Prevalence of chronic rhinosinusitis in Sao Paulo.

INTRODUCTION: Studies designed to investigate chronic rhinosinusitis (CRS) epidemiology play an important role to assess population`s distribution and risk factors to result in the development and promotion of public health policies. METHOD: This study design is a survey carried out with a complex two-stage cluster sampling plan. Personal interviews were carried out with 2,003 individuals. The questionnaire included the epidemiological criteria for CRS. Demographic data, history of physician-diagnosed respiratory diseases (asthma, sinusitis, rhinitis), smoking, family income, educational attainment, and household characteristics were also evaluated. RESULTS: The overall response rate was 93.9% of the households. Mean age was 39.8 +- 21 years; 45.33% were male. The overall prevalence of CRS in the city of Sao Paulo was 5.51%. We found a significant association between diagnosis of CRS and diagnosis of asthma and CRS and diagnosis of rhinitis and a significant association between presence of CRS and belonging to the low-income subgroup. CONCLUSION: The municipality of Sao Paulo has an urban population of 11 million. According to the present study, the prevalence of CRS is 5.51%, which represents more than 500,000 individuals affected by this condition in the city.

Effects of bilateral vestibular nucleus lesions on cardiovascular regulation in conscious cats.

The vestibular system participates in cardiovascular regulation during postural changes. In prior studies (Holmes MJ, Cotter LA, Arendt HE, Cas SP, and Yates BJ. Brain Res 938: 62-72, 2002, and Jian BJ, Cotter LA, Emanuel BA, Cass SP, and Yates BJ. J Appl Physiol 86: 1552-1560, 1999), transection of the vestibular nerves resulted in instability in blood pressure during nose-up body tilts, particularly when no visual information reflecting body position in space was available. However, recovery of orthostatic tolerance occurred within 1 wk, presumably because the vestibular nuclei integrate a variety of sensory inputs reflecting body location. The present study tested the hypothesis that lesions of the vestibular nuclei result in persistent cardiovascular deficits during orthostatic challenges. Blood pressure and heart rate were monitored in five conscious cats during nose-up tilts of varying amplitude, both before and after chemical lesions of the vestibular nuclei. Before lesions, blood pressure remained relatively stable during tilts. In all animals, the blood pressure responses to nose-up tilts were altered by damage to the medial and inferior vestibular nuclei; these effects were noted both when animals were tested in the presence and absence of visual feedback. In four of the five animals, the lesions also resulted in augmented heart rate increases from baseline values during 60 degrees nose-up tilts. These effects persisted for longer than 1 wk, but they gradually resolved over time, except in the animal with the worst deficits. These observations suggest that recovery of compensatory cardiovascular responses after loss of vestibular inputs is accomplished at least in part through plastic changes in the vestibular nuclei and the enhancement of the ability of vestibular nucleus neurons to discriminate body position in space by employing nonlabyrinthine signals.

Locations of neurons with respiratory-related activity in the ferret brainstem.

Previous transneuronal tracing studies conducted in the ferret revealed that a large population of neurons that provides inputs to diaphragm and abdominal motoneurons is located in the ventral magnocellular portion of the medial medullary reticular formation. These observations raise the possibility that the neural substrate underlying respiratory rhythmogenesis may be different in the ferret than in other species in which this circuitry has been explored. In the present study, systematic tracking was conducted through the ferret medulla to map the locations of neurons with activity related to the contractions of respiratory muscles. As in the cat, rat, and rabbit, neurons with respiratory-related discharges were distributed either lateral or ventrolateral to the solitary nucleus (dorsal respiratory group) or in the vicinity of nucleus retroambigualis, nucleus ambiguus and the retrofacial nucleus (ventral respiratory group). Although the general organization of respiratory group neurons appeared to be similar in the ferret to that in other mammals, a difference was that few expiratory neurons were located rostrally in the ventral respiratory group. These data suggest that the ventral magnocellular medullary reticular formation is not essential for respiratory rhythm generation, at least during quiet breathing, but may participate in regulating the excitability of respiratory motoneurons or in coordinating the contractions of respiratory muscles during nonrespiratory responses (e.g. coughing or emesis).

Role of the vestibular system in regulating respiratory muscle activity during movement.

1. Changes in posture can affect the resting length of the diaphragm, which is corrected through increases in both diaphragm and abdominal muscle activity. Furthermore, postural alterations can diminish airway patency, which must be compensated for through increases in firing of particular upper airway muscles. 2. Recent evidence has shown that the vestibular system participates in adjusting the activity of both upper airway muscles and respiratory pump muscles during movement and changes in body position. 3. Vestibulo-respiratory responses do not appear to be mediated through the brainstem respiratory groups; labyrinthine influences on respiratory pump muscles may be relayed through neurons in the medial medullary reticular formation, which have recently been demonstrated to provide inputs to both abdominal and diaphragm motoneurons. 4. Three regions of the cerebellum that receive vestibular inputs, the fastigial nucleus, the nodulus/uvula and the anterior lobe, also influence respiratory muscle activity, although the physiological role of cerebellar regulation of respiratory activity is yet to be determined. 5. It is practical for the vestibular system to participate in the control of respiration, to provide for rapid adjustments in ventilation such that the oxygen demands of the body are continually matched during movement and exercise.

Role of the medial medullary reticular formation in relaying vestibular signals to the diaphragm and abdominal muscles.

Changes in posture can affect the resting length of respiratory muscles, requiring alterations in the activity of these muscles if ventilation is to be unaffected. Recent studies have shown that the vestibular system contributes to altering respiratory muscle activity during movement and changes in posture. Furthermore, anatomical studies have demonstrated that many bulbospinal neurons in the medial medullary reticular formation (MRF) provide inputs to phrenic and abdominal motoneurons; because this region of the reticular formation receives substantial vestibular and other movement-related input, it seems likely that medial medullary reticulospinal neurons could adjust the activity of respiratory motoneurons during postural alterations. The objective of the present study was to determine whether functional lesions of the MRF affect inspiratory and expiratory muscle responses to activation of the vestibular system. Lidocaine or muscimol injections into the MRF produced a large increase in diaphragm and abdominal muscle responses to vestibular stimulation. These vestibulo-respiratory responses were eliminated following subsequent chemical blockade of descending pathways in the lateral medulla. However, inactivation of pathways coursing through the lateral medulla eliminated excitatory, but not inhibitory, components of vestibulo-respiratory responses. The simplest explanation for these data is that MRF neurons that receive input from the vestibular nuclei make inhibitory connections with diaphragm and abdominal motoneurons, whereas a pathway that courses laterally in the caudal medulla provides excitatory vestibular inputs to these motoneurons.