RESUMEN
In this paper, we describe a method for measuring the average flow velocity of a sample by means of Nuclear Magnetic Resonance. This method is based on the Carr-Purcell-Meiboom-Gill (CPMG) sequence and does not require the application of any additional static or pulsed magnetic field gradients to the background magnetic field. The technique is based on analyzing the early-time behavior of the echo amplitudes of the CPMG sequence. Measurements of average flow velocity of water are presented. The experimental results show a linear relationship between the slope/y-intercept ratio of a linear fit of the first echoes in the CPMG sequence, and the average flow velocity of the flowing fluid. The proposed method can be implemented in low-cost Low-Field NMR spectrometers allowing a continuous monitoring of the average velocity of a fluid in almost real-time, even if the flow velocity changes rapidly.
Asunto(s)
Espectroscopía de Resonancia Magnética/métodos , Algoritmos , Calibración , Centrifugación , Campos Electromagnéticos , Modelos Lineales , MovimientoRESUMEN
OBJECTIVES: To determine the prevalence of current hormone replacement therapy (HRT) use and describe its correlates among community-dwelling, Mexican-American women aged 67 and older. DESIGN: A population-based survey of older Mexican-Americans conducted in 1995/1996. SETTING: Five Southwestern states: Texas, New Mexico, California, Arizona, and Colorado. PARTICIPANTS: An area probability sample of 1,424 noninstitutionalized Mexican-American women aged 67 and older (mean age = 75.1) completed the survey instrument via a 90-minute in-home interview, which included examination and recording of all medications taken. MEASUREMENTS: Current use of HRT. RESULTS: In this sample of older Mexican-American women, 4.7% were current users of HRT. Controlling for sociodemographic characteristics (age, marital status, living arrangements, years of education, income, language of interview), current HRT use is significantly related to years of education (per each year) (odds ratio (OR) = 1.13; 95% confidence interval (CI) = 1.05-1.20), having had a hysterectomy (OR = 4.37; 95% CI 2.50-7.64), a diagnosis of osteoporosis (OR = 3.40, 95% CI = 1.58-7.33), age at menopause (per each year) (OR = 1.07; 95% CI = 1.03-1.12), ever having a mammogram (OR = 3.72; 95% CI = 1.66-8.37), ever having a Pap test/pelvic examination (OR = 2.11; 95% CI = 1.08-4.12), having spoken with a pharmacist within the past year regarding health conditions (OR = 1.96; 95% CI = 1.06-3.65), and having Medicare plus private insurance (OR = 2.13; 95% CI = 1.14-3.97). CONCLUSION: The prevalence of HRT use is lower than that reported in the older non-Hispanic white female population. In general, these findings indicate that access to and utilization of the traditional U.S. health care system are indicators of HRT use.
Asunto(s)
Terapia de Reemplazo de Estrógeno/estadística & datos numéricos , Americanos Mexicanos/estadística & datos numéricos , Posmenopausia , Actividades Cotidianas , Anciano , Anciano de 80 o más Años , Femenino , Accesibilidad a los Servicios de Salud , Estado de Salud , Humanos , México/etnología , Oportunidad Relativa , Factores Socioeconómicos , Sudoeste de Estados UnidosRESUMEN
BACKGROUND: Published information about cancer screening in older Mexican-American women is scarce. This study reported the patterns of mammogram and Pap test use among older Mexican-American women. The patterns and associated factors were examined and compared with Healthy People 2000 targets. METHODS: Data were obtained from the Hispanic Established Population for the Epidemiological Study of the Elderly, the largest representative survey of community-dwelling Mexican Americans aged 67 years or over, from the southwestern United States. RESULTS: Among older Mexican-American women, 68.3% reported ever having a mammogram, and 41.2% reported having a mammogram in the last two years; 64.0% reported ever having a Pap test, with 43.6% reported having a Pap test in the last three years. CONCLUSIONS: The data for older Mexican-American women demonstrated that they approached the targets for breast cancer screening, but not for Pap test use.
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Mamografía/estadística & datos numéricos , Tamizaje Masivo/tendencias , Americanos Mexicanos/estadística & datos numéricos , Frotis Vaginal/estadística & datos numéricos , Anciano , Femenino , Humanos , Neoplasias/epidemiología , Factores de Riesgo , Sudoeste de Estados Unidos/epidemiologíaRESUMEN
To identify the critical vector density that potentiates dengue outbreaks in an endemic site and to identify obstacles to anti-dengue activities, we correlated a series of dengue outbreaks in a Brazilian city with the intensity of its anti-vector source-reduction activities. The proportion of houses infested by vector mosquitoes correlated inversely with intensity of anti-mosquito interventions, and the vector population developed independently of rainfall. Local periods of drought promoted vector abundance in two ways: residents stored water in which vector mosquitoes could breed, and cholera outbreaks due to contaminated water diverted local health workers from routine anti-vector activities. One dengue outbreak became apparent to authorities more than two months after it commenced but would have been identified almost immediately had dengue-like disease in indicator hospitals been monitored. Active surveillance, therefore, offers a window of opportunity for promptly executed anti-dengue interventions. Source-reduction measures that suppress vector infestations to less than 1% of houses effectively avert outbreaks of dengue.
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Culicidae , Dengue/epidemiología , Brotes de Enfermedades , Insectos Vectores , Animales , Brasil/epidemiología , Cólera/epidemiología , Humanos , Densidad de Población , Lluvia , Dengue Grave/epidemiologíaRESUMEN
SETTING: Public ambulatory care centers in three districts of northern metropolitan Lima, Peru. OBJECTIVE: To document drug resistance patterns of isolates of Mycobacterium tuberculosis from patients identified as treatment failures under a model tuberculosis (TB) control program based on directly observed, short-course chemotherapy (DOT-SCC). DESIGN: Case series. RESULTS: In a referred, consecutive sample of 173 patients identified as treatment failures on DOT-SCC, 160 (92.5%) had culture-positive TB. Of those 160, 150 (93.8%) had active, pulmonary multidrug-resistant TB (MDR-TB, resistance to at least isoniazid [INH] and rifampicin [RIF]). Sixty of the 150 (40.0%) had isolates resistant to at least INH, RIF, ethambutol (EMB) and pyrazinamide (PZA), the initial first-line empiric treatment regimen used locally. Forty-four (29.3%) had isolates resistant to at least INH, RIF, EMB, PZA and streptomycin (SM), the first retreatment regimen. This series of patients had isolates resistant to a mean of 4.5 of the ten drugs tested. The local profile of multidrug resistance is very different from that obtained from national data from Peru. CONCLUSION: In this setting, treatment failure on DOT-SCC is strongly predictive of active MDR-TB. Because of existing local drug resistance patterns in northern Lima, 89.3% of MDR-TB patients identified as treatment failures will receive ineffective therapy with two or fewer secondary TB drugs if they are given the five-drug empiric retreatment regimen endorsed by the World Health Organization. Further short-course chemotherapy for these patients would only serve to amplify ominous existing drug resistance patterns.
Asunto(s)
Antituberculosos/administración & dosificación , Mycobacterium tuberculosis/efectos de los fármacos , Insuficiencia del Tratamiento , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/epidemiología , Antituberculosos/farmacología , Países en Desarrollo , Esquema de Medicación , Femenino , Humanos , Incidencia , Masculino , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/aislamiento & purificación , Perú/epidemiología , Medición de Riesgo , Muestreo , Tuberculosis Resistente a Múltiples Medicamentos/diagnóstico , Tuberculosis Pulmonar/diagnósticoRESUMEN
OBJECTIVE: This study examines the prevalence of self-reported physician-diagnosed arthritis and arthritis symptoms and their relationship to functional limitations in Mexican American elderly. METHODS: We conducted a cross-sectional study using a probability sample of 2,873 non-institutionalized Mexican American men and women aged 65 or older, residing in the southwestern United States. Measures included self-reported physician-diagnosed arthritis, morning pain or stiffness, pain when standing, global health rating, activities of daily living (ADL), instrumental activities of daily living (IADL), depressive symptoms, presence of chronic diseases (diabetes mellitus, hypertension, heart attack, stroke), and body mass index. The Mantel-Haenszel chi-square statistic was used to test differences by arthritis status, and a logistic regression model was used to predict the odds of having arthritis. RESULTS: The overall prevalence of self-reported physician-diagnosed arthritis in the sample was 40.8 percent, 50.0 percent among women and 28.8 percent among men (P < 0.001). Morning pain or stiffness was reported by 37.7 percent of respondents and pain when standing or walking by 31.9 percent. All comorbid conditions, and both IADL and ADL limitations, were more prevalent in those with arthritis than in those without arthritis. Female sex and several medical conditions were independently associated with self-reported arthritis. CONCLUSIONS: Self-reported physician-diagnosed arthritis is common among older Mexican Americans. Functional limitation and disability are more prevalent among subjects with arthritis than among those without arthritis.
Asunto(s)
Artritis/etnología , Americanos Mexicanos/estadística & datos numéricos , Actividades Cotidianas , Distribución por Edad , Anciano , Anciano de 80 o más Años , Artritis/complicaciones , Artritis/fisiopatología , Distribución de Chi-Cuadrado , Comorbilidad , Estudios Transversales , Femenino , Estado de Salud , Humanos , Modelos Logísticos , Masculino , Dolor/etiología , Vigilancia de la Población , Valor Predictivo de las Pruebas , Prevalencia , Factores de Riesgo , Distribución por Sexo , Sudoeste de Estados Unidos/epidemiología , Soporte de PesoAsunto(s)
Accesibilidad a los Servicios de Salud/tendencias , Comercio , Canadá , México , América del Norte , Estados UnidosRESUMEN
Sixty-nine patients undergoing liver transplantation were evaluated to elucidate the relationship between hypotension and physiological changes seen on reperfusion of the grafted liver. Measured variables included hemodynamic profiles, core temperature, serum potassium, ionized calcium levels, arterial blood-gas tensions, and acid-base state. Measurements were taken 60 minutes after skin incision (baseline), 5 minutes before reperfusion, and 30 seconds and 5 minutes after reperfusion. On the basis of changes in mean arterial pressure (MAP) patients were divided in two groups. Group 1 (n = 49) maintained MAP greater than 70% and group 2 (n = 20) had MAP less than 70% of the baseline value for at least 1 minute within 5 minutes after reperfusion. On reperfusion, changes common to both groups were 27% increase in cardiac filling pressures, 23% base deficit, and 30% serum potassium level and a decrease of 16% in cardiac output and 9% in temperature. Compared with group 1, group 2 had greater decrease in systemic vascular resistance (SVR) (1097 +/- 868 and 741 +/- 399 dyn.s-1. cm-5, respectively, P < .05) and higher potassium level (4.5 +/- 0.8 and 5.3 +/- 0.8 mmol/L, P < .05). Collectively in both groups, there was no correlation between MAP and physiological variables; however, there was a poor correlation with SVR (r = .32, P < .01). Reperfusion hypotension seen in group 2 patients correlated only with a decrease in systemic vascular resistance (r = .5, P < .05). Acute hyperkalemia, hypothermia, and acidosis do not appear to be major causes of reperfusion hypotension.
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Hipotensión/fisiopatología , Trasplante de Hígado , Daño por Reperfusión/fisiopatología , Adulto , Anciano , Análisis de los Gases de la Sangre , Temperatura Corporal , Gasto Cardíaco , Técnica de Dilución de Colorante , Electrólitos/sangre , Hemodinámica , Humanos , Persona de Mediana EdadRESUMEN
The empty sella syndrome has become a rather frequent finding in magnetic resonance imaging (MRI) scanning. The usual presentation of empty sella syndrome involves an incidental finding on a computed tomography scan or an MRI scan. It is unusual to find empty sella syndrome associated with hypopituitarism. The authors describe such an unusual finding in a 54-year-old nulliparous woman.
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Síndrome de Silla Turca Vacía/complicaciones , Hipopituitarismo/complicaciones , Hipófisis/patología , Síndrome de Silla Turca Vacía/diagnóstico , Femenino , Humanos , Hipopituitarismo/diagnóstico , Imagen por Resonancia Magnética , Persona de Mediana EdadRESUMEN
Although preoxygenation has been extensively studied, to our knowledge this is the first study addressing its optimal length in children, who form a high risk group for developing hypoxaemia during induction of anaesthesia. Recommended preoxygenation times in children range between 1 and 4 min, but whether one of these times maintains arterial oxygen saturation (Sao2) at an adequate level for a longer time period is unknown. This study was performed on 11 healthy children, randomly distributed into either Group 1 (1 min of preoxygenation, n = 6) or Group 2 (3 min of preoxygenation, n = 5). Sao2 was measured by pulse oximetry. While the patients were breathing room air, Sao2 was similar in both groups (97%) and rose to 100% after preoxygenation in all patients. After intravenous induction of anaesthesia and muscle relaxation, all patients became apnoeic. The time taken for the Sao2 to decrease to 90% was measured. In Group 1 this occurred in 91 s, whereas Group 2 required 144 s. Thus, a 3-min rather than a 1-min period of preoxygenation would appear to maintain Sao2 at a safe level for a longer time in children.
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Oxígeno/administración & dosificación , Pediatría , Niño , Preescolar , Humanos , Oxígeno/sangre , Factores de TiempoRESUMEN
We determined the pharmacokinetics and duration of action of a bolus dose of doxacurium (15 micrograms/kg) in 27 patients anesthetized with isoflurane and nitrous oxide. Nine patients had normal renal and liver functions and were undergoing a variety of surgical procedures, nine were undergoing cadaveric kidney transplantation because of end-stage renal disease, and nine were undergoing cadaveric liver transplantation because of end-stage hepatocellular disease. Plasma concentrations of doxacurium were measured for 6 h after administration using a sensitive and specific capillary gas chromatographic assay. Plasma concentration versus time data were analyzed by a noncompartmental method based on statistical moments. Neuromuscular blockade was assessed by measuring the electromyographic evoked response of the adductor pollicis muscle to train-of-four stimulation of the ulnar nerve. The degree of neuromuscular blockade after doxacurium administration was described as the percent of control of the first train-of-four response. The pharmacokinetic variables were (normal vs hepatic failure vs renal failure, respectively): volume of distribution at steady state (220 +/- 110 vs 290 +/- 60 vs 270 +/- 130 mL/kg [mean +/- SD]), plasma clearance (2.7 +/- 1.6 vs 2.3 +/- 0.4 vs 1.2 +/- 0.7 mL.kg-1.min-1), mean residence time (95.2 +/- 57 vs 129.4 +/- 30 vs 270 +/- 210 min), and elimination half-life (99 +/- 54 vs 115 +/- 31 vs 221 +/- 156 min). Plasma clearance and mean residence time differed significantly between patients with renal failure and control patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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Isoquinolinas/farmacocinética , Fallo Renal Crónico/metabolismo , Hepatopatías/metabolismo , Fármacos Neuromusculares no Despolarizantes/farmacocinética , Adulto , Anestesia General , Presión Sanguínea/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Isoquinolinas/farmacología , Fallo Renal Crónico/fisiopatología , Fallo Renal Crónico/cirugía , Hepatopatías/fisiopatología , Hepatopatías/cirugía , Tasa de Depuración Metabólica/efectos de los fármacos , Persona de Mediana Edad , Unión Neuromuscular/efectos de los fármacos , Fármacos Neuromusculares no Despolarizantes/farmacologíaRESUMEN
Despite its effectiveness, cerebrospinal shunting for hydrocephalus continues to be accompanied by considerable complications and morbidity. Medical therapy with acetazolamide 100 mg/kg/day and furosemide 1 mg/kg/day can be an effective alternative to shunting by halting progression of hydrocephalus until such time as sutures can become fibrosed and spontaneous arrest can occur. In an appropriately selected population older than 2 weeks with hydrocephalus of varied origin, our success rate in avoiding shunting is greater than 50%. The dramatic difference between the number of hospitalizations of patients with shunts and those treated medically, and the potential to avoid shunt dependence would appear to make an initial trial with medical therapy worthwhile.
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Acetazolamida/administración & dosificación , Furosemida/administración & dosificación , Hidrocefalia/tratamiento farmacológico , Acetazolamida/efectos adversos , Desequilibrio Ácido-Base/inducido químicamente , Factores de Edad , Derivaciones del Líquido Cefalorraquídeo/efectos adversos , Quimioterapia Combinada , Estudios de Seguimiento , Furosemida/efectos adversos , Humanos , Hidrocefalia/etiología , Hidrocefalia/cirugía , Lactante , Recién Nacido , Tiempo de InternaciónRESUMEN
Plasma samples from St. Lucians were tested for the presence of antibodies which cooperate in vitro with normal human luekocytes in causing cytotoxic damage to schistosomula of Schistosoma mansoni. The in vitro antibody activity, which has been previosly shown to depend on eosinophil effector cells was detected in 56 percent of the individuals with known, current S. mansoni infections and in 14 percent of control subjects from the same endemic area. Quantitatively, eosinophil dependent cytoxic antibody (EDCA) activity, when expressed as the maximum amount of damage to schistosomula induced at high plasma concentration, correlated significantly with the intensity of S.mansoni infection as detemined by fecal egg count, the highest levels of activity occuring in patients with stool counts of 60 eggs/ml or greater. In addition, plasma ECDA activity was found to correlate with the in vitro blastogenic responsiveness of patients' lympjocytes to three different parasite antigen preparations. In contrast, titrations of ECDA activity failed to reveal a relationship between ECDA titer and the most recent egg count performned on each subjects. However, a significant correlation was observed when titers were compared to egg counts averaged over a 3-year period. Neither maximal ECDA activity nor titer was found to correlate with the duration of known schistosome infection (AU)