient rats showed retardation in cartilage and bone differentiation and matrix calcification. Magnesium content was markedly reduced when compared to the control plaques. Histological appearance of the matrix-induced plaques confirmed the retardation in bone development and mineralization suggested by the chemical indicators. Most marked was the virtual absence of bone marrow in 20-day-old plaques in Mg-depleted rats. These data show that bone cell differentiation can occur in a severely Mg-depleted environment, although the onset of mineralization and bone remodeling was delayed and bone marrow differentiation was impaired.

Alkaline Phosphatase↗
PubMed2005

Contribution of reference frames for movement planning in peripersonal space representation.

The principal goal of our study is to gain an insight into the representation of peripersonal space. Two different experiments were conducted in this study. In the first experiment, subjects were asked to represent principal anatomical reference planes by drawing ellipses in the sagittal, frontal and horizontal planes. The three-dimensional hand-drawing movements, which were achieved with and without visual guidance, were considered as the expression of a cognitive process per se: the peripersonal space representation for action. We measured errors in the spatial orientation of ellipses with regard to the requested reference planes. For ellipses drawn without visual guidance, with eyes open and eyes closed, orientation errors were related to the reference planes. Errors were minimal for sagittal and maximal for horizontal plane. These disparities in errors were considerably reduced when subjects drew using a visual guide. These findings imply that different planes are centrally represented, and are characterized, by different errors when subjects use a body-centered frame for performing the movement and suggest that the representation of peripersonal space may be anisotropic. However, this representation can be modified when subjects use an environment-centered reference frame to produce the movement. In the second experiment, subjects were instructed to represent, with eyes open and eyes closed, sagittal, frontal and horizontal planes by pointing to virtual targets located in these planes. Disparities in orientation errors measured for pointing were similar to those found for drawing, implying that the sensorimotor representation of reference planes was not constrained by the type of motor tasks. Moreover, arm postures measured at pointing endpoints and at comparable spatial locations in drawing are strongly correlated. These results suggest that similar patterns of errors and arm posture correlation, for drawing and pointing, can be the consequence of using a common space representation and reference frame. These findings are consistent with the assumption of an anisotropic action-related representation of peripersonal space when the movement is performed in a body-centered frame.

Adult↗
PubMed2004

An "eye" in the gut: the appendix as a sentinel sensory organ of the immune intelligence network.

Neural systems are the traditional model of intelligence. Their complex interconnected network of wired neurons acquires, processes, and responds to environmental cues. We propose that the immune system is a parallel system of intelligence in which the gut, including the appendix, plays a prominent role in data acquisition. The immune system is essentially a virtual unwired network of interacting cells that acquires, processes, and responds to environmental data. The data is typically acquired by antigen-presenting cells (APCs) that gather antigenic information from the environment. The APCs chemically digest large antigens and deconstruct them into smaller data packets for sampling by other cells. The gut performs the same function on a larger scale. Morsels of environmental content that enter the gut are sequentially deconstructed by physical and chemical digestion. In addition to providing nutrients, the componentized contents offer environmental data to APCs in mucosa-associated lymphoid tissues (MALT) that relay the sampled information to the immune intelligence network. In this framework, positioning of the appendix immediately after the ileocecal valve is strategic: it is ideally positioned to sample environmental data in its maximally deconstructed state after small bowel digestion. For single-celled organisms, digestion of the environment has been the primary way to sample the surroundings. Prior to the emergence of complex sensory systems such as the eye, even multi-cellular organisms may have relied heavily on digestion to acquire environmental information. While the relative value of immune intelligence has diminished since the emergence of neural intelligence, organisms still use information from both systems in integrated fashion to respond appropriately to ecologic opportunities and challenges. Appendicitis may represent a momentary maladaptation in the evolutionary transition of sensory leadership from the gut to the eye. Relationships between immune dysfunctions and cognition are explored.

Animals↗
PubMed2003

Blockade of the locomotor stimulant effects of amphetamine by group I, group II, and group III metabotropic glutamate receptor ligands in the rat nucleus accumbens: possible interactions with dopamine receptors.

Previous investigations have shown that mGlu receptors would be involved in the amphetamine-induced motor response. However, data are somewhat controversial across studies where methodological protocols vary. The aim of the present study was to determine the involvement of mGlu receptors in the NAcc in the locomotor-activating properties of amphetamine in rats well habituated to their experimental environment, a condition known to modulate the motor response to amphetamine. Focal infusion of the group I mGlu receptor antagonist S-4-CPG, which has no effect on basal motor activity, virtually suppressed the locomotor response to amphetamine, while infusion of the group II mGlu receptor antagonist LY 341495 or the group III mGlu receptor agonist AP4, at the minimal dose that produces locomotor activation, reduced it by approximately a half. These effects were blocked by the group I mGlu receptor agonist DHPG, the group II mGlu receptor agonist APDC, and the group III mGlu receptor antagonist MPPG, respectively. These data confirm that mGlu receptors in the NAcc contribute to the psychostimulant motor effect of amphetamine. Results are discussed from the view of recent neuropharmacological studies that have defined the effects of these mGlu receptor ligands on basal motor activity and DA receptor agonists-induced locomotor responses in rats exposed to similar experimental procedures (Eur J Neuroscience 13 (2001) 2157; Neuropharmacology 41 (2001) 454; Eur J Neuroscience 13 (2001) 869). It is suggested that the contribution of mGlu receptors to the amphetamine-induced motor response may result mainly from their functional, either direct or indirect, interactions with D1-like receptors in the NAcc.

Amphetamine↗
PubMed1975

Experimental studies on environmental contamination with infected blood during haemodialysis.

To assess the relative importance of different postulated modes of spread of hepatitis B in dialysis units, blood charged with various tracer organisms was used in simulated haemodialysis runs in four laboratories, and the resulting contamination of equipment and environment was measured semi-quantitatively. Some airborne spread of the tracer organism occurred when tubing containing contaminated blood was needled as the "patient" went on and came off the dialyser. Virtually no small airborne particles could be demonstrated however in simulated emergencies in which a blood line was disconnected, or even when bottles of blood were dropped on to a hard floor from a height of 2 metres. Bacillus globigii spores from contaminated blood leaked in small numbers into the dialysing fluid through apparently intact coils. T3 phage, with a particle size of the same order as hepatitis B virus, passed in small quantities through the membrane of a Kiil dialyser from blood to dialysing fluid and also in the reverse direction when added to the header tank. A number of other dialysers were also permeable to phage. Visual assessment of the appropriate moment for inserting the venous line into the "patient" at the onset of dialysis was shown to be unreliable, as the displaced fluid from the end of the venous line was already contaminated before it contained visible red blood cells. Considerable contamination of exposed surfaces and of the buttons on the proportionating unit cabinet occurred. Minor visible splashing of blood was a common-place of the laboratory experiments and was shown to be also a common event during routine haemodialysis in two of the dialysis units taking part in the studies.

Air Microbiology↗
PubMed2004

Epidemiology and genetics of childhood cancer.

Childhood cancer is rare everywhere in the world, with age-standardized annual incidence usually between 70 and 160 per million at age 0-14 years. Greater variation is seen between populations for some specific tumour types. Some of the largest variations are geographical and are attributable to environmental factors, whereas variation mainly on ethnic lines seems likely to be a marker of genetic predisposition. A wide range of familial and genetic syndromes is associated with an increased risk of childhood cancer. Virtually all the excess risk of cancer among first-degree relatives of children with cancer can be accounted for by known hereditary syndromes. Studies of weak predisposition and gene-environment interaction have so far shown limited consistency. There are very few established environmental or exogenous risk factors and most of these are infective agents. Many putative risk factors can hardly ever be investigated epidemiologically except by interview or questionnaire studies. Some recent examples illustrate the continuing problems of participation bias and recall bias.

Adolescent↗
PubMed1997

A health insurance scheme for hospital care in Bwamanda District, Zaire: lessons and questions after 10 years of functioning.

A voluntary insurance scheme for hospital care was launched in 1986 in the Bwamanda District in northwest Zaire. The paper briefly reviews the rationale, design and implementation of the scheme and discusses its results and performance over time. The scheme succeeded in generating stable revenue for the hospital in a context where government intervention was virtually absent and external subsidies were most uncertain. Hospital data indicate that hospital services were used by a significantly higher proportion of insured patients than uninsured people. The features of the environment in which the insurance scheme thrived are discussed and the conditions that facilitated its development reviewed. These conditions comprise organizational-managerial, economic-financial, social and political factors. The Bwamanda case study illustrates the feasibility of health insurance-at least for hospital-based inpatient care-at rural district level in sub-Saharan Africa, but also exemplifies the managerial and social complexity of such financing mechanisms.

Adult↗
PubMed2003

Network-based real-time radiation monitoring system in Synchrotron Radiation Research Center.

The real-time radiation monitoring system (RMS) in the Synchrotron Radiation Research Center (SRRC) has been upgraded significantly during the past years. The new framework of the RMS is built on the popular network technology, including Ethernet hardware connections and Web-based software interfaces. It features virtually no distance limitations, flexible and scalable equipment connections, faster response time, remote diagnosis, easy maintenance, as well as many graphic user interface software tools. This paper briefly describes the radiation environment in SRRC and presents the system configuration, basic functions, and some operational results of this real-time RMS. Besides the control of radiation exposures, it has been demonstrated that a variety of valuable information or correlations could be extracted from the measured radiation levels delivered by the RMS, including the changes of operating conditions, beam loss pattern, radiation skyshine, and so on. The real-time RMS can be conveniently accessed either using the dedicated client program or World Wide Web interface. The address of the Web site is http:// www-rms.srrc.gov.tw.

Computer Communication Networks↗