ABSTRACT
Repeated stress is a major public health concern where many stress responses are mediated by neuronal nicotinic acetylcholine receptors. In the present study we evaluated the effects of the nicotinic receptor partial agonists, cytisine and its derivative 3-(pyridin-3'-yl)-cytisine (3-pyr-Cyt) on two main biological outputs associated with activation of nAChR-release of neurotransmitters and increase in catecholamine biosynthesis to replenish the releasable pool. We compared these substances to the maximal response triggered by nicotine (full agonist) in PC12 cells. Cytisine, 3-pyr-Cyt or nicotine induced time-, dose- and Ca(2+)-dependent significant release of norepinephrine (NE) into the culture media. These effects were completely inhibited by mecamylamine but not by α-bungarotoxin, and only partially affected by α-conotoxin AulB, consistent with the involvement of α3ß4 receptors. Co-application of cytisine (or 3-pyr-Cyt) and nicotine resulted in attenuated nicotine-induced NE release. Cytisine or 3-pyr-Cyt alone induced a modest rise in tyrosine hydroxylase (TH) mRNA levels (index of the cell's catecholamine biosynthetic capacity). We conclude that both, cytisine and 3-pyr-Cyt (i) display typical partial agonist properties at naturally existing ganglionic nAChR (α3ß4 and α7 nAChR) with regard to catecholamine homeostasis (i.e. NE release and re-synthesis) and (ii) modulated the effect of nicotine during combined treatment.
Subject(s)
Catecholamines/biosynthesis , Homeostasis/drug effects , Neurons/drug effects , Nicotine/pharmacology , Nicotinic Agonists/pharmacology , Receptors, Nicotinic/drug effects , Alkaloids/pharmacology , Animals , Azocines/pharmacology , Blotting, Northern , Homeostasis/physiology , Neurons/metabolism , PC12 Cells , Quinolizines/pharmacology , Rats , Receptors, Nicotinic/metabolismABSTRACT
Recent publications show that DPOAE measurements can generate a more accurate diagnosis, if (1) their fine structure is suppressed, and (2) if the calibration of the sound field is improved. Reduction of the fine structure is particularly important in the frequency range below 4 kHz in subjects with intact cochlear amplifier and can reduce the standard deviation of threshold estimations based on DPOAE-input/output functions from 11 dB to 6 dB. Improving the sound-field calibration has most impact in the frequency range above 4 kHz. Threshold estimations based on laserinterferometrically measured DPOAE input-output functions where the sound field was calibrated close to the tympanic membrane have been shown to reduce the standard deviation down to 8.6 dB in humans and 6.5 dB in guinea pigs. Compared with conventional DPOAE measures, such as amplitude or signal-to-noise ratio, threshold estimation based on DPOAE-I/O functions has the advantage that its slope provides additional information about the middle-ear; however, its specificity is limited. In the future, combined methods such as acoustic reflectance or laser vibrometry on the umbo promise a reliable assessment of the middle-ear contribution to DPOAE.
Subject(s)
Hearing Loss, Sensorineural/diagnosis , Otoacoustic Emissions, Spontaneous/physiology , Signal Processing, Computer-Assisted , Sound Spectrography , Auditory Threshold/physiology , Basilar Membrane/physiopathology , Ear, Middle/physiopathology , Hair Cells, Auditory, Outer/physiology , Hearing Loss, Sensorineural/physiopathology , Humans , Reference Values , Sensitivity and SpecificityABSTRACT
BACKGROUND: Up to now, laser interferometric vibration measurements of the human eardrum have not provided any information about cochlear function, because the measurement devices have not been sufficiently sensitive. METHODS: After designing a new type of laser Doppler vibrometer (LDV) that allows detection of displacement amplitudes down to about 1 pm, we used this device in 20 subjects to measure growth functions of the distortion products of otoacoustic emissions (DPOAE) as vibrations of the umbo. For comparison, DPOAE growth functions were also measured conventionally with an acoustic probe in the closed external auditory meatus. Hearing thresholds were estimated from both sets of measurements and compared with Békésy thresholds. RESULTS: The standard deviation of the threshold estimate obtained from the vibration DPOAEs was 8.6 dB, which is significantly smaller than that of the threshold estimate (16.7 dB) obtained from the acoustic DPOAEs. We attribute the smaller standard deviation for the LDV data to the fact that these measurements are made in an open sound field and are therefore less susceptible to pressure calibration errors. CONCLUSIONS: Being relatively free of sound-field measurement artefacts, the LDV method allows precise estimation of the hearing threshold. Vibration measurements of the umbo have, therefore, considerable potential for the differential diagnosis of mechanical dysfunction of the middle and inner ear.
Subject(s)
Auditory Threshold/physiology , Ear, Inner/physiology , Ear, Middle/physiology , Hearing Tests/methods , Lasers , Otoacoustic Emissions, Spontaneous/physiology , Adult , Female , Humans , Male , Sensitivity and Specificity , VibrationABSTRACT
It has previously not been possible to measure eardrum vibration of human subjects in the region of auditory threshold. It is proposed that such measurements should provide information about the status of the mechanical amplifier in the cochlea. It is this amplifier that is responsible for our extraordinary hearing sensitivity. Here, we present results from a laser Doppler vibrometer that we designed to noninvasively probe cochlear mechanics near auditory threshold. This device enables picometer-sized vibration measurements of the human eardrum in vivo. With this sensitivity, we found the eardrum frequency response to be linear down to at least a 20-dB sound pressure level (SPL). Nonlinear cochlear amplification was evaluated with the cubic distortion product of the otoacoustic emissions (DPOAEs) in response to sound stimulation with two tones. DPOAEs originate from mechanical nonlinearity in the cochlea. For stimulus frequencies, f1 and f2, with f2/f1 = 1.2 and f2 = 4-9.5 kHz, and intensities L1 and L2, with L1 = 0.4L(2) + 39 dB and L2 = 20-65 dB SPL, the DPOAE displacement amplitudes were no more than 8 pm across subjects (n = 20), with hearing loss up to 16 dB. DPOAE vibration was nonlinearly dependent on vibration at f2. The dependence allowed the hearing threshold to be estimated objectively with high accuracy; the standard deviation of the threshold estimate was only 8.6 dB SPL. This device promises to be a powerful tool for differentially characterizing the mechanical condition of the cochlea and middle ear with high accuracy.
Subject(s)
Audiometry/instrumentation , Audiometry/methods , Hearing Tests/methods , Hearing , Otoacoustic Emissions, Spontaneous/physiology , Tympanic Membrane/physiology , Adult , Ear, Middle/anatomy & histology , Female , Hearing Loss/diagnosis , Humans , Male , Reproducibility of Results , Sensitivity and Specificity , Sound , Tympanic Membrane/anatomy & histology , VibrationABSTRACT
The study of evaluation and rehabilitation of COPD patient (SERBOC) started in January 2004 in the 6th Medical Clinic of the Iasi Rehabilitation Hospital. One of its goals is to evaluate the left cardiac morphology and function in the chronic obstructive pulmonary disease. The inn-patients have been complexly approached by physical examination, chest X-ray, rest electrocardiogram, echocardiography and Holter monitoring. The stage result is that physical examination, chest X-ray and rest electrocardiogram fails in offering satisfactory information regarding left cardiac dysfunction; it is necessary to add Holter monitoring and especially echocardiography. The conventional and Doppler echocardiography performed in our clinic allowed the possibility to identify diastolic dysfunction in all 9 patients and systolic dysfunction in 7 of them.
Subject(s)
Pulmonary Disease, Chronic Obstructive/complications , Pulmonary Disease, Chronic Obstructive/physiopathology , Ventricular Dysfunction, Left/etiology , Ventricular Dysfunction, Left/physiopathology , Aged , Echocardiography , Electrocardiography , Electrocardiography, Ambulatory , Female , Humans , Male , Middle Aged , Pulmonary Disease, Chronic Obstructive/diagnosis , Pulmonary Disease, Chronic Obstructive/rehabilitation , Retrospective Studies , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/rehabilitationABSTRACT
In this article, the sensorineural hearing loss is presented as a possible sequelae of neonatal hyperbilirubinemia. In our program of early hipoacusia detection, 241 babies were examined from January 1996 until November 1999; 7 cases had a history of hyperbilirubinemia in the neonatal period and 2 of them were diagnosed of sensorineural hearing loss. We discuss how the bilirubin or any other associated factor might have been the cause and this could explain the selective affectation of some children.
Subject(s)
Hearing Loss, Sensorineural/etiology , Jaundice, Neonatal/complications , Algorithms , Hearing Loss, Sensorineural/diagnosis , Humans , Infant, Newborn , Male , Severity of Illness IndexABSTRACT
En este artículo, la hipoacusia neurosensorial es presentada como una posible secuela de la hiperbilirrubinemia neonatal. En nuestro programa de detección precoz de la hipoacusia fueron investigados 241 niños lactantes, desde enero de 1996 hasta noviembre de 1999, de los cuales 7 casos tenían antecedentes de hiperbilirrubinemia neonatal inmediata y, de ellos, 2 presentaron hipoacusia neurosensorial bilateral. Realizamos una discusión de los posibles mecanismos de acción de la bilirrubina y las causas que explicarían la afectación selectiva de algunos niños (AU)
In this article, the sensorineural hearing loss is presented as a possible sequelae of neonatal hyperbilirubinemia. In our program of early hipoacusia detection, 241 babies were examined from January 1996 until November 1999; 7 cases had a history of hyperbilirubinemia in the neonatal period and 2 of them were diagnosed of sensorineural hearing loss. We discuss how the bilirubin or any other associated factor might have been the cause and this could explain the selective affectation of some children (AU)
Subject(s)
Male , Infant, Newborn , Humans , Jaundice, Neonatal/complications , Hearing Loss, Sensorineural/etiology , Algorithms , Severity of Illness IndexABSTRACT
Hypertension is present in epidemic proportion and is associated with a markedly increased risk of developing numerous cardiovascular disorders. All current treatment guidelines emphasise the role of nonpharmacological interventions, physical activity included, in the treatment of mild to moderate hypertension. A large number of studies have demonstrated that regular exercise reduces the incidence of hypertension. In addition to preventing hypertension, regular exercise has been found to lower blood pressure (10 mmHg average reduction in both systolic and diastolic pressure), improve lipoprotein-lipid profiles and insulin sensitivity. As part of the initial treatment, exercise is recommended for 12 months in patients with stage 1 hypertension, with no other coronary risk factors and no evidence of cardiovascular disease, and for as long as 6 months in those with other risk factor, but not diabetes. In patients with diabetes, cardiovascular disease or with stage 2 or 3 hypertension, drug therapy should be initiated first. Dynamic exercise of moderate intensity, 50-75% VO2max, (e.g. brisk walking, cycling) for 50-60 minutes, 3-5 times per week, is preferable to vigorous exercise because it appears to be more effective in lowering blood pressure. In addition to reducing hypertension, physical activity improves other cardiovascular risk factors.
Subject(s)
Exercise , Hypertension/prevention & control , Guidelines as Topic , Humans , Life Style , Walking , Weight LossABSTRACT
Los tumores benignos que aparecen en el tejido salivar ectópico cervical son muy raros. La mayoría de estos tumores son adenomas pleomorfos y muchos de ellos son encontrados en el adulto. Presentamos 2 casos de adenoma pleomorfo en el tejido salivar ectópico en el niño, así como una revisión de la patogenia de las heterotopias salivares y de estos tumores benignos (AU)
Benign tumors appearing in cervical ectopic salivary tissue are rare. Most of these tumors are pleomorphic adenomas and many occur in adults. We report two cases of pleomorphic adenoma developing in cervical ectopic salivary tissue in children and review the pathogenesis of salivary heterotopia and these benign tumors (AU)
Subject(s)
Child , Female , Humans , Salivary Glands , Adenoma, Pleomorphic/pathology , Choristoma/pathology , Head and Neck Neoplasms/pathologyABSTRACT
Benign tumors appearing in cervical ectopic salivary tissue are rare. Most of these tumors are pleomorphic adenomas and many occur in adults. We report two cases of pleomorphic adenoma developing in cervical ectopic salivary tissue in children and review the pathogenesis of salivary heterotopia and these benign tumors.
