RESUMEN
Accurate eating time can be used as an index of forage dry matter intake in grazing cows. To develop a method for easily estimating the eating time of dairy cows in a pasture, 8 lactating Holstein cows were fitted with collars equipped with commercial uniaxial accelerometers; namely, the Kenz Lifecorder EX (LCEX; Suzuken Co. Ltd., Nagoya, Japan), and were allowed to graze in a pasture for 4, 8, or 20 h daily for 7 d. The LCEX device recorded the intensity of the physical activity categorized into 1 of 11 activity levels ranging among 0 (no movement), 0.5 (subtle) and from 1 to 9 (1, light; 9, vigorous intensity) every 4s during the experimental period. The activities of the animals were also video-recorded for 11h and were manually classified into 7 categories (eating, searching, ruminating, standing resting, lying resting, drinking, and walking) at 4-s intervals. According to the count distribution of the activity levels for the categorized activities, 94.4% of the counts involving eating activity ranged from activity level 1 to 7. On the other hand, most of the counts were activity level 0 or 0.5 when ruminating and resting activities were observed. No records of activity level 8 or 9 were found in any activities. When activity level 1 was used as a threshold for discriminating eating from the other activities, the lowest misclassification rate of 5.5% was observed. With a threshold of activity level 1, the eating times in pasture for cows grazing for 4, 8, and 20 h/d were 142.8, 290.6, and 438.4 min/d, respectively, and the proportions of the time spent in pasture that were made up of eating time were 0.66, 0.67, and 0.38, respectively [the proportion during daytime (8h of the 20-h grazing treatment) was 0.63 and that at nighttime (12h of the 20-h grazing treatment) was 0.23]. The use of the LCEX device allows for easy measurement of eating time and facilitates the determination of the pattern of eating activity in pasture for grazing cows.
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Industria Lechera/instrumentación , Ingestión de Alimentos , Monitoreo Ambulatorio/veterinaria , Actividad Motora , Animales , Bovinos , Industria Lechera/métodos , Conducta Alimentaria , Femenino , Factores de TiempoRESUMEN
Sialic acid, which is located at the terminal end of glycoconjugates, is believed to have important biological functions. Its concentration in bovine milk varies depending on lactation stage and season. However, it remains unclear whether dietary factors, especially fresh forage, affect the total sialic acid concentration in milk. The purpose of the present study was to investigate the effect of grazing on the concentrations of total sialic acid and hexose in bovine milk. Six healthy dairy cows were used in a crossover design (3 cows fed fresh forage and 3 cows fed grass silage) for 2 wk. Individual milk samples were collected at 2 consecutive milkings (morning and evening) at 0, 1, 3, 5, 8, 11, and 14 d of the experimental period, and 2 consecutive samples in each cow were combined on each sampling day in proportion of the morning and evening milk yields. No differences in body weight, milk yield, or milk composition were observed between the 2 groups during the experimental period. The hexose concentration in milk did not differ between these groups during the experimental period. Conversely, the total sialic acid concentration in the milk of each grazing cow significantly increased at 11 and 14 d of the experimental period compared with that at 0 d. In the grass silage group, the total sialic acid concentration at the end of the experimental period tended to be lower than that at 0 d, but the decrease was not significant. These results indicate that grazing management could have increased the concentration of sialoglycoconjugates in milk. This suggests that grazing may increase the biological function of milk because it is thought that sialic acid is significant in many ways.
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Bovinos/fisiología , Dieta/veterinaria , Hexosas/análisis , Leche/química , Ácido N-Acetilneuramínico/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Estudios Cruzados , Femenino , Poaceae/metabolismo , EnsilajeRESUMEN
OBJECTIVES: Human colostrum is known to be important for the protection of infants against infection by pathogenic microorganisms. This protection is thought to be due, partially, to various neutral and acidic oligosaccharides that are present in colostrum and milk. However, the concentrations of each of the oligosaccharide of human colostrum have not yet been determined. The aim of this present study was to determine the concentration of each of the major neutral oligosaccharide for three consecutive days from the start of lactation. METHOD: We analyzed the level of each neutral oligosaccharide in human colostrum, for three consecutive days from the start of lactation, obtained from 12 healthy Japanese women (ranging in age from 21 to 35 years; primipara 6 and multipara 6). The ABO blood groups of the donors were determined: A, three; B, three; O, five; AB, one. The determined human milk oligosaccharides were 2'-fucosyllactose (2'-FL), 3-fucosyllactose (3-FL), lactodifucotetraose (LDFT), lacto-N-tetraose (LNT), lacto-N-neotetraose (LNnT), three lacto-N-fucopentaose (LNFP I, II and III) and two lacto-N-difucohexaose (LNFDH I and II) using high-performance liquid chromatography (HPLC) with two derivatization techniques. RESULTS: The concentrations of 2'-FL and LDFT in colostrum on day 1 were significantly higher than those on days 2 and 3 (P<0.05). An increase in LNT was observed on day 3 compared with day 1 (P<0.05). CONCLUSION: These changes in concentrations of 2'-FL, LDFT and LNT may reflect the requirements for prebiotics and anti-infection agents by human infants during early lactation.
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Cromatografía Líquida de Alta Presión/métodos , Calostro/química , Lactancia/metabolismo , Oligosacáridos/análisis , Adulto , Femenino , Humanos , Paridad , Periodo Posparto/metabolismo , Embarazo , Factores de TiempoRESUMEN
Recent experimental studies show that the opioid system is important to the pathophysiology of cardiovascular impairment in congestive heart failure. Plasma beta-endorphin levels were measured in 37 patients with congestive heart failure and compared with those of 21 age- and gender-matched normal subjects. The relation of plasma beta-endorphin levels and cardiac function at rest and exercise capacity was assessed in 17 of the patients with dilated cardiomyopathy. Exercise capacity was determined by symptom-limited maximal treadmill exercise with expired gas analysis. Plasma beta-endorphin levels were elevated and correlated with the patients' New York Heart Association functional cardiac status (control: 14.0 +/- 4.4 pg/ml; class II: 17.9 +/- 3.6 pg/ml; class III: 28.3 +/- 8.8 pg/ml; class IV: 46.7 +/- 14.6 pg/ml, mean +/- SD). No relation was found between plasma beta-endorphin levels and left ventricular systolic performance as assessed by M-mode and Doppler echocardiography. Plasma beta-endorphin levels were negatively correlated with cardiac output determined by Doppler echocardiography and positively correlated with systemic vascular resistance (r = -0.733, r = 0.747, respectively, both p less than 0.001), but not correlated with calf blood flow as measured by a plethysmography. A good correlation was found between plasma beta-endorphin levels at rest and exercise capacity. The correlations with peak oxygen consumption, anaerobic threshold, and peak rate-pressure product were r = -0.721, -0.672, and -0.674, respectively (p less than 0.01). The data show that plasma beta-endorphin levels are elevated in patients with congestive heart failure and reflect, to some degree, the severity of the disease.
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Insuficiencia Cardíaca/sangre , Hemodinámica/fisiología , betaendorfina/sangre , Ecocardiografía , Ecocardiografía Doppler , Ejercicio Físico/fisiología , Prueba de Esfuerzo , Femenino , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/fisiopatología , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Leptin suppresses food intake and increases energy expenditure in the hypothalamus. Rats consume most of their daily food intake during the dark phase of the diurnal cycle. Lactating rats have increased food intake, but the involvement of leptin in the regulation of food intake in this physiological condition is not well understood. The present experiment was carried out to determine the circadian pattern of leptin concentrations in plasma and cerebrospinal fluid (CSF) in relation to the feeding behavior of non-lactating and lactating rats. Female rats were maintained on a controlled lighting schedule (lights on between 0600 and 1800 h) and the food intake of lactating rats was two- or threefold higher than that of non-lactating rats. In both groups, food intake was three times greater in the dark phase (P<0.01) compared with the light phase. The plasma concentrations of leptin were lower (P<0.01) in lactating rats than non-lactating rats in both light and dark phases, but there were no differences in plasma leptin levels between light and dark phases. In contrast, and in both groups, the leptin concentrations in CSF were lower (P<0.01) in the dark phase than in the light phase. Leptin levels in CSF were lower (P<0.01) in lactating rats than in non-lactating rats. We conclude that a diurnal pattern of leptin levels within the brain (but not in plasma) reflects characteristics of feeding behavior in lactating and non-lactating rats.
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Ritmo Circadiano , Ingestión de Alimentos/fisiología , Lactancia/fisiología , Leptina/líquido cefalorraquídeo , Animales , Metabolismo Energético , Femenino , Leptina/sangre , Ratas , Ratas WistarRESUMEN
OBJECTIVE: The accurate determination of limitations in physical activity is important in evaluating patients with heart failure and in assessing the efficacy of treatment. However, the conventional measures used to evaluate hemodynamics, functional class, and exercise capacity all have limitations. Our objective was to develop a simple method (The Master-Borg test) for evaluating the physical activity of patients with chronic heart failure using self-evaluation of the sensation of dyspnea at a constant workload. METHODS: Patients with NYHA class I (N = 20), class II (N = 20), and class III (N = 20) chronic heart failure performed a symptom-limited treadmill exercise test to determine peak VO2 and anaerobic threshold (AT). Patients subsequently performed Master's two-step test for 90 s and maximal dyspnea was self-rated using the visual analog Borg scale (the Master-Borg test). RESULTS: The mean workload in the Master-Borg test was 15.2+/-1.6 mL x min(-1) x kg(-1). A significant correlation was found between the Master-Borg score and peak VO2 (r = 0.87) or AT (r = 0.84). The reproducibility of the Master-Borg tests was represented by a correlation coefficient of 0.93. CONCLUSION: Although simple and inexpensive, the Master-Borg test accurately represents ordinary activity levels, relates the sensation of dyspnea to peak exercise tolerance, and can be completed by most patients with heart failure. Master-Borg scores correlated with peak VO2 and AT, and can differentiate among NYHA classes I, II, and III. The Master-Borg test appears to be clinically useful for evaluating the value of physical activity and exercise capacity of patients with chronic heart failure.
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Prueba de Esfuerzo , Estado de Salud , Insuficiencia Cardíaca , Anciano , Disnea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Aptitud Física , Reproducibilidad de los ResultadosRESUMEN
The relationship between the calculated value of the effective electrical resistance of the cochlear partition and the distance between the electrode for measuring the EP and the stimulating electrodes has been studied. The calculated value of the effective electrical resistance of the cochlear partition declines linearly with increasing distance between these electrodes. The correlation coefficient (r) is -0.806. In calculations of the effective electrical resistance of the cochlear partition, attention must be paid to the distance between the microelectrodes.
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Cóclea/fisiología , Conductividad Eléctrica , Animales , Cobayas , Modelos BiológicosRESUMEN
The electrophysiologic and histopathologic changes in the inner ear caused by the administration of cis-diamminedichloroplatinum (CP) were studied in guinea pigs. The endocochlear dc potential (EP) gradually decreased after the intravenous injection of CP and reached approximately 0 mV on the fourth day, but the EP did not become negative. The cochlear microphonics also diminished and could not be recorded on the fourth day. The negative potential of the organ of Corti remained in the normal range during the experiment. A large negative summating potential (SP) was observed one day after injection, but the amplitude of the negative SP became small on the second day. Light microscopic examination demonstrated that the outer hair cells are destroyed in the basal turn of the cochlea and are preserved in the upper turns, while the inner hair cells are almost completely preserved in all turns. The stria vascularis was found to be slightly atrophic. Severe collapse of Reissner's membrane was observed in the basal turn.
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Cisplatino/toxicidad , Cóclea/efectos de los fármacos , Sordera/inducido químicamente , Animales , Cóclea/patología , Cóclea/fisiopatología , Potenciales Microfónicos de la Cóclea/efectos de los fármacos , Potenciales Evocados Auditivos/efectos de los fármacos , Cobayas , Órgano Espiral/patologíaRESUMEN
20 mg/kg of body weight of nitrogen mustard-N-oxide hydrochloride ( NMNO ) causes a transient decrease in the magnitude of the endocochlear d.c. potential (EP) in the same manner as does nitrogen mustard (NM). NMNO does not, however, change the electrical resistance of the cochlear partition. When the administered dose of NMNO is increased to 40, 60 and 80 mg/kg body weight, a corresponding diminution in the EP is not observed. No ultrastructural changes in the stria vascularis are observed, even in animals administered 80 mg/kg body weight. The reduction of the EP with NMNO could not be attributed to a loss of the electrical insulator effect of the cochlear partition, or to a functional derangement of the stria vascularis. In the experimental animals whose organ of Corti was already destroyed with kanamycin sulfate (KM), NMNO did not reduce the magnitude of the EP. The organ of Corti may be central in understanding the mechanism of NMNO -induced reduction of the EP.
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Antineoplásicos/toxicidad , Cóclea/efectos de los fármacos , Potenciales Evocados Auditivos/efectos de los fármacos , Órgano Espiral/efectos de los fármacos , Estría Vascular/efectos de los fármacos , Animales , Cóclea/fisiología , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Electrofisiología , Cobayas , Células Ciliadas Auditivas/efectos de los fármacos , Células Ciliadas Auditivas/fisiología , Estría Vascular/ultraestructuraRESUMEN
Two-hundred forty-one patients with acute low-tone sensorineural hearing loss (ALSH) who consulted my clinic from 1987 to 1996 were retrospectively investigated. The results were as follows: (1) In 110 patients, the sum of hearing level in three low frequencies (125 Hz, 250Hz and 500Hz) was more than 100dB, and that in three high frequencies (2KHz, 4KHz and 8KHz) was less than 60dB. This audiological finding is a widely accepted criterion for the diagnosis of ALSH. One-hundred thirty-one patients did not fit this criterion. (2) The annual number of ALSH patients gradually increased during these ten years due to an increase in the number of female patients. (3) A high incidence of young females characterized these ALSH patients. (4) Of 162 patients, 64.8% and 17.9% showed complete and partial recovery of hearing, respectively. (5) The recovery rates were compared in two groups, one group consisted of patients whose sum of hearing level in the three lower frequencies was more than 100dB, and the other group was comprised of patients whose sum of hearing level in the same lower frequencies was less than 100 dB. There was no statistical difference in recovery rate between the two groups. (6) The frequency distribution of the mean of hearing level in the three lower frequencies was investigated. The mean and standard deviation was 39.1 +/- 11.8dB. By histogram, these results resembled a normal distribution. This suggests that these 241 patients has same disease entity. The pathophysiological condition of ALSH must not be various. Also, that ALSH has the peculiarity that an approximate 40 dB hearing loss may be a normal occurrence.
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Pérdida Auditiva Sensorineural/fisiopatología , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Niño , Femenino , Audición , Pérdida Auditiva Sensorineural/epidemiología , Humanos , Incidencia , Japón/epidemiología , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos , Distribución por SexoRESUMEN
We reviewed hearing recovery in 3,430 patients with sudden deafness reported between 1989 and 1998 in Japan, evaluated using standards of the Research Group on Sudden Deafness of the Ministry of Health and Welfare of Japan. Complete recovery was seen in 30.8%, marked in 24.7%, slight in 23.3% and no change in 21.8%. No remarked improvement in recovery of hearing was seen in patients with sudden deafness in these 10 years. The number of patients studied in evaluating the efficacy of therapies may thus affect results. Complete recovery from sudden deafness was nearly 30% in proportion to the increase of number of patients studied in the literature. At least 200 patients should be studied to make a reliable evaluation.
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Pérdida Auditiva Súbita/tratamiento farmacológico , Humanos , Resultado del TratamientoRESUMEN
The present study was carried out to establish porcine defined IVP. In Experiments 1 and 2, we investigated the efficacy of additional 0.6 mM cystine and/or 100 microM cysteamine (Cys) to a defined TCM199 maturation medium with regard to the intracellular glutathione (GSH) concentration and the developmental competence of in vitro matured porcine oocytes following intracytoplasmic sperm injection (ICSI). The control medium was a modified TCM199 containing 0.05% (w/v) polyvinyl alcohol (PVA). Cys and/or cystine were added to the control medium. The control group and immature oocytes (presumptive germinal vesicle oocytes; GV) were prepared for GSH assay. In Experiment 3, the efficacy of epidermal growth factor (EGF) addition to a modified porcine zygote medium (mPZM) for in vitro culture (IVC) medium was investigated on embryonic development and the mean cell number of blastocysts following ICSI. As a positive or negative control, 0.3% BSA (mPZM-3) or 0.3% PVA (mPZM-4), respectively, was added to the base medium. The defined IVC medium was supplemented with 5 or 10 ng/ml EGF. In Experiment 1, no significant difference was found in the rates of cleavage (31.4-64.3%) and blastocyst formation (6.5-22.9%) among the treatment and control groups. The mean cell numbers per blastocyst ranged from 30 to 48 among the groups without significant differences. However, in Experiment 2, the intracellular GSH concentrations in the oocytes cultured in the medium supplemented with 100 microM Cys (9.6 pmol/oocyte) or Cys + cystine (9.9 pmol/oocyte) were significantly (p < 0.05) higher than the control (2.5 pmol/oocyte) and 0.6 mM cystine (6.5 pmol/oocyte) groups, but not different from the GV group (9.0 pmol/oocyte). The GSH concentration in the cystine group was also significantly (p < 0.05) higher than that in the control group, but not different from the GV group. In Experiment 3, the rates of cleavage and blastocyst formation and the mean cell numbers of blastocysts were not significantly different among the groups. However, the addition of 5 ng/ml EGF into the mPZM-4 resulted in a significantly (p < 0.05) higher blastocyst rate per cleaved embryo than the other two defined groups (mPZM-4 + 5 ng/ml: 48.6%, mPZM-4 and mPZM-4 +10 ng/ml: 23.4% and 23.1%, respectively). The present results indicate that the addition of Cys to a defined medium for in vitro maturation (IVM) of porcine oocytes increases intracellular GSH concentration. Further addition of cystine into the IVM medium containing 100 microM Cys is not necessary and TCM199 plus Cys (100 microM) could be used as a defined IVM medium for porcine oocytes. The addition of 5 ng/ml EGF to a defined IVC medium has enhanced subsequent development after ICSI. This study shows that porcine blastocysts can be produced by defined media throughout the steps of IVP (IVM, ICSI and IVC).
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Blastocisto/fisiología , Desarrollo Embrionario , Oocitos/fisiología , Inyecciones de Esperma Intracitoplasmáticas/veterinaria , Porcinos , Animales , Medios de Cultivo , Cisteína/química , Cisteína/metabolismo , Factor de Crecimiento Epidérmico/farmacología , Femenino , Fertilización In Vitro , Glutatión/metabolismo , Masculino , Oocitos/citología , Embarazo , Espermatocitos/fisiología , Técnicas de Cultivo de TejidosRESUMEN
This article reviews simple, noninvasive ways to assess physical activity in patients with chronic heart failure. Six- or 9-minute walk tests appear to be useful not only for selecting patients with relatively advanced heart failure but also as prognostic screening tests. The Master-Borg test (Master's two-step testing and 10-point Borg scale) is useful for assessing symptoms during exercise. Weekly pedometer counts show that the level of activity in patients with heart failure is dramatically less than in healthy controls. Physical activity can be determined directly by an ambulatory calorie counter that measures step scores and energy expenditure using specific accelerometers. Careful clinical interviewing regarding symptoms, together with submaximal exercise testing and use of motion sensors, are recommended as useful, simple, noninvasive alternatives for assessing physical activity in this patient population. (c)2000 by CHF, Inc.
RESUMEN
OBJECTIVES: Improvement in exercise tolerance is an important goal in cardiac rehabilitation, but improvement in quality of life (QOL) must also be considered. Therefore, we planned a non-supervised walking exercise program at home for 1 year in patients in the convalescent phase of myocardial infarction to study the exercise tolerance and QOL. METHODS: Thirty-two patients (mean age 60.3 +/- 10 years, 23 men and 9 women) performed our non-supervised home exercise program in which the exercise prescription was based on the rating of perceived exertion. Before discharge, 1 month and 1 year after discharge, exercise tolerance was measured by the cardiopulmonary treadmill exercise test, and QOL was investigated by questionnaire. RESULTS: Anaerobic threshold increased from 15.8 +/- 3.4 ml/kg/min before discharge to 17.5 +/- 3.0 ml/kg/min 1 month after (p < 0.05) and to 18.3 +/- 3.0 ml/min/kg 1 year after (p < 0.05 vs at discharge), and peak oxygen consumption increased from 22.2 +/- 4.3 to 25.2 +/- 5.1 ml/kg/min (p < 0.05) and to 26.4 +/- 5.2 ml/kg/min (p < 0.05 vs at discharge), respectively. QOL score by questionnaire was maintained in 13 patients (improved in 3, same in 10) and decreased in 19 of 32 patients from discharge to 1 month, and the score was maintained in 18 patients (improved in 13, same in 5) and decreased in 14 of 32 patients from 1 month to 1 year after discharge. CONCLUSIONS: In patients with myocardial infarction in the convalescent phase, our non-supervised home exercise program resulted in improvement in exercise tolerance, but QOL score decreased gradually. Therefore, we should not only prescribe an exercise program, but also must give more psychosocial support to the patients. The reasons for the decreased QOL by cardiac rehabilitation must be further investigated.
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Terapia por Ejercicio , Infarto del Miocardio/rehabilitación , Calidad de Vida , Umbral Anaerobio , Tolerancia al Ejercicio , Femenino , Humanos , Cuidados a Largo Plazo , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , CaminataRESUMEN
The respiratory quotient (RQ = VCO2/VO2) provides important information (ie, the ratio of carbohydrate to fat utilization) concerning energy expenditure. We studied the effects of various antianginal drugs on energy expenditure during steady-state aerobic exercise in 9 healthy adult men. The drugs used were propranolol (a non-selective beta-blocker), metoprolol (a beta-1 selective blocker), amosulalol (an alpha- and beta-blocker), nicardipine (a calcium antagonist) and isosorbide dinitrate. Each drug was administered for 2 weeks, followed by a 2-week washout period. VO2, VCO2 and RQ were measured with an expired gas analyzer during treadmill exercise tests before and during the administration of each drug. Two protocols of constant-load exercise were performed: Protocol 1 lasted for 10 min at a speed of 5.5 km/h and a grade of 0%, (at a level of about 30% peak VO2), while Protocol 2 lasted for 10 min at a speed of 7 km/h and a grade of 0%, (at a level of about 40% peak VO2). RQ during exercise was significantly increased and VO2 was decreased after propranolol, metoprolol and amosulalol (P < 0.05). Neither nicardipine nor isosorbide dinitrate produced significant changes in these values. These data suggest that propranolol, metoprolol and amosulalol increase the efficiency of energy expenditure during ordinary physical activity by increasing the utilization of carbohydrate and by decreasing the utilization of fat.
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Antagonistas Adrenérgicos beta/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Metabolismo Energético/efectos de los fármacos , Ejercicio Físico , Adulto , Etanolaminas/farmacología , Humanos , Dinitrato de Isosorbide/farmacología , Masculino , Metoprolol/farmacología , Persona de Mediana Edad , Nicardipino/farmacología , Propranolol/farmacologíaRESUMEN
The effects of nitrogen mustard on the electrical potentials of the inner ear were studied, and the results were correlated with the histopathologic findings which have been reported in nitrogen mustard ototoxicity. The endocochlear DC potential (EP) decreased rapidly after an injection of nitrogen mustard (NM). The amplitude of the cochlear microphonics potential (CM) diminished rapidly, and no substantial recoveries were observed. No significant changes in the magnitude of the negative potential of organ of Corti (NPOC) were observed. A large negative summating potential (SP) was recorded even when the amplitude of the CM had diminished.
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Cóclea/efectos de los fármacos , Mecloretamina/efectos adversos , Potenciales de la Membrana/efectos de los fármacos , Estimulación Acústica , Animales , Cóclea/fisiología , Electrofisiología , Cobayas , Células Ciliadas Auditivas/efectos de los fármacos , Células Ciliadas Auditivas/fisiología , Órgano Espiral/efectos de los fármacos , Órgano Espiral/fisiologíaRESUMEN
The effects of loop diuretics on the endocochlear direct current (DC) potential and the effective electrical resistance of the cochlear partition were studied. The effective electrical resistance was increased, and the endocohlear DC potential was decreased. The decrease in the endocohlear DC potential must not be caused by breaks in the electrical insulation of the cochlear partition. With loop diuretics the endocochlear DC potential decreased less in guinea pigs treated with kanamycin sulfate than it did in the control group. Two interpretations of these phenomena are presented.
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Cóclea/efectos de los fármacos , Ácido Etacrínico/farmacología , Furosemida/farmacología , Kanamicina/farmacología , Animales , Cóclea/fisiología , Conductividad Eléctrica , Electrofisiología , Cobayas , Células Ciliadas Auditivas/efectos de los fármacos , Cloruro de Sodio/farmacología , Estría Vascular/efectos de los fármacos , Estría Vascular/fisiología , SulfatosRESUMEN
The magnitudes of the endocochlear dc potential (EP) during adequate ventilation and during five minutes of anoxia were recorded in control guinea pigs and guinea pigs administered various dosages of kanamycin sulfate. The magnitudes of the EP after five minutes of anoxia were -44.6 +/- 5.9 mV in the controls and +26.6 +/- 9.9 mV in the guinea pigs that received kanamycin for seven or ten days. This change occurred after five or six days of administration of kanamycin. However, there was no significant change in the magnitude ot the EP with adequate ventilation with kanamycin intoxication. There is a significant correlation between the magnitude of the negative EP and the maximum output of the cochlear microphonics (r = -.770, P less than .001). These results suggest that the EP may not be the mathematical summation of the positive electrogenic potential and the negative diffusion potential. The mechanism for generating the negative EP during anoxia may have some relationship to hair cell integrity.
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Cóclea/fisiopatología , Kanamicina/farmacología , Potenciales de la Membrana/efectos de los fármacos , Animales , Cobayas , Células Ciliadas Auditivas/fisiopatología , Hipoxia/fisiopatologíaRESUMEN
Gastric acid secretion basally and in response to intragastric meat extract instillation or to tetragastrin, and circulating gastrin concentration basally and after meat extract stimulation were studied in 67 patients with gastroduodenal ulcer, 30 patients after highly selective vagotomy or selective vagotomy for duodenal ulcer, 12 patients after antrectomy for or gastric ulcer and 10 control subjects. Circulating gastrin concentration increased significantly after meat extract stimulation in control subjects, patients with ulceration and patients after highly selective vagotomy, and acid secretion in each group was increased significantly above basal level. In patients after selective vagotomy, significant increase of circulating gastrin concentration was observed, but it was not associated with significant increase of acid secretion. After antrectomy, neither gastrin nor acid secretion increased significantly after meat extract stimulation. In conclusion, present study suggested that (1) gastric acid secretion in response to intragastric meat extract is chiefly affected by the responsiveness of oxyntic cells and release of antral gastrin and that (2) the presence of the antrum is almost essential for acid secretion after a test meal, and release of duodenal gastrin after antrectomy would not be so potent biologically as to result in an acid secretion.