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PubMed2003

Food handling behaviors of special importance for pregnant women, infants and young children, the elderly, and immune-compromised people.

This study used a Web-based Delphi process with a group of nationally recognized food safety experts to identify food-handling behaviors of special importance in reducing the risk of foodborne illness among pregnant women, infants and young children, elderly people, and people with compromised immune systems because of disease or pharmacologic therapy. Behaviors were related to 13 pathogens. Top-rated behaviors for pregnant women were associated with Listeria monocytogenes, Toxoplasma gondii, and Salmonella species. Top-rated behaviors for infants and young children, elderly people, and immune-compromised people were associated with a number of different pathogens. The results should help dietetics professionals and community health educators focus their efforts on those behaviors of special importance to the population being targeted.

Age Factors↗
PubMed2005

Efferent connections of the "olfactostriatum": a specialized vomeronasal structure within the basal ganglia of snakes.

The olfactostriatum is a portion of the basal ganglia of snakes that receives substantial vomeronasal afferents through projections from the nucleus sphericus. In a preceding article, the olfactostriatum of garter snakes (Thamnophis sirtalis) was characterized on the basis of chemoarchitecture (distribution of serotonin, neuropeptide Y and tyrosine hydroxylase) and pattern of afferent connections [Martinez-Marcos, A., Ubeda-Banon, I., Lanuza, E., Halpern, M., 2005. Chemoarchitecture and afferent connections of the "olfactostriatum": a specialized vomeronasal structure within the basal ganglia of snakes. J. Chem. Neuroanat. 29, 49-69]. In the present study, its efferent connections have been investigated. The olfactostriatum projects to the main and accessory olfactory bulbs, lateral cortex, septal complex, ventral pallidum, external, ventral anterior and dorsolateral amygdalae, bed nucleus of the stria terminalis, preoptic area, lateral posterior hypothalamic nucleus, ventral tegmental area, substantia nigra and raphe nuclei. Tracer injections in the nucleus accumbens proper, a structure closely associated with the olfactostriatum, result in a similar pattern of efferent connections with the exception of those reaching the main and accessory olfactory bulbs, lateral cortex, external, ventral anterior and dorsolateral amygdalae and bed nucleus of the stria terminalis. These data, therefore, help to characterize the olfactostriatum, an apparently specialized area of the nucleus accumbens. Double labeling experiments after tracer injections in the nucleus sphericus and the lateral posterior hypothalamic nucleus demonstrate a pathway between these two structures through the olfactostriatum. Injections in the olfactostriatum and in the medial amygdala show parallel projections to the lateral posterior hypothalamic nucleus. Since this hypothalamic nucleus has been previously described as projecting to the hypoglossal nucleus, both, the medial amygdala and the olfactostriatum may mediate vomeronasal influence on tongue-flick behavior.

Amygdala↗
PubMed2004

Discovery of a highly-specialized plesiadapiform primate in the early-middle Eocene of northwestern Africa.

In this paper we report the first occurrence of an endemic African plesiadapiform primate from the early-middle Eocene locality of Glib Zegdou (Hammada du Dra, Algeria). Dralestes (new genus) is a very specialized taxon, and its closest known relative is the enigmatic and controversial genus Azibius from Gour Lazib (Hammada du Dra). We group both together as the Azibiidae (new rank). Dralestes provides the first evidence of the upper dentition in this group. Some critical dental characters, such as a postprotocingulum on upper teeth, consistently reveal a primate status for the azibiids. Dralestes exhibits, however, a very unusual configuration of the upper molars by the enlarged parastyle, the lack of a metaconule, and the ectoloph structure (preparacrista, centrocrista and postmetacrista are aligned in a high blade-like structure). The apparent dental specializations of both lower premolars and molars of azibiids (exaenodonty, large P(4) bearing sharp apical cusps, and M(1) having a highly elongated trigonid) point to potential relationships with Chronolestes and carpolestid plesiadapiforms. A phylogenetic analysis, performed on 55 dental characters scored for 19 primate genera, clarifies the euprimate status of Altiatlasius, and thus indicates that azibiids are the only known plesiadapiforms from Africa. Azibiids are the sister group of the clade carpolestids/Chronolestes in the superfamily Plesiadapoidea. However, the azibiids differ fundamentally from carpolestids by the combined lack of a centroconule and multiple buccal cusps on P(4). The exact position of both Chronolestes and azibiids in the plesiadapoids appears difficult to resolve. A basal position of Chronolestes in this superfamily cannot be ruled out because it exhibits a simple morphology of I(1) and no conule on P(3). Considering this ad hoc hypothesis, azibiids are found to lie outside a clade including carpolestids/plesiadapids/saxonellids, and they are the sister group to Chronolestes. The clade including the carpolestid, saxonellid, and plesiadapid families is characterized by the occurrence of a centroconule on P(3-4). The lack of this trait in Dralestes and Chronolestes could mean that azibiids are basal plesiadapoids that diverged before the evolution of the common ancestor of the three derived plesiadapoid families, i.e. at least around the Paleocene-Eocene boundary or more probably during the Paleocene. The report of the first offshoot in Africa of plesiadapoids enhances the role of Africa in the early primate radiation.

Algeria↗
PubMed2004

Desire for death and requests to hasten death of Japanese terminally ill cancer patients receiving specialized inpatient palliative care.

A desire for death and requests to hasten death are major topics in recent medical literature. The aim of this study was to clarify the bereaved family-reported incidence and reasons for desiring death and requests to hasten death during the whole course of terminally ill cancer patients receiving specialized palliative care in Japan. A nationwide questionnaire survey of 500 primary caregivers yielded a total of 290 responses (effective response rate, 62%). Sixty-two (21%) families reported that the patients had expressed a desire to die, and 29 (10%) families reported that the patients had requested that death be hastened. The major reasons for desiring death and requests to hasten death were: burden on others, dependency, meaninglessness, unable to pursue pleasurable activities, general malaise, pain, dyspnea, concerns about future distress, and wish to control the time of death. No intolerable physical symptoms were reported in 32% and 28% of the patients who desired death and those who requested to hasten death, respectively. Concerns about future distress and wishes to control the time of death were significantly more likely to be listed as major reasons for desiring death in patients who requested that death be hastened than those who did not. A desire for death and requests to hasten death are not uncommon in terminally ill cancer patients receiving specialized inpatient palliative care in Japan. More intensive strategies for general malaise, pain, and dyspnea near the end of life, and for feelings of being a burden, meaninglessness, and concerns about future distress would alleviate the serious suffering of patients with a desire for death. However, some patients with a strong wish to control the time of death might not receive benefit from conventional palliative care.

Adult↗
PubMed2005

Ethical validity of palliative sedation therapy: a multicenter, prospective, observational study conducted on specialized palliative care units in Japan.

Although palliative sedation therapy is often required in terminally ill cancer patients to achieve acceptable symptom relief, empirical data supporting the ethical validity of this approach are lacking. The primary aim of this study was to systematically investigate whether empirical evidence supports the ethical validity of sedation. This was a multicenter, prospective, observational study, which was conducted by 21 specialized palliative care units in Japan. One-hundred two consecutive adult cancer patients who received continuous deep sedation were enrolled. Continuous deep sedation was defined as the continuous use of sedative medications to relieve intolerable and refractory distress by achieving almost or complete unconsciousness until death. Prior to the study, we conceptualized the ethical validity of sedation from the viewpoints of physicians' intent, proportionality, and autonomy. Sedation was performed mainly with midazolam and phenobarbital. The initial doses of midazolam and phenobarbital were 1.5 mg/hour and 20 mg/hour, respectively. Main administration routes were continuous subcutaneous infusion and continuous intravenous infusion, and no rapid intravenous injection was reported. Of 59 patients who received artificial hydration or could intake adequate fluids/foods orally before sedation, 63% received artificial hydration therapy after sedation, and in the remaining patients, artificial hydration was withheld or withdrawn due to fluid retention symptoms and/or patient wishes. Of 66 patients who were able to verbally express themselves, 95% explicitly stated that symptoms were intolerable. The etiologies of the symptoms requiring sedation were primarily related to the progression of the underlying malignancy, such as cancer cachexia and organ failure, and standard palliative treatments had failed: steroids in 68% of patients with fatigue, opioids in 95% of patients with dyspnea, antisecretion medications in 75% of patients with bronchial secretion, antipsychotic medications in 74% of patients with delirium, and opioids in all patients with pain. On the basis of the Palliative Prognostic Index, 94% of the patients were predicted to die within 3 weeks. Before sedation, 67% of the patients expressed explicit wishes for sedation. In the remaining 34 patients, previous wishes for sedation were noted in 4 patients, and in the other 30 patients, the families were involved in the decision-making process. The chief reason for patient non-involvement in the decision making was cognitive impairment. These data indicate that palliative sedation therapy performed in specialized palliative care units in Japan generally followed the principles of double effect, proportionality, and autonomy.

Adult↗
PubMed2006

Are mistakes inevitable? Sex allocation specialization by workers can reduce the genetic information needed to assess queen mating frequency.

Insect workers can increase their inclusive fitness by biasing colony sex allocation towards males when their mother queen is mated to multiple males and females when she is singly mated. Workers need heritable variation in odour diversity to assess queen mating frequency. Here we present a simple one-locus two-allele model, which shows that the sex ratio specialization itself will often select against rare alleles that would provide additional information for the assessment of queen mating frequency. However, under certain rather restricted conditions, such as when sex ratios are highly female biased, and when worker reproduction is rare, sex ratio specialization can select for rare alleles. This suggests that sex allocation biasing by workers will usually reduce the very information that workers need to assess queen mating frequency. Our model is an example where an explicit treatment of underlying genetics and mechanisms of behaviour, such as information use, is necessary to fully understand the evolution of an adaptive behavioural strategy.

Alleles↗
PubMed2005

When do mixotrophs specialize? Adaptive dynamics theory applied to a dynamic energy budget model.

In evolutionary history, several events have occurred at which mixotrophs specialized into pure autotrophs and heterotrophs. We studied the conditions under which such events take place, using the Dynamic Energy Budget (DEB) theory for physiological rules of the organisms' metabolism and Adaptive Dynamics (AD) theory for evolutionary behavior of parameter values. We modeled a population of mixotrophs that can take up dissolved inorganic nutrients by autotrophic assimilation and detritus by heterotrophic assimilation. The organisms have a certain affinity for both pathways; mutations that occur in the affinities enable the population to evolve. One of the possible evolutionary outcomes is a branching point which provides an opportunity for the mixotrophic population to split up and specialize into separate autotrophs and heterotrophs. Evolutionary branching is not a common feature of the studied system, but is found to occur only under specific conditions. These conditions depend on intrinsic properties such as the cost function, the level of the costs and the boundaries of the trait space: only at intermediate cost levels and when an explicit advantage exists to pure strategies over mixed ones may evolutionary branching occur. Usually, such an advantage (and hence evolutionary branching) can be induced by interference between the two affinities, but this result changes due to the constraints on the affinities. Now, only some of the more complicated cost functions give rise to a branching point. In contrast to the intrinsic properties, extrinsic properties such as the total nutrient content or light intensity were found to have no effect on the evolutionary outcomes at all.

Adaptation, Physiological↗
PubMed2004

Shape perception in human vision: specialized detectors for concentric spatial structures?

It has been suggested that second-order shape integration mechanisms in human spatial vision (e.g. the neurons at V2 and V4 cortical areas) may contain specialized detectors for concentric shapes [Vision Res. 37 (1997) 2325; Vision Res. 38 (1998) 2933]. We tested this notion using psychophysical techniques in which the observers' task was to detect orientation noise (randomly oriented dot pairs) in concentric and linear Glass patterns. Our results showed that the detection of orientation noise was easier in concentric Glass patterns, thus supporting the notion of specialized detectors.

Analysis of Variance↗
PubMed2005

Specialization in pyramidal cell structure in the cingulate cortex of the Chacma baboon (Papio ursinus): an intracellular injection study of the posterior and anterior cingulate gyrus with comparative notes on the macaque and vervet monkeys.

This study forms part of an ongoing investigation of pyramidal cell structure in the cingulate cortex of primates. Recently we have demonstrated that layer III pyramidal cells in the anterior cingulate gyrus are considerably larger, more branched and more spinous than those in the posterior cingulate gyrus (areas 24 and 23, respectively) in the macaque and vervet monkeys. Moreover, the extent of the interareal difference in specialization in pyramidal cell structure differed between the two species. These data suggest that pyramidal cell circuitry may have evolved differently in these closely related species. Presently there are too few data to speculate on what is selecting for this specialization in structure. Here we extend the basis for comparison by studying pyramidal cell structure in cingulate gyrus of the Chacma baboon (Papio ursinus). Methodology used here is the same as that for our previous studies: intracellular injection of Lucifer Yellow in flat-mounted cortical slices. We found that pyramidal cells in anterior cingulate gyrus (area 24) were more branched and more spinous than those in posterior cingulate gyrus (area 23). Moreover, the complexity in pyramidal cell structure in both the anterior and posterior cingulate gyrus of the baboon differed to that in the corresponding regions in either the macaque or vervet monkeys.

Animals↗
PubMed2005

A functional neural network computing some eigenvalues and eigenvectors of a special real matrix.

How to quickly compute eigenvalues and eigenvectors of a matrix, especially, a general real matrix, is significant in engineering. Since neural network runs in asynchronous and concurrent manner, and can achieve high rapidity, this paper designs a concise functional neural network (FNN) to extract some eigenvalues and eigenvectors of a special real matrix. After equivalent transforming the FNN into a complex differential equation and obtaining the analytic solution, the convergence properties of the FNN are analyzed. If the eigenvalue whose imaginary part is nonzero and the largest of all eigenvalues is unique, the FNN will converge to the eigenvector corresponding to this special eigenvalue with general nonzero initial vector. If all eigenvalues are real numbers or there are more than one eigenvalue whose imaginary part equals the largest, the FNN will converge to zero point or fall into a cycle procedure. Comparing with other neural networks designed for the same domain, the restriction to matrix is very slack. At last, three examples are employed to illustrate the performance of the FNN.

Algorithms↗
PubMed2004

Hemispheric specialization of the lateral prefrontal cortex for strategic processing during spatial and shape working memory.

OBJECTIVE: We investigated whether spatial working memory (WM) is associated with functional specialization of the right prefrontal cortex (PFC) relative to WM for shapes. We designed spatial and shape WM tasks that are relatively easy to perform and that minimize both task-switching and manipulation demands. The tasks use identical stimuli and require the same motor response. METHODS: We presented 12 subjects with target shapes that appeared in particular locations. Subjects maintained either the location or the shape of the targets in WM and responded to each probe by indicating whether it was a target. During a non-WM control task, subjects indicated whether the probe appeared on the right or left side of the screen. Subjects were scanned with a 3.0 T Siemens scanner and data were analyzed using SPM99. The WM tasks were compared to identify PFC activation that was different for spatial versus shape WM. Each WM task was also compared to the control task. RESULTS: compared with shape WM, spatial WM performance was faster and more accurate and was associated with increased right ventrolateral and frontopolar PFC activation. In contrast, compared to spatial WM, shape WM was associated with increased left ventrolateral PFC activity. CONCLUSIONS: These findings demonstrate hemispheric specialization for spatial versus shape WM in the ventrolateral PFC. The increased activity in the right PFC for spatial WM cannot be attributed to increased task difficulty, the stimuli used, or the response requirements. Rather, we propose that differences in performance and activation reflect the use of configural processing strategies for spatial WM.

Adult↗
PubMed2004

Cerebral regions and hemispheric specialization for processing spatial frequencies during natural scene recognition. An event-related fMRI study.

It has been suggested that visual scene recognition is mainly based on spatial frequency (Fourier) analysis of the image. This analysis starts with processing low spatial frequencies (LSF), followed by processing high spatial frequencies (HSF). Within the framework of the spatial frequency analysis, the right/left hemisphere would be predominantly involved in LSF/HSF analysis, respectively. The aim of this event-related fMRI study was to evaluate neural correlates and hemispheric specialization of spatial frequency analysis during recognition of nonfiltered (NF) and filtered, either in LSF or HSF, natural scenes. Comparing LSF or NF to HSF scene recognition, significant activation was obtained within right anterior temporal cortex and right parahippocampal gyrus. As these regions are known to be involved in scene processing, we interpret this result as suggesting that scene recognition is mainly based on LSF extraction and analysis. When LSF scene was compared to HSF scene recognition, supplementary activation was obtained within the right inferior parietal lobule that likely reflects attentional modulation on spatial frequency processing. A direct interhemispheric comparison for each particular band of spatial frequencies highlighted predominance within the early visual areas (such as the middle occipital gyrus) to the right for LSF processing and to the left for HSF processing. This result provides supplementary evidence for hemispheric specialization at early levels of visual analysis when spatial frequencies are processed.

Adult↗
PubMed2005

Hemispheric specialization of human inferior temporal cortex during coarse-to-fine and fine-to-coarse analysis of natural visual scenes.

Recent models of visual recognition have suggested that perceptual analysis may start with a parallel extraction of different spatial frequencies (SF), using a preferential coarse-to-fine (low-to-high SF) sequence of processing. A rapid extraction of low spatial frequency (LSF) information may thus provide an initial and crude parsing of the visual scene, subsequently refined by slow but more detailed high spatial frequency (HSF) information. However, the sequence of SF analysis could be flexible, a high-to-low (HtL) being sometimes preferred to a low-to-high (LtH) SF sequence depending on task demands. Furthermore, it has also been suggested that the right vs. left hemisphere might be differentially specialized in LSF vs. HSF analysis, respectively. By manipulating the temporal succession of LSF and HSF stimuli, the present fMRI study investigated whether such hemispheric specialization may underlie the flexible use of different time-course in SF analysis. Participants performed a matching task between two successive images of natural scenes (LSF or HSF) that were displayed either in an LtH (LSF scene presented first and HSF scene second) or in a reverse HtL sequence. A direct inter-hemispheric comparison of the neural responses evoked by each SF sequence revealed greater activations within the right occipito-temporal cortex for the LtH sequence and within the left occipito-temporal cortex for the HtL sequence. These fMRI results suggest that the hemisphere preferentially engaged during the sequential processing of different SF might be determined by the initial SF-band appearing in this sequence, and that both a coarse-to-fine and fine-to-coarse analysis might independently take place in the two hemispheres.

Adult↗
PubMed2006

The processing of prosody: Evidence of interhemispheric specialization at the age of four.

Beyond its multiple functions in language comprehension and emotional shaping, prosodic cues play a pivotal role for the infant's amazingly rapid acquisition of language. However, cortical correlates of prosodic processing are largely controversial, even in adults, and functional imaging data in children are sparse. We here use an approach which allows to experimentally determine brain activations correlating to the perception and processing of sentence prosody during childhood. In 4-year-olds, we measured focal brain activation using near-infrared spectroscopy and demonstrate that processing prosody in isolation elicits a larger right fronto-temporal activation whereas a larger left hemispheric activation is elicited by the perception of normal language with full linguistic content. Hypothesized by the dual-pathway-model, the present data provide experimental evidence that in children specific language processes rely on interhemispheric specialization with a left hemispheric dominance for processing segmental (i.e. phonological) and a right hemispheric dominance for processing suprasegmental (i.e. prosodic) information. Generally in accordance with the imaging data reported in adults, our finding underlines the notion that interhemispheric specialization is a continuous process during the development of language.

Brain↗
PubMed2005

Auditory hair cell-afferent fiber synapses are specialized to operate at their best frequencies.

Auditory afferent fiber activity is driven by high-fidelity information transfer from the sensory hair cell. Presynaptic specializations, posited to maintain fidelity, are investigated at synapses with characteristic frequencies of 120 Hz and 320 Hz. Morphological data indicate that high-frequency cells have more synapses and higher vesicle density near dense bodies (DBs). Tracking vesicular release via capacitance changes identified three overlapping kinetic components of release corresponding to morphologically identified vesicle pools. High-frequency cells released faster; however, when normalized to release site number, low-frequency cells released faster, likely due to a greater Ca2+ load per synapse. The Ca(2+)-dependence of release was nonsaturating and independent of frequency, suggesting that release, not refilling, was rate limiting. A model of release derived from vesicle equilibration between morphologically defined pools reproduced the capacitance data, supporting a critical role in vesicle trafficking for DBs. The model suggests that presynaptic specializations enable synapses to operate most efficiently at their characteristic frequencies.

Animals↗
PubMed2005

Specialization in pyramidal cell structure in the sensory-motor cortex of the vervet monkey (Cercopethicus pygerythrus).

Recent studies have revealed systematic differences in the pyramidal cell structure between functionally related cortical areas of primates. Trends for a parallel in pyramidal cell structure and functional complexity have been reported in visual, somatosensory, motor, cingulate and prefrontal cortex in the macaque monkey cortex. These specializations in structure have been interpreted as being fundamental in determining cellular and systems function, endowing circuits in these different cortical areas with different computational power. In the present study we extend our initial finding of systematic specialization of pyramidal cell structure in sensory-motor cortex in the macaque monkey [Cereb Cortex 12 (2002) 1071] to the vervet monkey. More specifically, we investigated pyramidal cell structure in somatosensory and motor areas 1/2, 5, 7, 4 and 6. Neurones in fixed, flat-mounted, cortical slices were injected intracellularly with Lucifer Yellow and processed for a light-stable 3,3'-diaminobenzidine reaction product. The size of, number of branches in, and spine density of the basal dendritic arbors varied systematically such that there was a trend for increasing complexity in arbor structure with progression through 1/2, 5 and 7. In addition, cells in area 6 were larger, more branched, and more spinous than those in area 4.

Animals↗
PubMed2006

New endoscopic technique to analyze various modern specialized intraocular lenses in research eyes and human eyes obtained postmortem.

PURPOSE: To describe a new modification of the Miyake-Apple posterior video photographic technique and its 2 variations. We have developed a new endoscopic technique that is especially amenable for observation of modern specialized intraocular lenses (IOLs). DESIGN: Laboratory study. PARTICIPANT: Three cadaver eyes obtained postmortem. METHODS: Human eyes obtained postmortem were prepared according to our modified preparation technique used for analyses of whole globes. An intraocular endoscope was utilized to demonstrate all aspects of the interior of an experimentally implanted IOL, with specialized reference to anterior segment structures, obtaining posterior, oblique, and side view images. MAIN OUTCOME MEASURES: Different interior dynamic views of the anterior segment structures before and after implantation of an IOL. RESULTS: High-magnification images of different intraocular structures both before and after device insertion as well as the device itself were obtained. Oblique and side view images from different locations were also available and informative. These images helped to create a 3-dimensional view of these objects and their relations to the surrounding structures. CONCLUSION: The combination of the intraocular endoscope with the closed-system technique is a useful addition to our 3 previously described techniques: (1) the original Miyake-Apple posterior video/photograph technique and the (2) closed system and (3) side/oblique view (keyhole technique) modifications.

Anterior Eye Segment↗
PubMed2006

An evidence-based approach to nasogastric tube management: special considerations.

Although there have been helpful literature reviews on pediatric nasogastric (NG) tube management, there is a lack of evidence with regards to special circumstances, such as at-risk patients with altered neurological status or developmental disabilities. At our hospital, an interdisciplinary Enteral Feeding Task Force was created to address the special needs and concerns of complex pediatric patients. We carefully weighed the evidence from the literature, incidents at our hospital and other children's hospitals, and a synthesis of expert opinion. This article describes our evidence-based process of policy revision, and it includes excerpts from our revised NG tube management policy.

Benchmarking↗