Kv7/M channel dysfunction produces hyperexcitability in hippocampal CA1 pyramidal cells of Fmr1 knockout mice.

Fragile X syndrome (FXS), the most frequent monogenic form of intellectual disability, is caused by transcriptional silencing of the FMR1 gene that could render neuronal hyperexcitability. Here we show that pyramidal cells (PCs) in the dorsal CA1 region of the hippocampus elicited a larger action potential (AP) number in response to suprathreshold stimulation in juvenile Fmr1 knockout (KO) than wild-type (WT) mice. Because Kv7/M channels modulate CA1 PC excitability in rats, we investigated if their dysfunction produces neuronal hyperexcitability in Fmr1 KO mice. Immunohistochemical and western blot analyses showed no differences in the expression of Kv7.2 and Kv7.3 channel subunits between genotypes; however, the current mediated by Kv7/M channels was reduced in Fmr1 KO mice. In both genotypes, bath application of XE991 (10 µM), a blocker of Kv7/M channels: produced an increased AP number, produced an increased input resistance, produced a decreased AP voltage threshold and shaped AP medium afterhyperpolarization by increasing mean velocities. Retigabine (10 µM), an opener of Kv7/M channels, produced opposite effects to XE991. Both XE991 and retigabine abolished differences in all these parameters found in control conditions between genotypes. Furthermore, a low concentration of retigabine (2.5 µM) normalized CA1 PC excitability of Fmr1 KO mice. Finally, ex vivo seizure-like events evoked by 4-aminopyiridine (200 µM) in the dorsal CA1 region were more frequent in Fmr1 KO mice, and were abolished by retigabine (5-10 µM). We conclude that CA1 PCs of Fmr1 KO mice exhibit hyperexcitability, caused by Kv7/M channel dysfunction, and increased epileptiform activity, which were abolished by retigabine. KEY POINTS: Dorsal pyramidal cells of the hippocampal CA1 region of Fmr1 knockout mice exhibit hyperexcitability. Kv7/M channel activity, but not expression, is reduced in pyramidal cells of the hippocampal CA1 region of Fmr1 knockout mice. Kv7/M channel dysfunction causes hyperexcitability in pyramidal cells of the hippocampal CA1 region of Fmr1 knockout mice by increasing input resistance, decreasing AP voltage threshold and shaping medium afterhyperpolarization. A Kv7/M channel opener normalizes neuronal excitability in pyramidal cells of the hippocampal CA1 region of Fmr1 knockout mice. Ex vivo seizure-like events evoked in the dorsal CA1 region were more frequent in Fmr1 KO mice, and such an epileptiform activity was abolished by a Kv7/M channel opener depending on drug concentration. Kv7/M channels may represent a therapeutic target for treating symptoms associated with hippocampal alterations in fragile X syndrome.

2023 GEIS Guidelines for gastrointestinal stromal tumors.

Gastrointestinal stromal tumor (GIST) is the most common malignant neoplasm of mesenchymal origin. GIST spans a wide clinical spectrum that ranges from tumors with essentially no metastatic potential to malignant and life-threatening spread diseases. Gain-of-function mutations in KIT or PDGFRA receptor tyrosine kinases are the crucial drivers of most GISTs, responsible for tumor initiation and evolution throughout the entire course of the disease. The introduction of tyrosine kinase inhibitors targeting these receptors has substantially improved the outcomes in this formerly chemoresistant cancer. As of today, five agents hold regulatory approval for the treatment of GIST: imatinib, sunitinib, regorafenib, ripretinib, and avapritinib. This, in turn, represents a success for a rare neoplasm. During the past two decades, GIST has become a paradigmatic model in cancer for multidisciplinary work, given the disease-specific particularities regarding tumor biology and tumor evolution. Herein, we review currently available evidence for the management of GIST. This clinical practice guideline has been developed by a multidisciplinary expert panel (oncologist, pathologist, surgeon, molecular biologist, radiologist, and representative of patients' advocacy groups) from the Spanish Group for Sarcoma Research, and it is conceived to provide, from a critical perspective, the standard approach for diagnosis, treatment, and follow-up.

Spatial localization and projection densities of brainstem mossy fibre afferents to the forelimb C1 zone of the rat cerebellum.

The present study uses a double retrograde tracer technique in rats to examine the spatial localization and pattern of axonal branching in mossy fibres arising from three major sources in the medulla-the external cuneate nucleus, the sensory trigeminal nucleus and the reticular formation, to two electrophysiologically-identified parts of the cerebellar cortex that are linked by common climbing fibre input - the forelimb-receiving parts of the C1 zone in lobulus simplex and the paramedian lobule. In each experiment a small injection of rhodamine-tagged beads was injected into one cortical region and an injection of fluorescein-tagged beads was injected into the other region. The main findings were: (i) the proportion of double-labelled cells in each of the three precerebeller sources of mossy fibres was positively correlated with those in the inferior olive; and (ii) the C1 zone in lobulus simplex was found to receive a greater density of projections from all three sources of mossy fibres than the C1 zone in the paramedian lobule. These data suggest that two rostrocaudally separated but somatotopically corresponding parts of the C1 zone receive common mossy fibre and climbing fibre inputs. However, the differences in projection densities also suggest that the two parts of the zone differ in the extent to which they receive mossy fibre signals arising from the same precerebellar nuclei. This implies differences in function between somatotopically corresponding parts of the same cortical zone, and could enable a higher degree of parallel processing and integration of information within them.

Long-term remodeling in proximal femur around a hydroxyapatite-coated anatomic stem: ten years densitometric follow-up.

Bone remodeling after a hip arthroplasty has been quantified with dual energy x-ray absorptiometry, usually for short-term follow-up. We used this technique to determine the long-term remodeling produced by a hydroxyapatite-coated, anatomic stem. Eighty patients with unilateral hip osteoarthritis were included in the study. The contralateral, healthy hip was taken as control. Bilateral dual energy x-ray absorptiometry scans were done before the surgery, at 15 days, and 1 and 10 years postoperatively. There was a decrease of bone mineral density in zones 1 and 7, which ranged from 12.2% to 27.3% at the end of the first year. There were no changes in zones 1 to 6 from the 1st to the 10th year, but there was a late decrease, up to 42.9%, in zone 7. The changes of bone mineral density promoted by this stem occurred in the first postoperative year. Late loss was seen only in area 7.

Changes in periprosthetic bone remodelling after redesigning an anatomic cementless stem.

The aim of this prospective cohort study was to determine the densitometric relevance of minor design modifications of a cementless stem designed to improve proximal load transfer. We used a prospective cohort study with densitometric analysis over a five-year period of two groups of patients with primary osteoarthritis. The first group, 56 hips, received the first version of the ABG stem (ABG-I); the second group, 54 hips, had the ABG-II stem. The results obtained with the ABG-I stem showed a decrease of bone density in proximal areas that ranged from 13% to 37%. However, the new design had a decrease of the same areas that ranged from 9% to 23%. These differences were noted at the end of the first post-operative year and remained stable, except in zone 7, where they were progressive. There is little evidence that the modified stem reduces femoral bone density loss.

Connections of eye-saccade-related areas within mesencephalic reticular formation with the optic tectum in goldfish.

Physiological studies demonstrate that separate sites within the mesencephalic reticular formation (MRF) can evoke eye saccades with different preferred directions. Furthermore, anatomical research suggests that a tectoreticulotectal circuit organized in accordance with the tectal eye movement map is present. However, whether the reticulotectal projection shifts with the gaze map present in the MRF is unknown. We explored this question in goldfish, by injecting biotin dextran amine within MRF sites that evoked upward, downward, oblique, and horizontal eye saccades. Then, we analyzed the labeling in the optic tectum. The main findings can be summarized as follows. 1) The MRF and the optic tectum were connected by separate axons of the tectobulbar tract. 2) The MRF was reciprocally connected mainly with the ipsilateral tectal lobe, but also with the contralateral one. 3) The MRF received projections chiefly from neurons located within intermediate and deep tectal layers. In addition, the MRF projections terminated primarily within the intermediate tectal layer. 4) The distribution of labeled neurons in the tectum shifted with the different MRF sites in a manner consistent with the tectal motor map. The area containing these cells was targeted by a high-density reticulotectal projection. In addition to this high-density topographic projection, there was a low-density one spread throughout the tectum. 5) Occasionally, boutons were observed adjacent to tectal labeled neurons. We conclude that the organization of the reticulotectal circuit is consistent with the functional topography of the MRF and that the MRF participates in a tectoreticulotectal feedback circuit.

Diagnostic efficacy of sentinel node biopsy in oral squamous cell carcinoma. Cohort study and meta-analysis.

OBJECTIVES: To evaluate the efficacy of sentinel node biopsy (SNB) in oral squamous cell carcinoma (OSCC). DESIGN: A prospective study of a cohort of 25 consecutive patients with OSCC anatomopathological confirmation through biopsy, without oncological pre-treatment, in clinical stage T1-T4N0, of these 25 patients 14 were T1-T2N0. The absence of regional disease (N0) was determined by means of clinical exploration and cervical tomography (CT). To establish the overall sensitivity of the technique, a meta-analysis was carried out of 10 series published to February 2005 where SNB had been applied to head and neck cancer, adding our 14 T1-T2N0 cases, thus making a total of 260 patients. RESULTS: Identification by SNB was accurate in 96% of the 25 cases, with a sensitivity of 66.7%. Analyzing only the T1-T2N0 cases (n=14), the accuracy was 100% with a sensitivity of 1 (CI 95%, 0.29-1.00). The overall sensitivity was 93%. The accuracy in identifying the sentinel node varied between 66% and 100%. The SN was identified in 251 of 260 cases, of those, 71 were true positive, 5 false negative and 175 true negative. The overall sensitivity was 93.4% (CI 95%, 85.3-97.8), with a specificity of 100% (CI 95%, 0.98-100). The weighted negative probability quotient was 0.176 (CI 0.103-0.301) and that of positive probability 24.75 (CI 95%, 10.8-56.71). The weighted diagnostic odds ratio was 183.71 (CI 95%, 59.36-568.56). If we accept that the prevalence of hidden regional disease is 30%, a negative sentinel node has 5% possibility of having hidden disease. CONCLUSIONS: Our data provide a certain degree of evidence that, due to its high sensitivity, the SNB procedure can be applied to the initial stages of OSCC.

Excitability is increased in hippocampal CA1 pyramidal cells of Fmr1 knockout mice.

Fragile X syndrome (FXS) is caused by a failure of neuronal cells to express the gene encoding the fragile mental retardation protein (FMRP). Clinical features of the syndrome include intellectual disability, learning impairment, hyperactivity, seizures and anxiety. Fmr1 knockout (KO) mice do not express FMRP and, as a result, reproduce some FXS behavioral abnormalities. While intrinsic and synaptic properties of excitatory cells in various part of the brain have been studied in Fmr1 KO mice, a thorough analysis of action potential characteristics and input-output function of CA1 pyramidal cells in this model is lacking. With a view to determining the effects of the absence of FMRP on cell excitability, we studied rheobase, action potential duration, firing frequency-current intensity relationship and action potential after-hyperpolarization (AHP) in CA1 pyramidal cells of the hippocampus of wild type (WT) and Fmr1 KO male mice. Brain slices were prepared from 8- to 12-week-old mice and the electrophysiological properties of cells recorded. Cells from both groups had similar resting membrane potentials. In the absence of FMRP expression, cells had a significantly higher input resistance, while voltage threshold and depolarization voltage were similar in WT and Fmr1 KO cell groups. No changes were observed in rheobase. The action potential duration was longer in the Fmr1 KO cell group, and the action potential firing frequency evoked by current steps of the same intensity was higher. Moreover, the gain (slope) of the relationship between firing frequency and injected current was 1.25-fold higher in the Fmr1 KO cell group. Finally, AHP amplitude was significantly reduced in the Fmr1 KO cell group. According to these data, FMRP absence increases excitability in hippocampal CA1 pyramidal cells.

Olivo-cortico-nuclear localizations within crus I of the cerebellum.

Retrograde and anterograde tracers were microinjected into the folia of crus I of the cat cerebellum to investigate spatial localization in olivo-cerebellar and cortico-nuclear projections. The folia were shown to be mainly occupied in rostrocaudal succession by three zones receiving their olivo-cerebellar climbing fiber afferents from parts of, respectively, the dorsal lamella of the principal olive, the ventral lamella of the principal olive, and the rostral half of the medial accessory olive. These zones are presumably parts of the D(2), D(1), and C(2) cerebellar cortical zones, as earlier proposed by Rosina and Provini ([1982] Neuroscience 7:2657-2676). Their respective nuclear target territories were found to be in the rostroventral quadrant of nucleus lateralis, the caudoventral quadrant of nucleus lateralis, and the ventral half of nucleus interpositus posterior. The medial-to-lateral width of each zone was shown to be innervated by different groups of olive cells and to project respectively to medial and lateral parts of the nuclear territory for that zone, consistent with the existence in crus I of olivo-cortico-nuclear microcomplexes (cf. Ito [1984] New York: Raven Press). Parts of the length of each zone located within different folia were also shown to relate to different groups of olive cells and to different regions of the zone's overall nuclear territory. Interfolial localizations, which were heavily overlapping in nature, intersected orthogonally with those for zone width. The fine-grain topography implies that individual microzones exist within each of the zones present within crus I. The results also have implications for the possibility that lateral cerebellar pathways are involved in cognition.

Complexation of Nickel(II) with Guanosine 5'-Monophosphate and Inosine 5'-Monophosphate: A Potentiometric and Calorimetric Study.

The constants (K(s)) and enthalpies (DeltaH(s)) for stacking interactions between purine nucleoside monophosphates were determined by calorimetry; the values thus obtained were guanosine as follows: K(s) = 2.1 +/- 0.3 M(-)(1) and DeltaH(s) = -41.8 +/- 0.8 kJ/mol for adenosine 5'-monophosphate (5'AMP); K(s) = 1.5 +/- 0.3 M(-1) and DeltaH(s) = -42.0 +/- 1.5 kJ/mol for guanosine 5'-monophosphate (5'GMP); and K(s) = 1.0 +/- 0.2 M(-1) and DeltaH(s) = -42.3 +/- 1.1 kJ/mol for inosine 5'-monophosphate (5'IMP). The interaction of nickel(II) with purine nucleoside monophosphates was studied using potentiometric and calorimetric methods, with 0.1 M tetramethylammonium bromide as the background electrolyte, at 25 degrees C. The presence in solution of the complexes [Ni(5'GMP)(2)](2)(-) and [Ni(5'IMP)(2)](2)(-) was observed. The thermodynamic parameters obtained were log K(ML) = 3.04 +/- 0.02, log K(ML2) = 2.33 +/- 0.02, DeltaH(ML) = -18.4 +/- 0.9 kJ/mol and DeltaH(ML2) = -9.0 +/- 1.9 kJ/mol for 5'GMP; and log K(ML) = 2.91 +/- 0.01, log K(ML2) = 1.92 +/- 0.01, DeltaH(ML) = -16.2 +/- 0.9 kJ/mol and DeltaH(ML2) = -0.1 +/- 2.3 kJ/mol for 5'IMP. The relationships between complex enthalpies and the degree of macrochelation, as well as the stacking interaction between purine bases in the complexes are discussed in relation to previously reported calorimetric data.

Implications of a positive sentinel node in oral squamous cell carcinoma.

BACKGROUND: The role of sentinel node biopsy in head and neck cancer is currently being explored. Patients with positive sentinel nodes were investigated to establish if additional metastases were present in the neck, their distribution, and their impact on outcome. METHODS: In all, 109 patients (n = 109) from 15 European centers, with cT1/2,N0 tumors, and a positive sentinel lymph node were identified. Kaplan-Meier and univariate and multivariate logistic regression analysis were used to identify variables that predicted for additional positive nodes and their position within the neck. RESULTS: A total of 122 neck dissections were performed in 109 patients. Additional positive nodes were found in 34.4% of cases (42/122: 18 same, 21 adjacent, and 3 nonadjacent neck level). Additional nodes, especially if outside the sentinel node basin, had an impact on outcome. CONCLUSIONS: The results are preliminary but suggest that both the number and the position of positive sentinel nodes may identify different prognostic groups that may allow further tailoring of management plans.

GABAergic Projections to the Oculomotor Nucleus in the Goldfish (carassius Auratus).

The mammalian oculomotor nucleus receives a strong γ-aminobutyric acid (GABA)ergic synaptic input, whereas such projections have rarely been reported in fish. In order to determine whether this synaptic organization is preserved across vertebrates, we investigated the GABAergic projections to the oculomotor nucleus in the goldfish by combining retrograde transport of biotin dextran amine, injected into the antidromically identified oculomotor nucleus, and GABA immunohistochemistry. The main source of GABAergic afferents to the oculomotor nucleus was the ipsilateral anterior octaval nucleus, with only a few, if any, GABAergic neurons being located in the contralateral tangential and descending nuclei of the octaval column. In mammals there is a nearly GABAergic inhibitory inputs; thus, the vestibulooculomotor GABAergic circuitry follows a plan that appears to be shared throughout the vertebrate phylogeny. The second major source of GABAergic projections was the rhombencephalic reticular formation, primarily from the medial area but, to a lesser extent, from the inferior area. A few GABAergic oculomotor projecting neurons were also observed in the ipsilateral nucleus of the medial longitudinal fasciculus. The GABAergic projections from neurons located in both the reticular formation surrounding the abducens nucleus and the nucleus of the medial reticular formation have primarily been related to the control of saccadic eye movements. Finally, all retrogradely labeled internuclear neurons of the abducens nucleus, and neurons in the cerebellum (close to the caudal lobe), were negative for GABA. These data suggest that the vestibuloocular and saccadic inhibitory GABAergic systems appear early in vertebrate phylogeny to modulate the firing properties of the oculomotor nucleus motoneurons.

Primary pulmonary artery sarcoma extending retrograde into the superior vena cava.

Primary pulmonary artery sarcoma is a rare tumor that is highly fatal. It can be misdiagnosed as acute or chronic pulmonary thromboembolic disease. Herein, we report the case of a 22-year-old woman with a preoperative diagnosis of pulmonary embolism and superior vena caval thrombosis. Intraoperatively, an extensive sarcoma was seen to extend retrograde from the pulmonary artery, past the right ventricle and right atrium, and into the superior vena cava. Surgical resection of the tumor and reconstruction of the central pulmonary arteries, followed by adjuvant chemotherapy, relieved the clinical symptoms. The patient remained free of cancer at 14 months postoperatively. We believe that this is the 1st report of a primary pulmonary artery sarcoma that extended retrograde into the superior vena cava.

Involvement of the optic tectum and mesencephalic reticular formation in the generation of saccadic eye movements in goldfish.

The circuitry and physiological properties underlying saccadic eye movement generation have been studied mainly in monkeys and cats. By contrast, current knowledge in nonmammalian species is rather scarce. We review here some of our recent findings about the involvement of the optic tectum and mesencephalic reticular formation in the generation of saccades in goldfish. Electrical microstimulation of the optic tectum evokes contraversive saccadic eye movements. In goldfish, as in mammals, the amplitude and direction of saccades are encoded in a spatial topographical map. In addition, there are some areas that have evolved, such as the extreme anteromedial tectal zone, whose activation yields eye convergence. Injections of the bidirectional tracer biotin dextran amine within functionally identified sites of the tectum provide reciprocal, site-dependent connectivity with different downstream structures. Of these structures, the major tectofugal target is the mesencephalic reticular formation. In goldfish, as in mammals, the mesencephalic reticular formation and optic tectum establish reciprocal connections at regional and neuronal levels which support the presence of feedback circuits. Electrical microstimulation demonstrates that the mesencephalic reticular formation can be functionally parceled-the rostral part is linked to vertical saccades, while the caudal part is related with horizontal ones. Finally, these zones are also differently connected to the optic tectum. From these data, we conclude that the involvement of the optic tectum and mesencephalic reticular formation in eye movement generation in goldfish is similar to that reported in cats and monkeys.

Pontine and lateral reticular projections to the c1 zone in lobulus simplex and paramedian lobule of the rat cerebellar cortex.

Spatial localization and axonal branching in mossy fiber projections to two rostrocaudally-separated regions of the 'forelimb' c1 zone in lobulus simplex and paramedian lobule were studied in rats using a retrograde double-labelling tracer technique. In four animals the two cortical regions were localized electrophysiologically and each was micro-injected with tracer material, yielding a total of eight different cases. Single- and double-labelled cell bodies were plotted in the basal pontine nucleus (BPN), nucleus reticularis tegmenti pontis (NRTP), and the lateral reticular nucleus (LRN). As a control, cells labelled in the contralateral inferior olive were also counted. The parts of the c1 zone in lobulus simplex and the paramedian lobule were found to receive mossy fiber inputs from similar regions of BPN, NRTP and LRN. Double-labelled cells were not found in NRTP but were present in BPN and LRN (on average 6% and 25% of the smaller single-labelled population, respectively). The incidence of double-labelled cells in the olive and LRN was positively correlated, but no relation was found between olive and BPN, suggesting a zonal organization within the mossy fiber projections from LRN, but not from the pons. In quantitative terms, the c1 zone in lobulus simplex received a greater density of mossy fiber projections from BPN, NRTP and LRN than the c1 zone in the paramedian lobule. This suggests that the two parts of the same cerebellar cortical zone differ, at least partially, in regard to their inputs from three major sources of mossy fibers. This is consistent with the modular hypothesis and could enable a higher degree of parallel processing and integration of information within different parts of the same zone.

Interactions in solution of cobalt(II) and nickel(II) with nicotinamide adenine dinucleotide: a potentiometric and calorimetric study.

The equilibrium constants and the thermodynamic parameters enthalpy and entropy of the interaction between Ni(II) and Co(II) with NAD(+) in aqueous solution were determined by calorimetry and potentiometry methods (ionic strength adjusted to 0.1 with sodium nitrate at 25 degrees C). The macrochelation of the systems was also studied. All the data, including the protonation enthalpy data of NAD(+) (very similar to the protonation enthalpy of 5'-AMP) suggest a less restrictive model for the NAD(+) "folded" conformation without intramolecular stacking between the bases, in agreement both with recent theoretical calculations and with the X-ray structure of trimethylene-bisadeninium or the free acid form of NAD(+).