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At least 883 records · Page 49Linked to original sources
PubMed1998

Lateral approach to the orbit: an anatomical study.

The authors have identified and described three lateral approaches to the intraorbital portion of the optic nerve in cadavers. The structures exposed via the superior, inferior or central approaches were directed through the lateral orbital wall. The superior approach in which the lateral rectus muscle is retracted inferiorly exposes the superolateral aspect of the orbit. The inferior approach in which the lateral rectus muscle is retracted superiorly, provided the inferolateral aspect of the optic nerve from the globe to the muscle cone. The central approach in which the lateral rectus muscle was disinserted and retracted provided excellent exposure of the structures of the lateral part of the orbit and the optic nerve. There were no structures blocking access to the ciliary ganglion and two third anterior optic nerve and lateral surface of the globe. The structures encountered in these approaches are demonstrated under magnification in cadavers, and the exposure of the optic nerve is discussed.

Facial Muscles↗
PubMed2000

Lateral spike conduction velocity in the visual cortex affects spatial range of synchronization and receptive field size without visual experience: a learning model with spiking neurons.

Classical receptive fields (cRF) increase in size from the retina to higher visual centers. The present work shows how temporal properties, in particular lateral spike velocity and spike input correlation, can affect cRF size and position without visual experience. We demonstrate how these properties are related to the spatial range of cortical synchronization if Hebbian learning dominates early development. For this, a largely reduced model of two successive levels of the visual cortex is developed (e.g., areas V1 and V2). It consists of retinotopic networks of spiking neurons with constant spike velocity in lateral connections. Feedforward connections between level 1 and 2 are additive and determine cRF size and shape, while lateral connections within level 1 are modulatory and affect the cortical range of synchronization. Input during development is mimicked by spike trains with spatially homogeneous properties and a confined temporal correlation width. During learning, the homogeneous lateral coupling shrinks to limited coupling structures defining synchronization and related association fields (AF). The size of level-1 synchronization fields determines the lateral coupling range of developing level-1-to-2 connections and, thus, the size of level-2 cRFs, even if the feedforward connections have distance-independent delays. AFs and cRFs increase with spike velocity in the lateral network and temporal correlation width of the input. Our results suggest that AF size of V1 and cRF size of V2 neurons are confined during learning by the temporal width of input correlations and the spike velocity in lateral connections without the need of visual experience. During learning from visual experience, a similar influence of AF size on the cRF size may be operative at successive levels of processing, including other parts of the visual system.

Action Potentials↗
PubMed2003

Patients with lateral tracking patella have better pain relief following CT-guided tuberosity transfer than patients with unstable patella.

In patients with either lateral tracking patella or unstable patella the pathological lateral position of the tuberosity can be corrected by a medial transfer. This study compared the results of subtle CT-guided correction of the tuberosity for objective unstable patella (n=27) with the results for lateral tracking patella (potential instability) as described by Dejour (n=16). Follow-up was 37 months. CT revealed a pathological lateralization of the tibial tuberosity-trochlear groove greater than 15 mm in 41 knees. These patients underwent medialization of the tibial tuberosity up to 10-12 mm lateral from the trochlear groove, and 28 patients underwent a distalization to normalize the Caton index to 1.0-1.2. Results were evaluated using Cox' method. Patients with objective patellar instability were rated as 11% excellent, 52% good, 33% fair, and 4% poor. All patients became stable except one who had a 6 degrees valgus alignment. Although 96% had improved stability, 33% of the patients still had pain. The patients with lateral tracking patella (potential instability) were rated as 37.5% excellent, 44% good, and 19% fair. The lower proportion of pain relief in patients with unstable patella is likely the result of the cartilage damage experienced by these patients following multiple dislocations. Thus the patient with lateral tracking patella without patella dislocations must be differentiated from the one with unstable patella. Their prognosis in pain relief is better.

Cohort Studies↗
PubMed2001

Local lateral connectivity of inhibitory clutch cells in layer 4 of cat visual cortex (area 17).

To characterise spatially a major component of the anatomical basis of local lateral inhibition in layer 4 of cat visual cortex (area 17), we analysed the lateral distribution of neuronal somata postsynaptic to electrophysiologically characterised GABAergic clutch (basket) cell axons (CC1 and CC2). We report two main results. First, the clutch cell axons appear to show isotropic lateral connectivity near their cell body (less than 50 microm radius), but beyond this core region they show anisotropic lateral connectivity, preferring particular angular sectors around their cell body. Second, we estimated the probability of lateral connection for each axon arbor as a function of radial distance from the parent soma. We found that this radial function has a brief rising phase, to a peak at 30-45 microm, and a longer, exponential decaying phase, with a space constant of around 50 microm. The shape of the radial connection probability function suggests that most lateral inhibitory connections of clutch cells are formed with neurons in nearest-neighbour cortical columns. Taken together, the results suggest that these individual layer-4 clutch cell axons may inhibit all (isotropic) nearest-neighbour cortical columns with a relatively high probability of connection, but outside this core region may provide a type of anisotropic lateral inhibition of cortical columns with a radially decreasing probability of connection.

Animals↗
PubMed2003

Evaluation of vertebral fractures on lateral chest radiographs of inner-city postmenopausal women.

We assessed the prevalence of vertebral fractures as a marker for osteoporosis on lateral chest radiographs in inner-city, minority, postmenopausal women. We reviewed outpatient lateral chest radiographs on all women 55 years and older at an inner-city hospital during two randomly selected months, August 2000 and April 2002. There were 106 women with a mean age of 65 (range 55-89) years, 45 were Hispanic, 42 Black, 9 White, 10 of other ethnicity. Deformity was graded on a 0-3 scale with Grades 2 (moderate) and 3 (severe) deformities considered fractures. Interval lateral chest radiographs within 1-2 years were evaluated. Of the group 25% (26/106) had vertebral fractures. The fracture prevalence increased with age: 13% (17/54) of women under 65 years and 37% (19/52) of women 65 years and older had fractures ( P < 0.05). The fracture was described as part of the radiographic report in only 15% (4/26) of the women. Of the group 15% (16/106) had interval lateral chest radiographs. Among those with interval lateral chest radiographs, 19% (3/16) developed new fractures. In this series 29% (31/106) of women were scheduled for bone density studies, but the studies were only completed in 6% (6/106). Lateral chest radiographs showed that vertebral fractures occurred commonly, increased with age, and progressed on follow-up. In a population of underserved minority women, the lateral chest radiograph provides an opportunity to identify women with osteoporosis for possible treatment.

Aged↗
PubMed2007

Lateral and mediastinal lymph node dissection in differentiated thyroid carcinoma: indications, benefits, and risks.

BACKGROUND: There are 3 compartments of regional lymph nodes to which thyroid carcinoma metastasizes: central, lateral, and mediastinal compartments. The central compartment is the nearest to the thyroid and usually dissected routinely. However, the indication for dissection of the lateral and mediastinal compartments for differentiated thyroid carcinoma remains an open question. METHODS: The indication for dissection of lateral and mediastinal compartments is evaluated based on previous reports, including those from our department. RESULTS: There is nothing controversial about the indication for therapeutic lateral node dissection for tumors with clinically apparent lateral node metastasis. Such cases are more likely to show recurrence, especially in previously dissected compartments, and surgeons must perform dissection carefully. Although there are no randomized studies on the indication for prophylactic lateral node dissection, it is recommended for papillary carcinoma with aggressive characteristics such as large size and massive extrathyroid extension. Prophylactic mediastinal dissection via median sternotomy is not recommended. CONCLUSIONS: Node dissection of the lateral and mediastinal compartments must be performed aggressively and radically to prevent recurrence in previously dissected regions.

Adenocarcinoma, Follicular↗
PubMed2006

Lateral flexion in Parkinson's disease and Pisa syndrome.

Various types of abnormal posture are observed in Parkinson's disease (PD). Lateral flexion is very common and frequent among them. The clinical characteristics of lateral flexion in PD vary and are classified into two types, the chronic and subchronic types. The chronic type of lateral flexion in PD appears subclinically and worsens, which is related to the laterality of parkinsonian symptoms and the progression of the disease. The subchronic type of lateral flexion in PD develops subacutely and worsens rapidly in several months. An atypical and rare type of tonic truncal dystonia, Pisa syndrome, may be induced following the intake of neuroleptics. The clinical features of the subchronic type of lateral flexion in PD are similar to those of Pisa syndrome. Differences between lateral flexion in PD and Pisa syndrome are described.

Dyskinesias↗
PubMed1998

Radical resection with autonomic nerve preservation and lymph node dissection techniques in lower rectal cancer surgery and its results: the impact of lateral lymph node dissection.

Lateral lymph node metastases occur in 9% of rectal cancer patients. For cancers localized in the lower rectum below peritoneal reflection, the frequency increases to 13% of all cases and to 25.5% in those of Dukes' stage C. The most important technique in colorectal surgery for decreasing local failure in the pelvis is lateral lymph node dissection. Today, however, it is also regarded as crucial that with perfect lymph node dissection of the lateral area outside of the pelvic plexus, the postoperative functions of urination and sexual ability are preserved. Since 1988 we have performed autonomic nerve-preserving curative resection (ANP) with lateral dissection in most patients with advanced lower rectal cancer. The mean 5-year survival rate of patients with lateral lymph node metastasis from the lower rectum was 37.5%, improving from 32.1% to 43.4% during this period. In cases of ANP with lateral dissection the local recurrence rate was 4.8% overall and 7.4% in the Dukes' C group. Postoperative urinary function has been good or fair in all ANP patients. Sexual function remained problematic, especially regarding male ejaculation. We describe our method for preserving the autonomic nervous system in the pelvis and for achieving complete dissection in the lateral area.

Autonomic Nervous System↗
PubMed2002

Inhibition of tobacco mosaic virus replication in lateral roots is dependent on an activated meristem-derived signal.

Viral invasion of the root system of Nicotiana benthamiana was studied noninvasively with a tobacco mosaic virus (TMV) vector expressing the green-fluorescent protein (GFP). Lateral root primordia, which developed from the pericycle of primary roots, became heavily infected as they emerged from the root cortex. However, following emergence, a progressive wave of viral inhibition occurred that originated in the lateral-root meristem and progressed towards its base. Excision of source and sink tissues suggested that the inhibition of virus replication was brought about by the basipetal movement of a root meristem signal. When infected plants were inoculated with tobacco rattle virus (TRV) expressing the red-fluorescent protein, DsRed, TRV entered the lateral roots and suppressed the host response, leading to a reestablishment of TMV infection in lateral roots. By infecting GFP-expressing transgenic plants with TMV carrying the complementary GFP sequence it was possible to silence the host GFP, leading to the complete loss of fluorescence in lateral roots. The data suggest that viral inhibition in lateral roots occurs by a gene-silencing-like mechanism that is dependent on the activation of a lateral-root meristem.

Gene Silencing↗
PubMed2005

Importance of the lateral anatomic tibial slope as a guide to the tibial cut in total knee arthroplasty in Japanese patients.

Using three-dimensional computed tomography in 50 osteoarthritic knees, we simulated at various cutting angles the tibial cut for total knee arthroplasty. Cutting angles of 0 degrees, 3 degrees, 5 degrees, 7 degrees, 9 degrees, and 11 degrees were used. We then calculated the anterior and posterior thicknesses, the medial-lateral widths, and the medial and lateral condylar depths of the resected tibial bone at each cutting angle. Each set of measurements was evaluated according to a comparison between the cutting angle and the anatomic posterior slopes. The cutting angles showing the smallest anterior-posterior difference at the medial and lateral plateaus were 9 degrees and 7 degrees, respectively. The mean anatomic posterior slopes at the medial and lateral plateaus were 9.0 degrees and 8.1 degrees, respectively. When the tibia was cut at the cutting angle closest to the medial anatomical posterior slope in each knee, the thickness of the lateral posterior plateaus resected from 12 knees (24%) was more than 10 mm. Among these 12 knees, the cutting angle was more than 9 degrees in 9 knees (75%). In contrast, when the tibia was cut at the cutting angle closest to the lateral anatomical posterior slope, only one resected medial posterior plateau was more than 10 mm. The cutting angle of this case was 7 degrees. Therefore, in consideration of the thickness of bone resection from anatomic posterior slope, we demonstrated the importance of using the lateral anatomic posterior tibial slope as a guide to the tibial cut. There was no significant difference with respect to resected bone morphology at any cutting angle.

Aged↗
PubMed1998

Do occlusal carious lesions spread laterally at the enamel-dentin junction? A histolopathological study.

It is conventionally taught that the carious lesion in dentin undermines the enamel due to lateral spread of the lesion at the enamel-dentin junction (EDJ). The aim of the present study was to challenge this hypothesis by testing an alternative hypothesis, that lateral spread is related to advanced lesions where the dentin is infected. Selected points in the groove-fossa system of 100 unrestored occlusal surfaces were examined and the teeth divided into five groups (scores 0-4) depending on the clinical appearance of the lesion. Teeth were sectioned through these sites and texture of the dentin was assessed by probing. Colour slides of the section face with the more extensive changes in the dentin were projected and the dimensions of the lesions at the EDJ were assessed by three examiners on two separate occasions. Inter- and intra-examiner reproducibility was assessed and found acceptable. Results showed that in 47 teeth demineralisation had not reached the EDJ. In the remaining teeth the presence or absence of lateral spread of the lesion at the EDJ was related to the clinical features of the lesion. Lateral spread was rarely found in lesions with an apparently intact enamel surface (scores 0-2). However, 32% of sites with microcavitation (score 3) and 63% of sites with obvious cavitation (score 4) showed lateral spread. Of those 31 sections which were judged to have soft dentin, 80% had lateral spread. In conclusion, the phenomenon of lateral spread of caries at the FDJ is related to advanced lesions with cavity formation where the dentin is soft and infected.

Bicuspid↗
PubMed2002

Structural microdomains in the lateral plasma membrane of cochlear outer hair cells.

The basal and lateral regions of the plasma membrane of cochlear outer hair cells are structurally and functionally distinct. The lateral region contains thousands of motor proteins but few voltage-gated channels. The basal region, conversely, contains a high number of voltage-gated channels but is devoid of motor proteins. It has been suggested that the cortical cytoskeleton is responsible for maintaining this regional distinction. Toward elucidating the structure of the outer hair cell's electromotile mechanism, we investigated the physical organization of the lateral plasma membrane in living guinea pig outer hair cells by analyzing the distribution pattern of the anionic long-chain carbocyanine SP-DiIC18(3) within this area, before and after electrical stimulation and with an intact and a disrupted cytoskeleton. We observed punctate, intensely fluorescent patches as well as areas of weaker fluorescence, with clear local maxima and minima, upon labeling the cells with this membrane-soluble probe. This discrete distribution of SP-DilC18(3) suggests that the lateral plasma membrane of guinea pig outer hair cells may be composed of small structural domains (microdomains). Disrupting the cytoskeleton with either trypsin or toxin B from Clostridium difficile did not change this pattern of distribution, thus indicating that this treatment did not facilitate the lateral diffusion of the probes. Electrical stimulation using whole-cell patch-clamp techniques, on the other hand, induced two responses: fast motility and reversible displacement of the fluorescent probes. Both responses were inhibited by internal perfusion with salicylate, while disruption of the cytoskeleton did not inhibit OHC fast motility but affected the electrically induced redistribution of fluorescent probes. Together, these results suggest that the lateral plasma membrane of guinea pig outer hair cells contains structural microdomains and that the cytoskeleton does not appear to be playing a major role in maintaining the lateral separation of these distinct molecular regions.

Animals↗
PubMed2006

An auxin-inducible F-box protein CEGENDUO negatively regulates auxin-mediated lateral root formation in Arabidopsis.

Previously, we characterized 92 Arabidopsis genes (AtSFLs) similar to the S-locus F-box genes involved in S-RNase-based self-incompatibility and found that they likely play diverse roles in Arabidopsis. In this study, we investigated the role of one of these genes, CEGENDUO (CEG, AtSFL61), in the lateral root formation. A T-DNA insertion in CEG led to an increased lateral root production, which was complemented by transformation of the wild-type gene. Its downregulation by RNAi also produced more lateral roots in transformed Arabidopsis plants whereas its overexpression generated less lateral roots compared to wild-type, indicating that CEG acts as a negative regulator for the lateral root formation. It was found that CEG was expressed abundantly in vascular tissues of the primary root, but not in newly formed lateral root primordia and the root meristem, and induced by exogenous auxin NAA (alpha-naphthalene acetic acid). In addition, the ceg mutant was hyposensitive to NAA, IAA (indole-3-acetic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid), as well as the auxin transport inhibitor TIBA (3,3,5-triiodobenzoic acid), showing that CEG is an auxin-inducible gene. Taken together, our results show that CEG is a novel F-box protein negatively regulating the auxin-mediated lateral root formation in Arabidopsis.

Arabidopsis↗
PubMed1996

Lateral tunnel suture line variation reduces atrial flutter after the modified Fontan operation.

BACKGROUND: Atrial flutter (AFL) is a common postoperative sequela of the modified Fontan operation, or total cavopulmonary connection. We hypothesized that injury to the crista terminalis (CT) by the lateral tunnel suture line contributes to the development of AFL in this setting. This study was designed to determine the effects of alteration of the lateral tunnel suture line, relative to the CT, on the inducibility of AFL in an acute canine model of the modified Fontan operation. METHODS: Adult mongrel dogs (n = 25) underwent a median sternotomy and normothermic cardiopulmonary bypass. In groups 1, 2, and 3, through a right atriotomy, a suture line was placed to simulate the lateral tunnel of the modified Fontan operation (n = 20). The lateral aspect of the suture line ran along the CT in group (n = 10), 5 mm medial to the CT in group 2 (n = 5), and 10 mm anterior to the CT, incorporated into the atriotomy closure, in group 3 (n = 5). In group 4 (n = 5), only the lateral portion of the suture line, along the CT, was placed. Form-fitting 253-point unipolar endocardial mapping electrodes were inserted in the left and right atria via bilateral ventriculotomies. Induction of AFL was then attempted using atrial burst pacing. If sustained AFL could not be induced, isoproterenol was administered and the pacing protocol repeated. Endocardial activation sequence maps of spontaneous rhythm and AFT were constructed. RESULTS: Under baseline conditions, after placement of the suture line, sustained AFL could reproducibly be induced in 8/10 dogs in group 1, 0/5 dogs in group 2, 0/5 dogs in group 3, and 5/5 dogs in group 4 (p < 0.001). After isoproterenol administration, sustained AFL was reproducibly inducible in the remaining 2 dogs in group 1, 4/5 dogs in group 2, and 0/5 dogs in group 3 (p = 0.01). The mean cycle length of AFL was 189 +/- 25 ms in group 1, 136 +/- 8 ms in group 2, and 182 +/- 20 ms in group 4 (p < 0.001). Atrial activation sequence maps, during sinus rhythm, demonstrated a line of conduction block along the lateral portion of the suture line in all cases in groups 1 and 4 and in only those cases in group 2 in which sustained AFL was inducible. During AFL this block facilitated unidirectional conduction, permitting propagation of the reentrant wavefront. Mean conduction velocity along the CT during sinus rhythm was 0.63 +/- 0.10 m/s in group 1, 1.04 +/- 0.17 m/s in group 2, 1.01 +/- 0.12 m/s in group 3, and 0.44 +/- 0.13 m/s in group 4 (p < 0.01). CONCLUSIONS: In an acute canine model of the modified Fontan operation, conduction block imposed by the lateral tunnel suture line is an essential component of the AFL circuit. The inducibility of AFL is increased by suture line placement along the CT. Slow conduction, resulting from injury to the CT, promotes this increased inducibility. Avoidance of the CT may reduce the incidence of AFL in children undergoing the modified Fontan operation.

Animals↗
PubMed1995

Biomechanical implications of lateral pterygoid contribution to biting and jaw opening in humans.

The contributions of the lateral pterygoid muscle to a variety of different tasks were analysed by a linear programming mode based on the equations for static equilibrium in three dimensions and containing 12 muscles. The model was used to study lateral pterygoid activity at maximum bite force (MBF) for changes in (i) the direction and point of application of the bite force, (ii) the orientation of the masseter and medial pterygoid muscles and (iii) the slope of the articular eminence (glenoid slope). The effects on MBF of removing one or both lateral pterygoids were also examined. Lateral pterygoid provided a very important indirect contribution to some clenching forces. Under some conditions removing one lateral pterygoid muscle (simulating guarding an injured muscle) halved the MBF. Its activity at MBF was reduced as masseter was tilted more forward, the glenoid slope was made more horizontal and the bite force was made more vertical. The muscle helped to oppose (balance) the horizontal reaction forces at the bite point and joints, which potentially pushed the condyle backward. A balancing muscle is now defined as one (like lateral pterygoid) whose activity increases the output force by far more than its direct contribution to that force. In a larger model containing 16 muscles, every muscle was most active when its line of action was parallel to the output force. Finally, in a model which divided lateral pterygoid into superior and inferior heads, activity suddenly switched from the superior head to the inferior head when the angle of opening changed from 120 degrees (forward from the vertical) to 140 degrees.

Biomechanical Phenomena↗
PubMed1977

Preparation of renal cortex basal-lateral and bursh border membranes. Localization of adenylate cyclase and guanylate cyclase activities.

Luminal brush border and contraluminal basal-lateral segments of the plasma membrane from the same kidney cortex were prepared. The brush border membrane preparation was enriched in trehalase and gamma-glutamyltranspeptidase, whereas the basal-lateral membrane preparation was enriched in (Na+ + K+1)-ATPase. However, the specific activity of (Na+ + K+)-ATPase in brush border membranes also increased relative to that in the crude plasma membrane fraction, suggesting that (Na+ + K+)-ATPase may be an intrinsic constituent of the renal brush border membrane in addition to being prevalent in the basal-lateral membrane. Adenylate cyclase had the same distribution pattern as (Na+ + K+)-ATPase, i.e. higher specific activity in basal-lateral membranes and present in brush border membranes. Adenylate cyclase in both membrane preparations was stimulated by parathyroid hormone, calcitonin, epinephrine, prostaglandins and 5'-guanylylimidodiphosphate. When the agonists were used in combination enhancements were additive. In contrast to the distribution of adenylate cyclase, guanylate cyclase was found in the cytosol and in basal-lateral membranes with a maximal specific activity (NaN3 plus Triton X-100) 10-fold that in brush border membranes. ATP enhanced guanylate cyclase activity only in basal-lateral membranes. It is proposed that guanylate cyclase, in addition to (Na+ + K+)-ATPase, be used as an enzyme "marker" for the renal basal-lateral membrane.

Adenosine Triphosphate↗
PubMed1995

Visualization of lateral phases in cholesterol and phosphatidylcholine monolayers at the air/water interface--a comparative study with two different reporter molecules.

This study has compared two chemically distinct NBD-lipids with regard to their partitioning properties into lateral phases of pure and mixed cholesterol/phosphatidylcholine monolayers. Pure NBD-cholesterol (22-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor++ +-5-cholen-3-ol), which has the NBD-function in the sterol side chain (at carbon 22), gave a liquid-expanded force-area isotherm on water at 22 degrees C (having a compressibility of 0.005 to 0.007 m/mN), although epifluorescence microscopy of the compressed NBD-cholesterol monolayer revealed that it had a solid-like surface texture. When the compressed NBD-cholesterol monolayer was allowed to expand, it fragmented into large flakes (tens to hundreds of microns in width) which eventually dissolved into a liquid state. The force-area isotherm of pure NBD-phosphatidylcholine (1-hexadecanoyl-2-(12-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dod ecyl-sn- glycero-3-phosphocholine) was also liquid-expanded. When a compressed (30 mN/m) monolayer of NBD-phosphatidylcholine was examined by microscopy, it displayed many bright crystalline spots (about 50 microns across) which appeared to form when the monolayer was allowed to stabilize at this lateral surface pressure. These bright spots disappeared when the monolayer was expanded. When the surface texture of a pure cholesterol monolayer was examined, both probes (at 1 mol%) partitioned very similarly in the sterol monolayer. At low lateral surface pressures (1 and 5 mN/m) the probes appeared to be excluded from the cholesterol phase, forming very bright liquid-like areas against a uniformly black cholesterol phase. At 30 mN/m, NBD-phosphatidylcholine appeared to distribute increasingly into the cholesterol phase, whereas NBD-cholesterol still did not to mix with cholesterol. The characteristic surface texture of the liquid-expanded to liquid-condensed lateral phase transition of pure dipalmitoyl phosphatidylcholine (DPPC) monolayers could be visualized identically with both probes, indicating that these were similarly excluded from the liquid-condensed solid phase of DPPC. Finally, in mixed monolayers containing cholesterol and DPPC (molar ratio 33:67), both probes (at 1 mol%) revealed a similar surface texture of the monolayers (examined at a lateral surface pressure of 0.5 mN/m), suggesting that these partitioned similarly between the different lateral phases present in the mixed monolayer. In conclusion, although the two NBD-probes differed from each other in chemical and physical properties, both acted like 'impurities' when admixed into pure or mixed monolayers, and appeared to be equally excluded from lateral phases in which the packing density was high.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1975

An autoradiographic study of the projections from the lateral geniculate body of the rat.

The projections from the lateral geniculate body of the rat were followed using the technique of autoradiography after injections of [3H] proline into the dorsal and/or ventral nuclei of this diencephalic structure. Autoradiographs were prepared from either frozen or paraffin coronal sections through the rat brain. The dorsal nucleus of the lateral geniculate projected via the optic radiation to area 17 of the cerebral cortex. There was also a slight extension of label into the zones of transition between areas 17, 18 and 18a. The distribution of silver grains in the various layers of the cerebral cortex was analyzed quantitatively and showed a major peak of labeling in layer IV with minor peaks in outer layer I and the upper half and lowest part of layer VI. The significance of these peaks is discussed in respect to the distribution of geniculocortical terminals in other mammalian species. The ventral nucleus of the lateral geniculate body had 5 major projections to brain stem structures both ipsilateral and contralateral to the injected nucleus. There were two dorsomedial projections: (1) a projection to the superior colliculus which terminated mainly in the medial third of the stratum opticum, and (2) a large projection via the superior thalamic radiation which terminated in the ipsilateral pretectal area; a continuation of this projection passed through the posterior commissure to attain the contralateral pretectal area. The three ventromedial projections involved: (1) a geniculopontine tract which coursed through the basis pedunculi and the lateral lemniscus to terminate in the dorsomedial and dorsolateral parts of the pons after giving terminals to the lateral terminal nucleus of the accessory optic tract, (2) a projection via Meynert's commissure to the suprachiasmatic nuclei of both sides of the brain stem as well as to the contralateral ventral lateral geniculate nucleus and lateral terminal nucleus of the accessory optic tract, and (3) a medial projection to the ipsilateral zona incerta. The results obtained in these experiments are contrasted with other data on the rat's central visual connections to illustrate the importance of these connections in many subcortical visual functions.

Animals↗