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PubMed1981

Ultrastructural analysis of hyphal tip cell growth in fungi: Spitzenkörper, cytoskeleton and endomembranes after freeze-substitution.

The ultrastructure of freeze-substituted tip cells of Fusarium acuminatum was analysed by conventional and high-voltage transmission electron microscopy (HVEM). At least 2 morphologically distinct types of Golgi-like endomembrane cisternae were observed, each existing as single, fenestrated sheets and tubular elements that were often very closely associated with mitochondria. From HVEM observations of thick (0.25 and 0.5 micron) sections, the Spitzenkörper appeared to correspond to an apical mass of vesicles. A network of microfilaments was identified among component vesicles of the Spitzenkörper and adjacent to developing septa. Microtubules were oriented primarily parallel to the direction of hyphal growth and were located in all areas of the cytoplasm, including the tip cell apex. Cytoplasmic vesicles were closely associated with these microtubules. From these observations it is suggested that cytoskeletal elements play important roles in localized cell wall formation. The filasome, a previously unreported type of coated vesicle in fungi, might also be involved in wall synthesis.

Cytoskeleton↗
PubMedDate not supplied

[Epidemiologic study of S. haematobium bilharziasis in the rice fields of Yagoua (North Cameroon) II. Distribution and ecology of intermediate hosts].

While inventoring the local malacological fauna and evaluating the density of species acting as intermediate hosts of human schistosomes it has been shown that Bulinus truncatus is predominant in the study area. Bulinus globosus is scarcely encountered. Biomphalaria pfeifferi is only found in the Mayo Guerleo, in irrigation canals and draining ditches. But B. globosus and B. pfeifferi have not yet invaded the recent aquatic network and are not found in the lake nor in the newly created irrigation systems. Snails shedding cercariae of S. haematobium and S. mansoni have been collected in the area. Bulinus forskalii is found in all types of permanent of temporary waterbodies but S. intercalatum has not yet been reported from North-Cameroon. Lymnaea natalensis, the intermediate host of Fasciola gigantica, is found in the lake and in the canals, in the Mayo Guerleo and in the Toupasko pool. The rice field does not form by itself a favorable environment for snails to develop in it. Spots where transmission occurare more often in the area the secondary of tertiary irrigation canals and the brains. The ditches obstructed by plants are the places where the snails are developing best. Bulinus spp. are found in large numbers in the lowest parts of the aquatic network and they accumulate there to survive drought conditions in the mud. The recently built irrigation systems are not massively invaded by the snails yet and the prevalence of bilharziasis in the area correspond to the distribution of the intermediate hosts of schistosomes and to the density of the snails populations.

Agriculture↗
PubMed2006

Exploring Aboriginal people's experience of relocation for treatment during end-of-life care.

AIM: to explore indigenous peoples' experience of relocation for medical treatment during end-of-life care. METHODS: the data were collected from 72 qualitative interviews conducted throughout the regional, rural and remote areas of the Northern Territory, Australia, with Aboriginal patients and carers and the health professionals who cared for them. RESULTS: relocation for indigenous peoples is a frightening experience. There are a myriad of fears including: the fear of leaving home, especially for people who had never been away from their home lands; the fear of dis-empowerment associated with leaving the support of family networks; fears about hospital environments and 'high-tech' treatments; fear of cultural alienation for familiar foods and ways of being; fear of travel; fear of loneliness; fear of language and communication barriers; financial fears; and fear of dying away from the homeland. CONCLUSION: the findings demonstrate the strong need for building-up local palliative care services and raise significant questions about the cultural appropriateness of the Western biomedical rationale for relocation during end-of-life care.

Cross-Sectional Studies↗
PubMed1995

Growth rates or radiobiological hypoxia are not correlated with local metabolite content in human melanoma xenografts with similar vascular network.

Investigations were carried out on two lines of human melanomas (MF; n = 12 and EE; n = 13) xenografted in nude mice. The tumours were characterised by a similar vascular supply but showed a pronounced difference in the rate of volume growth and in the radiobiologically hypoxic fraction. The distribution of ATP, glucose and lactate in the tumours was investigated using quantitative bioluminescence and single photon imaging. Concentrations of the metabolites were obtained as global values for the entire tumour mass, in regions with densely packed, structurally intact tumour cells ('viable zones'), in areas with necrosis, stromal cells and fibrous material ('necrotic zones') and in adjacent normal tissue. In all melanomas investigated glucose concentrations were significantly lower and lactate concentrations were significantly higher than in normal tissue. In contrast, no significant differences for ATP were detected. ATP and glucose concentrations were significantly less in necrotic than in viable tumour zones, whereas lactate concentrations were nearly equal in these tumour parts. Corresponding results were obtained in central versus peripheral tumour zones. There was no dependency of global or regional metabolite concentrations on tumour size within the volume range 110-1470 mm3. Based on this lack of dependency, metabolic concentrations were averaged over the whole tumour size range. Metabolite concentrations were not significantly different either globally or regionally between the two tumour entities investigated, a finding which held true for all three metabolites registered. Thus, metabolite distributions apparently mirror the similarity in vascularity of MF and EE melanomas rather than reflecting intrinsic properties with regard to tumour growth rates or susceptibility to radiation.

Adenosine Triphosphate↗
PubMed1998

Pathways of dependence: the impact of health and social care restructuring--the voluntary experience.

The current emphasis on community over institutionally based modes of health and social care delivery in the UK, together with legislative change, has placed a renewed emphasis on the role of the informal sector in service provision. Simultaneously, there has been an attempt to modify the provider-role of the statutory sector, in favour of an evolving role as purchaser and enabler of independently provided services. Drawing on material that forms part of a 3 year study into health and social care restructuring, and its effect on the caring networks of elderly dependent populations, this paper focuses on the changing role of the voluntary sector. Using empirical material drawn from the Scottish environment, it illustrates how the restructuring process may be modifying the voluntary sector and contributing to a growth in geographical inequity in voluntary service provision. In doing so, it considers four main factors affecting local voluntary organisations--the growth of contracting, external constraints on voluntary provisioning, the influence of the local authority and Wolch's concept of the "Shadow State". It highlights the emerging social and spatial manifestations arising from such change, and how these modifications may also be contributing to a growth in geographical inequity for service recipients linked within the dependence network.

Catchment Area, Health↗
PubMed1999

Intracellular localization and in vivo trafficking of p24A and p23.

Recently, p24A and p23 (also termed Tmp21), two members of the p24 protein family, have been proposed to function as integral receptors for the COPI-vesicle coat. This study describes the intracellular localization and trafficking of p24A in comparison to p23. For immunolocalization of p24A and p23, strong reduction and denaturation conditions were necessary to allow antibody interaction. Both p24A and p23 cycle continuously between intermediate compartment (IC) elements and the cis-Golgi network. In vivo trafficking of p24A and p23 tagged to green fluorescent protein (GFP) revealed that both proteins travel by large (up to 1 micrometer in length) microtubule-dependent pre-Golgi carriers with a maximum speed of up to 1.6 micrometer s-1 from the IC to the Golgi cisternae. Aluminum fluoride, a general activator of heterotrimeric G-proteins, blocked peripheral pre-Golgi movements of GFP-p24A/p23 and inhibited fluorescence recovery after photobleaching in the perinuclear Golgi area. p24A and p23 are predominantly colocalized. Overexpression of GFP-p24A, to an extent which did not destroy the Golgi complex, induced delocalization of part of the proteins into ER elements. This study therefore gives new insights into the localization and trafficking behavior of the two COPI-binding proteins p24A and p23.

Aluminum Compounds↗
PubMed2006

Multicentre study on hand hygiene facilities and practice in the Mediterranean area: results from the NosoMed Network.

Hand hygiene literature is scarce in the southern Mediterranean area. In order to establish a baseline position, a study was performed in four Mediterranean countries. Seventy-seven hospital wards in 22 hospitals were enrolled and information on hand hygiene practice and facilities were collected. The overall compliance rate was very low (27.6%), and was significantly higher where the perceived risk was considered to be high. Intensive care units showed the highest level of compliance. Analysis by country indicated higher compliance in Egypt (52.8%) and Tunisia (32.3%) compared with Algeria (18.6%) and Morocco (16.9%). Facilities for hand hygiene, particularly consumables, were shown to be deficient. Multi-approach programmes combining the production of official local recommendations, education and regular evaluation of hand hygiene practice are much needed to improve the present situation.

Africa, Northern↗
PubMed1991

The place of health in the health of place: the case of the Hokianga special medical area.

Contemporary models of health have broadened the concept so that health includes, but is not exclusively, biomedical wellness. One concern arising from this widened perspective is the degree to which health service provision promotes healthier, more convivial communities. This paper examines the contribution of health services to the experience of place in the Hokianga, an isolated and predominantly Maori area of New Zealand. While other public services are being increasingly privatised, charged to users and restructured to central nodes of provision, health care in the Hokianga remains free and delivered within a network of community clinics. It is argued that the taking of health care into communities both enhances the wellness of the population and positively enhances the experience of place for local residents.

Attitude to Health↗
PubMed2004

Morphology, development and comparative anatomical evaluation of the testicular excretory pathway in Acipenser.

In the differentiated state, the testicular excurrent duct system of the sturgeon begins as a longitudinal marginal network of the testis, extending along the entire length of the male gonad. From here, mesorchial transversal ducts travel to the ventral aspect of the pars sexualis of the opisthonephros where they merge behind the dorsal coelomic wall to form the longitudinal marginal network of the kidney. Then, the seminal pathways enter the confines of the pars sexualis of the opisthonephros and divide into a complicated, multipartite system consisting of (1) centropapillary ducts, situated in the center of a group of urinary collecting ducts, (2) lacunary basal sinuses, located on the bases of opisthonephric columns and (3) intracolumnar ducts running inside the renal columns, the latter representing typical functional units of the adult sturgeon kidney. The contacts between intracolumnar ducts and the vascular poles of corresponding renal corpuscles represent the urogenital junction in the sturgeon. The nephrons of the pars sexualis involved in sperm transport do not lose their urinary functions, but are histologically identical to those of the pars excretoria which are solely urinary. The opisthonephros of sturgeons grows continuously by the formation of new nephrons from an opisthonephric blastema located on the base of each renal column. A close topographical association between this blastema tissue and the lacunary basal sinuses of the testicular excurrent duct system guarantees that new renal corpuscles in the pars sexualis are included in the seminal passage from their beginning. From the urogenital junctions, on their way to the exterior, the spermatozoa have to travel through Bowman's capsules and tubules of the nephrons involved, then through the urinary collecting ducts, the wolffian duct and finally the sinus urogenitalis. The development of the testicular excurrent duct system begins in 8-month-old animals in the pregonadal area of the gonadal fold. Here, a primary gonoductal blastema proliferates to form a longitudinal network of anastomosing strands, situated in the dorsal mesogonadal attachment. From this primary longitudinal network, small tubules grow into the direction of the opisthonephros and into the direction of the testis. In the period from 8 to 18 months, the testicular excurent duct system reaches the adult state. In conclusion, the testicular excurrent ducts of sturgeons initially develop similar to those of Polypterus and in modern teleosts from a primary longitudinal system, beginning in the pregonadal area, localized in the mesogonadal attachment and extending caudally. Then, in a second step of development, the phylogenetically older situation, using parts of the kidney as passage, already seen in Chondrichthyes, but preserved also in higher vertebrates, is achieved in Acipenser. For this, seminal ducts grow into the opisthonephros and establish here the urogenital junctions with corresponding renal corpuscles. Furthermore, the initially longitudinally oriented ducts in the mesogonadal attachment partly lose their continuity and become integrated into the course of the transversal mesorchial ducts, represented by their portions with the widest lumina and the thickest walls.

Animals↗
PubMed1998

Family history of cancer and risk of colorectal cancer in Italy.

Subjects with a family history of colorectal cancer (CRC) are at increased risk of CRC, but quantification of the risk in different populations, the possible differences in risk according to localization of the cancer and the association of family history of other cancers with CRC risk are still open issues. We have therefore analysed data from a multicentric case-control study conducted in six Italian areas between 1992 and 1996 of 1225 incident cases of colon cancer, 728 cases of rectal cancer and 4154 controls admitted for acute conditions to the same network of hospitals as the cases. Unconditional logistic regression models including terms for gender, age, study centre, years of education and number of siblings were used to estimate the odds ratios (ORs) of CRC according to various aspects of history of CRC and other cancers in first-degree relatives. The OR for family history of CRC was 3.2 (95% confidence interval, CI, 2.5-4.1) for colon cancer and 2.2 (95% CI 1.6-3.1) for rectal cancer. Colon cancer was significantly associated with a family history of stomach (OR 1.4), bone (OR 2.1) and kidney (OR 2.3) cancers, while rectal cancer was significantly associated with a family history of lymphomas (OR 2.8). There was a 30% higher risk of colon and rectal cancer in subjects with a family history of any cancer, excluding intestine. The ORs for family history of CRC were 5.2 for colon and 6.3 for rectum when the proband's age was below 45 years. The ORs were similar when the affected relative was a parent or a sibling and in different strata of age of relative(s). For subjects with two or more first-degree relatives with CRC, the risk was 6.9 for the right colon, 5.8 for the transverse and descending colon, 3.8 for the sigma, 3.2 for the rectosigmoid junction and 1.9 for the rectum. This study confirms that a family history of CRC in first-degree relatives increases the risk of both colon and rectal cancer, the association being stronger at younger ages and for right colon.

Adult↗
PubMed2003

Closed-loop neuronal computations: focus on vibrissa somatosensation in rat.

Two classes of neuronal architectures dominate in the ongoing debate on the nature of computing by nervous systems. The first is a predominantly feedforward architecture, in which local interactions among neurons within each processing stage play a less influential role compared with the drive of the input to that stage. The second class is a recurrent network architecture, in which the local interactions among neighboring neurons dominate the dynamics of neuronal activity so that the input acts only to bias or seed the state of the network. The study of sensorimotor networks, however, serves to highlight a third class of architectures, which is neither feedforward nor locally recurrent and where computations depend on large-scale feedback loops. Findings that have emerged from our laboratories and those of our colleagues suggest that the vibrissa sensorimotor system is involved in such closed-loop computations. In particular, single unit responses from vibrissa sensory and motor areas show generic signatures of phase-sensitive detection and control at the level of thalamocortical and corticocortical loops. These loops are likely to be components within a greater closed-loop vibrissa sensorimotor system, which optimizes sensory processing.

Afferent Pathways↗
PubMed2005

A magnetoencephalography spatiotemporal analysis of neural activities during feature binding.

Previous literature shows that feature binding processes elicit fronto-hippocampal areas. The time course of this process, however, remains unknown. This is the first study that investigates feature binding using magnetoencephalography. Synthetic aperture magnetometry analysis was used to localize sources of increased power in the theta band during the encoding phases of a feature-binding task in the left and right medial frontal gyri (Brodmann's area 10) and left and right anterior cingulate gyri. Theta band synchronization was observed in many of these same areas, but also in other areas not noted to have increased theta band power suggesting a broad network of regions subserving the encoding phase of feature binding.

Adult↗
PubMed2005

Without nerves, immunology remains incomplete -in vivo veritas.

Interest in the interactions between nervous and immune systems involved in both pathological and homeostatic mechanisms of host defence has prompted studies of neuroendocrine immune modulation and cytokine involvement in neuropathologies. In this review we concentrate on a distinct area of homeostatic control of both normal and abnormal host defence activity involving the network of peripheral c-fibre nerve fibres. These nerve fibres have long been recognized by dermatologists and gastroenterologists as key players in abnormal inflammatory processes, such as dermatitis and eczema. However, the involvement of nerves can all too easily be regarded as that of isolated elements in a local phenomenon. On the contrary, it is becoming increasingly clear that neural monitoring of host defence activities takes place, and that involvement of central/spinal mechanisms are crucial in the co-ordination of the adaptive response to host challenge. We describe studies demonstrating neural control of host defence and use the specific examples of bone marrow haemopoiesis and contact sensitivity to highlight the role of direct nerve fibre connections in these activities. We propose a host monitoring system that requires interaction between specialized immune cells and nerve fibres distributed throughout the body and that gives rise to both neural and immune memories of prior challenge. While immunological mechanisms alone may be sufficient for local responsiveness to subsequent challenge, data are discussed that implicate the neural memory in co-ordination of host defence across the body, at distinct sites not served by the same nerve fibres, consistent with central nervous mediation.

Animals↗
PubMed1989

A university rural teaching practice: a model for collaboration in rural health care.

After nearly two decades of Federal, State and local incentives, primary medical services in rural areas remain for short of target. Numerous demonstration projects supported by public and private funds have had some success but models with both broad replicability and independence of external start-up and/or maintenance support are rare. The Department of Family Medicine at the State University of New York at Buffalo has established a novel collaborative network of public and private organizations to emplace a four-physician rural group practice concurrently accomplishing three major goals: high quality primary and specialty medical services to two medically underserved populations; enriched training opportunities for students, residents, and fellows; and financial viability. Beyond meeting regional needs, however, the components and nature of the collaborative effort indicate reproducibility in many communities throughout the country. To emphasize exportable features we will focus on: opportunities, operational strategies, financial feasibility, training advantages, and impact.

Academic Medical Centers↗
PubMed1999

Associative memory properties of multiple cortical modules.

The existence of recurrent collateral connections between pyramidal cells within a cortical area and, in addition, reciprocal connections between connected cortical areas, is well established. In this work we analyse the properties of a tri-modular architecture of this type in which two input modules have convergent connections to a third module (which in the brain might be the next module in cortical processing or a bi-modal area receiving connections from two different processing pathways). Memory retrieval is analysed in this system which has Hebb-like synaptic modifiability in the connections and attractor states. Local activity features are stored in the intra-modular connections while the associations between corresponding features in different modules present during training are stored in the inter-modular connections. The response of the network when tested with corresponding and contradictory stimuli to the two input pathways is studied in detail. The model is solved quantitatively using techniques of statistical physics. In one type of test, a sequence of stimuli is applied, with a delay between them. It is found that if the coupling between the modules is low a regime exists in which they retain the capability to retrieve any of their stored features independently of the features being retrieved by the other modules. Although independent in this sense, the modules still influence each other in this regime through persistent modulatory currents which are strong enough to initiate recall in the whole network when only a single module is stimulated, and to raise the mean firing rates of the neurons in the attractors if the features in the different modules are corresponding. Some of these mechanisms might be useful for the description of many phenomena observed in single neuron activity recorded during short term memory tasks such as delayed match-to-sample. It is also shown that with contradictory stimulation of the two input modules the model accounts for many of the phenomena observed in the McGurk effect, in which contradictory auditory and visual inputs can lead to misperception.

Action Potentials↗
PubMed2001

EEG frequency and phase coupling during human information processing.

Neuronal activity during information processing is represented by oscillations within local or widespread neuronal networks. These oscillations may be recorded by the EEG (electroencephalogram). The oscillatory interaction between neuronal ensembles may be at one single frequency or at different frequencies due to non-linear coupling. The investigation of momentary coherence and phase enables the examination of synchronized oscillatory network activity during fast-changing cognitive processes. On this basis information transfer from occipital areas towards frontal areas could be described during processing of visual presented words. Non-linear phase coupling between oscillations with different frequencies during memory processing was detected by means of cross-bicoherence.

Adult↗
PubMed2003

[Ecological footprint calculation and development capacity analysis of China in 1999].

The ecological footprint method put forward and improved by William Rees and Mathis Wackernagel presents a methodologically simple but integrated framework for national natural capital accounting, which is capable of measuring the impact of Human's consumption on ecosystem. Based on the ecological footprint theory and calculation method, a flow network analysis method was introduced to illuminate the structure of complex ecological economic system, and the relationship among ecological footprint, diversity and development capacity was analyzed. In this paper, the ecological footprints of China and its provinces was calculated and compared with the national and local ecological carrying capacity. The results showed that the ecological footprints of China and most of its provinces were beyond the available ecological capacity, and China and its most provinces run 'national or regional ecological deficit'. In case of China, the national ecological deficit was 0.645 hm2 per cap in 1999. Secondly, we introduced a flow network analysis method, taking various ecological productive area as note, and adopted Ulanowicz's development capacity formula to analyze the relationship among ecological footprint diversity, development capacity and output. The results demonstrated that Ulanowicz's development capacity was a good predictor of economic system output. At the same time, two distinct ways to change development capacity were produced. Increasing ecological footprint or increasing ecological footprint's diversity would both increase development capacity. Due to the fact that the ecological footprints had already been beyond bio-capacities, the only way to increase development capacity was to increase ecological footprint's diversity. The positive relationship between ecological footprint diversity and resources utilization efficiency demonstrated that there was no conflict between increasing ecological footprint's diversity and reducing footprints while not comprising our quality of life.

China↗
PubMed1996

[Structural changes in the cytoskeletal actin in cultured muscle cells when the cultures are stimulated by polystyrene latex].

As we reported elsewhere, the addition of polysterol latex (180 nm) to chick muscle culture accelerated several myogenesis stages, such as proliferation and fusion. In the present work we tried to determine the role of cytoskeletal actin in the mechanism of acceleration. The localization of cytoskeletal actin was studied in normal and latex induced cultures with the help of rodamine--phalloidin. The obtained data have shown that latex beads added to the cultural medium brought about acceleration of cell spreading (the number of spread cell was approximately five times more in comparison with the norm) and enhanced the development of actin network (90% of the cell area was filled with stress-fibrils in 20 h, instead of within 1-3 in the norm). It is proposed that muscle cells interact primarily with latex beads in the cultural medium before seeding on the glass. From this point of view latex beads can be considered as a primary substratum. The cell contact with the primary substratum initiates the actin network reorganization that leads to activation of cell spreading with a subsequent acceleration of myogenesis process: adhesion, proliferation and fusion.

Actins↗