RESUMEN
Enlargement of the cisterna magna has been reported to be associated with aneuploidy. In prior studies of cisterna magna enlargement, however, those fetuses with abnormal chromosomes have had other sonographic abnormalities in addition to a large cisterna magna. Our goal was to assess the clinical significance of the isolated finding of a cisterna magna measuring more than 10 mm in anteroposterior dimension on a prenatal sonogram. We retrieved all prenatal sonograms performed at our institution between 1989 and 1996 in which an enlarged cisterna magna was the only sonographic abnormality. Cases were included in our study if the cisterna magna measured more than 10 mm in the appropriate plane and the fetal survey was otherwise normal, including normal cerebellar size and morphology. Pregnancy outcome and postnatal follow-up were obtained in each case. Fifteen cases comprised our study population. In all 15 fetuses, the enlarged cisterna magna was first seen in the third trimester (gestational age range, 26 to 37 weeks). The cisterna magna ranged from 11 to 19 mm in size (mean, 12.9 mm). All 15 pregnancies resulted in phenotypically normal liveborn infants. All the mother and infants had short hospital stays (1 to 4 days), and the infants were normal at discharge. Longer follow-up was available in eight cases (range, 2 to 69 months), and all eight of these infants were normal. Our results suggest that isolated enlargement of the cisterna magna to more than 10 mm is associated with normal pregnancy and neonatal outcome.
Asunto(s)
Cisterna Magna/diagnóstico por imagen , Enfermedades Fetales/diagnóstico por imagen , Ultrasonografía Prenatal , Femenino , Edad Gestacional , Humanos , Embarazo , Resultado del Embarazo , Estudios RetrospectivosRESUMEN
RATIONALE AND OBJECTIVES: The purpose of the study was to determine the relationship between pulmonary artery (PA) size at computed tomography (CT) and PA pressures, to develop a noninvasive CT method of PA pressure measurement, and to determine a PA diameter that can enable differentiation of normal subjects from those with pulmonary hypertension. METHODS: PA vessel diameters in 55 candidates for lung and heart-lung transplantation were measured at CT and correlated with PA pressures with both linear and stepwise multiple regression. The multiple regression equations were then tested prospectively in 35 pretransplantation patients. RESULTS: Combined main and left main PA cross-sectional area corrected for body surface area showed the best correlation with mean PA pressure (r = .87). The multiple regression equations helped predict mean PA pressure within 5 mm Hg in 50% of patients with chronic lung disease and in only 8% of patients with pulmonary vascular disease. CONCLUSION: There was a very good correlation between main and left main PA size and mean PA pressure. At present, however, CT has not demonstrated sufficient accuracy to be used clinically.
Asunto(s)
Arteria Pulmonar/anatomía & histología , Arteria Pulmonar/fisiología , Tomografía Computarizada por Rayos X , Adolescente , Adulto , Presión Sanguínea , Superficie Corporal , Cateterismo Cardíaco , Enfermedad Crónica , Femenino , Trasplante de Corazón , Trasplante de Corazón-Pulmón , Humanos , Hipertensión Pulmonar , Enfermedades Pulmonares/fisiopatología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Análisis de Regresión , Reproducibilidad de los Resultados , Estudios Retrospectivos , Enfermedades Vasculares/fisiopatologíaRESUMEN
Disturbances in hepatic pH homeostasis are thought to participate in the functional damage to liver grafts caused by the cold preservation and warm reperfusion necessitated by transplantation surgery. We have used an in vitro model of isolated rat hepatocytes suspended in cold University of Wisconsin (UW) solution and subsequently cultured at 37 degrees C to evaluate liver cell pH regulatory mechanisms after cold preservation and rewarming. Cells were kept for up to 72 h in cold UW solution, and at 24-h intervals intracellular pH (pHi) was measured after 60-90 min of warm culture by cytofluorometry using the fluorochrome 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. When challenged with an alkaline load by isohydric HCO(3)(-)-CO(2) steps, hepatocytes exhibited similar maximal pH(i) values and recovered at the same rate, irrespective of cold storage time, indicating that Cl-/HCO(3)- exchange activity is quite resistant to hypothermic storage and subsequent rewarming. In parallel studies, cells were subjected to an acid load by the NH4Cl pulse technique in bicarbonate buffer containing 50 microM ethylisopropylamiloride to block Na+/H+ exchange. Despite similar nadir pH(i) (lowest pH(i) values due to acid load), the subsequent pH(i) recovery rate that reflects Na+-(HCO(3)-)n cotransport activity was increased significantly after hypothermic preservation. Hepatocytes were also perfused with a bicarbonate-free N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid buffer, and Na+/H+ exchange activity was evaluated using the same acid load protocol. Although cells always exhibited similar steady-state initial pH(i) and nadir, the rate of pH(i) recovery decreased significantly as a function of cold storage time in UW solution. Finally, intracellular buffering capacity was calculated from the sudden pH(i) changes induced by HCO(3)(-)-CO(2) steps or NH4Cl pulses and was found to remain stable throughout the 72 h of cold preservation. Therefore, the results strongly suggest that cold preservation and rewarming disturb hepatocellular pH regulatory mechanisms by attenuating Na+/H+ exchange and increasing Na+-(HCO(3)-)n cotransport, whereas Cl-/HCO(3)- exchange is not affected.
Asunto(s)
Antiportadores/metabolismo , Proteínas Portadoras , Frío , Concentración de Iones de Hidrógeno , Hígado/fisiología , Soluciones Preservantes de Órganos , Preservación de Órganos , Intercambiadores de Sodio-Hidrógeno/metabolismo , Adenosina , Alopurinol , Animales , Tampones (Química) , Antiportadores de Cloruro-Bicarbonato , Cloruros/metabolismo , Glutatión , Insulina , Masculino , Preservación de Órganos/métodos , Rafinosa , Ratas , Ratas Sprague-Dawley , Sodio/metabolismo , Simportadores de Sodio-BicarbonatoRESUMEN
Indirect evidence suggests that insulin, like epidermal growth factor (EGF), stimulates liver cell Na+/H+ exchange. We directly studied the effect of insulin on intracellular pH (pHi) and the Na+/H+ exchanger in isolated rat hepatocytes with the fluorescent probe, 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). The effects of insulin were compared with those of EGF. Studies were carried out in the absence of HCO3- and in the presence of acetazolamide to isolate the Na+/H+ exchanger from other pH regulatory mechanisms. Insulin (9 nM) caused a reversible acidification of baseline pHi, whereas no significant effect was observed with EGF (30 nM). pHi was acidified by two different methods (NH4Cl pulse and external Na+ removal) to assess liver cell Na+/H+ exchange activity. In the NH4Cl pulse experiments, insulin had no significant effect on the Na+/H+ exchanger compared with the control (0.141 +/- 0.009 pH units/min, n = 14, and 0.122 +/- 0.023 pH units/min, n = 16, respectively). However, in the same conditions, EGF nearly doubled the rate of the Na+/H+ exchange activity (0.193 +/- 0.015 pH units/min, P < 0.05, n = 6). In the Na+ removal experiments, EGF again significantly increased the pHi recovery rate (0.542 +/- 0.032 pH units/min, n = 3) compared with the control (0.227 +/- 0.028 pH units/min, n = 5) and insulin (0.245 +/- 0.053 pH units/min, n = 5). Compared with control conditions, a subchronic administration of insulin (9 nM) in vitro had no significant effect on the Na+/H+ exchanger, nor did it affect baseline pHi.(ABSTRACT TRUNCATED AT 250 WORDS)