Corticospinal excitability and sleep: a motor threshold assessment by transcranial magnetic stimulation after awakenings from REM and NREM sleep

Transcranial magnetic stimulation (TMS) is a recently established technique in the neurosciences that allows the non-invasive assessment, among other parameters, of the excitability of motor cortex. Up to now, its application to sleep research has been very scarce and because of technical problems it provided contrasting results. In fact delivering one single suprathreshold magnetic stimulus easily awakes subjects, or lightens their sleep. For this reason, in the present study we assessed motor thresholds (MTs) upon rapid eye movement (REM) and non-rapid eye movement (NREM) sleep awakenings, both in the first and in the last part of the night. Taking into account that a full re-establishment of wake regional brain activity patterns upon awakening from sleep needs up to 20-30 min, it is possible to make inferences about the neurophysiological characteristics of the different sleep stages by analyzing the variables of interest immediately after provoked awakenings. Ten female volunteers slept in the lab for four consecutive nights. During the first night the MTs were collected, following a standardized procedure: 5 min before lights off, upon stage 2 awakening (second NREM period), upon REM sleep awakening (second REM period), upon the final morning awakening (always from stage 2). Results showed that MTs increased linearly from presleep wakefulness to REM sleep awakenings, and from the latter to stage 2 awakenings. There was also a time-of-night effect on MTs upon awakening from stage 2, indicating that MTs decreased from the first to the second part of the night. The increase in corticospinal excitability across the night, which parallels the fulfillment of sleep need, is consistent with the linear decrease of auditory arousal thresholds during the night. The maximal reduction of corticospinal excitability during early NREM sleep can be related to the hyperpolarization of thalamocortical neurons, and is in line with the decreased metabolic activity of motor cortices during this sleep stage. On the contrary, the increase of MTs upon REM sleep awakenings should reflect peripheral factors. We conclude that our findings legitimate the introduction of the TMS technique as a new proper tool in sleep research.     

Two cases of misinterpretation of molecular results in incontinentia pigmenti,and a PCR-based method to discriminate NEMO/IKKgamma dene deletion

Familial incontinentia pigmenti (IP) is a rare X-linked dominant disorder that affects ectodermal tissues. Over 90% of IP carrier females have a recurrent genomic deletion of exons 4-10 of the NEMO (IKBKG-IKKgamma) gene, which encodes a regulatory component of the IkB kinase complex, required to activate the NF-kB pathway. In IP, mutations in NEMOlead to the complete loss of NF-kB activation creating a susceptibility to cellular apoptosis in response to TNF-alpha. This condition is lethal for males during embryogenesis while females, who are mosaic as a result of X-inactivation, can survive. Recently, a second nonfunctional copy of the gene, DeltaNEMO, was identified, opposite in direction to NEMO in a 35.5-kb duplicated sequence tract. PCR-based detection of the NEMO deletion is diagnostic for IP disease. However, we present instances in which ex 4-10 DeltaNEMO pseudogene deletion occurs in unaffected parents of two females with clinically characteristic IP. These were missed by the currently standard PCR-based method, but can be easily discriminated by a new PCR-based test reported here that permits unambiguous molecular diagnosis and proper familial genetic counseling for IP.     

Congenital posterior cervical spine malformation due to biallelic c.240‐4T>G RIPPLY2 variant: A discrete entity

The clinical and radiological spectrum of spondylocostal dysostosis syndromes encompasses distinctive costo‐vertebral anomalies. RIPPLY2 biallelic pathogenic variants were described in two distinct cervical spine malformation syndromes: Klippel–Feil syndrome and posterior cervical spine malformation. RIPPLY2 is involved in the determination of rostro‐caudal polarity and somite patterning during development. To date, only four cases have been reported. The current report aims at further delineating the posterior malformation in three new patients. Three patients from two unrelated families underwent clinical and radiological examination through X‐ray, 3D computed tomography and brain magnetic resonance imaging. After informed consent was obtained, family‐based whole exome sequencing (WES) was performed. Complex vertebral segmentation defects in the cervico‐thoracic spine were observed in all patients. WES led to the identification of the homozygous splicing variant c.240‐4T>G in all subjects. This variant is predicted to result in aberrant splicing of Exon 4. The current report highlights a subtype of cervical spine malformation with major atlo‐axoidal malformation compromising spinal cord integrity. This distinctive mutation‐specific pattern of malformation differs from Klippel–Feil syndrome and broadens the current classification, defining a sub‐type of RIPPLY2‐related skeletal disorder. Of note, the phenotype of one patient overlaps with oculo‐auriculo‐vertebral spectrum disorder.     

Microvasculature of the buffalo epididymis

The microvasculature of the water buffalo (Bubalus bubalis) epididymis was investigated using light (LM), scanning electron (SEM), and transmission electron (TEM) microscopy techniques. SEM analysis of the buffalo epididymis showed fenestrations that occupied ovoid inside the endothelium of the postcapillary venules located in the caput, corpus, and cauda. They varied in shape and dimension, but more importantly, they connected the venules of the blood vascular system to the capillaries of the peripheral lymphatic vascular system. Morphofunctional analysis of these connections suggests that the microvasculature of the buffalo epididymis plays a role in facilitating the circulation of biologically active substances, and the absorption and secretion processes necessary for the survival and maturation of spermatozoa. The lymphatic capillaries at the connection points formed a network of variously sized polygonal links. These capillaries then converged to form the precollector lymphatic vessels, which in turn converged with the larger vessels originating from the testis. It was further noted that in the capillary endothelium there were no fenestrations, and in the large veins there were many diverticula. These diverticula appear to play a role in the regulation of the seasonal variations of the blood reflux. In general, the microvascular architecture of the buffalo epididymis, particularly its connection to the lymphatic vascular system, appears to play an important role in the absorption and secretion processes of the epididymal epithelium. Anat Rec 266:58–68, 2002. © 2002 Wiley‐Liss, Inc.     

Fatal pulmonary arterial dissection and sudden death as initial manifestation of primary pulmonary hypertension: a case report.

We report a rare case of sudden death due to cardiac tamponade following intrapericardial rupture of a main pulmonary artery dissecting aneurysm. On pathology examination, the pulmonary artery showed an intimal tear in an arterial wall area with reduced thickness. However, no degenerative, inflammatory or necrotic processes were evident within the vessel wall. Hypertrophy of the wall of vasa vasorum in the adventitia of the pulmonary artery was found, as well as bilaterally diffuse myointimal arterial hyperplasia of the lung vasculature. According to these findings, we conclude that pulmonary artery rupture occurred in a patient with chronic unrecognized primary pulmonary hypertension.     

Reduced Left Ventricular Compliance and Mechanical Efficiency after Prolonged Inhibition of NO Synthesis in Conscious Dogs

Acute inhibition of NO synthesis decreases left ventricular (LV) work and external efficiency, but it is unknown whether compensatory mechanisms can limit the alterations in LV mechanoenergetics after prolonged NO deficiency. Eight chronically instrumented male mongrel dogs received 35 mg kg⁻¹ day⁻¹ of N ^ω-nitro-L-arginine methyl ester orally for 10 days to inhibit NO synthesis. At spontaneous beating frequency, heart rate, coronary blood flow, peak LV pressure, end-diastolic LV pressure and the maximum derivative of LV pressure (d P /d t _max) were not significantly different vs. baseline, whereas LV end-diastolic diameter (32.5 ± 1.0 vs. 37.6 ± 1.4 mm) and LV stroke work (515 ± 38 vs. 650 ± 44 mmHg mm), were reduced (all P < 0.05). The slope of the LV end-systolic pressure-diameter relationship was increased at 10 days vs. baseline (13.9 ± 1.0 vs. 9.6 ± 0.9 mmHg mm⁻¹, P < 0.05), while the end-diastolic LV diameter was smaller at matched LV end-diastolic pressures. At fixed heart rate (130 beats min⁻¹), cardiac oxygen consumption was increased (12.2 ± 1.5 vs. 9.9 ± 1.0 ml min⁻¹), and the ratio between stroke work and oxygen consumption was decreased by 33 ±7 % (all P < 0.05) after NO inhibition. We conclude that sustained inhibition of NO synthesis in dogs causes a decrease in LV work despite an increased contractility, which is most probably due to reduced diastolic compliance and a decrease in external efficiency. Thus, prolonged NO deficiency is not compensated for on the level of LV mechanoenergetics in vivo .     

Could mitochondrial haplogroups play a role in sporadic amyotrophic lateral sclerosis?

Mitochondrial impairment has been implicated in the pathogenesis of the amyotrophic lateral sclerosis (ALS). Furthermore, mitochondrial-specific polymorphisms were previously related to other neurodegenerative diseases, such as Parkinson, Friedreich and Alzheimer disease. To investigate if specific genetic polymorphisms within the mitochondrial genome (mtDNA) could act as susceptibility factors and contribute to the clinical expression of sporadic ALS (sALS), we have genotyped predefined European mtDNA haplogroups in 222 Italian patients with sALS and 151 matched controls. Individuals classified as haplogroup I demonstrated a significant decrease in risk of ALS versus individuals carrying the most common haplogroup, H (odds ratio 0.08, 95% confidence interval 0.04-0.4, p < 0.01). Further stratification of the dataset by sex, age and site of onset of disease and survival failed to reach significance for association. Our study provides evidence of the contribution of mitochondrial variation to the risk of ALS development in Caucasians. Further it may help elucidate the mechanism of the mitochondrial dysfunction detectable in ALS, and may be of relevance in development of strategies for the treatment of this disease.     

Fibroblastic reticular cell tumor of the spleen: report of a case and review of the entity

Fibroblastic reticulum cells (FBRCs) are stromal support cells located in the parafollicular area and deep cortex of lymph nodes and in the extrafollicular areas of the spleen and tonsils. We report a case of malignant FBRC tumor of the spleen occurring in a 61-year-old woman. Two years after splenectomy, multiple hepatic lesions were found, which were resected. Histologically, the tumor showed similar morphological features in the spleen as in the liver metastases. There was a whorled pattern of oval and spindle cells in a collagenized background admixed with an inflammatory cell infiltrate composed of lymphocytes and plasma cells. The tumor cells were positive for common muscle actin, smooth muscle actin, and focally for CD68. In situ hybridization for Epstein Barr virus was negative. To the best of our knowledge, this is the first report of malignant FBRC tumor arising in the spleen. The differential diagnosis of splenic tumors with inflammatory pseudotumor-like features is discussed.     

Multiple pathways of cell invasion are regulated by multiple families of serine proteases

The complex process of tumor invasion requires the coordinated expression and activity of cell-substratum adhesive interactions and of cell-associated protease systems, which destroy the extracellular matrix (ECM), in order to enable the invading cells to simultaneously grip and destroy the anatomical barriers that control cell spreading. A number of data indicate that such a `grip and go' process may be performed by an enlarging series of cell membrane-associated serine proteases and serine protease receptors, which provide the invasive cells with a functional unit (the protease and its receptor), able to mediate cell-substratum adhesion through specific receptor domains, to proteolytically degrade ECM and to deliver into the cell signals that up-regulate the expression either of the protease/receptor complex, or of other adhesion molecules, such as integrins. There is evidence that some proteases and protease receptor expression are under the control of tumor hypoxia, which is the result of an imbalance in oxygen supply and demand. The urokinase-type plasminogen activator (u-PA) receptor (u-PAR) is under hypoxic control and cooperates with other serine proteases of the blood coagulation pathways that may extravasate in the tumor milieu as a result of hypoxia-simulated increase of vessel permeability. Other serine proteases and their receptors cooperate with the cell-associated fibrinolytic system to promote cell invasion. Among these, tissue factor and its ligand coagulation factor VII, thrombin and its protease-activated receptors, and type II trans-membrane serine proteases seem to play a crucial role. This Review takes into consideration the complex scenario of the single serine proteases and related receptors that are involved in cell invasion, as well as the protease receptor/adhesion molecule interplay which is necessary to focus the cell surface-driven proteolysis where adhesion provides a grip to the invading cell. This revised version was published online in July 2006 with corrections to the Cover Date.