The NMDA Type Glutamate Receptors Expressed by Primary Rat Osteoblasts Have the Same Electrophysiological Characteristics as Neuronal Receptors

Cells of mammalian bone express glutamate receptors. Functional N-methyl-D-aspartate (NMDA) receptors have been demonstrated in human, osteoblastic MG-63 cells, but currents in these cells, unlike those of mammalian neurons, are blocked by Mg(2+) in a voltage-insensitive manner. Differences between the characteristics of NMDA currents in bone cells and in neurons may reflect molecular variation of the receptors or associated molecules, with implications for the role(s) of glutamate in these different tissues and for targeting of ligands/antagonists. To determine whether NMDA receptors in primary bone cells are functional, and whether the currents carried by these receptors resemble those of MG-63 cells or those of mammalian neurons, we have applied the whole cell patch clamp technique to primary cultures of rat osteoblasts. In 0-Mg(2+) saline, 25% of cells showed a slowly developing inward current in response to bath perfusion with 1 mM or 100 microM NMDA. Antibodies against NMDA receptors stained approximately 26% of cells. When NMDA was applied by rapid superfusion, kinetics of the currents were similar to those of neuronal NMDA currents, reaching a peak within 20-30 ms. 1 mM Mg(2+) reduced current amplitude at negative holding potentials and caused the I-V relationship of the currents to adopt a 'J' shape rather than the linear relationship seen in the absence of added Mg(2+). Co-application of glycine (20 microM) with NMDA increased current amplitude by only 18%, suggesting that glycine is released from cells within the cultures. Currents were blocked by (+)-MK-801 and DL-2-amino-5-phosphonovaleric acid. Fluorimetric monitoring of [Ca(2+)](i) using fura-2 showed that, in Mg(2+)-free medium, NMDA caused a sustained rise in [Ca(2+)](i) that could be reversed by subsequent application of MK-801. We conclude that rat femoral osteoblasts express functional NMDA receptors and that these receptors differ from those previously identified in MG-63 cells. NMDA receptors of primary osteoblasts show a 'classical' voltage-sensitive Mg(2+) block, similar to that seen in neuronal NMDA receptors, and will therefore function as detectors of coincident receptor activation and membrane depolarization.     

Evidence for Visual Cortical Area Homologs in Cat and Macaque Monkey

The maps of visuotopically discrete visual cerebral corticalareas in the cat and the macaque monkey are compared and gapsin knowledge are identified that limit such comparisons. Catareas 17, 18, and 19 can be equated with macaque areas VI, V2,and V3, respectively, based on criteria of relative positionin the cortical mantle, internal organization of visual fieldrepresentations, and trans- and subcortical connections. Usingthese same criteria, a visual area on the medial bank of thelateral suprasylvian sulcus (area PMLS) in the cat can be equatedwith macaque area V5. The equivalences are supported by dataon neuronal receptive field properties and the contributionsthe areas make to visual behavior. Although the data are scantyfor most other visual areas, there are enough data tentativelyto equate collectively cat areas 20a and 20b with macaque areasTF and TH and to liken cat areas 21a and 21b with macaque areaV4. What is not clear is if there is a region in cat that isequivalent to area TE in the macaque monkey. If there is, itlikely lies on the banks of the posterior suprasylvian sulcusbetween areas 20 and 21 and the polysensory cortex of the posteriorectosylvian gyrus. Knowledge gained from prior research on macaqueareas V4 and TE can be used to formulate specific additionalinvestigations of cat area 21 and the uncharted posterior suprasylviansulcus. In addition, prior investigations carried out on catarea 20 can be used to devise specific explorations of macaqueareas TF and TH.     

Pattern in the Cortical Distribution of Prefrontally Directed Neurons with Divergent Axons in the Rhesus Monkey

Neurons with divergent branched axons have been noted in severalstructures, but their organization across cortical systems,cortical types, or cortical layers is not known. The above questionswere addressed with the aid of multiple fluorescent retrogradetracers injected in one hemisphere of the prefrontal cortexof rhesus monkeys. The prefrontal cortex is well suited forthis study because it receives input from diverse cortical systems.A small number of neurons (     

Estrogen and Progesterone Receptors in Primary Breast Cancer

Abstract: The purpose of this study was to determine biological variable profiles and survival experiences associated with different combinations of estrogen receptor (ER) and progesterone receptor (PR) status (ER+PR+, ER+PR-, ER-PR+, ER-PR-). Data were collected and provided by the State Health Registry (SHR) of Iowa, part of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program. Significant associations were determined for individual prognostic variables with each ER/PR categories, and overall survival was compared between each ER/PR category. Multiple logistic regression analyses were conducted to determine all significant prognostic variables associated with each ER/ PR category. All women diagnosed with primary breast cancer in Iowa from 1990 through 1992 were included in this study (N = 6, 178). In unadjusted analyses, Caucasian woman and older women were significantly more likely to be ER + PR+, while African American women and younger women were significantly more likely to be ER-PR-. In multivariate analyses, each ER/PR category was associated with distinct profile of age, menopausal status, histologic grade, and histology. Survival was best for women in the ER+PR+ group, followed, in decreasing order, by ER+PR-, ER-PR+, and ER-PR-. In this population-based study of primary breast cancer, combined hormone receptor status was a significant prognostic determinant for primary breast cancer, and was associated with distinct biological variables and survival experiences. In combination with other variables such as age, menopausal status, tumor histologic grade, and tumor histology, combined hormone receptor status can provide important prognostic information to the clinician.?     

Involvement of Glutamate Receptors in Strychnine- and Bicuculline-induced Allodynia in Conscious Mice

Background: Glycine and gamma-aminobutyric acid (GABA) are inhibitory neurotransmitters that appear to be important in sensory processing in the spinal dorsal horn. Intrathecal administration of strychnine (strychnine-sensitive glycine receptor antagonist) or bicuculline (GABAA antagonist) was reported to induce allodynia. Although the strychnine-induced allodynia was shown to be mediated through the N-methyl-D-aspartate (NMDA)-type glutamate receptor, it is not clear whether the bicuculline-evoked allodynia is mediated through the glutamate receptor system or how different the allodynia induced by strychnine and bicuculline are.

Methods: Male ddY mice weighing 20+/-2 g were used in this study. A 27-G stainless-steel needle attached to a microsyringe was inserted between the L5 and L6 vertebrae by a slight modification of the method of Hylden and Wilcox. Drugs in vehicle were injected slowly into the subarachnoid space to conscious mice at 22+/-2 degrees Celsius. The volume of the intrathecal injection was 5 micro liter. Studies on allodynia were carried out essentially according to the method of Yaksh and Harty.

Results: The intrathecal administration of strychnine or bicuculline in conscious mice resulted in allodynia elicited by nonnoxious brushing of the flanks. The maximum allodynia induced by strychnine was observed 5 min after intrathecal injection, but that induced by bicuculline was observed 10 min after intrathecal injection. Both responses gradually decreased over the experimental period of 50 min. The allodynia induced by strychnine was dose-dependently relieved by NMDA receptor antagonists (D-AP5, ketamine, and 7-Cl-KYNA) and non-NMDA receptor antagonists (GAMS and CNQX) but not by metabotropic receptor antagonists (L-AP3 and L-AP4). On the other hand, allodynia induced by bicuculline was dose-dependently relieved by GAMS, L-AP3, and L-AP4, but not by D-AP5, ketamine, 7-Cl-KYNA, and CNQX. Whereas the strychnine-evoked allodynia was dose-dependently relieved by the nitric oxide synthase inhibitor Nomega -nitro-L-arginine methyl ester (L-NAME) and the soluble guanylate cyclase inhibitor methylene blue, the bicuculline-induced one was dose-dependently relieved by methylene blue but not by L-NAME.     

Respiratory Depression by Tramadol in the Cat: Involvement of Opioid Receptors

Background: Tramadol hydrochloride (tramadol) is a synthetic opioid analgesic with a relatively weak affinity at opioid receptors. At analgesic doses, tramadol seems to cause little or no respiratory depression in humans, although there are some conflicting data. The aim of this study was to examine whether tramadol causes dose-dependent inhibitory effects on the ventilatory carbon dioxide response curve and whether these are reversible or can be prevented by naloxone.

Methods: Experiments were performed in cats under [alpha]-chloralose-urethane anesthesia. The effects of tramadol and naloxone were studied by applying square-wave changes in end-tidal pressure of carbon dioxide (Petco2; 7.5-11 mmHg) and by analyzing the dynamic ventilatory responses using a two-compartment model with a fast peripheral and a slow central component, characterized by a time constant, carbon dioxide sensitivity, time delay, and a single offset (apneic threshold).

Results: In five animals 1, 2, and 4 mg/kg tramadol (intravenous) increased the apneic threshold (control: 28.3 +/- 4.8 mmHg [mean +/- SD]; after 4 mg/kg: 36.7 +/- 7.1 mmHg;P < 0.05) and decreased the total carbon dioxide sensitivity (control: 109.3 +/- 41.3 ml [middle dot] min-1 [middle dot] mmHg-1) by 31, 59, and 68%, respectively, caused by proportional equal reductions in sensitivities of the peripheral and central chemoreflex loops. Naloxone (0.1 mg/kg, intravenous) completely reversed these effects. In five other cats, 4 mg/kg tramadol caused an approximately 70% ventilatory depression at a fixed Pet co2 of 45 mmHg that was already achieved after 15 min. A third group of five animals received the same dose of tramadol after pretreatment with naloxone. At a fixed Petco2 of 45 mmHg, naloxone prevented more than 50% of the expected ventilatory depression in these animals.     

Reflux Control Following Extended Myotomy in Primary Disordered Motor Activity (Diffuse Spasm) of the Esophagus

We have previously reported the results of extended esophageal myotomy and Belsey hiatal hernia repair in 21 patients. Reflux was considered to be a late complication of this operation, and gastroplasty has subsequently been added.Thirty-four patients have now been surgically treated, 17 with myotomy and Belsey repair and 17 with myotomy, gastroplasty, and Belsey repair. Eight of the 17 with Belsey repair developed clinical and roentgenographic signs of reflux 6 to 27 months following operation without evidence of hernia recurrence; 5 of the 8 patients have required further operation, with the addition of gastroplasty for reflux control. Seventeen patients were treated primarily by extended myotomy, gastroplasty, and Belsey repair. None of the patients who underwent gastroplasty have reflux symptoms, and only 1 shows a trace of reflux radiologically.     

Comparison of Intrinsic Connectivity in Different Areas of Macaque Monkey Cerebral Cortex

We have used small injections of biocytin to label and comparepatterns of intreareal, laterally spreading projections of pyramidalneurons in a number of areas of macaque monkey cerebral cortex.In visual areas (V1, V2, and V4), somatosensory areas (3b, 1,and 2), and motor area 4, a punctate discontinuous pattern ofconnections is made from 200-µm-diameter biocytin injectionsin the superficial layers. In prefrontal cortex (areas 9 and46), stripe-like connectivity patterns are observed. In allareas of cortex examined, the width of the terminal-free gapsis closely scaled to the average diameter of terminal patches,or width of terminal stripes. In addition, both patch and gapdimensions match the average lateral spread of the dendriticfield of single pyramidal neurons in the superficial layersof the same cortical region. These architectural features ofthe connectional mosaics are constant despite a twofold differencein scale across cortical areas and different species. They thereforeappear to be fundamental features of cortical organization.A model is offered in which local circuit inhibitory "basket"interneurons, activated at the same time as excitatory pyramidalneurons, could veto pyramidal neuron connections within eithercircular or stripe-like domains; this could lead to the formationof the pattern of lateral connections observed in this study,and provides a framework for further theoretical studies ofcerebral cortex function.     

Involvement of Peripheral Adenosine A2 Receptors in Adenosine A1 Receptor-Mediated Recovery of Respiratory Motor Function After Upper Cervical Spinal Cord Hemisection

Abstract

Background/Objective: In an animal model of spinal cord injury, a latent respiratory motor pathway can be pharmacologically activated through central adenosine A₁ receptor antagonism to restore respiratory function after cervical (C2) spinal cord hemisection that paralyzes the hemidiaphragm ipsilateral to injury. Although respiration is modulated by central and peripheral mechanisms, putative involvement of peripheral adenosine A₂ receptors in functional recovery in our model is untested. The objective of this study was to assess the effects of peripherally located adenosine A₂ receptors on recovery of respiratory function after cervical (C2) spinal cord hemisection.

Methods: Respiratory activity was electrophysiologically assessed (under standardized recording conditions) in C2-hemisected adult rats with the carotid bodies intact (H-CBI; n = 12) or excised (H-CBE; n = 12). Animals were administered the adenosine A2 receptor agonist, CGS-21680, followed by the A1 receptor antagonist, 1, 3-dipropyl-8-cyclopentylxanthine (DPCPX), or administered DPCPX alone. Recovered respiratory activity, characterized as drug-induced activity in the previously quiescent left phrenic nerve of C2-hemisected animals in H-CBI and H-CBE rats, was compared. Recovered respiratory activity was calculated by dividing drug-induced activity in the left phrenic nerve by activity in the right phrenic nerve.

Results: Administration of CGS-21680 before DPCPX (n = 6) in H-CBI rats induced a significantly greater recovery (58.5 ± 3.6%) than when DPCPX (42.6 ± 4.6%) was administered (n = 6) alone. In H-CBE rats, prior administration of CGS-21680 (n = 6) did not enhance recovery over that induced by DPCPX (n = 6) alone. Recovery in H-CBE rats amounted to 39.7 ± 3.7% and 38.4 + 4.2%, respectively.

Conclusions: Our results suggest that adenosine A2 receptors located in the carotid bodies can enhance the magnitude of adenosine A1 receptor-mediated recovery of respiratory function after C2 hemisection. We conclude that a novel approach of targeting peripheral and central adenosine receptors can be therapeutically beneficial in alleviating compromised respiratory function after cervical spinal cord injury.     

Anatomical Evidence for MT and Additional Cortical Visual Areas in Humans

We stained human visual cortex for myelin. cytochrome oxidase,and the monoclonal antibody CAT-301 in an attempt to demonstrateand map MT (V5) and other visual cortical areas in humans. Bothflattened and unflattened cortical tissue was examined. A likelycandidate for area MT (V5), which we refer to as MT was demonstratedusing all three stains. Myelin and CAT-301 labels for MT weredemonstrated to be coincident by comparing results from thetwo stains in adjacent sections. In all three stains, MT wasan oval area approximately 1.2 x 2.0 cm. located 5–6 cmanterior and dorsal to the foveal V1–V2 border. The positionand size of MT as defined by the present anatomy are consistentwith MT (V5) as defined by functional measures in humans. Inaddition, flattened cortical tissue stained for cytochrome oxidaserevealed a distinctive staining topography in several corticalareas, including areas V1, V2, MT, PX, and VX. Similar studiesin flattened cortex of macaque and green monkeys demonstrateddistinctive dark cytochrome oxidase staining in MT, PX, MTc,and V3.     

Synaptic Mechanisms of Thiopental-induced Alterations in Synchronized Cortical Activity

Background: Anesthetic depth after barbiturate administration has been correlated with distinct electroencephalogram (EEG) patterns. The current study used a rat neocortical brain slice micro-EEG preparation to investigate synaptic mechanisms underlying thiopental-induced transitions in synchronized neuronal activity.

Methods: Concentration-dependent cellular actions of thiopental were investigated in brain slices using specific pharmacologic probes, whole cell patch clamps, and extracellular field recordings. Theta-Like micro-EEG oscillations were elicited in neocortical slices by mimicking subcortical cholinergic and gamma-aminobutyric acid (GABA) afferent input with carbachol (100 micro Meter), a cholinergic agonist, and bicuculline (10 micro Meter) a GABAA antagonist.

Results: In the presence of 20 micro Meter thiopental, micro-EEG slowing from theta (7.3+/-0.9 Hz, mean+/-SD, n = 19) to delta frequencies (2.5+/-0.5 Hz, n = 11) was associated with a threefold prolongation of inhibitory currents. Burst suppression activity occurred at 50 micro Meter thiopental, and appeared to result from direct activation of GABAA -gated chloride currents, observed with voltage clamp recordings, and mimicked with a direct acting GABAA agonist, muscimol (1 micro Meter). Isoelectric activity occurred at 100 micro Meter thiopental, and likely resulted from reduced glutamatergic transmission, evidenced by depressed excitatory postsynaptic potentials. Glutamatergic excitation was required for burst suppression activity, because glutamate receptor antagonists blocked thiopental-induced bursts; forcing a transition to isoelectric activity.     

Prostaglandin D2 Receptors Control Osteoclastogenesis and the Activity of Human Osteoclasts

We recently showed that human osteoblasts synthesize prostaglandin D₂ (PGD₂) and express both DP and CRTH2 receptors. Activation of the DP receptor decreased osteoprotegerin production, whereas activation of the CRTH2 receptor induced osteoblast chemotaxis and decreased RANKL expression. Our objectives in this study were to determine the presence, distribution, and action of these receptors in the functions of human osteoclasts and in osteoclastogenesis. Immunohistochemistry was used to detect the presence of DP and CRTH2 in in vitro–differentiated human osteoclasts in culture and in osteoclasts in situ. The effects of the activation of PGD₂ receptors on the cytoskeleton were determined by fluorescence microscopy. Specific agonists and antagonists allowed the study of the roles of these receptors on bone resorption and osteoclast differentiation. Our results show that in vitro–differentiated human osteoclasts and authentic fetal osteoclasts express both DP and CRTH2 receptors, as shown by immunocytochemistry. Similar results were obtained in osteoclasts from normal, osteoporotic, pagetic, and osteoarthritic adult bone tissues. Stimulation of osteoclasts with PGD₂ induced a robust reorganization of the cytoskeleton with a decrease in the number of cells presenting actin rings and an increase of lamellipodia, effects mediated by the DP and CRTH2 receptors, respectively. PGD₂ showed an inhibitory effect on bone resorption activity acting through the DP receptor. In vitro osteoclastogenesis from peripheral blood mononuclear cells cultured in the presence of RANKL and macrophage‐colony stimulating factor was decreased by activation of either DP or CRTH2 receptors. These results suggest that PGD₂ receptors could be useful targets in certain bone diseases because their specific activation/inhibition leads to a decrease in osteoclastogenesis and to inhibition of bone resorption by osteoclasts.     

Enflurane Directly Depresses Glutamate AMPA and NMDA Currents in Mouse Spinal Cord Motor Neurons Independent of Actions on GABAA or Glycine Receptors

Background: The spinal cord is an important anatomic site at which volatile agents act to prevent movement in response to a noxious stimulus. This study was designed to test the hypothesis that enflurane acts directly on motor neurons to inhibit excitatory synaptic transmission at glutamate receptors.

Methods: Whole-cell recordings were made in visually identified motor neurons in spinal cord slices from 1- to 4-day-old mice. Excitatory postsynaptic currents (EPSCs) or potentials (EPSPs) were evoked by electrical stimulation of the dorsal root entry area or dorsal horn. The EPSCs were isolated pharmacologically into glutamate N-methyl-d-aspartate (NMDA) receptor- and non-NMDA receptor-mediated components by using selective antagonists. Currents also were evoked by brief pulse pressure ejection of glutamate under various conditions of pharmacologic blockade. Enflurane was made up as a saturated stock solution and diluted in the superfusate; concentrations were measured using gas chromatography.

Results: Excitatory postsynaptic currents and EPSPs recorded from motor neurons by stimulation in the dorsal horn were mediated by glutamate receptors of both non-NMDA and NMDA subtypes. Enflurane at a general anesthetic concentration (one minimum alveolar anesthetic concentration) reversibly depressed EPSCs and EPSPs. Enflurane also depressed glutamate-evoked currents in the presence of tetrodotoxin (300 nm), showing that its actions are postsynaptic. Block of inhibitory [gamma]-aminobutyric acid A and glycine receptors by bicuculline (20 [mu]m) or strychnine (2 [mu]m) or both did not significantly reduce the effects of enflurane on glutamate-evoked currents. Enflurane also depressed glutamate-evoked currents if the inhibitory receptors were blocked and if either D,L-2-amino-5-phosphonopentanoic acid (50 [mu]m) or 6-cyano-7-nitroquinoxaline-2,3-dione disodium (10 [mu]m) was applied to block NMDA or [alpha]-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-kainate receptors respectively.     

The Inhibitory Role of Acetylcholine and Muscarinic Receptors in Bladder Afferent Activity

Background

The main treatment for overactive bladder (OAB) is the use of anticholinergic drugs initially believed to inhibit the effect of parasympathetic acetylcholine (ACh) on the detrusor; however, there is now evidence to suggest that anticholinergic drugs could interact with sensory pathways.

Objective

Investigate the role of muscarinic receptors and ACh in modulating bladder afferent sensitivity in the mouse.

Design, setting, and participants

Bladder and surrounding tissue were removed from wild-type male mice, placed in a recording chamber, and continually perfused with fresh oxygenated Krebs solution at 35 °C. Bladders were cannulated to allow infusion and intravesical pressure monitoring, and afferent nerve fibres innervating the bladder were dissected and put into a suction electrode for recording.

Measurements

Multiunit afferent activity and intravesical pressure were recorded at baseline and during bladder distension. Experiments were conducted in the presence of muscarinic agonists and antagonist or in the presence of the cholinesterase inhibitor physostigmine.

Results and limitations

Blocking muscarinic receptors using atropine (1 μM) had no effect on spontaneous afferent discharge, the afferent response to bladder distension, or on bladder compliance. However, stimulation of muscarinic receptors directly using bethanechol (100 μM) and carbachol (100 μM) or indirectly using physostigmine (10 μM) significantly inhibited the afferent response to bladder distension and concurrently reduced bladder compliance. Furthermore, prior application of nifedipine prevented the changes in bladder tone but did not prevent the attenuation of afferent responses by bethanechol or physostigmine.

Conclusions

These data indicate that stimulation of muscarinic receptor pathways can depress sensory transduction by a mechanism independent of changes in bladder tone, suggesting that muscarinic receptor pathways and ACh could contribute to normal or pathologic bladder sensation.     

Multiple Corticospinal Neuron Populations in the Macaque Monkey Are Specified by Their Unique Cortical Origins, Spinal Terminations, and Connections

In primates, multiple corticospinal projections from the sensorimotorcortex operate in concert to regulate voluntary action. We examinedthe soma distributions of all those corticospinal neuron populationsprojecting to different zones in the cervical and more caudalspinal segments in the macaque that are labeled with retrogradelytransported fluorescent tracers; 2–4 differentiable dyeswere injected into different sites in the cervical spinal cordof each of 11 monkeys. Lamina V of the cerebral cortex, in whichall corticospinal neuron somas were located, was unfolded withcomputer assistance to form a flat surface, and local soma densitieswere displayed on this plane as contour and 3-D maps. At leastnine discrete, somatotopically organized corticospinal projectionswere identified. Three separate corticospinal projections originatedin frontal cortex. The first projected mostly from area 4 (     

Sex-Specific Muscular Mediation of the Relationship Between Physical Activity and Cortical Bone in Young Adults

Muscle mass is a commonly cited mediator of the relationship between physical activity (PA) and bone, representing the mechanical forces generated during PA. However, neuromuscular properties (eg, peak force) also account for unique portions of variance in skeletal outcomes. We used serial multiple mediation to explore the intermediary role of muscle mass and force in the relationships between cortical bone and moderate-to-vigorous intensity PA (MVPA). In a cross-sectional sample of young adults (n = 147, 19.7 ± 0.7 years old, 52.4% female) cortical diaphyseal bone was assessed via peripheral quantitative computed tomography at the mid-tibia. Peak isokinetic torque in knee extension was assessed via Biodex dynamometer. Thigh fat-free soft tissue (FFST) mass, assessed via dual-energy X-ray absorptiometry, represented the muscular aspect of tibial mechanical forces. Habitual MVPA was assessed objectively over 7 days using Actigraph GT3X+ accelerometers. Participants exceeded MVPA guidelines (89.14 ± 27.29 min/day), with males performing 44.5% more vigorous-intensity activity relative to females (p < 0.05). Males had greater knee extension torque and thigh FFST mass compared to females (55.3%, and 34.2%, respectively, all p < 0.05). In combined-sex models, controlling for tibia length and age, MVPA was associated with strength strain index (pSSI) through two indirect pathways: (i) thigh FFST mass (b = 1.11 ± 0.37; 95% CI, 0.47 to 1.93), and (i) thigh FFST mass and knee extensor torque in sequence (b = 0.30 ± 0.16; 95% CI, 0.09 to 0.73). However, in sex-specific models MVPA was associated with pSSI indirectly through its relationship with knee extensor torque in males (b = 0.78 ± 0.48; 95% CI, 0.04 to 2.02) and thigh FFST mass in females (b = 1.12 ± 0.50; 95% CI, 0.37 to 2.46). Bootstrapped CIs confirmed these mediation pathways. The relationship between MVPA and cortical structure appears to be mediated by muscle in young adults, with potential sex-differences in the muscular pathway. If confirmed, these findings may highlight novel avenues for the promotion of bone strength in young adults. © 2019 American Society for Bone and Mineral Research.     

A Comparison of Primary and Secondary Rhytidectomy Results

Background  

This study aimed to evaluate the authors’ surgical experience with secondary rhytidectomy and to compare these results with those for primary rhytidectomy patients.     

Primary and Secondary Displacement of Central Venous Catheters

The purpose of this study was to investigate the frequency of primary and secondary displacement of central venous catheters. One hundred and two central venous catheters, inserted through a peripheral or a central vein before surgery or in the intensive care unit, were controlled by chest X-ray 5–720 min after insertion. The number of primarily displaced catheters was 27. Of these, the position was corrected in 8. Thereafter, the 83 correctly placed catheters were observed for 4–560 h. The number of X-ray controls was 2–24. The number of secondary displacements was 2 , whereas 12 catheters showed minimal secondary displacement. The rate of complications was very low.
We conclude that chest X-ray immediately after insertion of central venous catheters is absolutely necessary, but since the number of secondary displacements is very low, daily chest X-ray control is not necessary. We also conclude that the internal jugular vein is the best route for introducing a central venous catheter, since complications are very few and the number of displacements is very low.     

Usefulness of Motor Functional MRI Correlated to Cortical Mapping in Rolandic Low-Grade Astrocytomas

Summary  The indications for surgery of slow growing tumours like low grade astrocytomas in eloquent areas are difficult. The timing and the benefit/risk ratio of the surgery must be evaluated, taking into account the potential post operative deficit. The purpose of this study was: a) to validate the data obtained with functional MRI (FMRI) by direct cortical stimulation in patients who are candidate for surgery; b) to demonstrate the usefulness of FMRI coupled with cortical brain mapping and 3D reconstructions of the surfaces of the brain in low grade astrocytoma. FMRI of the hand-motor cortex was performed in 8 patients with low grade astrocytomas. They subsenquently underwent direct cortical mapping to correlate the results of FMRI and resective surgery sparing the functional area. In the 8 cases, the results of direct cortical mapping in the precentral region matched accurately those obtained from FMRI. When surgical resection of low grade astrocytoma in the motor areas is considered, FMRI used with intra-operative cortical mapping can help the surgeon to spare functional areas during tumour removal.