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1.
Adv Exp Med Biol ; 1232: 85-90, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31893398

RESUMEN

Delayed orthostatic hypotension (OH) is a minor subset of orthostatic dysregulation (OD). Cerebral blood oxygenation in juvenile patients with delayed OH has not been studied. We investigated the bilateral changes in cerebral oxygenation in the prefrontal cortex during an active standing test in 23 juvenile patients with delayed OH using near-infrared spectroscopy (NIRS). We measured the oxy-Hb, deoxy-Hb, and total-Hb during the active standing test. Four observations were made during the test: t1 in a resting supine position, t2 when maintaining blood pressure, and the remaining two (t3, t4) during hypotension. The concentration of oxy-Hb significantly decreased prior to satisfying the diagnostic criteria of delayed OH after standing and did not change thereafter. The concentration of deoxy-Hb increased gradually during the measurement periods. In addition, total-Hb increased from t2 to t3. There was no significant difference in the change in each Hb parameter between the left and right cerebral hemispheres. Our results indicate that NIRS parameters are more sensitive than blood pressure for the interpretation of cerebral autoregulation in juvenile patients with delayed OH.


Asunto(s)
Sistema Cardiovascular , Circulación Cerebrovascular , Hipotensión Ortostática , Oxígeno , Posición de Pie , Adolescente , Presión Sanguínea , Circulación Cerebrovascular/fisiología , Humanos , Hipotensión Ortostática/sangre , Hipotensión Ortostática/diagnóstico , Oxígeno/sangre , Espectroscopía Infrarroja Corta
3.
J Hosp Infect ; 84(1): 66-70, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23561425

RESUMEN

BACKGROUND: The neonatal intensive care unit (NICU) is a high-risk setting for transmission of meticillin-resistant Staphylococcus aureus (MRSA). Very few studies have investigated the impact of pre-emptive contact precautions applied to outborn neonates transferred to an NICU on the incidence of healthcare-associated (HA)-MRSA transmission. AIM: To assess the efficacy of pre-emptive contact precautions for outborn neonates implemented in an NICU. METHODS: A before-and-after intervention study was conducted in the NICU of Kobe University Hospital. Pre-emptive contact precautions for outborn neonates were introduced in September 2008. The period before the introduction of pre-emptive contact precautions (January 2007-August 2008) was compared with the period after the introduction of pre-emptive contact precautions (September 2008-December 2010). Data for all admitted neonates, neonates who stayed in the NICU for more than three days, length of NICU stay, incidence of MRSA-positive outborn neonates on admission, hand hygiene compliance and incidence of HA-MRSA transmission were compared between the two periods. FINDINGS: There were no significant differences in the percentage of outborn patients admitted to the NICU, percentage of patients who stayed in the NICU for more than three days, length of NICU stay, and incidence of MRSA-positive outborn patients at NICU admission between the groups enrolled before and after the introduction of pre-emptive contact precautions. However, hand hygiene compliance increased, and the incidence of HA-MRSA transmission reduced significantly from 3.5/1000 to 1.3/1000 patient-days after the introduction of pre-emptive contact precautions (P < 0.0001). CONCLUSION: Pre-emptive contact precautions for outborn neonates were effective in reducing the incidence of HA-MRSA transmission in a Japanese NICU.


Asunto(s)
Infección Hospitalaria/prevención & control , Infección Hospitalaria/transmisión , Control de Infecciones/métodos , Unidades de Cuidado Intensivo Neonatal/normas , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Infecciones Estafilocócicas/prevención & control , Infecciones Estafilocócicas/transmisión , Infección Hospitalaria/epidemiología , Higiene de las Manos , Hospitales , Humanos , Incidencia , Recién Nacido , Japón/epidemiología , Tiempo de Internación , Infecciones Estafilocócicas/epidemiología
4.
J Perinatol ; 32(7): 514-9, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21941232

RESUMEN

OBJECTIVE: To assess renin, aldosterone, human atrial natriuretic peptide (hANP) and brain natriuretic peptide (BNP) levels in cord blood from monochorionic diamniotic (MD) twins with a birthweight (BW) discordance that do not satisfy the criteria of twin-to-twin transfusion syndrome (TTTS). STUDY DESIGN: Cord blood samples were obtained from 28 MD twins without TTTS. They were divided into two groups on the basis of BW discordance as follows: large (>7.5%) and small (7.5%). Cord blood renin, aldosterone, hANP and BNP levels were measured. RESULT: Renin levels in MD twins with a large BW discordance were significantly higher than those in MD twins with a small BW discordance, with no significant differences in aldosterone, hANP and BNP levels. A significant correlation was found between renin levels and BW discordance. CONCLUSION: Renin is activated in MD twins with a BW discordance of >7.5%, even in non-TTTS.


Asunto(s)
Sangre Fetal/química , Renina/sangre , Gemelos , Aldosterona/sangre , Amnios , Factor Natriurético Atrial/sangre , Peso al Nacer , Corion , Femenino , Transfusión Feto-Fetal/sangre , Humanos , Recién Nacido , Masculino , Péptido Natriurético Encefálico/sangre , Embarazo , Gemelos Monocigóticos
5.
J Perinatol ; 30(5): 359-62, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20428179

RESUMEN

We present an autopsy case of intrauterine pneumonia in a term newborn in whom Ureaplasma parvum was confirmed by PCR examinations, including a novel diagnostic tool for detecting pathogens that caused neonatal infections using multiplex PCR. This is the first report of U. parvum being implicated in the pathogenesis of congenital pneumonia with sepsis in a term newborn.


Asunto(s)
Corioamnionitis/microbiología , Neumonía Bacteriana/congénito , Complicaciones Infecciosas del Embarazo/microbiología , Sepsis/congénito , Infecciones por Ureaplasma/congénito , Ureaplasma , Resultado Fatal , Femenino , Humanos , Recién Nacido , Masculino , Neumonía Bacteriana/diagnóstico , Neumonía Bacteriana/terapia , Embarazo , Sepsis/diagnóstico , Sepsis/terapia , Infecciones por Ureaplasma/diagnóstico , Infecciones por Ureaplasma/terapia
6.
Eye (Lond) ; 24(6): 1024-7, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19893590

RESUMEN

PURPOSE: In this study, the effects of maternal smoking along with other clinical risk factors in developing severe retinopathy of prematurity (ROP) were evaluated. DESIGN: A case-control study. METHODS: Records of newborn infants with an estimated postmenstrual age of 32 weeks or less (n=86) were reviewed. ROP grading was evaluated in accordance with the International Classification of Retinopathy of Prematurity. Severe ROP was diagnosed when it progressed to stage 3 with plus disease. The factors were first evaluated using a univariate logistic regression analysis between the groups of severe and non-severe ROP, followed by a multivariate logistic regression analysis using STATA version 10 and R version 2.71. RESULTS: A low birth weight, a long duration of artificial ventilation and oxygen supplementation, presence of chronic lung disease, and absence of maternal smoking were found to be significantly associated with severe ROP in the univariate logistic regression analysis. In the multivariate logistic regression analysis, maternal smoking was revealed as a significant factor independently associated with the incidence of severe ROP. CONCLUSIONS: An inhibitory effect of maternal smoking against developing severe ROP is suggested. The mechanism by which smoking may reduce the incidence of severe ROP needs to be further investigated.


Asunto(s)
Retinopatía de la Prematuridad/prevención & control , Fumar , Peso al Nacer , Estudios de Casos y Controles , Femenino , Humanos , Incidencia , Recién Nacido , Recien Nacido Prematuro , Modelos Logísticos , Enfermedades Pulmonares/epidemiología , Masculino , Terapia por Inhalación de Oxígeno , Respiración Artificial , Retinopatía de la Prematuridad/epidemiología , Retinopatía de la Prematuridad/etiología , Factores de Riesgo , Fumar/efectos adversos
7.
J Hum Hypertens ; 23(7): 444-50, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19078989

RESUMEN

Measurement of brachial-ankle pulse wave velocity (baPWV) is recognized as a simple and practical method for assessing arterial stiffness. We determined whether the baPWV of adolescents is affected by obesity and its associated metabolic risk variables. A cross-sectional sample of 754 apparently healthy adolescents (383 men and 371 women), aged 15-17 years, was recruited for this study. baPWV was measured by a simple automatic oscillometric technique. Adiposity measures, blood pressure, serum lipoproteins, fasting glucose and insulin were evaluated. The baPWV of the adolescents was significantly higher in men than in women and increased with age in both genders. After being statistically adjusted for age and gender, baPWV was significantly correlated with body mass index, percent body fat, waist-to-height ratio, systolic and diastolic blood pressures, mean arterial pressure, triglycerides, high-density lipoprotein cholesterol (HDL-C), atherogenic index, glucose, insulin, and homoeostasis model assessment of insulin resistance (HOMA-IR). In the multivariate regression analysis, mean arterial pressure, atherogenic index, HOMA-IR, systolic blood pressure and age were found to be significant determinants of baPWV (P<0.001). An increasing number of clustered risk variables, including high values (>gender-specific top quartiles) of waist-to-height ratio, mean arterial pressure, atherogenic index and HOMA-IR showed a graded association with baPWV (P<0.001 for trend). These results suggest that obesity and its associated metabolic abnormalities are important factors in the increased baPWV of adolescents and that baPWV may be useful in investigating early arterial wall changes in this population.


Asunto(s)
Tobillo/irrigación sanguínea , Arteria Braquial/fisiopatología , Síndrome Metabólico/fisiopatología , Obesidad/fisiopatología , Adolescente , Factores de Edad , Aterosclerosis/diagnóstico , Velocidad del Flujo Sanguíneo , Estudios Transversales , Femenino , Humanos , Modelos Lineales , Masculino , Análisis Multivariante , Flujo Pulsátil , Caracteres Sexuales
8.
Eur J Appl Physiol ; 86(2): 119-24, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11822470

RESUMEN

To clarify the clinical usefulness of the second derivative of the waveform of the fingertip photoplethysmogram (SDPTG), we examined the relationship between the pattern of the SDPTG waveform and risk factors related to atherosclerosis in 1,495 boys and girls aged 9-17 years. The fingertip photoplethysmogram and its second derivative wave were automatically recorded from the second digit of the right hand with the subjects lying in a supine position. The SDPTG waveform consisted of a, b, c and d waves in systole and an e wave in diastole. The heights of the a and d waves were measured from the baseline, and the ratio of the height of the d wave to that of the a wave (d/a ratio) was calculated. The d/a ratio had a negative correlation with the systolic (SBP) and diastolic blood pressures (DBP), atherogenic index (AI) and immunoreactive insulin concentrations (IRI) after adjustment for age. Multiple linear regression analysis revealed that the d/a ratio was associated more with body height than the risk factors for atherosclerosis in boys and girls at the growth period. The effect of sex- and height-specific cutoff values of the 10th percentile for the d/a ratio was therefore tested. The results showed that subjects with d/a ratios lower than the 10th percentile had significantly higher SBP, DBP, AI and IRI values compared to those with higher d/a ratios. These findings suggest that differences in the length of the vascular system, which are related to increases in body height, may modify the SDPTG waveform pattern during adolescence. When the body height as well as age and sex is adequately allowed for, the d/a ratio may be useful for the evaluation of arterial distensibility and for identification of individuals at an increased risk of developing atherosclerosis.


Asunto(s)
Arterias/fisiología , Vasodilatación/fisiología , Adolescente , Envejecimiento/fisiología , Arteriosclerosis/etiología , Niño , Femenino , Humanos , Masculino , Fotopletismografía , Factores de Riesgo , Caracteres Sexuales
9.
J Am Coll Cardiol ; 36(5): 1626-31, 2000 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-11079668

RESUMEN

OBJECTIVES: This study was designed to assess the clinical usefulness of an exaggerated blood pressure (BP) response to exercise (EBPR) in predicting the development of hypertension from a high-normal state. BACKGROUND: Exaggerated BP response during both dynamic and isometric exercises are associated with increased risk of future hypertension, while the significance of these responses concerning the identification of individuals with high-normal BP who are prone to develop hypertension is unknown. METHODS: The study population comprised a sample of 239 men with high-normal BP (aged 42.3 +/- 5.9 years) who underwent a symptom-limited bicycle ergometer exercise testing at baseline and then were followed for 5.1 years. RESULTS: The Kaplan-Meier survival analysis showed that the subjects in the upper quartile of BP response to exercise had a significantly higher cumulative incidence of hypertension on follow-up than those in the middle two and lower quartiles (log-rank test, p < 0.05). Multivariate analysis using the Cox proportional hazards survival model showed that the EBPR was significantly and independently associated with the risk of developing hypertension after adjustment for some traditional risk factors for hypertension (RR = 2.31, 95% confidence interval = 1.45 to 6.25). CONCLUSIONS: These findings suggest that an EBPR is an important risk factor for new-onset hypertension from a high-normal state and, thus, exercise testing can provide valid information that may help identify individuals with high-normal BP at a greater risk of future hypertension.


Asunto(s)
Presión Sanguínea/fisiología , Ejercicio/fisiología , Hipertensión/fisiopatología , Adulto , Estudios de Seguimiento , Humanos , Masculino , Análisis Multivariante , Estudios Prospectivos
10.
Ind Health ; 38(2): 252-7, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10812851

RESUMEN

To clarify the combined effects of organic solvents and noise on hearing, the upper limit of hearing was measured in 48 male workers exposed to organic solvents and/or noise in a factory producing plastic buttons. Measuring the organic solvent concentrations in working environments and breathing zone air, and the noise level in workplaces were also done. The readings suggested that most exposures to organic solvents and/or noise were within the occupational exposure limits. The prevalence rate of the upper limit of hearing below 75th percentile curve was higher in workers exposed to organic solvents and noise than expected (25 percent) and the other groups, whereas it was about 25 percent in the noise and control groups. The results suggest that the probable combined effects of organic solvents and noise on hearing should be considered even when the exposures are within the occupational exposure limits.


Asunto(s)
Sordera/etiología , Ruido en el Ambiente de Trabajo/efectos adversos , Solventes/efectos adversos , Adulto , Anciano , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Persona de Mediana Edad , Exposición Profesional , Compuestos Orgánicos/efectos adversos
11.
Ind Health ; 37(4): 426-31, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10547958

RESUMEN

The aims of this study were (1) to measure frequency-weighted vibration acceleration and (2) to study the effects of introducing a vibration-proof impact wrench on VWF in workers. The subject pool was 383 male workers who were regularly using an impact wrench and taking special medical examinations for vibration syndrome in a factory from 1982 to 1999. The prevalence of workers with VWF increased gradually after 1982, reached a peak value (4.8%) in 1986, gradually decreased after 1987, and disappeared in 1994. Sixteen subjects who had had VWF at least one time during the observation period were selected for this study. The stages of VWF were at stage I on the Stockholm Workshop scale in all subjects. After the vibration-proof impact wrench was introduced in 1986, the vibration acceleration of the impact wrench measured on the handle decreased from 8.6-11.1 m/s2 to 5.1-7.1 m/s2. The actual time per day that subjects were assumed to use the impact wrench was 108 minutes. The subjects actually used an impact wrench more than the occupational exposure limit allowed. However, VWF disappeared after the introduction of a vibration-proof impact wrench. This might have resulted from the combined effect of introducing the vibration-proof impact wrench and certain countermeasures that were taken against cold working environments.


Asunto(s)
Enfermedades Profesionales/fisiopatología , Enfermedades del Sistema Nervioso Periférico/fisiopatología , Enfermedad de Raynaud/fisiopatología , Vibración/efectos adversos , Adulto , Brazo , Frío , Diseño de Equipo , Mano , Humanos , Masculino , Enfermedades Profesionales/prevención & control , Enfermedades del Sistema Nervioso Periférico/prevención & control , Síndrome
12.
Arch Environ Health ; 54(5): 341-6, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10501151

RESUMEN

To clarify the effects of organic solvents on hearing, we measured the upper limit of hearing in 93 male workers exposed to organic solvents in 7 factories that produced plastic buttons or baths. Medical examinations, environmental monitoring (i.e., concentration in breathing-zone air), and biological monitoring (i.e., concentration in urine) of the organic solvents were also done. Although the organic solvent concentrations in the environmental monitoring were lower than the occupational exposure limit, the upper limit of hearing was reduced in workers who were exposed for 5 y or more. This reduction was dose-dependent and was related to styrene concentrations in breathing-zone air and mandelic acid concentrations in urine. Even individuals who had normal medical examinations showed a reduced upper limit of hearing. The upper limit of hearing may serve as an early detection indicator of health effects in workers constantly exposed to styrene.


Asunto(s)
Pérdida Auditiva de Alta Frecuencia/inducido químicamente , Enfermedades Profesionales/inducido químicamente , Exposición Profesional/efectos adversos , Solventes/efectos adversos , Acetona/efectos adversos , Adulto , Distribución por Edad , Relación Dosis-Respuesta a Droga , Monitoreo del Ambiente , Monitoreo Epidemiológico , Pérdida Auditiva de Alta Frecuencia/epidemiología , Humanos , Industrias , Japón/epidemiología , Masculino , Metanol/efectos adversos , Persona de Mediana Edad , Enfermedades Profesionales/epidemiología , Estireno/efectos adversos , Tolueno/efectos adversos
13.
Ind Health ; 37(1): 3-8, 1999 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10052293

RESUMEN

To clarify the effect of lead exposure on peripheral hemodynamics, acceleration plethysmography (APG) was performed for 48 male subjects occupationally exposed to lead (exposure group) and 43 male subjects with no history of occupational exposure to lead (control group). In the exposure group, the blood lead concentration (Pb-B) was also measured. Each APG parameter was assessed by comparing measured data with the standard aging curves. A significant negative correlation was obtained between the parameter--b/a and Pb-B. The exposure group showed significantly lower values of parameters--b/a (p < 0.01) and d/a (p < 0.05) than the control group. The parameter--b/a in the exposure group dose-dependently decreased with increases in length of working career (duration of exposure to lead) and Pb-B. The parameter--b/a significantly (p < 0.05) decreased in subjects with working careers of 5 years or more and in subjects whose Pb-B was 40 micrograms/100 ml or more. These results suggest that lead exposure affects peripheral hemodynamics as evaluated by APG.


Asunto(s)
Hemodinámica/efectos de los fármacos , Plomo/efectos adversos , Exposición Profesional , Adulto , Factores de Edad , Relación Dosis-Respuesta a Droga , Humanos , Plomo/sangre , Masculino , Persona de Mediana Edad , Pletismografía/métodos
14.
Public Health ; 112(3): 143-6, 1998 May.
Artículo en Inglés | MEDLINE | ID: mdl-9629019

RESUMEN

To evaluate hearing levels among young Chinese in an urban area, audiometry was carried out in Jinan city, Shandong Province, China. The subjects were 442 healthy school children and students ranging in age from 6-19 y. All subjects were asked to complete a brief questionnaire on otological symptoms, personal histories and use of noisy playthings. Audiometric threshold testing was performed at the audiometric frequencies of 0.5, 1, 2, 4 and 8 kHz. Logistic regression analysis was used to analyse the items of personal histories related to hearing impairment. Forty-five subjects (10% of the subjects) were classified as abnormal. Nineteen ears of the abnormal subjects showed 4 kHz-dip and 38 ears showed high-frequency hearing impairment. Lower prevalence of hearing impairment was found when compared with young Chinese in a rural area (20%). The logistic regression analysis showed that head trauma may be the cause of hearing impairment among young Chinese in urban areas. Otological examinations for all children sustaining head trauma are recommended.


Asunto(s)
Trastornos de la Audición/epidemiología , Salud Urbana , Adolescente , Adulto , Distribución por Edad , Audiometría , Estudios de Casos y Controles , Niño , China/epidemiología , Traumatismos Craneocerebrales/complicaciones , Femenino , Trastornos de la Audición/etiología , Humanos , Modelos Logísticos , Masculino , Prevalencia , Factores de Riesgo , Distribución por Sexo , Encuestas y Cuestionarios
15.
Ind Health ; 36(2): 160-5, 1998 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9583313

RESUMEN

To clarify the trends in the number and the severity of vibration syndrome in Wakayama for these 23 years, the records of the medical examinations for vibration syndrome were analyzed with 4,652 (a total of 9,920) private forestry workers exposed to hand-arm vibration. The number of the subjects who took the medical examinations reached a maximum of 1,242 in 1978. After that, it decreased year by year, but remained at about 300 or less from 1988. There was a corresponding increase in age and the number of years of operating chain saws among the subjects examined. The compensated cases reached a maximum number of 393 cases in 1977, and then a drastic decrease was noted. Year by year there was an increase in the number of cases whose medical examinations revealed no abnormality. The regional occupational health care system including the surveillance card, which has been active since 1975, has probably contributed to the decrease or prevention of occurrence of vibration syndrome in Wakayama.


Asunto(s)
Síndrome del Túnel Carpiano/epidemiología , Agricultura Forestal , Enfermedades Profesionales/epidemiología , Exposición Profesional/efectos adversos , Vigilancia de la Población , Enfermedad de Raynaud/epidemiología , Vibración/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Síndrome del Túnel Carpiano/prevención & control , Agricultura Forestal/instrumentación , Humanos , Japón/epidemiología , Masculino , Persona de Mediana Edad , Enfermedades Profesionales/prevención & control , Exposición Profesional/prevención & control , Enfermedad de Raynaud/prevención & control , Factores de Riesgo
16.
Ind Health ; 36(1): 20-6, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9473854

RESUMEN

Clinical data of workers (40-69 yrs) operating chain saws for a ten-year period from 1986 to 1995 were analyzed to assess the evaluation standard of finger skin temperature for a cold provocation test (10 degrees C 10 min). Screening points of finger skin temperature for screening 191 workers with a vibration induced white finger (VWF) were obtained from receiver operating characteristic (ROC) curves. The screening points at 5 min and 10 min after a cold provocation were approximately equal to 50th percentiles of 217 workers with no symptoms (NS group). The screening points of recovery rates at 5 min and 10 min after a cold provocation almost agreed with 50th percentiles in NS group. A new evaluation standard was prepared in reference to these screening points and finger skin temperatures by fraction in NS group. The new one will be useful for the health care of workers operating vibrating tools under present working conditions.


Asunto(s)
Frío , Dedos/irrigación sanguínea , Enfermedades Profesionales/diagnóstico , Enfermedad de Raynaud/diagnóstico , Temperatura Cutánea , Vibración/efectos adversos , Adulto , Anciano , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Profesionales/etiología , Curva ROC , Enfermedad de Raynaud/etiología
17.
Public Health ; 110(5): 293-7, 1996 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8885666

RESUMEN

To evaluate hearing levels in Chinese young people, audiometry was carried out at a rural village in Shandong Prefecture. The subjects were 282 healthy school children and students ranging in age from 7-17 y. All subjects were asked to complete a brief questionnaire on otological symptoms, personal histories and use of noisy playthings. Audiometric threshold testing was performed at the audiometric frequencies of 0.5, 1, 2, 4 and 8 kHz. Cluster analysis was used to estimate the associations between questions in the questionnaire and hearing impairment. Fifty-six subjects (20% subjects) were excluded from the normal groups. Twenty-two ears of the excluded subjects showed 4 kHz-dip and 38 ears showed high frequency hearing loss. An increased prevalence of hearing impairment was found when compared with young Japanese (1% from the nationwide school health survey) and with young Chinese in Shandong Prefecture (0.5%). In the questionnaire, 4 questions on dizziness, head trauma, aminoglycoside administration, and suspicion of Meniere's syndrome, were included in the cluster of hearing impairment. The cause of this hearing impairment was proposed to be the potentiating effects of aminoglycoside antibiotics and exposure to noise.


Asunto(s)
Trastornos de la Audición/prevención & control , Tamizaje Masivo , Salud Rural , Adolescente , Distribución por Edad , Audiometría , Niño , China/epidemiología , Análisis por Conglomerados , Femenino , Trastornos de la Audición/epidemiología , Trastornos de la Audición/etiología , Humanos , Masculino , Tamizaje Masivo/métodos , Prevalencia , Factores de Riesgo , Distribución por Sexo , Encuestas y Cuestionarios
18.
Environ Health Prev Med ; 1(2): 71-5, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21432425

RESUMEN

To clarify the effects of infrasound on gastric mucosal blood flow, rats were exposed to infrasound for 20 minutes. The sounds were pure tones of 8, 16 and 32 Hz, at sound levels ranging from 80 dB to 130 dB. Gastric mucosal blood flow was determined by the inhaled hydrogen gas clearance method. Norepinephrine and epinephrine concentrations in the plasma were also measured. The exposed rats showed decreased gastric mucosal blood flow with increasing sound levels of infrasound at each octave-band frequency. To significantly decrease the gastric mucosal blood flow, infrasound at 32, 16 and 8 Hz needed sound levels of 100, 110 and 130 dB, respectively. These findings suggest that, as the frequency of infrasound decreases, an increased sound level is necessary to decrease the gastric mucosal blood flow. The norepinephrine and epinephrine concentrations in the plasma were 0.65±0.47n.g/ml and 0.35±0.43 ng/ml, respectively, in the control rats, while the corresponding values were 0.91±0.87 ng/ml and 0.74±0.81 ng/ml, respectively, in the exposed rats. There were significant increases (p>0.05) in norepinephrine and epinephrine. Thus, it is probable that exposure to infrasound stimulates the sympathetic nervous system and causes a decrease in gastric mucosal blood flow.

19.
ORL J Otorhinolaryngol Relat Spec ; 57(6): 299-304, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-8789477

RESUMEN

The temperature of Hanks' solution changed its potential (-0.48 mV/degrees C in Na(+)-Hanks' and -0.23 mV/degrees C in K(+)-Hanks' solution), but the pH had no clear effect on the potential. The time course of the endocochlear potential (EP) in the isolated cochlea of the guinea pig was measured under some different conditions. When the cochlea was moistened with Hanks' solution, negative EP increased gradually toward 0 mV at 124 min after death. When the cochlea was immersed in Hanks' solution, positive EP was obtained but it depended on the oxygen and the circulation of Hanks' solution. Moderate cooling (5 degrees C) of Hanks' solution had no significant effect on the EP of the isolated cochlea immersed in oxygen-saturated Hanks' solution circulated by oxygen bubbles. The space constant and the amplitude of the displacement responses were independent of the EP in the isolated cochlea. Thus, the positive EP might not show the physiological condition of the isolated cochlea.


Asunto(s)
Potenciales Microfónicos de la Cóclea/fisiología , Animales , Cóclea/fisiología , Cobayas , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Oxígeno/farmacología , Temperatura Ambiental , Factores de Tiempo
20.
Hear Res ; 83(1-2): 142-50, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7607980

RESUMEN

Sound-induced displacement responses in the plane of the organ of Corti were studied in the apical turn in the isolated temporal-bone preparation of the guinea-pig cochlea. Swept sinusoidal sound stimuli (100-500 Hz) were delivered closed-field to the external auditory meatus. The surface of the organ of Corti was continuously monitored using a CCD video camera. Displacement responses in the plane of the organ of Corti were determined by analyzing the change of the location of the cells (pixel-by-pixel) within the visual field of the microscope. Displacement responses followed the stimulus amplitude and were observable at Hensen's cells, three rows of outer hair cells and inner hair cells. The most prominent displacement responses were over the outer hair cells; the maximum amplitude was 0.6-1.7 microns at 100 dB SPL. Tuned displacement responses were found; the Q10 dB was 1.3 +/- 0.6. The best frequency was tonotopically organized, decreasing toward the apex with a space constant of 0.4-0.9 mm/oct. The motion was directed either strial-apically or strial-basally in a frequency dependent manner. With the aid of laser interferometric measurements of the transverse displacement, it was concluded that sound stimulation does not induce slow DC motion in the organ of Corti for the isolated temporal-bone preparation.


Asunto(s)
Estimulación Acústica/efectos adversos , Células Ciliadas Auditivas Internas/citología , Células Ciliadas Auditivas Externas/citología , Órgano Espiral/patología , Animales , Cobayas , Células Ciliadas Auditivas Internas/patología , Células Ciliadas Auditivas Internas/fisiología , Células Ciliadas Auditivas Externas/patología , Células Ciliadas Auditivas Externas/fisiología , Técnicas In Vitro , Interferometría , Flujometría por Láser-Doppler , Microscopía Fluorescente , Microscopía por Video , Órgano Espiral/fisiología , Presión , Hueso Temporal/patología
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