Diagnostic value of vestibulo-ocular reflex parameters in the detection and characterization of labyrinthine lesions.

OBJECTIVE: To evaluate the power of various parameters of the vestibulo-ocular reflex (VOR) in detecting unilateral peripheral vestibular dysfunction and in characterizing certain inner ear pathologies. STUDY DESIGN: Prospective study of consecutive ambulatory patients presenting with acute onset of peripheral vertigo and spontaneous nystagmus. SETTING: Tertiary referral center. PATIENTS: Seventy-four patients (40 females, 34 males) and 22 normal subjects (11 females, 11 males) were included in the study. Patients were classified in three main diagnoses: vestibular neuritis: 40; viral labyrinthitis: 22; Meniere's disease: 12. METHODS: The VOR function was evaluated by standard caloric and impulse rotary tests (velocity step). A mathematical model of vestibular function was used to characterize the VOR response to rotational stimulation. The diagnostic value of the different VOR parameters was assessed by uni- and multivariable logistic regression. RESULTS: In univariable analysis, caloric asymmetry emerged as the most powerful VOR parameter in identifying unilateral vestibular deficit, with a boundary limit set at 20%. In multivariable analysis, the combination of caloric asymmetry and rotational time constant asymmetry significantly improved the discriminatory power over caloric alone (p<0.0001) and produced a detection score with a correct classification of 92.4%. In discriminating labyrinthine diseases, different combinations of the VOR parameters were obtained for each diagnosis (p<0.003) supporting that the VOR characteristics differ between the three inner ear disorders. However, the clinical usefulness of these characteristics in separating the pathologies was limited. CONCLUSION: We propose a powerful logistic model combining the indices of caloric and time constant asymmetries to detect a peripheral vestibular loss, with an accuracy of 92.4%. Based on vestibular data only, the discrimination between the different inner ear diseases is statistically possible, which supports different pathophysiologic changes in labyrinthine pathologies.

Clonal, self-renewing and differentiating human and porcine urothelial cells, a novel stem cell population.

Although urothelial progenitor-like cells have been described in the human urinary tract, the existence of stem cells remains to be proven. Using a culture system that favors clonogenic epithelial cell growth, we evaluated and characterized clonal human urothelial cells. We isolated human urothelial cells that were clonogenic, capable of self-renewal and could develop into fully differentiated urothelium once re-implanted into the subcapsular space of nude mice. In addition to final urothelial cell differentiation, spontaneous formation of bladder-like microstructures was observed. By examining an epithelial stem cell signature marker, we found p63 to correlate with the self-renewal capacity of the isolated human urothelial clonal populations. Since a clinically relevant, long-term model for functional reconstitution of human cells does not exist, we sought to establish a culture method for porcine urothelial cells in a clinically relevant porcine model. We isolated cells from porcine ureter, urethra and bladder that were clonogenic and capable of self-renewal and differentiation into fully mature urothelium. In conclusion, we could isolate human and porcine cell populations, behaving as urothelial stem cells and showing clonogenicity, self-renewal and, once re-implanted, morphological differentiation.

A selective nociceptive block is not sufficient to prevent central changes after peripheral nerve injury

Background: Providing analgesia without suppressing motor or sensory function is a challenge for regional anesthesia and postoperative pain management. Resiniferatoxin (RTX), an ultrapotent agonist for transient receptor potential subtype-1 (TRPV1) can produce this selective blockade, as TRPV1 is selectively expressed on nociceptors. Futhermore, after peripheral nerve injury, spontaneous ectopic activity arises from all types of nerve fibers that can affect spinal neurons and glial cells. The goal of the present experiment is to determine whether spontaneous activity generated in C-fibers or in both A&C-fibers is required for microglia activation. Method: We applied RTX (0.01%) or bupivacaine microspheres to the sciatic nerve of rats to block the conduction of C-fibers or A&C-fibers, respectively, before spared nerve injury (SNI). Behavior was tested and all the rats were sacrificed 2 days later; immunohistochemistry was performed on their spinal cord for mitogen-activated protein kinase (MAPK) p38, bromodeoxyuridine (BrdU, marker of proliferation) and Iba1 (microglial marker). Result: At day 2 after SNI robust mechanical allodynia and p38 activation in spinal microglia were documented. There was also a substantial cell proliferation in the spinal cord, all proliferating cells (BrdU+) being microglia (Iba1+). RTX blocked heat sensitivity and produced heat hypoalgesia without affecting mechanical allodynia and motor function. Microglial proliferation and p38 activation in the spinal cord were not affected by RTX (p >0.05). In contrast, a complete sensory and motor blockade was seen with bupivacaine which also significantly inhibited p38 activation and microglial proliferation in the spinal cord (p <0.05). Conclusion: We conclude that (1) RTX can provide a selective nociceptive blockade but that (2) blocking only nociceptive fibers does not impair the development of mechanical allodynia and microglia activation. Therefore (3) if microglia activation is important for chronic pain development then specific nociceptive blockade won't be sufficient to prevent it.

Genes encoding tumor necrosis factor alpha and granzyme A are expressed during development of autoimmune diabetes.

Progressive destruction of the insulin-producing beta cells in nonobese diabetic mice is observed after infiltration of the pancreas with lymphocytes [Makino, S., Kunimoto, K., Muraoka, Y., Mizushima, Y., Katagiri, K. &amp; Tochino, Y. (1980) Exp. Anim. (Tokyo) 29, 1-13]. We show that the genes for tumor necrosis factor alpha and granzyme A, a serine protease associated with cytoplasmic granules of cytotoxic cells, are expressed during the development of spontaneous diabetes mellitus in the nonobese diabetic mouse. Granzyme A-positive cells are found both in and surrounding the islets, implying induction prior to islet infiltration. Tumor necrosis factor alpha expression is exclusively observed in the intra-islet infiltrate, predominantly in lymphocytes adjacent to insulin-producing beta cells, the targets of the autoimmune destruction, implying that tumor necrosis factor alpha expression is induced locally--i.e., in the islet. A considerable portion of cells expressing tumor necrosis factor alpha appear to be CD4+ T cells. This T-cell subset was previously shown to be necessary for development of the disease. Thus, these findings may be important for understanding the pathogenesis of autoimmune diabetes mellitus and potentially also for that of other T-cell-mediated autoimmune diseases.

Large A-fiber activity is required for microglial proliferation and p38 MAPK activation in the spinal cord: different effects of resiniferatoxin and bupivacaine on spinal microglial changes after spared nerve injury.

BACKGROUND: After peripheral nerve injury, spontaneous ectopic activity arising from the peripheral axons plays an important role in inducing central sensitization and neuropathic pain. Recent evidence indicates that activation of spinal cord microglia also contributes to the development of neuropathic pain. In particular, activation of p38 mitogen-activated protein kinase (MAPK) in spinal microglia is required for the development of mechanical allodynia. However, activity-dependent activation of microglia after nerve injury has not been fully addressed. To determine whether spontaneous activity from C- or A-fibers is required for microglial activation, we used resiniferatoxin (RTX) to block the conduction of transient receptor potential vanilloid subtype 1 (TRPV1) positive fibers (mostly C- and Adelta-fibers) and bupivacaine microspheres to block all fibers of the sciatic nerve in rats before spared nerve injury (SNI), and observed spinal microglial changes 2 days later. RESULTS: SNI induced robust mechanical allodynia and p38 activation in spinal microglia. SNI also induced marked cell proliferation in the spinal cord, and all the proliferating cells (BrdU+) were microglia (Iba1+). Bupivacaine induced a complete sensory and motor blockade and also significantly inhibited p38 activation and microglial proliferation in the spinal cord. In contrast, and although it produced an efficient nociceptive block, RTX failed to inhibit p38 activation and microglial proliferation in the spinal cord. CONCLUSION: (1) Blocking peripheral input in TRPV1-positive fibers (presumably C-fibers) is not enough to prevent nerve injury-induced spinal microglial activation. (2) Peripheral input from large myelinated fibers is important for microglial activation. (3) Microglial activation is associated with mechanical allodynia.

Diurnal variation in the release of alpha-MSH from rat hypothalamus and pituitary

Release of alpha-MSH from rat hypothalamic slices was characterized with respect to ionic requirements and possible diurnal variations using a sensitive radioimmunoassay. Addition of 47 mM KCl to the superfusion medium resulted in a twofold increase in alpha-MSH functions as a neurotransmitter or neuromodulator in the hypothalamus. Both spontaneous and potassium-induced alpha-MSH release compared to spontaneous release. Removal of calcium from the superfusion medium abolished the potassium-evoked release of alpha-MSH. This supports the concept that alpha-MSH release were related to diurnal variation. Marked release from the slices was observed at 10.10 h, corresponding to a peak in the alpha-MSH concentration in the hypothalamus [18] and to a lower levels of alpha-MSH in the blood. Contrarily, no significant release from the hypothalamus was obtained at 17.00 h when hypothalamic alpha-MSH content was low, but blood levels exhibited a peak. These findings suggest that there are differences in the regulation of the alpha-MSH from the pituitary and that in the hypothalamus.

Discordant increases in CD4+ T cells in human immunodeficiency virus-infected patients experiencing virologic treatment failure: role of changes in thymic output and T cell death.

Some patients infected with human immunodeficiency virus (HIV) who are experiencing antiretroviral treatment failure have persistent improvement in CD4+ T cell counts despite high plasma viremia. To explore the mechanisms responsible for this phenomenon, 2 parameters influencing the dynamics of CD4+ T cells were evaluated: death of mature CD4+ T cells and replenishment of the CD4+ T cell pool by the thymus. The improvement in CD4+ T cells observed in patients with treatment failure was not correlated with spontaneous, Fas ligand-induced, or activation-induced T cell death. In contrast, a significant correlation between the improvement in CD4+ T cell counts and thymic output, as assessed by measurement of T cell receptor excision circles, was observed. These observations suggest that increased thymic output contributes to the dissociation between CD4+ T cell counts and viremia in patients failing antiretroviral therapy and support a model in which drug-resistant HIV strains may have reduced replication rates and pathogenicity in the thymus.

Constitutively active mutants of the alpha 2-adrenergic receptor.

We have mutated a single residue, Thr373 [corrected], in the C-terminal portion of the third intracellular loop of the alpha 2C10-adrenergic receptor into five different amino acids. In analogy with the effect of similar mutations in the alpha 1B- and beta 2-adrenergic receptors, these substitutions resulted in two major biochemical modifications: 1) increased constitutive activity of the alpha 2-adrenergic receptor leading to agonist-independent inhibition of adenylyl cyclase and 2) increased affinity of the receptor for binding agonist but not antagonists. The increased constitutive activity of the mutated alpha 2-adrenergic receptors could be inhibited by pertussis toxin, clearly indicating that it results from spontaneous ligand-independent receptor coupling to Gi. In contrast, the increased affinity of the mutant receptors for binding agonists was unaffected by pertussis toxin treatment, indicating that this is an inherent property of the receptors not dependent on interaction with Gi. Coexpression of the receptor mutants with the receptor-specific kinase, beta ARK1, indicated that the constitutively active alpha 2-adrenergic receptors are substrates for beta-adrenergic receptor kinase (beta ARK)-mediated phosphorylation even in the absence of agonist. These findings strengthen the idea that constitutively active adrenergic receptors mimic the "active" state of a G protein-coupled receptor adopting conformations similar to those induced by agonist when it binds to wild type receptors. In addition, these results extend the notion that in the adrenergic receptor family the C-terminal portion of the third intracellular loop plays a general role in the processes involved in receptor activation.

Circadian and circaseptan patterns of natality and perinatal mortality of infants with different birth weights

OBJECTIVE. Data on human natality, stillbirth and perinatal mortality from Switzerland (1979-1987), available in four birthweight categories, are reexamined to assess any about-weekly (circaseptan) and changes in about-daily (circadian) patterns in central Europe over a century and a halfDESIGN. Retrospective analyses on archived data.SETTING. Federal Office of Statistics for Switzerland.RESULTS. In addition to prominent circadians, weekly patterns are also documented.CONCLUSION. Exogenous variations, prominent in early extrauterine life, such as changes of scheduling in obstetrics, may contribute to circadian and cireaseptan natality patterns. Information on these patterns serves in the optimization of neonatal care. Partly endogenous, partly physical environmental aspects, at least of about-weekly patterns, remain to be elucidated in series consisting exclusively of spontaneous parturitions.

Reelin controls progenitor cell migration in the healty and pathological adult brain

Understanding the signals that control migration of neural progenitor cells in the adult brain may provide new therapeutic opportunities. Reelin is best known for its role in regulating cell migration during brain development, but we now demonstrate a novel function for reelin in the injured adult brain. First, we show that Reelin is upregulated around lesions. Second, experimentally increasing Reelin expression levels in healthy mouse brain leads to a change in the migratory behavior of subventricular zone-derived progenitors, triggering them to leave the rostral migratory stream (RMS) to which they are normally restricted during their migration to the olfactory bulb. Third, we reveal that Reelin increases endogenous progenitor cell dispersal in periventricular structures independently of any chemoattraction but via cell detachment and chemokinetic action, and thereby potentiates spontaneous cell recruitment to demyelination lesions in the corpus callosum. Conversely, animals lacking Reelin signaling exhibit reduced endogenous progenitor recruitment at the lesion site. Altogether, these results demonstrate that beyond its known role during brain development, Reelin is a key player in post-lesional cell migration in the adult brain. Finally our findings provide proof of concept that allowing progenitors to escape from the RMS is a potential therapeutic approach to promote myelin repair.

Stem cell populations derived from heart and pancreas show a with a unique phenotype and give rise to functional cardiomyocytes and insulin-producing cells, respectively

Introduction: Recently, mesenchymal stem cells (MSC) of perivascular origin have been identified in several organs not including the heart. Using a novel cell isolation protocol, we have isolated cells sharing common characteristics from mouse hearts and pancreas. The aim of the present study was to characterize these cells in vitro.Methods: Cells were isolated from neonatal and adult mouse hearts and pancreas and cultured for more than 6 months. Surface marker expression was analyzed by flow cytometry and immunocytochemistry. Cell differentiation was tested using multiple differentiation media. Insulin production by pancreas-derived cells was tested by dithizone staining.Results: Cells showing a similar, distinctive morphology were obtained from the heart and pancreas after 4-8 weeks of culture. Cells from the two organs also showed a very similar immunophenotype, characterized by expression of c-kit (stem cell factor receptor), CD44, the common leukocyte marker CD45, and the monocytic markers CD11b and CD14. A significant proportion of cardiac and pancreatic cells expressed NG2, a marker for pericytes and other vascular cells. A significant proportion of cardiac, but not of pancreatic cells expressed stem cell antigen-1 (Sca-1). However, cells did not express T, B or dendritic cell markers. Cells of both cardiac and pancreatic origin spontaneously formed "spheres" (spherical cell aggregates similar to "neurospheres" formed by neural stem cells) in vitro. Cardiosphere formation was enhanced by TNF-alpha. Several cardiospheres (but no "pancreatospheres") derived from neonatal (but not adult) cells showed spontaneous rhythmic contractions, thus demonstrating cardiac differentiation (this was confirmed by immunostaining for alpha-sarcomeric actinin). Beating activity was enhanced by low serum conditions. Cells from both organs formed adipocytes, osteocytes and osteocytes under appropriate conditions, the typical differentiation pattern of MSCs. Pancreas-derived cells also formed dithizonepositive insulin-producing cells.Conclusions: We have defined cardiac and pancreatic cell populations that share a common morphology, growth characteristics, and a unique immunophenotype. Expression of perivascular and monocytic markers, along with stem/priogenitor cell markers by these cells suggests a relationship with pericytes-mesoangioblasts and so-called multipotent monocytes. Cells show MSC-typical growth and differentiation patterns, together with tissue-specific differentiation potential: cardiomyocytes for cardiac-derived cells and insulinproducing cells for pancreas-derived cells.

Perforation cardiaque d'un ulcère gastrique: une cause inhabituelle de décès, après résection oesogastrique pour carcinome épidermoïde de l'oesophage [Cardiac perforation by a gastric ulcer: an unusual cause of death, after an esophageal and gastric resection of an epidermoid esophageal carcinoma]

We report here the case of a 55 year old female that underwent surgery for a well differentiated squamous cell carcinoma of the esophagus (middle third). Four months after surgery, she complains of neck pain, for which she is prescribed non steroidal antiinflammatory drugs (NSAID). A CT-scan and a Barium swallow are then normal. After three weeks of treatment, the patient is admitted on emergency to the Intensive Care Unit for a resuscitation hematemesis and atrial fibrillation with a fast ventricular response. The symptoms are stabilized after the transfusion of a few packed red blood cells. A few hours later, however, a massive hematemesis recurs and the patient dies despite intense resuscitation measures. Autopsy reveals three gastric ulcers, one of which had perforated through the cardiac left ventricular wall

Fractal temporal organisation of motricity is altered in major depression.

OBJECTIVE: Motor changes in major depression (MD) may represent potential markers of treatment response. Physiological rhythms (heart rate/gait cycle/hand movements) have been recently shown to be neither random nor regular but to display a fractal temporal organisation, possibly reflecting a unique central "internal clock" control. Sleep and mood circadian rhythm modifications observed in MD also suggest a role for this "internal clock". We set out to examine the fractal pattern of motor activity in MD. METHODS: Ten depressed patients (46±20 years) and ten age- and gender-matched healthy controls (48±21 years) underwent a 6-h ambulatory monitoring of spontaneous hand activity with a validated wireless device. Fractal scaling exponent (α) was analysed. An α value close to 1 means the pattern is fractal. RESULTS: Healthy controls displayed a fractal pattern of spontaneous motor hand activity (α: 1.0±0.1), whereas depressed patients showed an alteration of that pattern (α:1.2±0.15, p<0.01), towards a smoother organisation. CONCLUSION: The alteration of fractal pattern of hand activity by depression further supports the role of a central internal clock in the temporal organisation of movements. This novel way of studying motor changes in depression might have an important role in the detection of endophenotypes and potential predictors of treatment response.

X-ray diffraction, thermal analysis, and Raman scattering study of K2BeF4 and comparation to other member of the (beta)-K2SO4 family with ferroelectric -paraelectric transition

Thermal analysis, powder diffraction, and Raman scattering as a function of the temperature were carried out on K2BeF4. Moreover, the crystal structure was determined at 293 K from powder diffraction. The compound shows a transition from Pna21 to Pnam space group at 921 K with a transition enthalpy of 5 kJ/mol. The transition is assumed to be first order because the compound shows metastability. Structurally and spectroscopically the transition is similar to those observed in (NH4)2SO4, which suggests that the low-temperature phase is ferroelectric. In order to confirm it, the spontaneous polarization has been computed using an ionic model.

Mechanisms of apoptosis in retinitis pigmentosa.

Mutations in humans are associated with several forms of inherited retinal dystrophies, such as Retinitis Pigmentosa which lead to retinal cell death and irreversible loss of vision. Genes involved in affected patients mainly encode proteins related to vision physiology including visual cycle and light-dependent phototransduction cascade. As reported in spontaneous and genetically engineered mouse models, apoptosis is a common fate in retinal degeneration, although the triggered signals to retinal apoptosis remain largely unraveled. Several studies highlighted that many of the molecular pathways involved in ocular diseases rely on caspase-dependent or -independent apoptotic mitochondrial pathway involving the Bcl-2 family of proteins. Anti- and pro-apoptotic Bcl-2 members are present in retinal tissues and are thought to play a role in the pathogenesis of several retinal disorders. Since almost no efficient treatments are available so far, it remains a great challenge to decipher the molecular pathways involved in retinal dystrophies and to develop alternative therapies to prevent or inhibit eye defect. Toward this goal, mutation-independent strategies such as molecular therapy provides promising and exciting approaches to deliver anti-apoptotic molecules targeting the Bcl-2 pathway through the use of cell permeable transport peptides. Modulation of common apoptotic signaling pathways may be of outstanding potential to target multiple retinal dystrophies regardless of the primary genetic defect.