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PubMedDate not supplied

Organization of network properties of cells in local and distributed neuronal networks of the brain of cats.

The network properties of neurons of the visual and motor cortex and of the lateral nucleus of the hypothalamus were investigated on the basis of identified interneuronal interactions, using the cross-correlation method of analysis, in cats with developed alimentary conditioned instrumental reflexes to light. The varied organization of the network properties of cortical neurons in the organization of local and distributed neuronal networks was demonstrated, namely: the predominance of divergent properties over convergent properties for large cells in local networks and the leveling out of these relationships in distributed networks. The neurons of the lateral nucleus of the hypothalamus had an equal representation of convergent and divergent properties in the organization of local and distributed networks. The network properties of neurons of the cortical and subcortical structures were manifested in the background, following the development of conditioned reflexes, and during extinction. Only the small cells of the visual cortex were functionally dependent and changed the relationship of network properties in local networks during the extinction of conditioned reflexes.

Action Potentials↗
PubMed2000

Neural network-based digitized cell image diagnosis of bladder wash cytology.

In this pilot study, we tested whether it is possible to apply neural network-based diagnostics on bladder washings to detect urothelial cell carcinoma of the bladder. Eighty-five bladder wash (BW) samples were chosen at random from our own database. Cystoscopy, histology, and follow-up data concerning tumor recurrence were available. Each slide was scanned by the neural network-based digitized cell image system. The neural network-based diagnosis (NNBD) was based on 128 digitized cell images provided by the system. The light microscopic diagnosis (LMD) was rendered by an experienced cytopathologist using the same terminology, i.e., negative, low-grade tumor, and high-grade tumor. Finally, an automatic QUANTICYT analysis was performed on the same material, with as classification low, intermediate, and high risk. The sensitivity for diagnosing a histologically confirmed tumor was for NNBD 92%, for LMD 50%, and for QUANTICYT 69%. For the three methods, receiver operating characteristic (ROC) curves were made for the thresholds low grade/intermediate risk and high grade/high risk. For the prediction of a positive cystoscopy, the highest area under the curve (AUC) was found for NNBD, being 0.71. The AUC for LMD was 0.58. QUANTICYT analysis had the highest AUC value (0.62) for predicting tumor recurrence after a negative cystoscopy, with a lower value for NNBD (0.50). These findings indicate that neural network-based diagnosis of bladder washing samples is highly promising.

Area Under Curve↗
PubMed1993

Alterations in visual receptive fields in the superior colliculus induced by amphetamine.

Visual response properties were examined in the superficial layers of the superior colliculus (SC) of anesthetized, paralyzed cats before and after i.v. administration of d-amphetamine. Receptive fields (RFs) of single SC units were plotted using small spots of light presented to the contralateral eye. Within the first hour following d-amphetamine injections, RF size gradually increased, reaching a maximum 86 min post-injection. On average, the area of the RF increased by 5.6 times and RF expansion was observed in all single units examined in the superficial layers. Over the subsequent 4-8 h following the injection, RF area gradually decreased and returned to control dimensions. Most RFs displayed asymmetrical patterns of expansion, showing relatively more horizontal than vertical growth. As RF expansion developed, responses to stimuli flashed "on" and "off" at various locations both inside and outside the borders of the control RF became progressively more vigorous. In contrast, no significant changes were noted in direction-selective responses at any time after d-amphetamine injections. Using an array of light bar stimuli of different lengths, the strength of surround suppression was found to be significantly diminished by d-amphetamine. The reduction in surround suppression was especially clear for bar lengths which exceeded the diameter of the control RF. No RF expansion was observed in the superficial layers of the SC when d-amphetamine was injected intravitreally. Furthermore, d-amphetamine had no discernable effect on the RF sizes of cells in the visual cortex. These results suggest that the RF changes in the SC were not of either retinal or cortical origin. We conclude that the mean retinal area which can potentially influence the activity of RFs in the superficial layers of the SC may be on average over 5 times greater than the RF area determined using conventional methods and criteria. These findings raise the interesting possibility that the relatively small size and sharp borders characteristic of RFs in the superficial layers arise from local inhibitory networks which delimit a broader field of excitatory activity supplied by retinal and cortical afferent terminals. Thus, in order to generate the RF changes observed here, either these local inhibitory circuits are amphetamine sensitive, or more likely, these inhibitory networks are dynamically modulated by an, as yet unidentified, amphetamine-sensitive input affecting visual RFs in the superficial layers.

Animals↗
PubMed2006

Brain network dysfunction in bipolar disorder.

Bipolar disorder is a common psychiatric condition with significant associated morbidity and mortality. Despite its significance, the neurophysiology and neuropathology of this illness is incompletely understood. Recent advances in neuroimaging techniques have helped to begin clarifying these areas. Specifically, bipolar disorder appears to arise from abnormalities within discrete brain networks (eg, the anterior limbic network). The expression of the symptoms of bipolar disorder does not appear to result from single, localized brain lesions, but rather are emergent properties of dysfunction of these brain networks. As neuroimaging techniques continue to improve, the underlying neural basis of bipolar disorder will be clarified.

Affect↗
PubMed2002

Estimation of ambient PM2.5 concentrations in Maryland and verification by measured values.

In 1997, Maryland had no available ambient Federal Reference Method data on particulate matter less than 2.5 microm in aerodynamic diameter (PM23), but did have annual ambient data for PM smaller than 10 microm (PM10) at 24 sites. The PM10 data were analyzed in conjunction with local annual and seasonal zip-code-level emission inventories and with speciated PM2.5 data from four nearby monitors in the IMPROVE network (located in the national parks, wildlife refuges, and wilderness areas) in an effort to estimate annual average and seasonal high PM2.5 concentrations at the 24 PM10 monitor sites operating from 1992 to 1996. All seasonal high concentrations were estimated to be below the 24-hr PM2.5 National Ambient Air Quality Standards (NAAQS) at the sites operating in Maryland between 1992 and 1996. The estimates also indicated that 12 monitor sites might exceed the 3-year annual average PM2.5 NAAQS of 15 microg/m3, but Maryland's air quality shows signs that it has been improving since 1992. The estimates also were compared with actual measurements after the PM2.5 monitor network was installed. The estimates were adequate for describing the chemical composition of the PM2.5, forecasting compliance status with the 24-hr and annual standards, and determining the spatial variations in PM2.5 across central Maryland.

Air Pollutants↗
PubMed2004

Dynamic molecular resolution imaging of preocular fluid impressions.

AIM: The preocular fluid is renewed with molecules secreted by the underlying cells and with lacrimal gland secretions, while maintaining a stable surface topography. The authors tested the hypothesis that interactions between gelled and newly inserted mucins are the key to this stability. METHODS: Using atomic force microscopy, the authors studied the topography of the freshly isolated preocular fluid obtained by impression cytology. The effects of adding mucins to this impression were compared with adding mucins to a pure mucin macromolecular assembly as a single component control to the more complex preocular fluid. The control structure was built up by repeated addition of pure ocular mucin to a tethering surface. RESULTS: Imaging at molecular resolution showed a thin layer of superficial preocular fluid with an appearance consistent with a gel that was very flat, with surface roughness of approximately 0.1 nm. Mucin molecules adhering to a clean flat surface maintained their individual character when overlapping, whereas molecules integrating in the impression could not be followed individually. Both the preocular impression and the pure mucin assembly were stable under imaging for at least 90 minutes. The roughness of the pure mucin network decreased as more mucin was added. In contrast, there was a small increase in the roughness of the 2.25 microm2 area of impression over the 60 minutes of continuous imaging, although locally there appeared to be infill of low height features. Disulphide bond breaking resulted in the collapse of the imaged structure in both the pure mucin control and the more complex ex vivo preocular impression. CONCLUSIONS: Polymeric mucins linked by disulphide bonds prevent or lessen loss of ocular surface material into the surrounding aqueous tears.

Conjunctiva↗
PubMed1996

Are there oxygen-deficient regions in resting skeletal muscle?

The purpose of this study was to determine whether there are local regions in resting skeletal muscle in which the oxygen delivery is insufficient to support oxidative metabolism. This hypothesis was tested by stopping the blood supply to the exteriorized cat sartorius muscle for 5 min while monitoring NADH fluorescence in localized tissue areas 15-25 microns in diameter. A rise in fluorescence was taken to indicate a shift to anaerobic metabolism. Tissue sites in the arteriolar and venular regions of the capillary network were selected for study. After flow stoppage, fluorescence did not change for an average of 48 +/- 22 (SD) s and then rose over a period of 61 +/- 27 s to an average value 55 +/- 19% above control for arteriolar and venular sites combined. Fluorescence began to rise within 5 s of flow stasis in only 1 of 61 sites and within 10 s in 2 sites. There was no difference in the time course or magnitude of fluorescence changes at arteriolar and venular sites. The data indicate that in resting skeletal muscle, oxygen supply appears sufficient to support oxidative metabolism in over 95% of the tissue.

Animals↗
PubMed1997

Paclitaxel inhibits arterial smooth muscle cell proliferation and migration in vitro and in vivo using local drug delivery.

BACKGROUND: The antineoplastic compound paclitaxel (Taxol) causes an increased assembly of extraordinarily stable microtubules. The present study was designed to characterize the effects of paclitaxel on proliferation and migration of human arterial smooth muscle cells (haSMCs) in vitro and on neointima formation in an in vivo experimental rabbit model. METHODS AND RESULTS: Both monocultures of haSMCs and cocultures with human arterial endothelial cells (haECs) were used. Cell growth after 4, 8, and 14 days was determined in the absence or presence of platelet-derived growth factor-AB (PDGF-AB), basic fibroblast growth factor (bFGF), or thrombin. Nonstop paclitaxel exposure, as well as single-dose applications of paclitaxel for 24 hours or even 20 minutes (0.1 to 10.0 micromol/L), caused a complete and prolonged inhibition of haSMC growth up to day 14, with an IC50 of 2.0 nmol/L. Mitogens or cocultures with stimulating haECs did not significantly attenuate paclitaxel-induced effects. Immunohistochemistry showed characteristic cytoskeletal changes predominantly in the microtubule network. Additionally, in 20 male New Zealand White rabbits, intimal plaques were produced by electrical stimulation. In 10 animals, paclitaxel was locally applied by use of microporous balloons. Histologically, the intima wall area, wall thickness, and degree of stenosis were reduced significantly in paclitaxel-treated animals compared with controls. CONCLUSIONS: Our data show that paclitaxel inhibits haSMC proliferation and migration in a dose-dependent manner in monocultures and cocultures even in the presence of mitogens. Furthermore, paclitaxel prevents neointima formation in rabbits after balloon angioplasty. The long-lasting effect after just several minutes' exposure time makes this lipophilic substance a promising candidate for local antiproliferative therapy of restenosis.

Animals↗
PubMed2000

Multidimensional telecare strategies for rural residents with brain injury.

Rural residents with brain injury have difficulty in accessing care from qualified psychologists for consequent cognitive, emotional and behavioural symptoms. We examined high-quality videoconferencing to enhance care for persons with brain injury in three areas: cognitive assessment, psychotherapy and rural mental health training. The assessment study evaluated 52 outpatients seen for diagnostic visits over videoconferencing, and compared their experiences with those of 52 age- and diagnosis-matched controls seen in person. Persons seen via telemedicine were more likely than controls to want to repeat their experience and more satisfied than were the neuropsychologists who examined them. In the psychotherapy study, neurorehabilitation patients were seen via videoconferencing for therapy related to brain injury or stroke. Persons receiving psychotherapy were less likely than persons receiving assessment services to want to repeat their experience. In the training study, 39 rural mental health providers were trained via videoconferencing, and trainees demonstrated significant improvement on tests of knowledge about brain injury. Trainees formed a network of mental health provider referrals for persons with brain injury in a wide geographic area. Given adequate training and ongoing support, rural clinicians can treat many brain-injury adjustment issues locally, reserving specialist consultation for emergency or complex problems.

Brain Injuries↗
PubMedDate not supplied

[The pyramid trap].

This paper discusses the impact of globalization on public health practice. Neoliberal supremacy has resulted in both greater interdependence between countries and increasing inequalities. Globalization of health risks and the dependence of local health conditions on external forces precludes the use of local/national solutions for global problems. In this context, the classical organization of public health services in a hierarchical pyramid based on geographically defined areas (from the local to the regional and national levels) no longer makes sense. We thus suggest some characteristics of a different type of organization based on new information technologies: a transnational network, horizontally shaped, more independent from political power, allowing for exchange of information and good practices, promoting dissemination of knowledge and producing "glocal" solutions. Through the creation of work opportunities between health professionals, the model will permit the creation of common strategies and increase the power of their political demands, perhaps allowing for the collective development of a more equitable world.

Brazil↗
PubMed1989

[Ultrastructural regularities of new growth of secondary micro blood vessels in the prenatal period of human morphogenesis].

By means of transmissive electron microscopy structural aspects of new formation of secondary blood microvessels in functionally different organs have been studied during fetal period of the human development. Growth buds appear on the basal surface of the endothelial lining of the blood microvessels predominantly in those areas of the vascular wall, where pericytes and adventitial cells are absent. The first stage in formation of the growth bud is separating of small compartments in the lumen of the maternal vessel. Then, connected by means of specialized contacts, endothelial cells of such a compartment move one by one towards periphery of the vessel and form the growth bud, protruding outside. In the area of the growth bud local destruction of the basal membrane is observed. Newly formed microvessels, anastomising, form vascular loops. Further processes in differentiation of separate segments of the newly formed capillary network into links of the hemomicrocirculatory bed are analogous to those, observed in the course of differentiation of the primary protocapillary network into the secondary intraorganic blood bed.

Fetus↗
PubMed1989

Histamine-immunoreactive nerve fibers in the rat brain.

A new immunohistochemical method that utilizes carbodiimide as a tissue fixative was applied to study the distribution of histamine-immunoreactive neuronal fibers and terminals in the rat brain. Immunoreactive fibers were observed in almost all major regions of the brain. They were most numerous in the different hypothalamic nuclei. Dense networks of immunoreactive fibers were also seen in the medial septum, nucleus of the diagonal band and ventral tegmental area. A moderate density of fibers was seen throughout the cerebral cortex, in some parts of the olfactory bulb and tubercle, bed nucleus of the stria terminalis, amygdala, basal parts of the hippocampus, inferior and superior colliculi, substantia nigra, lateral and medial parabrachial nucleus, and the nucleus of the solitary tract. Few histamine-immunoreactive fibers were seen in most parts of the caudate putamen, most thalamic nuclei, most pontine and ventral medullary nuclei. Histamine-immunoreactive neuronal cell bodies were found exclusively in the tuberomammillary nucleus, in agreement with previous reports. The results provide evidence for a widespread distribution of histamine-containing nerve fibers and terminals in the rat brain. Although immunohistochemical localization of histamine does not give direct evidence of a functional role of histamine in any brain area, this distribution suggests involvement in functions of the limbic system including the septal nuclei, hypothalamus and amygdala. The relatively dense histamine-immunoreactive fiber networks in the colliculi and dorsal cochlear nucleus indicate that this amine may play a role in visual functions and hearing. The paucity of immunoreactive fibers in the pontine and medullary areas suggests that the caudal projections originating from the tuberomammillary complex are minor ones compared to the major rostral projections. Several fiber projections originating from the tuberomammillary complex could be deduced from serial frontal, sagittal and horizontal sections. They contained fibers that crossed the midline at several levels of the brain. The results provide information on the target areas of the histaminergic neurons and form a basis for the examination of cellular contracts between the histaminergic neurons and other cells.

Animals↗
PubMed2001

Use of artificial neural networks (computer analysis) in the diagnosis of microcalcifications on mammography.

INTRODUCTION/OBJECTIVE: The purpose of this study was to evaluate a computer based method for differentiating malignant from benign clustered microcalcifications, comparing it with the performance of three physicians. METHODS AND MATERIAL: Materials for the study are 240 suspicious microcalcifications on mammograms from 220 female patients who underwent breast biopsy, following hook wire localization under mammographic guidance. The histologic findings were malignant in 108 cases (45%) and benign in 132 cases (55%). Those clusters were analyzed by a computer program and eight features of the calcifications (density, number, area, brightness, diameter average, distance average, proximity average, perimeter compacity average) were quantitatively estimated by a specific artificial neural network. Human input was limited to initial identification of the calcifications. Three physicians-observers were also evaluated for the malignant or benign nature of the clustered microcalcifications. RESULTS: The performance of the artificial network was evaluated by receiver operating characteristics (ROC) curves. ROC curves were also generated for the performance of each observer and for the three observers as a group. The ROC curves for the computer and for the physicians were compared and the results are:area under the curve (AUC) value for computer is 0.937, for physician-1 is 0.746, for physician-2 is 0.785, for physician-3 is 0.835 and for physicians as a group is 0.810. The results of the Student's t-test for paired data showed statistically significant difference between the artificial neural network and the physicians' performance, independently and as a group. DISCUSSION AND CONCLUSION: Our study showed that computer analysis achieves statistically significantly better performance than that of physicians in the classification of malignant and benign calcifications. This method, after further evaluation and improvement, may help radiologists and breast surgeons in better predictive estimation of suspicious clustered microcalcifications and reduce the number of biopsies for non-palpable benign lesions.

Adult↗
PubMed2000

What role for the general practitioner in child protection?

BACKGROUND: New government guidance on cooperation in child protection confirms the importance of the general practitioner (GP) contribution. While research highlights the concerns of others about their role in the multi-agency process, relatively little is known about the views and experiences of GPs themselves. AIM: To examine the understanding that each of the key professional groups had of its own and each other's roles in child protection to identify those factors seen to enhance or inhibit the effective performance of these roles. METHOD: The research formed part of a larger investigation of the role of health professionals in child protection, which combined case study investigations of child protection networks in three health authority sites with a regional survey of Area Child Protection Committee members. RESULTS: A lack of correspondence was identified between GPs' perception and performance of their role in child protection and the expectations placed upon them by other child protection professionals and government guidance. CONCLUSION: The study identifies the need for more explicit discussion of the nature and extent of the GP role in local interagency child protection networks.

Child↗
PubMed1985

A new, simple, non-invasive imaging technique of internal organs and various cancer tissues using extended principles of the "Bi-Digital O-Ring Test" without using expensive imaging instruments or exposing the patient to any undesirable radiation--Part I.

A new, simple, non-invasive and inexpensive imaging method of internal organs, using the "Bi-Digital O-Ring Test" was developed by the author. This new imaging technique does not require any bulky expensive instruments or electric power source. Unlike currently available imaging techniques, such as NMR tomography, CAT-Scan, angiography, or ultrasonography, which expose the patient to undesirable radiation, this new imaging technique does not expose the patient to undesirable radiation, such as X-rays, strong magnetic field, ultra-sound, etc. Material required for this present simplest form is a sample of internal organs in the form of a microscopic slide or a small piece of dessicated internal organ from a human or animal and a fine probe, or its alternative method (using a focused beam of light or a positive electrical field). The imaging can be carried out any place in any emergency situation, even in a place where there are no medical facilities or electricity. In addition to imaging of the internal organs, without any prior knowledge of the patient's chief complaint or history, not only can the presence or absence of cancer of specific internal organs be suspected, even in very small size, but also the exact location of such a suspected area within the specific internal organ can be localized, even when NMR tomography or CAT-Scan has failed to detect the cancer. As a further extension of the "Bi-Digital O-Ring Test" application and imaging technique, the presence or absence of specific bacteria can be suspected and localized, using the patient's "Bi-Digital O-Ring Test" response to glass slides of pure bacteria, which can often be confirmed by bacterial culture, when culturing is feasible. Imaging of different internal organs, including the heart, blood vessels, pancreas, gall bladder, duodenum, bile ducts, pancreatic ducts, kidneys, uterus, ovaries, fallopian tubes, thymus networks, appendix, etc. were studied. Also, detection and localization of cancer of the head of the pancreas was studied, and some of the clinical examples of these various studies are shown in this article. When the "Bi-Digital O-Ring Test" of the pancreas representation area showed minus 3 or minus 4, the author often found an abnormally enlarged body of the pancreas, with prolonged and enlarged tail of the pancreas, with suspected bacterial infection in that part of the pancreas, often accompanied by enlarged gall bladder.(ABSTRACT TRUNCATED AT 400 WORDS)

Acupuncture Therapy↗
PubMed1998

Population-based study of the adequacy of well-child care services: a rural county's report card.

OBJECTIVE: To determine the adequacy of well-child care services using a population-based study. DESIGN: The medical records of all county providers and the immunization records at the local health department were reviewed. A county birth cohort, identified using electronic birth certificates, was compared with those who migrated into the area (hereafter, in-migrants). SETTING: All primary care sites (private, network, etc) in a rural county. PATIENTS: Two-year-old children born between May 31, 1993, and May 30, 1994. MAIN OUTCOME MEASURES: Immunization rates and preventive screenings. RESULTS: A total of 674 medical records were reviewed. Of these, 377 (56%) belonged to a county birth cohort and 297 (44%) were in-migrants. Medical records of 64% of the birth cohort were reviewed. Among all 2-year-olds, 80% received 4 doses of diphtheria and tetanus toxoids and pertussis vaccine; 89%, 3 doses of Haemophilus influenzae type b (Hib); 75%, 4 doses of Hib; 77%, 3 doses of hepatitis B vaccine; 85%, measles-mumps-rubella vaccine; 85%, 3 doses of oral poliovirus vaccine; 17%, varicella live virus vaccine (Varivax). The 4:3:1 rate was 75% at age 2 years. Sixty-eight percent had had 1 hematocrit, 74% had 1 lead screening test, and 43% had 2 lead screening tests. A total of 64% had had 6 well-child visits and 30% had had 9. The mean number of weights and heights measured was 4.8 and 4.5, respectively, at age 1 year and 7.3 and 6.8, respectively, at age 2 years. The birth cohort had notably higher rates of documented immunization and preventive screening than in-migrants. CONCLUSIONS: This study demonstrated immunization coverage at or below the national average, and well-child care service provisions below American Academy of Pediatrics standards at a county level. This study enabled individual primary care sites to assess their well-child care provision and provided a useful baseline for targeting the improvement of well-child care services in the county.

Child Health Services↗
PubMed1997

Ultrastructural immunocytochemistry of collagenous and non-collagenous proteins in fast-frozen, freeze-substituted, and low-temperature-embedded renal tissue in Alport syndrome.

This paper describes the ultrastructural immunolocalization of the alpha 2 chain of collagen IV, laminin, and the amino terminal propeptide of collagen I (N-Pro I) in glomeruli of rapidly frozen, freeze-substituted, and low-temperature-embedded renal biopsy specimens from two cases of Alport disease and from normal kidneys. The alpha 2 chain of collagen IV is present in the whole thickness of the basement membrane in glomeruli of Alport patients, while it is limited to the subendothelial portion of the basement membrane of normal glomeruli. Laminin has the same distribution in both normal and Alport glomeruli, but is apparently more concentrated along the basement membrane of normal glomeruli. N-Pro I is localized in mesangial areas and in the basement membrane in Alport cases, while it is not detected in normal glomeruli. These data suggest complex rearrangements of major constituents of the glomerular basement membrane network and demonstrate early deposition of fibrillary collagen proteins in the matrix before the appearance of banded collagen fibres. This finding could be an indicator of early evolution towards glomerulosclerosis.

Basement Membrane↗
PubMed2002

An investigation of submicrostructural evolution of freshly precipitated ZrO2 in digestion for ultrafine sulfated ZrO2 catalysts by SAXS technique.

Coupled with XRD, BET, and TEM, the small-angle X-ray scattering (SAXS) technique has been effectively used to probe and characterize the submicrostructure of freshly precipitated hydrous zirconia and its evolution during digestion. It has been found that fresh hydrous zirconia particles possess an average diameter of about 5 nm and rather rough surfaces describable in terms of fractal concepts. The digestion of zirconia precipitates at 100 degrees C with their mother liquors may remarkably smooth the particles' rough surface and provoke fractal aggregation of the particles but make little change in average particle dimensions. A local dissolution-reprecipitation mechanism is regarded as a basic process to accompany particle surface smoothing, particle aggregation, and coarsening at the neck areas between joint particles, which may greatly strengthen the particle networks and enhance their resistance to crumbling while calcinated at high temperatures. On the basis of the submicrostructural features unraveled by SAXS, a coherent and significant physical picture has been raised out to demonstrate and interpret the relationship underlying the submicrostructure, the surface area variation, and the heating behavior of hydrous zirconia precipitates.

Journal Article↗