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PubMedDate not supplied

Quantification of selected pesticide metabolites in human urine using isotope dilution high-performance liquid chromatography/tandem mass spectrometry.

The annual domestic use of pesticides is continually increasing, virtually ensuring that everyone is exposed to some level of pesticides on a regular basis through diet or environment. The potential developmental and physical adverse effects these chronic pesticide exposures have on children are of increasing concern. To adequately evaluate the potential adverse effects resulting from these exposures, accurate methods to measure the amount of the pesticide absorbed by the body must be developed. We have developed a sensitive method to measure the urinary metabolites of atrazine, diazinon, malathion, 2,4-dichlorophenoxyacetic acid (2,4-D), and certain synthetic pyrethroids in human urine. In our method, stable isotopically labeled analogues of the metabolites were spiked into the urine, which was subsequently extracted at both a neutral and acidic pH using organic solvents. The extracts were analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) using atmospheric pressure chemical ionization. Our method has limits of detection ranging from 20 to 500 ng/l (parts per trillion) and relative standard deviations of less than 11%. This method has been used to measure the internal doses of these pesticides in both adults and children (n = 130) with no documented exposure to the pesticides. We detected atrazine and synthetic pyrethroid metabolites in less than 12% of the samples analyzed. The metabolites of 2,4-D, malathion, and diazinon were detected in 22%, 32%, and 57% of the samples, respectively.

Adult↗
PubMed1998

Maternal mortality in Maiduguri, Nigeria.

Maternal mortality is an index of the standard of antenatal care in a given environment. In developed countries the level of antenatal care has risen to an extent that maternal mortality has virtually disappeared (Nylander and Adekunle, 1990). This is in sharp contrast with the situation in developing countries like Nigeria where maternal mortality is still deplorably high. According to the World Health Organization, only 29-36% of deliveries in Africa are attended to by trained health personnel (World Health Organization, 1985). Therefore the mortality rates reported from most developing countries may be just the tip of the iceberg. Another disturbing dimension to the problem of maternal deaths in developing countries is the fact that most of the deaths are due to causes that can be prevented by the provision of essential obstetric care. Nearly a decade after the launching of the international safe motherhood initiative the tragedy of maternal deaths remains unmitigated in most developing countries such as Nigeria. The purpose of this study is to evaluate the causes of maternal deaths in two tertiary level hospitals in Maiduguri, north-eastern Nigeria and to identify ways of reversing the trend.

Journal Article↗
PubMed2005

Simulation for trauma and combat casualty care.

Training medical providers to care for traumatically injured patients is a difficult undertaking and currently used training strategies are often suboptimal. The further strains placed on trauma care in the military environment only add to the challenge. Simulation applications ranging from simple physical models to complex, computer-based virtual reality systems have either been developed or are being developed to help support and improve trauma care training. Several of these applications have been shown to be as good as or better than the standard training methods they are designed to replace. Simulators are available for training in the treatment of disorders of the airway, difficulty with breathing, and problems dealing with circulation as well as various non-life-threatening but disabling injuries. Some of these simulators have already drastically changed how the standard Advanced Trauma Life Support course is taught. Advances in both technology and application of simulators will continue to affect trauma skills training for the foreseeable future.

Journal Article↗
PubMed1999

Prevalence of myopia in Sherpa and Tibetan children in Nepal.

BACKGROUND: Tibetan and Sherpa children living in Nepal share a common ancestry in Tibet and areas to the north of Nepal, but it is evident that these people experience widely contrasting educational and environmental conditions. The purpose of this study was to compare the prevalence of myopia in children with similar genetic backgrounds but who are exposed to contrasting environments. METHODS: Unaided vision and refractive error was measured in 555 Tibetan children in Kathmandu and 270 Sherpa children in the Solu Khumbu region of Nepal. RESULTS: There were marked differences in vision and the prevalence of myopia in the two groups. Ninety-two percent of the Sherpa children had Snellen vision of 20/22 (0.89) or better compared with 70% of the Tibetan children. The range of refractive errors was -6.50 to +7.00 D for the Tibetan children and -1.00 to +3.50 D for the Sherpa children. The Sherpa children had a prevalence of myopia of 2.9% compared with 21.7% for the Tibetan children. CONCLUSIONS: The prevalence of myopia in Sherpa children is low and their rural lifestyle appears to be relatively unstressed. Tibetan children have a higher prevalence of myopia and more rigorous schooling. We did not establish a causal relationship between myopia and the type of schooling, or the environment in general, but we did demonstrate that a simple, rural lifestyle is at least compatible with a virtual absence of myopia.

Adolescent↗
PubMed2001

The evolution of 'Close Care' as user-led care of the elderly in the UK.

The chronic ailments of old age such as stroke, coronary heart disease, severe arthritis and loss of sight have traditionally found care only in a nursing home. Taking care to the family house or sheltered home has drawbacks because of inappropriate accommodation. There is now an alternative that also reflects changing expectations on the part of the elderly. 'Close Care' offers a solution to the crises of carer shortages and ever increasing nursing costs. It also responds to the growing consumerist power of the elderly who seek more choice, more control and higher standards. Habell's involvement in the early growth of private purpose-designed nursing homes pointed to an emerging demand for accommodation which the residents identified as home and over which they exercised choice and control. The elderly were moving from passive subjects of assessment and care to become a market with consumer tastes and power. Coining the phrase Close Care, the team encouraged Habell's architectural solutions to evolve into hybrid schemes, which broke new ground by seeking to provide as normal a home as possible while flexibly accommodating all the disabilities of old age. In effect Close Care offers an invisible or virtual nursing home where the elderly are motivated in self-help by stimulating surroundings, control of their environment, choice of support and knowledge that they have their own home for life among friends and helpers. Close Care offers a solution to the rising costs of nursing care, overcomes the alienation of institutional environments and offers a way of integrating alert but frail and even confused persons back into a normal community.

Aged↗
PubMed1980

Preliminary studies on the use of monoclonal antibodies as probes for sympathetic development.

The precise structural organization and proper functioning of the adult nervous system depend on the ability of neurones to make highly ordered synaptic connexions. To define molecules involved in the development of these connexions and to study their functional roles, we use primary cultures of dissociated rat sympathetic neurones grown in the virtual absence of non-neuronal cells. These neurones can develop adrenergic or cholinergic properties, depending on the environment in which they are grown. This ability to manipulate neuronal phenotype is being used in an attempt to identify cell surface macromolecules that are important in the development or function of adrenergic and cholinergic properties. We have produced monoclonal antibodies against the surface membranes of these neurones and are in the process of characterizing them. Results are presented on the binding specificity of one of these antibodies and on the effect of two other antibodies on neurotransmitter synthesis, uptake, and release.

Acetylcholine↗
PubMed1999

The home visit.

With the advent of effective home health programs, an increasing proportion of medical care is being delivered in patients' homes. Since the time before World War II, direct physician involvement in home health care has been minimal. However, patient preferences and key changes in the health care system are now creating an increased need for physician-conducted home visits. To conduct home visits effectively, physicians must acquire fundamental and well-defined attitudes, knowledge and skills in addition to an inexpensive set of portable equipment. "INHOMESSS" (standing for: immobility, nutrition, housing, others, medication, examination, safety, spirituality, services) is an easily remembered mnemonic that provides a framework for the evaluation of a patient's functional status and home environment. Expanded use of the telephone and telemedicine technology may allow busy physicians to conduct time-efficient "virtual" house calls that complement and sometimes replace in-person visits.

Activities of Daily Living↗
PubMed2002

Generalized interactions using virtual tools within the spring framework: cutting.

We present schemes for real-time generalized mesh cutting. Starting with the a basic example, we describe the details of implementing cutting on single and multiple surface objects as well as hybrid and volumetric meshes using virtual tools with single and multiple cutting surfaces. These methods have been implemented in a robust surgical simulation environment allowing us to model procedures ranging from animal dissection to cleft lip correction.

Biomechanical Phenomena↗
PubMed1991

Acyl carrier protein-derived sequence encoded by the chloroplast genome in the marine diatom Cylindrotheca sp. strain N1.

The chloroplast genome of chromophytic and rhodophytic algae differs from the plastid genome of plants and green algae in that it encodes the gene for the small subunit (rbcS) of ribulose 1,5-bisphosphate carboxylase/oxygenase. Hybridization studies indicated that there was a second region of chloroplast DNA from the marine diatom Cylindrotheca sp. strain N1 that strongly hybridized to a previously isolated Cylindrotheca fragment that contained the rbcS gene and flanking sequences. Subsequent determination of the oligonucleotide sequence of this second chloroplast DNA fragment, however, indicated that hybridization was due to identical sequences 3' to the previously cloned Cylindrotheca chloroplast rbcL rbcS genes. Sequences derived from the 5' end of the second chloroplast DNA fragment contained a short open reading frame of 80 amino acids which was found to be highly homologous to bacterial acyl carrier protein and nuclear-encoded acyl carrier protein from plants. Amino acid residues in the environment of Ser-36 of the Escherichia coli protein, which is bound to a 4'-phosphopantetheine moiety, are virtually identical in the Cylindrotheca deduced sequence and all other sources of this protein. Unlike plant acyl carrier-deduced amino acid sequences, there was no leader peptide sequence found for the presumptive Cylindrotheca protein, consistent with the location of this DNA fragment on the chloroplast genome of this organism. DNA encoding the putative acyl carrier protein gene and rbcS thus represent two genes that are chloroplast-encoded in the chromophytic marine diatom Cylindrotheca, a significant departure from the organization of such genes in plants.

Acyl Carrier Protein↗
PubMedDate not supplied

[Voluntary acute drug poisoning in the health unit Navarra I, in 1989. Descriptive epidemiologic study].

Acute voluntary medicinal intoxications (AVMI) constitute a serious social-medical problem, frequently related to other problems, such as drug addiction and psychopathies. By means of a prospective study of AVMI cases seen in 1989 by the Emergency Room of Internal Medicine in our Hospital, and for persons over the age of 13 in the Health Area Navarra I, we can conclude that there is an incidence of 70.4/100,000 inhabitants, with a relative and absolute majority of females and of residents in urban areas. One third of cases had psychopathological case histories, while another third have a prior history of drug and/or alcohol abuse. The majority of patients are under 30. The peristaltic data seem to have only a tenuous relationship to the onset of AVMI, which mainly occurs at night. In 85% of cases, we are able to determine the causing factor. Psychopharmaceuticals are present in more than 60% of autolytic cases, the highest frequency belonging to benzodiazepines. In our environment, there is a high percentage of admittances despite the fact that a positive outcome is reached in virtually all cases: only 1 exitus out of 103 cases.

Adolescent↗
PubMed1988

[The contamination of a hospital with Bacillus cereus without an indication of cases of infection].

A hygienic investigation of a hospital revealed B. cereus in 60.5% (66 out of 109) of swab specimens taken from walls, apparatuses, airing devices and bedclothes. These findings were not associated with evidence of human infection caused by the organism within the hospital. In a similar investigation three weeks later, only 22.5% of the environmental specimens were positive for B. cereus. The hospital contamination with B. cereus has thus been virtually temporary and epidemiologically silent. Considering the potential pathogenicity of the organism however, its presence in the hospital environment cannot be approved of.

Bacillus cereus↗
PubMedDate not supplied

The lung at high altitude.

Men and mammals (excluding the indigenous mountain species) who are born at high altitude, or who ascend to live there for a long period, have to undergo acclimatization which affects virtually every system in the body. Since chronic hypoxia is the most important adverse factor in the mountain environment, the lung plays a major part in the process and shows many alterations in structure and function. However, we remain ignorant about many aspects of acclimatization of the lung to hypoxia especially at the ultrastructural level with respect to those cells whose normal function is not yet established. An account of what is known is given in this paper.

Acclimatization↗
PubMed1997

Adaptation and extinction in changing environments.

The extinction risk of a population is determined by its demographic properties, the environmental conditions to which it is exposed, and its genetic potential to cope with and adapt to its environment. All these factors may have stochastic as well as directional components. The present chapter reviews several types of models concerned with the vulnerability of small populations to demographic stochasticity and to random and directional changes of the environment. In particular, the influence of mutation and genetic variability on the persistence time of a population is explored, critical rates for environmental change are estimated beyond which extinction on time scales of tens to a few thousand generations is virtually certain, and the extinction risks caused by the above mentioned factors are compared.

Adaptation, Physiological↗
PubMed1998

Navigation and acquisition of spatial knowledge in a virtual maze.

Spatial behavior in humans and animals includes a wide variety of behavioral competences and makes use of a large number of sensory cues. Here we studied the ability of human subjects to search locations, to find shortcuts and novel paths, to estimate distances between remembered places, and to draw sketch maps of the explored environment; these competences are related to goal-independent memory of space, or cognitive maps. Information on spatial relations was restricted to two types: a visual motion sequence generated by simulated movements in a virtual maze and the subject's own movement decisions defining the path through the maze. Visual information was local (i.e., no global landmarks or compass information was provided). Other position and movement information (vestibular or proprioceptive) was excluded. The amount of visual information provided was varied over four experimental conditions. The results indicate that human subjects are able to learn a virtual maze from sequences of local views and movements. The information acquired is local, consisting of recognized positions and movement decisions associated to them. Although simple associations of this type can be shown to be present in some subjects, more complete configurational knowledge is acquired as well. The results are discussed in a view-based framework of navigation and the representation of spatial knowledge by means of a view graph.

Adolescent↗
PubMed1996

Sudden infant death syndrome: near-weightlessness and delayed neural transformation.

Dilation of the pulmonary arteries and increased pulmonary blood volume are recorded in sudden infant death syndrome and in infants living at low barometric pressures (high altitude). Low barometric pressure leads to chronic alveolar hypoxia (1,2). There is diversion and loss of body-fluid under conditions of microgravity (near-weightlessness) encountered in human space-travel and prolonged bedrest (3). The condition mimics shock and oligemia (4,5). The human neonate has underdeveloped postural mechanisms and low muscle-power. A transformation begins at about two months of age, which enables the human infant to adapt to the extrauterine environment (6). The neonate resembles the space traveller who, in a near-weightlessness antigravity environment, develops baroreceptor incompetence, visceral and venous congestion and oliguria. The low birthweight infant displays many of the disorders of the space traveller, viz. poor circulation, high blood-glucose, insulin resistance, weak muscles, slow gut absorption and bone demineralization (7-10). These conditions are virtually identical with the internal adjustments the body makes on lying down (negative gravity or near-weightlessness). We discuss the similarities of sudden infant death syndrome to low barometric pressure environment, orthostatic intolerance, the Pickwickian syndrome and X disease.

Altitude Sickness↗
PubMed2001

Life in extreme environments.

Each recent report of liquid water existing elsewhere in the Solar System has reverberated through the international press and excited the imagination of humankind. Why? Because in the past few decades we have come to realize that where there is liquid water on Earth, virtually no matter what the physical conditions, there is life. What we previously thought of as insurmountable physical and chemical barriers to life, we now see as yet another niche harbouring 'extremophiles'. This realization, coupled with new data on the survival of microbes in the space environment and modelling of the potential for transfer of life between celestial bodies, suggests that life could be more common than previously thought. Here we examine critically what it means to be an extremophile, and the implications of this for evolution, biotechnology and especially the search for life in the Universe.

Animals↗
PubMed2006

The effects of distraction on prospective remembering following traumatic brain injury assessed in a simulated naturalistic environment.

The aim of this investigation was to assess deficits in prospective remembering following chronic traumatic brain injuries (TBI), under conditions of high and low distraction. We constructed a virtual shopping precinct from photographs, sounds, and video segments linked together. The street was divided into halves, a low distraction zone and a high distraction zone (with increased visual and auditory noise). Twenty persons with TBI (7 severe, 7 very severe, 6 extremely severe) and 20 matched controls completed ongoing and prospective memory tasks while "walking" along the street. In the ongoing task, participants were given ten errands to complete with a checklist accessible at any time. The prospective component required responding to three targets that appeared repeatedly. As predicted, the TBI group performed both the ongoing and the prospective components of the street task poorly compared with the controls and was more affected by distractions. The results suggest that the real-life deficits in memory skills reported by persons with TBI may become more apparent when remembering engages executive processes and that computer simulations can be used to construct sensitive measures of practical memory abilities.

Acoustic Stimulation↗