Biomedical subjects

Kathrine Jáuregui-Renaud

Publications and source records attributed to Kathrine Jáuregui-Renaud.

11 recordsLinked to original sources

PubMed2006

Vitamin E effects on nasal symptoms and serum specific IgE levels in patients with perennial allergic rhinitis.

BACKGROUND: Studies have shown that vitamin E intake may reduce IgE production. OBJECTIVE: To evaluate the effects of vitamin E supplementation on the severity of nasal symptoms and the serum levels of specific IgE in patients with perennial allergic rhinitis. METHODS: Sixty-three patients (mean +/- SD age, 12 +/- 2.4 years) with a history of perennial allergic rhinitis participated in this study. None of the patients had evidence of acute infectious disease or used tobacco, corticosteroids, antihistamines, or vitamins. Patients were randomized to receive either vitamin E (400 IU/d) or placebo for 4 weeks, with loratadine-pseudoephedrine (0.2/0.5 mg/kg) during the first 2 weeks of treatment. The severity of nasal symptoms was evaluated using a validated questionnaire, which was administered weekly for 4 weeks. The serum concentrations of specific IgE to 5 common inhalant allergens and lipid peroxides were measured before treatment and at the end of the study. RESULTS: Before, during, and after treatment, the symptom severity scores were similar in the 2 groups; within each group, a significant decrease was observed after the first week of follow-up (P < .05), with no further changes. Serum levels of specific IgE and lipid peroxides did not show any significant changes related to vitamin E intake within and between groups. CONCLUSIONS: In patients with perennial allergic rhinitis, vitamin E supplementation (400 IU/d) did not have any significant effects on nasal symptom severity or on serum concentrations of specific IgE to 5 common allergens.

Adolescent↗

PubMed2006

Cardio-respiratory responses evoked by transient linear acceleration.

INTRODUCTION: Predictive control of the responses to re-orientating stimuli and its interaction with vestibular signals may be an important factor in protecting against spatial disorientation. Here we evaluated the influence of stimulus predictability on the cardio-respiratory responses to transient fore-aft linear accelerations. METHODS: There were 13 normal subjects and 6 patients with bilateral loss of vestibular function who were exposed to linear acceleration of +0.26 Gx peak while seated upright and restrained on a motorized bogie. Accelerations were: (1) 'unpredictable', triggered by the experimenter either at the end of expiration or at the end of inspiration; or (2) 'predictable', triggered by the subjects pressing a button. The two conditions included false trials when nothing would happen. Respiratory frequency, electrocardiogram, and trunk acceleration were recorded. RESULTS: For unpredictable accelerations, in all subjects, the RR interval decreased within the first to second beat after acceleration onset. In normal subjects this decrease was maintained or more evident during the third, fourth, or fifth heart beat after onset. Cardiac responses were not significantly different when acceleration was triggered at the end of inspiration or at the end of expiration. Self-triggered acceleration also provoked prolonged, but attenuated, heart rate responses in healthy subjects, while responses were absent in the patients. All subjects responded with a consistent rapid inspiration to the onset of acceleration, whether predictable or not. DISCUSSION: A vestibulo-cardiac response is evoked by transient linear acceleration, independently from the phase of the breathing cycle and from the predictability of the stimulus. A vestibular signal of motion appears to be required to produce a prolonged increase in heart rate.

Acceleration↗

PubMed2005

Benign paroxysmal positional vertigo can interfere with the cardiac response to head-down tilt.

OBJECTIVE: To assess the pulse rate and the respiratory rate responses to head-down tilt of the whole body in the plane of the posterior canals in healthy subjects and in patients with benign paroxysmal positional vertigo (BPPV). BACKGROUND: Although BPPV attacks are usually accompanied by autonomic symptoms, there are no studies assessing autonomic responses during triggering maneuvers for BPPV, neither in healthy subjects nor in patients. METHODS: We evaluated nine healthy subjects and four BPPV patients (3 unilateral and 1 bilateral). Using a two-axis rotator, from an upright position they were rotated 135 degrees backwards to head-down tilt, either in the plane of the right or the left posterior canal. RESULTS: In healthy subjects, head-down tilt always induced a significant decrease of the pulse rate, which was similar after rotation to the right and to the left posterior canals. This response was observed in patients with unilateral BPPV only when they were rotated toward the nonaffected side, and it was not evident when they were rotated toward the affected side (p < 0.025). In the patient with bilateral BPPV, no change of the pulse rate was observed after rotation toward the right or to the left posterior canal. Although, in all the patients, the respiratory rate increased during the tilt, a similar increase was observed in two healthy subjects. CONCLUSION: After rotation in the plane of the affected semicircular canal, BPPV can interfere with the cardiac response to head-down tilt of the whole body.

Adult↗

PubMed2003

Paced breathing can prevent vasovagal syncope during head-up tilt testing.

BACKGROUND: Clinical experience suggests that, through the control of heart rate, paced breathing may prevent syncope. OBJECTIVE: To assess the effect of metronome-paced breathing (0.2 Hz) on the outcome of head-up tilt test (HUT) in patients with vasovagal syncope. PATIENTS AND METHODS: Ten patients (two men), mean +/- SD age 18.4 +/- 5.1 years, with a positive HUT with spontaneous breathing and no evidence of cardiovascular or neurological disease, were exposed to a second HUT under metronome-paced breathing (0.2 Hz). Continuous electrocardiographic recordings were obtained during the two tests, and heart rate variability was analyzed off-line. RESULTS: During HUT with metronome-paced breathing, only one of the 10 patients developed bradycardia, hypotension and syncope (P<0.01, Wilcoxon). Compared with HUT with spontaneous breathing, HUT with paced breathing induced a larger increase in the heart rate in the first minute of tilt (4 +/- 6 beats/min versus 16 +/- 12 beats/min, P<0.05). CONCLUSIONS: The results show that paced breathing can prevent vasovagal syncope induced by HUT. This finding suggests that respiratory training could be useful to prevent vasovagal syncope.

Adolescent↗

PubMed2003

Subjective assessment of visual verticality in follow-up of patients with acute vestibular disease.

We conducted a study of 10 patients with acute unilateral peripheral vestibular failure in order to assess their ability to perceive visual verticality during the acute stage of their disease and during recovery. We also evaluated 31 healthy volunteers to test the reproducibility of our assessment methods. The 10 patients were first evaluated within 4 days of the onset of their vestibular failure, and follow-up tests were conducted 2 and 4 weeks later. The healthy subjects were similarly tested at 2 and 4 weeks following their baseline evaluation. All patients and subjects were tested 10 times during each evaluation session, and results from each as well as from the groups as a whole were calculated as a mean of all responses. The mean visual vertical tilt (the amount of deviation from true verticality) among the 10 patients declined from 8.4 degrees (+/- 2.4 degrees) at the first examination to 3.2 degrees (+/- 1.6 degrees) at week 2 and to 1.4 degrees (+/- 0.7 degree) at week 4. These decreases coincided with the pace of the resolution of their vestibular symptoms. The rates of reproducibility among the 31 healthy volunteers at 2 and 4 weeks following their initial assessment were 95 and 97%, respectively. We concluded that repeated measurements of the static visual vertical can be useful as a follow-up tool for patients with vestibular neuritis.

Adult↗

PubMed2002

[Effect of angiotensin blockade on the orthostatic response in patients with systemic arterial hypertension].

INTRODUCTION AND OBJECTIVES: The effect of the treatment of arterial hypertension with angiotensin inhibitors on the autonomic response to orthostatism was studied. PATIENTS AND METHOD: In 20 hypertensive patients, enalapril (10 to 20 mg) was administered daily for four weeks. Then, irbesartan (150 to 300 mg) was given for four weeks. Finally, 10 mg of enalapril combined with 150 mg of irbesartan was prescribed for another four weeks. Heart rate variability at rest and during the head-up tilt test with controlled respiration was assessed at the beginning and end of each period. RESULTS: Mean arterial pressure showed a similar reduction in the three treatment periods. There were no changes in heart rate. Heart rate variability at rest showed differences in the spectral high-frequency component between the control and the treatment periods (p = 0.10). There was an increase in the high-frequency component between the control and the third (p = 0.047) and the fourth periods (p = 0.03). In the head-up tilt test there was a decrease in total spectral high-frequency power. CONCLUSIONS: There was no increase in orthostatic intolerance with these drugs in hypertensive patients. The absence of changes in heart rate in spite of a decrease in blood pressure suggests resetting of the baroreflex function. The long-term control of hypertension with these drugs may have a favorable effect on heart rate variability, with an increase in parasympathetic activity.

Adult↗

PubMedDate not supplied

Auditory impairment in patients with type 2 diabetes mellitus.

BACKGROUND: We assessed the auditory function of 94 patients with type 2 diabetes mellitus and 94 age- and sex-matched healthy subjects. METHODS: To study the influence of the clinical characteristics of the disease on the auditory function, after a clinical interview with ophthalmological assessment, subjects were evaluated using pure-tone audiometry, speech audiometry, auditory brainstem responses, the Michigan Diabetic Neuropathy Score and albuminuria. The mean age when diabetes was diagnosed was 42.8 +/- 6.5 years (mean +/- SD) and the time elapsed since diabetes diagnosis was 7.2 +/- 5.4 years. RESULTS: Forty-eight patients (62%) had HbA1c >8%; diabetic retinopathy was evident in 14 patients (14%) and microalbuminuria was identified in 12 patients. Compared to healthy subjects, diabetic patients showed an increase of the perception threshold at 8000 Hz (p <0.01), higher hearing levels to discriminate at least 90% of 10 monosyllables (p <0.01), and longer latencies of wave V, interwave I-V and interwave III-V (p <0.01). Significant correlation was found between the hearing threshold at 8 KHz and patient age, and the former and the time elapsed since the diabetes was diagnosed (p <0.001). CONCLUSIONS: Patients with type 2 diabetes mellitus can have subclinical hearing loss and impaired auditory brainstem response, independent of peripheral neuropathy, retinopathy or nephropathy.

Adult↗

PubMedDate not supplied

Vestibular function interferes in cardiovascular reflexes [corrected].

BACKGROUND: Experimental work indicates that the vestibular system participates in autonomic reflexes during body movement and postural changes. However, there are no studies of cardiovascular reflexes during vertigo due to human acute vestibular lesions. METHODS: We assessed the response to active change of posture and hand immersion in cold water in seven patients with unilateral peripheral vestibular failure (vestibular neuritis) and seven age/sex-matched healthy subjects in acute phase (72 h from vertigo onset) and at 2 weeks of follow-up. RESULTS: During acute phase, patients showed decreased blood pressure response during cold hand test (p < 0.05). Upright stance induced deficient decrease of the respiratory component of heart rate variability (p < 0.05) with lack of increase in low frequency/high frequency (LF/HF) ratio. At 2 weeks of follow-up, these abnormalities improved. CONCLUSIONS: Results suggest that acute vestibular lesions can interfere with cardiovascular autonomic responses in humans. This may reflect disruption of normal vestibulo-autonomic reflexes.

Adult↗

PubMedDate not supplied

[Effects of air pollution on human health and their importance in Mexico City].

The impact of air pollution on human health is a complicated problem. In this review, we describe the main health effects of exposure to ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, lead and particulate matter. Geographical characteristics of the metropolitan area of Mexico City that favor pollutant persistence with adverse effects on the population are described; the use of the Indice Metropolitano de la Calidad del Aire (IMECA), current norms, and present programs to diminish this problem are discussed. Evidence shows that through these actions, air quality has improved. However, some pollutants such as ozone and particulate matter, still exceed the standard. To further improve air quality in the city, existing programs should continue and multidisciplinary research, both basic and applied, is required.

Air Pollutants↗

PubMedDate not supplied

[Disability due to auditory and vestibular dysfunction in a specialized care center].

OBJECTIVE: To assess the frequency and characteristics of the disability associated with hearing loss and vestibular disease in a Specialized Medical Center of the Mexican Social Security Institute. METHODS: 530 patients agreed to participate. They were assessed due to hearing loss (n = 252) and vestibular disease (n = 278), 54% and 50% of them worked. After a clinical evaluation and administration of a symptom questionnaire, they were asked about the frequency and days ofdisability to perform daily life activities related to their audiological or vestibular disease and how often they visited the physician during the last year because of their symptoms. RESULTS: Hearing loss patients visited the physician 1-6 times/ year and 15.8% reported disability. Vestibular patients visited the physician 1-8 times/ year and reported disability more frequently (60.8%) (p < 0.01). Among those who worked, 5% of patients with hearing loss and 51% of patients with vestibular disease stopped working during 1-15 cumulative days for the first group and 1-365 cumulative days for the second group. Spearmnan's correlation coefficient between the evolution of the disease and disability days was -0.14 (p < 0.01) for hearing loss patients and -0.27 (p < 0.01 ) for vestibular disease. CONCLUSION: Vestibular disease is a cause of disability. which can have financial impact on both the patient and the health care system.

Absenteeism↗

PubMedDate not supplied

[The subjective visual vertical in vestibular disease].

OBJECTIVE: To assess and compare the accuracy to perceive visual verticality, with and without trunk-head tilt in the frontal plane (30 degrees), in patients with peripheral or central vestibular disease. METHODS: Thirty eight patients accepted to participate, 23 with peripheral disease and 15 with central disease. We also evaluated 40 healthy subjects. Subjects were seated facing a screen with an anchored motorized bar (20 cm). They were asked to bring the line to vertical, using a joystick, 10 times while seated upright and 10 times while tilted 30 degrees to each side. An average of the distance from true vertical was calculated to determine the tilt of the visual vertical on each posture. RESULTS: Always, estimations made by healthy subjects were < 2 degrees from true vertical. In patients, in upright posture the largest tilt of the visual vertical was observed in patients with peripheral disease and spontaneous nystagmus. However, in all patients the accuracy to estimate the true vertical decreased when they were evaluated with trunk-head tilt (p < 0.05). In this condition the sensitivity of the test increased from 34 to 85% and the efficacy from 68 to 93% (p < 0.05). CONCLUSION: Trunk-head tilt in the frontal plane decreases the accuracy of patients with vestibular disease to visually perceive verticality. This finding shows that head-trunk tilt can improve the sensibility and efficacy of this test to assess the vestibular function.

Adult↗