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PubMed1993

[Development of a handy dental surveyor].

A small portable surveyor, easy to use, was newly devised. The surveyor is essentially a parallelometer, an instrument used for determining the relative parallelism of two or more surfaces of the teeth or other parts of the dental cast. The characteristic structures of this instrument is as follows: The vertical standard is directly connected to the cast table with a universal joint, different from the others, and it can be tilted in any given degree to the table. The vertical sliding spindle can move freely parallel to the standard with the two horizontal arms, and it carries pencil leads of 0.9mm phi inside just as a mechanical pencil in structure. The accuracy of this surveyor is thought to be equal to that of the conventional ones in ordinary use.

Dental Casting Technique↗
PubMed2000

Organization of callosal linkages in visual area V2 of macaque monkey.

In visual area V2 of the macaque monkey callosal cells accumulate in finger-like bands that extend 7-8 mm from the V1/V2 border, or approximately half the width of area V2. The present study investigated whether or not callosal connections in area V2 link loci that are located at the same distance from the V1/V2 border in both hemispheres. We analyzed the patterns of retrograde labeling in V2 resulting from restricted injections of fluorescent tracers placed at different distances from the V1/V2 border in contralateral area V2. The results show that varying the distance of V2 tracer injections from the V1/V2 border led to a corresponding variation in the location of labeled callosal cells in contralateral V2. Injections into V2 placed on or close to the V1 border produced labeled cells that accumulated on or close to the V1 border in contralateral V2, whereas injections into V2 placed away from the V1 border produced labeled cells that accumulated mainly away from the V1 border. These results provide evidence that callosal fibers in V2 preferentially link loci that are located at similar distances from the V1/V2 border in both hemispheres. Relating this connectivity pattern to the topographic map of V2 suggests that callosal fibers link topographically mirror-symmetrical regions of V2, i.e., callosal fibers near the V1/V2 border interconnect areas representing visual fields on, or close to, the vertical meridian, whereas callosal connections from regions away from the V1/V2 border interconnect visuotopically mismatched visual fields that extend onto opposite hemifields.

Animals↗
PubMed1993

Use of a rule based graph-theoretical system in evaluating the activity of a class of nucleoside analogues against human immunodeficiency virus.

A rule based graph-theoretical system has been used to evaluate qualitatively the activity of a class of nucleoside analogues against human immunodeficiency virus (HIV). The system identifies biologically relevant vertices (atoms) in the molecular graphs of the compounds which have the biological activity of interest. The idea is to relate biological activity with the structural or substructural characteristics of the compounds from the point of view of molecular topology (connectivity). The system brings vertices of similar or close topological environment in the respective compounds together and this is reflected in the ranges of values formed by a distance based index of the vertices, the 'distance exponent index (Dx)', where x is any real number. It is found that the system makes correct prediction of the activity of all the compounds (active as well as inactives) of both training set and the test set against HIV. It is also apparent from this study that the index D-4, which has been used here, can make a useful classification of the vertices according to their molecular environment and the system can produce significant result in a small as well as diverse data base.

Antiviral Agents↗
PubMed1996

Repair of an unusual type of total anomalous pulmonary venous connection.

A 9-day-old, 4.5-kg female infant was diagnosed with total anomalous pulmonary venous connections by echocardiography. The unusual nature of the pulmonary veins and their connections led to cardiac catheterization and angiography. Angiography demonstrated the left-sided veins connected, via a retropulmonary artery vertical vein, to the left inominate vein whereas the right-sided pulmonary veins connected to the right superior vena cava. We repaired this lesion uneventfully by creating a neo-common pulmonary vein and anastomosing this confluence to the left atrium.

Cardiac Catheterization↗
PubMed2006

Multiple subpial transections in pediatric epilepsy: indications and outcomes.

OBJECTIVE: Multiple subpial transection (MST) is a surgical technique mainly used when epileptiform activity arises from eloquent or functional brain cortex. In the medical literature, there are relatively few studies reporting the efficacy and safety of this procedure in adults and in children. We review the scientific rationale, the indications, and the results of this procedure. METHODS: Neuroanatomic studies show that the basic functional cortical unit is arranged vertically, and epileptic activity spreads horizontally. Minimal cortical unit is essential for maintenance of cortical activity. Vertical incisions in the cortex interrupt transverse synaptic connections, preventing seizure propagation while preserving the vertical column subserving neuronal function. In the past, it has been difficult to assess the efficacy of MSTs per se, as they have usually been performed together with cortical resection or lesionectomy. After MSTs, studies show that 33-46% of treated children are in Engel class I or II. The permanent complication rate is low with no permanent language or motor disabilities. CONCLUSIONS: MST is a safe procedure with unclear specific efficacy. It has been used mainly in conjunction with cortical resection or lesionectomy, when the eloquent cortex is involved in the seizure activity. Further prospective studies are needed to define the role of MST in epilepsy surgery.

Cerebral Cortex↗
PubMed2004

Characteristics of the bovine claw associated with the presence of vertical fissures (sandcracks).

Vertical fissures (sandcracks) affect approximately 20% of adult beef cattle in western Canada. The risk factors associated with the formation of these lesions are not well understood. This paper describes a case-control study that identifies the role of increased claw size (claw volume > 390 cm3, odds ratio 7.8) in the formation of the lesion. No connection was found between vertical fissures and horn hydration status. However, horn hydration was found to vary significantly between samples collected in the summer and winter, the latter samples having significantly reduced moisture content. The importance of these findings and the implications for the prevention of fissure formation are discussed.

Abattoirs↗
PubMed1987

The organization of the nucleus basalis-neostriatum complex of the mallard (Anas platyrhynchos L.) and its connections with the archistriatum and the paleostriatum complex.

The pattern of connections between the nucleus basalis, neostriatum, hyperstriatum ventrale, paleostriatum complex and archistriatum in the mallard has been analysed using Nissl material and a combination of neuroanatomical tracing procedures (autoradiography, horseradish peroxidase and horseradish peroxidase-wheat germ agglutinin histochemistry, lesion/degeneration technique). The frontal part of the mallard's telencephalon is characterized by its multilayered organization and the predominantly vertical arrangement of the connecting fiber systems. The nucleus basalis, endstation of the ascending sensory trigeminal system, is a large laminar cell area with a dorsal and a ventral layer. The overlying neostriatum frontale can be subdivided into a medial, a dorsal and a ventral intermediate, and a lateral area. The nucleus basalis has distinct connections with the ventral layer and sparse connections with the dorsal layer of the intermediate neostriatum, and abundant reciprocal connections with the ventral layer of the hyperstriatum ventrale. The ventral intermediate neostriatum also has reciprocal connections with the hyperstriatum ventrale; its projections overlap partly with those from the nucleus basalis. The ventral layer of the intermediate neostriatum frontale has a distinct projection upon the paleostriatum augmentatum. The dorsal layer sends fibers to the lateral neostriatum, to the rostral "sensorimotor" part of the archistriatum and to the lateral zone of the lobus parolfactorius. Another source of archistriatal afferents is the paleostriatum ventrale, an area that may also send fibers to the brainstem. Figure 21 summarizes the connections described in this paper. The functional significance of this organization is discussed in relation to its possible role in the guidance of pecking and other feeding behaviors in the mallard. Differences in the organization of the systems in pigeon and mallard are related to the differing degrees of visual and tactile (trigeminal) contributions to feeding in the two birds. It is suggested that the pattern of reciprocal connections between the hyperstriatum ventrale and the nucleus basalis and ventral intermediate neostriatum frontale forms the neuroanatomical substrate for a "comparator-system".

Animals↗
PubMed2005

[Spatial reorganization of horizontal connections of cat cortical area 17 induced by eye rotation].

In six cats with experimental unilateral or bilateral strabismus, surgically induced early in postnatal life, torsion eye rotation with a deviation angle of 10 to 20 degrees was also detected. Spatial distribution of retrogradely labeled neurons in area 17 was studied following microiontophoretic injection of horseradish peroxidase in area 17 or 18 cortical columns. Eye rotation was shown to cause the increase of the length of horizontal neuronal connections in area 17 along the projection of visual field vertical meridian. The reorganization of neuronal connections, detected in this work, may promote the functional changes, described in the literature, that compensate for the eye rotation.

Animals↗
PubMed2005

Evolutionary dynamics on graphs.

Evolutionary dynamics have been traditionally studied in the context of homogeneous or spatially extended populations. Here we generalize population structure by arranging individuals on a graph. Each vertex represents an individual. The weighted edges denote reproductive rates which govern how often individuals place offspring into adjacent vertices. The homogeneous population, described by the Moran process, is the special case of a fully connected graph with evenly weighted edges. Spatial structures are described by graphs where vertices are connected with their nearest neighbours. We also explore evolution on random and scale-free networks. We determine the fixation probability of mutants, and characterize those graphs for which fixation behaviour is identical to that of a homogeneous population. Furthermore, some graphs act as suppressors and others as amplifiers of selection. It is even possible to find graphs that guarantee the fixation of any advantageous mutant. We also study frequency-dependent selection and show that the outcome of evolutionary games can depend entirely on the structure of the underlying graph. Evolutionary graph theory has many fascinating applications ranging from ecology to multi-cellular organization and economics.

Biological Evolution↗
PubMed1980

Light- and electron microscopic characteristics of the vegetative centers in the guinea pig sacral spinal cord intermediate zone.

A dense AChE-negative and NA fluorescent network was visualized by light microscopy in the sacral spinal cord intermediate zone of grown-up guinea pigs of both sexes. This network connects in horizontal and vertical direction the preganglionic vegetative nuclei (n. intermediolateralis pars principalis (ILp), n. intermediolateralis pars funicularis (ILf), n. intercalatus spinalis (IC), n. intercalatus pars paraependimalis (ICpe), (Petras and Cummings 1972) along 2--4 segments of the spinal cord. Electron microscopy demonstrated dense core ves icles (40--100 nm) in the cytoplasm of the ILp cells. The surface of the ILp neurons is covered with synaptic boutons which have clear and dense core vesicles (40--100 nm). The bundles of fibres connecting the vegetative nuclei are built of parallel myelinated fibres and myelinfree axons and dendrites. On their course the axons form varicosites. In the latter and in the synaptic enlargements there are clear and dense core (40--100 nm) vesicles. The probable origin of the vegetative fibres of guinea pig sacral spinal cord is discussed.

Acetylcholinesterase↗
PubMed2001

[Biometric data on risk of pneumothorax from vertical infraclavicular brachial plexus block. A magnetic resonance imaging study].

In the present study 48 sagittal and transversal magnetic resonance images of volunteers were examined for biometric data concerning risk of pneumothorax at the vertical infraclavicular blockade (VIP) of the brachial plexus. With a correct puncture the plexus can be reached after 3 cm. The shortest way to the lung is 5.3 cm (3.1-8.7 cm) at a incorrect medial angle of puncture of 46.3 degrees (35-58 degrees). While moving the angle of puncture at a minimum of 24.1 degrees (1-51 degrees) in a medial direction, a depth of 6.1 cm (4-8.9 cm) has to be reached for fatal lung puncture. The puncture point has to be determined 2.8 cm (0-4.1 cm) towards the midline of the body to have a pleura connection by a strictly vertical puncture at 6 cm (4-8.9 cm). In asthenic women, shorter distances were obtained. A considerable lower deviation can lead to pleural damage (7.5 degrees; 4.7 cm). The plexus is very close to the skin surface (1.6-3 cm). In one case, the risk for pneumothorax could be measured even with the correct puncture technique. Overall, the VIP is a very safe method for brachial plexus anaesthesia with regard to the risk of pneumothorax. In asthenic women, the risk seems to be higher but can be minimised by reducing the maximum puncture depth.

Brachial Plexus↗
PubMed2005

(C4N3H15)[(BO2)2(GeO2)4]: the first organically templated 3D borogermanate showing 1D 12-rings, large channels, and a novel zeolite-type framework topology constructed from Ge8O24 and B2O7 cluster units.

The first organically templated 3D borogermanate with a novel zeolite-type topology, (C4N3H15)[(BO2)2(GeO2)4] FJ-17, has been solvothermally synthesized and characterized by IR spectroscopy, powder X-ray diffraction (PXRD), TGA, and single-crystal X-ray diffraction. The compound crystallized in the monoclinic space group P2(1)/c with a = 6.967(1) A, b = 10.500(1) A, c = 20.501(1) A, beta = 90.500(3) degrees , V = 1499.68(8) A3, and Z = 4. The framework topology of this compound is the previously unknown topology with the vertex symbols 3.4.3.9.3.8(2) (vertex 1), 3.8.3.4.6(2).9(2) (vertex 2), 3.8(2).4.6(2).6(2).8 (vertex 3), 4.8.4.8.8(3).12 (vertex 4), 4.8.4.8.8(2).12 (vertex 5), and 3.8.4.6(2).6.8(2) (vertex 6). The structure is constructed from Ge8O24 and B2O7 clusters. The Ge8O24 cluster contains eight GeO4 tetrahedra that share vertices; the B2O7 unit is composed of two BO4 tetrahedra sharing a vertex. The cyclic Ge8O24 clusters connect to each other through vertices to form a 2D layer with 8,12-nets. The adjacent layers are further linked by the dimeric B2O7 cluster units, resulting in a 3D framework with 12- and 8-ring channels along the a and b axes, respectively. In addition, there is a unique B2GeO9 3-ring in the structure.

Journal Article↗
PubMed2002

Influence of the embryonic preplate on the organization of the cerebral cortex: a targeted ablation model.

Transgenic mice were generated to permit the targeted ablation of cortical preplate cells at the time they are born. In these mice, the 1.3 kb golli promoter of the myelin basic protein gene was used to drive the herpes simplex virus thymidine kinase (TK) transgene in cortical preplate cells. Heterozygous transgenic pairs were bred, and pregnant dams were treated with ganciclovir at embryonic days 11-12 to ablate preplate cells at the time the preplate was forming. This paradigm exposed control (TK-) and experimental (TK+) littermates to exactly the same conditions. Embryological ablation of preplate cells led to an early disruption of the radial glial framework and subplate structure in the developing cortex and dramatically altered the cellular lamination and connectivity of the cortical plate. The disturbed radial glial network contributed to an impaired radial migration of neurons into the cortical plate from the ventricular zone. The cortical plate became dyslaminated, and there was a substantial reduction in short- and long-range cortical projections within the cortex and to subcortical regions. Cell death within the cortical plate and the proliferative zones was substantially increased in the ablated animals. After birth, a cortical lesion developed, which became exacerbated with the secondary onset of hydrocephaly in the second postnatal week. The results underscore the critical importance of the preplate in cortex formation, mediated through its guidance of the formation of radial glial scaffolding, subsequent neuronal migration into the incipient cortical plate, and the final arrangement of its vertical organization and cellular connectivity.

Animals↗
PubMed1979

Laminar origins and terminations of cortical connections of the occipital lobe in the rhesus monkey.

Cortical connections within the occipital lobe (areas 17, 18 and 19) of the rhesus monkey are investigated with the autoradiographic and horseradish peroxidase procedures. Two efferent systems, each with a specific laminar organization, are observed. (1) Rostrally directed connections, from area 17 to 18, area 18 to 19 and area 19 to the inferotemporal region (area TE), originate from neurons in layer IIIc (and, in area 19, from a small complement of neurons in layer Va), and terminate in and around layer IV. (2) In contrast, connections in the reverse direction ('caudally directed' connections), from area TE to 19, area 19 to 18, and area 18 to 17, originate from neurons in layers Vb, VI and, to a lesser extent, IIIa, and terminate mainly in layer I. In addition, the laminar organization of several intrinsic and callosal connections are observed. In trinsic connections within areas 18 and 19 originate from neurons in layers IIIc and, to a lesser extent, Va, and terminate in vertical bands in layers I to IV. Callosal connections from areas 18, 19, and the caudal inferotemporal region originate from neurons mainly in layer IIIc. From areas 18 and 19, these callosal connections terminate in vertical bands in layers I through IV. Thus, different cortical projection systems are characterized by specific laminar distributions of efferent terminations as well as of their neurons of origin.

Animals↗
PubMed1984

Model study of flow dynamics in human central airways. Part III: Oscillatory velocity profiles.

Measurements of oscillatory velocity were made in a 3:1 model of the human central airways. The model was built of acrylic plastic and mounted vertically. A reciprocating pump connected to the upper end of the model privided oscillatory flow frequencies of 0.25, 1, 2 and 4 Hz (equivalent to 2.25, 9, 18 and 36 Hz in the actual airways) and tidal volumes of 300, 500 and 1500 ml. A hot-wire anemometer probe was used to measure velocities along two perpendicular diameters and at six stations distributed through the model. The flow distribution through the five lobar bronchi was controlled by distally positioned linear resistors . The measurements indicate that the entry flow profile into the model during oscillatory flow was essentially flat. At low frequencies, the velocity profiles attained at peak flow rate resemble the profiles seen under steady flow conditions at the corresponding Reynolds number. In the frontal plant these profiles are asymmetric with a maximum in velocity directed towards the outer wall of the bend. In the sagittal plane the velocity profiles are symmetric and have the characteristic bi-peak (M-shaped) structure seen in the steady flows. However, as the frequency increases the velocity profiles throughout most branches tend to flatten except in the right upper lobar bronchus where the skewed velocity profiles persist even at the highest frequencies studied. As in steady flows the nature of the velocity profile is strongly influenced by the airway geometry. Furthermore, the peak velocity profiles resemble steady flow profiles at comparable Reynolds numbers up to a Womersley number of 16.

Biomechanical Phenomena↗
PubMed1996

Objective evaluation of the eyelids and eyebrows after blepharoplasty.

PURPOSE: Surgery of the upper and lower eyelids and eyebrows is primarily designed to enhance the esthetic appearance and provide functional visual field benefits. Paramount to successful surgical results is a carefully executed examination and treatment plan. The preoperative and postoperative evaluation of these individuals has been primarily subjective. This article describes a method for the quantification of periorbital relationships that is of use in the preoperative planning and postoperative evaluation of patients undergoing esthetic surgery of the eyelids and eyebrows. PATIENTS AND METHODS: The photographic records of 15 female patients who had undergone bilateral upper eyelid surgery were examined. None of the patients underwent lower eyelid or eyebrow surgery. Preoperative and postoperative frontal photographs were projected to a standard size, and measurements were made in a standardized fashion. For the comparison of intrapatient and interpatient relationships, objective anthropometric proportions rather than average measurements were used. Therefore, standard periorbital relationships were recorded and expressed as anthropometric ratios. Measurements were recorded for 30 eyes. The preoperative and postoperative relationships were measured and reported as mean values with standard deviation. The relationships studied were: 1) Upper lid height to orbit height, 2) Lower lid height to orbit height, 3) Lid sulcus height to orbit height, 4) Lid sulcus height to upper lid height, 5) Upper iris coverage to iris height, 6) Lower iris coverage to iris height, 7) Orbit height to middle facial height, 8) Medial brow to orbit height, 9) Lateral brow to orbit height, and 10) Eye fissure height to orbit height. Brow heights were measured vertically from a line connecting exocanthion and endocanthion. RESULTS: The postoperative changes in these patients showed the following: Upper lid height, eye fissure height, and brow position were not significantly affected by upper lid blepharoplasty surgery. The sulcus lid height was doubled postoperatively, and upper iris coverage was decreased slightly postoperatively. CONCLUSIONS: The results of the study indicate that the proposed methodology is appropriate for the objective evaluation of periorbital relationships pertinent to esthetic periorbital surgery. Its use is suggested as a diagnostic aid in preoperative planning and postsurgical evaluation.

Adult↗