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PubMed1993

Scinderin and chromaffin cell actin network dynamics during neurotransmitter release.

It has been demonstrated that filamentous actin (F-A) is mainly localized in the cortical surface of the chromaffin cell. This F-A network acts as a barrier to the chromaffin granules impeding their contact with the plasma membrane. Stimulation of chromaffin cells with either nicotine or a depolarizing concentration of K+ induces the disassembly of cortical F-A in focal areas underneath the plasma membrane. Sites of exocytosis are localised to these areas with low concentration of F-A. The cortical surface of the chromaffin cell also contains scinderin, a Ca(2+)-dependent actin filament-severing protein recently isolated in our laboratory. Nicotine and high K+ stimulation also induce redistribution of cortical scinderin. Both nicotine and high K(+)-induced scinderin redistribution and F-A disassembly are Ca(2+)-dependent events which seem to precede neurotransmitter secretion. A possible target for protein kinase C in the modulation of secretion is the cortical F-A network. Treatment of chromaffin cells with phorbol esters prior to secretion induced scinderin redistribution, F-A disassembly and enhanced the initial rate of subsequent nicotine-evoked catecholamine release. The present results strongly indicate the involvement of the cortical cytoskeleton in the regulation of neurotransmitter release.

Actin Cytoskeleton↗
PubMed2002

Chondroitin sulfate proteoglycan phosphacan/RPTPbeta in the hypothalamic magnocellular nuclei.

The hypothalamo-neurohypophysial system synthesizes and releases arginine vasopressin (AVP) and oxytocin (OXT) with physiological stimulation. In the present study, we investigated localization of a chondroitin sulfate proteoglycan (CSPG), phosphacan/RPTPbeta, in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of adult rats at both the light and electron microscopic levels. Immunohistochemical analyses demonstrated stronger phosphacan/RPTPbeta immunoreactivity within the SON and PVN compared with adjacent hypothalamic areas. Double labeling experiments showed phosphacan/RPTPbeta immunoreactivity constituting punctate networks to surround the somata and dendrites of AVP- and OXT-secreting magnocellular neurons. Electron microscopic examination further revealed strong phosphacan/RPTPbeta immunoreactivity at extracellular membrane surface of some axons, somata, and dendrites of the SON, but not of synaptic junctions. Interestingly, phosphacan/RPTPbeta immunoreactivity was also observed at extracellular surface membrane between astrocytic processes and neurons rather than between magnocellular neurons. The present results indicate the high expression of the CSPG, phosphacan/RPTPbeta at the extracellular space in the hypothalamic AVP- and OXT-secreting magnocellular neurons.

Animals↗
PubMed2003

Localized chemical stimulation to micropatterned cells using multiple laminar fluid flows.

Micropatterns of the electrically conjugating cardiomyocytes were prepared on a single cell level by microcontact printing (microCP), and the localized chemical stimulations were applied to the cellular pattern using multiple laminar flows. The locally delivered 1-octanol inactivated part of the myocyte patterns, while the other areas retained the activity showing spontaneous and synchronous pulsatility. Since both the cells and flows were well defined as micropatterns and each integrated on a chip, the obtained results simply demonstrate the cellular responses in a single-cell network.

1-Octanol↗
PubMed2004

Preexisting lymphatic endothelium but not endothelial progenitor cells are essential for tumor lymphangiogenesis and lymphatic metastasis.

Endothelial progenitor cells have been shown to contribute to angiogenesis in various tumor models. Here, we have studied the relative contributions of bone marrow (BM)-derived endothelial progenitors and pre-existing lymphatic vessels to tumor lymphangiogenesis. We did not find significant incorporation of genetically marked BM-derived cells in lymphatic vessels during tumor- or vascular endothelial growth factor C-induced lymphangiogenesis. The degree of tumor lymphangiogenesis correlated with lymphatic vessel density in the peritumoral area, and despite tumor lymphangiogenesis, lymphatic metastasis failed to occur in gene-targeted vascular endothelial growth factor C(+/-) mice that have hypoplasia of the lymphatic network. Our data demonstrate that during tumor lymphangiogenesis and cancer cell dissemination via the lymphatics, the newly formed lymphatic vessels sprout from the pre-existing local lymphatic network with little if any incorporation of BM-derived endothelial progenitor cells.

Animals↗
PubMed1994

Histochemical and immunoelectron microscopic localization of proteoglycans in calcified cartilage of rat epiphyseal growth plate.

Localization and ultrastructure of proteoglycans during endochondral calcification or mineralization in the rat epiphyseal growth plate cartilage were investigated histochemically and by immunoelectron microscopy, using ruthenium hexammine trichloride and/or mouse monoclonal antibody (2-B-6) which recognizes chondroitin-4-sulphated glycosaminoglycans. The gold particles of the second antibodies were distributed solitarily, lineally or in small clusters in calcified cartilage as well as in the surrounding non-calcified matrix. The labelled matrix glycosaminoglycans in the longitudinal septa increased from the proliferative to the upper hypertrophic zones and remained constant in calcified cartilage. After fixation with ruthenium hexammine trichloride, matrix proteoglycans precipitated and were observed as a reticular network of strands. Immunogold-labelled antibodies for the demonstration of the glycosaminoglycans were localized on these strands. Proteoglycans in calcified cartilage were observed as a network of fine-filamentous structures after ruthenium hexammine trichloride, showing their non-precipitated native state. Immunostaining for chondroitin-4-sulphate indicated that there was no change in the concentration of glycosaminoglycans on the small calcified nodules in the areas where calcification was just beginning.

Animals↗
PubMed1999

[Experimental study on the osteoradionerosis of jaw model of dogs with vascular corrosion casting].

OBJECTIVE: To study pathologic alterations of mandibular microvascular system in osteoradionecrosis of jaws (ORNJ) in order to disclose its pathologic mechanism. METHODS: The right maxillofacial regions of 10 dogs were exposed to cobalt-60 radiation with a total dose of 60-80 Gy and dental extraction were performed at 3, 6 months after radiation. The ORNJ was diagnosed by gross observation, X-ray film and histopathologic examination. Then, the vascular corrosion castings of jaws were implemented and investigated. RESULTS: At 12 months after radiation, 7 cases of ORNJ occured. It was discovered on the casting specimen that the continuity of inferior alveolar arteries remained intact except one case where the artery was obliterated due to lesion involvement. There were defects of vascular networks in the necrotic area with irregular capillaries proliferating in the periphery of lesions and around the inferior alveolar arteries, where x-ray examination showed new bone formation. CONCLUSION: Based on the experimental evidences, a new concept of pathogenesis of ORNJ is put forward: following the formation of "3-hypo" structures, local trauma-repairing process might induce capillary proliferation which bring about a large amount of mitotic death of endotheliocytes, the microcirculation failure takes place leading to ORNJ eventually.

Animals↗
PubMed1988

Dopamine-sensitive anticonvulsant site in the rat striatum.

The basal ganglia are involved in the organization of movement and function in the initiation and expression of generalized and limbic seizures. Dopamine is the principal neurotransmitter of the mesencephalic efferent pathways terminating in the mammalian striatum. No function has been ascribed to mesostriatal dopamine in the control of seizure spread in the brain. This work presents evidence that bilateral application of picomole amounts of apomorphine (a dopamine agonist) into the striatum confers protection against seizures produced by pilocarpine (a cholinergic agonist) in rats. The anticonvulsant effect of apomorphine is topographically confined to the caudate-putamen, nucleus accumbens, and olfactory tubercle. Bilateral application of nanomolar amounts of haloperidol (a dopamine antagonist) into the caudate-putamen or systemic application of haloperidol both lower the threshold for pilocarpine-induced seizures. Local application of an excitatory amino acid N-methyl-D-aspartate, into the substantia nigra pars compacta, ventral tegmental area, or retrorubral area, sites of origin of mesostriatal dopaminergic pathways, protects rats against seizures produced by pilocarpine. These results suggest that dopaminergic transmission in the striatum may be operative in complex neuronal networks modulating the seizure threshold.

Amino Acids↗
PubMed2002

Artificial neural network analysis for predicting pathological stage of clinically localized prostate cancer in the Japanese population.

BACKGROUND: Although prostate cancer has been prevalent in Japan, there has been no particular model for predicting the pathological stage in the Japanese population. We examined whether artificial neural network analysis (ANNA), which is a relatively new diagnostic tool in prostate cancer, can be one of the predictive methods for predicting organ confinement, compared with the traditional logistic regression model, in the Japanese population for the first time. METHODS: The study population comprised 178 men who underwent radical prostatectomy at our institutions between October 1992 and May 1999. As additional pretreatment parameters to the preoperative serum PSA level, clinical TNM classification and biopsy Gleason score, the percentage of number of cores exhibiting traces of tumor, maximum tumor length in biopsy cores, PSA density and patient age were used. The predictive ability of ANNA with several parameters for a set of 36 randomly selected test data was compared with those of logistic regression analysis and 'Partin Tables' by area under the receiver operating characteristics (ROC) curve analysis. RESULTS: Of 178 patients, 97 (54.5%) had organ-confined disease but 81 (45.5%) had locally advanced disease. With three parameters, the area under the ROC curve of ANNA (0.825 +/- 0.071) was larger than those for logistic regression (0.782 +/- 0.079) and Partin Tables (0.756 +/- 0.087), but not to a significant extent (P = 0.690 and 0.541). Although the expansion of the parameters did not increase the difference in area under the ROC curve between the best ANNA and logistic regression (0.899 +/- 0.053 and 0.873 +/- 0.065, respectively), the difference between the best ANNA and Partin Tables did not reach but approached statistical significance (P = 0.157). CONCLUSION: Although more modeling optimization is necessary to improve the predictive accuracy and generalizability of ANNA, we suggest that there is the possibility for this new predictive method to evolve in the analysis of clinical staging of prostate cancer.

Aged↗
PubMed1997

Coordinating rural divisions: the workforce window.

Divisions of General Practice have been established to alleviate the professional isolation which general practitioners face by being excluded from involvement in other parts of the health care system. Divisions facilitate the development of local communication networks and cooperative activities which improve the integration of general practice with other elements of the health system. Coordination of communication is one of the strengths of divisions at the local level and Rural Divisions Co-ordinating Units at the State level. This strength is being effectively utilised to target general practice workface issues. Given the significant proportion of general practitioners in the medical workforce, particularly in rural and remote areas, this has implications for broader medical workforce issues. Australia faces a maldistribution in its general practitioner workforce, with an excess supply in urban areas and a significant shortfall in rural and remote areas. Since 1995-96, the General Practice Rural Incentives Program, which targets the recruitment and retention of rural doctors, has devolved funding to the Rural Divisions Co-ordination Units to coordinate the statewide provision of practical assistance to rural general practitioners, through their divisions, in relation to continuing medical education and the provision of locums. There is potential to build on the success of these initiatives and also to work with urban divisions through the state-based organisational structures which are currently being developed.

Australia↗
PubMed2004

Immunocytochemical localization of aromatase in sensory and integrating nuclei of the hindbrain in Japanese quail (Coturnix japonica).

The distribution of the estrogen synthesizing enzyme (aromatase) in the hindbrain (rhombencephalon and mesencephalon) of male adult quail was investigated by immunocytochemistry. Aromatase-immunoreactive neuronal structures (perikarya and fibers bearing punctate structures) were observed in sensory (trigeminal, solitary tract, vestibular, optic tectum) and integrating (parabrachial, periaqueductal, cerulean, raphe) nuclei. Besides the expression of aromatase in these well-delineated nuclei, dense to scattered networks of immunoreactive fibers were found dispersed throughout the hindbrain and, in particular, in its rostral and dorsal parts. To a lesser extent, they were also present throughout the premotor nuclei of the reticular formation and in various fiber tracts. In contrast, no immunoreactive signal was found in motor nuclei, and in most of the statoacoustic (cerebellum, cochlear, olive, pontine, part of vestibular) nuclei. The expression of aromatase in perikarya and fibers in areas of the adult hindbrain where estrogen receptors have been identified previously suggests a role for estrogens locally produced in the regulation of sensory and integrating functions, contrary to the widespread assumption that these functions are regulated exclusively by steroids produced in the gonads.

Animals↗
PubMed2006

Precise long-range synchronization of activity and silence in neocortical neurons during slow-wave oscillations [corrected].

Slow-wave sleep is characterized by alternating periods of activity and silence in corticothalamic networks. Both activity and silence are stable network states, but the mechanisms of their alternation remain unknown. We show, using simultaneous multisite intracellular recordings in cats, that slow rhythm involves all neocortical neurons and that both activity and silence started almost synchronously in cells located up to 12 mm apart. Activity appeared predominantly at the area 5/7 border and spread in both anterior and posterior directions. The activity started earlier in fast-spiking cells and intrinsically bursting cells than in regular-spiking neurons. These results provide direct evidence for two mechanisms of active state generation: spread of activity from a local focus and synchronization of weaker activity, originating at multiple locations. Surprisingly, onsets of silent states were synchronized even more precisely than the onsets of activity, showing no latency bias for location or cell type. This most intriguing finding exposes a major gap in understanding the nature of state alternation. We suggest that it is the synchronous termination of activity and occurrence of silent states of the neuronal network that makes the EEG picture during slow-wave sleep so characteristic. Synchronous onset of silence in distant neurons cannot rely exclusively on properties of individual cells and synapses, such as adaptation of neuronal firing or synaptic depression; instead, it implies the existence of a network mechanism. Revealing this yet unknown large-scale mechanism, which switches network activity to silence, will aid our understanding of the origin of brain rhythms in normal function and pathology.

Action Potentials↗
PubMed2003

Imaging a science of mind.

I believe that the study of neuroimaging has supported localization of mental operations within the human brain. Most studies have shown a small number of widely distributed brain areas that must be orchestrated to carry out a cognitive task. Although, as in all sciences, there are disagreements, the convergence of results in areas of attention and language in particular seem impressive. Moreover, the anatomical data has helped us to specify the computations that are used by the brain to carry out cognitive tasks. Building upon localization of cognitive operations, imaging methods are being applied to studies of the circuitry, plasticity and individual development of neural networks. Working together with cellular and genetic methods, there is movement towards a more unified view of the role of the human brain in supporting the mind.

Journal Article↗
PubMed2005

Electrochemical functionalization of single-walled carbon nanotubes in large quantities at a room-temperature ionic liquid supported three-dimensional network electrode.

Electrochemical functionalization of single-walled carbon nanotubes (SWNTs) was one of selective, clean, and nondestructive chemical methods. But in previous studies it met difficulties in homogeneous electrografting of SWNTs in large quantities because the reaction was often localized on a very thin film (ca. 2 microm). In this report, a room-temperature ionic liquid (RTIL) supported three-dimensional network SWNT electrode was first utilized to break through this barrier. In this work, large quantities of SWNTs were considerably untangled in RTILs so as to greatly increase the effective area of the electrode. N-succinimidyl acrylate (NSA), as a model monomer, was dissolved in the supporting RTILs and was electrografted onto SWNTs (SWNTs-poly-NSA). As an application example, glucose oxidase was directly covalently anchored on the SWNTs-poly-NSA assembly, and the electrocatalytic oxidation of glucose in this assembly was investigated. RTILs opened a new path in electrochemical functionalization of SWNTs.

Journal Article↗
PubMed2001

Histochemical phenotypes of von Ebner's gland of ferret and their functional implications.

Von Ebner's gland of ferret was examined by means of light microscopy, protein, mucosubstance and enzyme histochemistry, and neurohistology. Acinar cells were replete with granules containing neutral mucosubstances and disulphides, and showed strong diffuse acid phosphatase activity and weak granular staining for peroxidase. Staining for cytochrome oxidase, succinate dehydrogenase, and NADH and NAD(P)H dehydrogenases was also seen. Basolateral plasmalemma of acinar cells showed weak, ouabain-sensitive Na+,K+-ATPase activity. Ductal cells were of a simple appearance, contained thiols and showed variable staining for acid phosphatase, dehydrogenases and cytochrome oxidase. Variable amounts of beta-glucuronidase reaction product were localized in the glandular parenchyma, being marked in atrophic areas. Prominent stellate myoepithelial cells embracing acini and also basal ductal cells were demonstrated by alkaline phosphatase. Thiamine pyrophosphatase reaction product was concentrated in blood vessels around parenchyma, with little Golgi-like staining in acinar cells. Acetylcholinesterase activity was associated with an extensive network of nerve fibres embracing parenchyma, whereas catecholamine fluorescence was not seen. The results suggest that the acini of von Ebner's gland of ferret synthesise neutral secretory glycoproteins and peroxidase. Water mobilization is inconspicuous. Lysosomal activities feature in the parenchyma, possibly a consequence of processing secretory products in acini, absorption in ducts and/or adaptation atrophy. The gland receives a rich cholinergic-type innervation, and has extensive myoepithelial and microvascular networks.

Animals↗
PubMed2000

Venomous snakebites in an urban area: what are the possibilities?

OBJECTIVE: To estimate the number of different species of venomous snakes privately kept in a large urban area. METHODS: An anonymous survey of potential snake owners in the Philadelphia urban and suburban area. The survey was mailed to members of the Philadelphia Herpetological Society. In addition, the survey was published in 2 herpetological newsletters and online in the Herpetology Network. RESULTS: One hundred sixty responses were obtained during a 6-month period. Ownership of 74 different varieties of venomous snakes was reported. Antivenin was not locally available for 13 of these species. CONCLUSION: A wide variety of venomous captive snakes can be found in the private sector. The potential for having to treat an envenomation requires the emergency physician to maintain an education of snakebite management options, including the various antivenin options available in their geographical location.

Animals↗
PubMed1999

Dual-plane lipoplasty for the superficial and deep layers.

Two embryologically and histologically distinct layers of the subcutaneous adipose tissue were treated individually by different modalities. The authors performed ultrasound-assisted lipoplasty at the superficial layer and traditional suction-assisted lipectomy in the deep subcutaneous tissue. The ultrasound procedure allowed tissue-specific destruction of the superficial layer supported by dense fibrous networks without disrupting them. Skin retractions caused by this procedure could diminish the necessity of surgical dermolipectomy such as an abdominoplasty in moderately deformed cases. On the other hand, the traditional liposuction was performed to remove the excessive deep fat contained in the loose fibrous network in a limited area. Although the advancement of ultrasound devices and regimens has now reduced their operating times significantly, the ultrasonic lipoplasty was slower than traditional liposuction at the beginning of our procedure. In the abdominal wall, the procedure was performed only in a confined area, because the skin retractions made over the locally managed areas created a circumferential tightness around the trunk, using the nontreated area as a bridge. Confinement on the managed area prevented unnecessary blood loss and tissue destruction. It was less a matter of fat volume to remove in the superficial layer; rather, a precise application to the exact target area was required to get a more natural result. Dual-plane lipoplasty was performed for 2 years in 35 patients, mostly for the abdomen. No serious complication such as seromas or skin loss was observed in our series of patients.

Abdominal Muscles↗
PubMed2005

Indicators predicting use of mental health services in Piedmont, Italy.

BACKGROUND: Since the 1978 Italian reform, an integrated network of community mental health services has been introduced. With few exceptions, research on determinants of mental health service use at the district level has focused on inpatient activities and social deprivation indicators. The European Psychiatric Care Assessment Team (EPCAT) standardized methodology allows for an evidence-based comparison of mental health systems between geographical areas. AIMS: To compare service provision and utilization between local catchment areas; to explore quantitative relationships between residential and community service use and socio-demographic indicators at the ecological level. METHODS: The European Socio-demographic Schedule (ESDS) was used to describe area characteristics, and the European Service Mapping Schedule (ESMS) to measure service provision and utilization in 18 catchment areas in Piedmont. RESULTS: Substantial variation in service use emerged. Acute hospital bed occupancy rates were lower in areas with more intensive community continuing care service users and with a smaller percentage of the population living alone. The non-acute hospital bed occupancy rate was directly related to the percentage of the population living alone or in overcrowded conditions, and to the level of mobile continuing care service users. Community continuing care service use was highest in areas with a larger percentage of the population living alone. DISCUSSION: Multiple regression models explained between 48 and 55% of the variation in inpatient and community service use between areas. Relationships based on ecological characteristics do not necessarily apply to the individual. This level of assessment, however, is necessary in evaluating mental health policy and service systems, and in allocating resources. IMPLICATIONS FOR HEALTH CARE PROVISION AND USE: The distribution of mental health care resources should be weighted in terms of indicators of social deprivation shown to be important predictors of both inpatient and community service use, as these are likely to be related. IMPLICATIONS FOR HEALTH POLICIES: To ensure horizontal equity in access to mental health care, particularly for people with severe mental illness, evaluation of mental health policy should be based on a concurrent evidence-based assessment of the organization and use of both residential and community services, in relation to area level indicators of social deprivation. IMPLICATIONS FOR FURTHER RESEARCH: Cross-national research using an internationally standardized methodology should consider the influence of the social network independently of other socio-economic indicators, to verify the relative importance of this in predicting service use in southern and in northern European countries.

Catchment Area, Health↗
PubMed1985

Immunocytochemical localization of substance P in the rat spinal cord with special reference to fibers within the ventral column of the rostral lumbar segments.

The distribution of substance P (SP) in the rat spinal cord was investigated by peroxidase-anti-peroxidase (PAP) immunocytochemistry. A dense network of SP-immunoreactive fibers and terminals was detected in the ventral column of the rostral lumbar cord with a different density and extent from the other segmental levels. These fibers and terminals were accumulated within and around the centromedial nucleus (CM) of the L1 and L2 segments, with some bundles of immunoreactive fibers between the CM and other areas; i.e. laminae V and X and the contralateral CM. They formed a dense network, such as in arborization of immunoreactive fibers and terminals on the transverse plane and in a comb-shaped structure on the horizontal plane. The origin of the SP in this network was examined. It was determined that neither a total transection of spinal cord at a low thoracic level or mid-lumbar level, nor at an ipsilateral or bilateral section of the 3-5 dorsal roots, containing L1 and L2 roots, induced any visible changes in the SP staining pattern. An intrathecal injection of colchicine revealed the presence of SP-immunoreactive neurons in the dorsal horn and intermediate gray matter at the spinal cord including the rostral lumbar cord. The present findings suggested that the majority of SP immunoreactivities in the above network are derived from local circuit interneurons of the spinal cord.

Animals↗