Near-infrared spectra absorbance of blood from sickle cell patients and normal individuals.

Limited data are available regarding the physicochemical dynamics of tissue hypoxia in sickle cell disease. Studies using near-infrared spectroscopy (NIRS) have reported that patients with sickle cell disease (SCD) have lower cerebral oxygen saturation values (rSO2) than normal individuals. The reason SCD patients have subnormal rSO2 values is not known. It may be related to the degree of anaemia, sickle haemoglobin, disease complications and the possibility of SCD different NIRS absorbance spectra than normal. This study compared NIRS absorbance spectra of blood with adult haemoglobin AA, sickle haemoglobin SS, and AS. Venous blood was collected from SCD (SS and AS) and non-SCD patients (AA). Whole blood, cell free haemoglobin samples were scanned through the wavelength range of 600-1000 nm. The results showed no different NIRS spectra absorbance between the haemoglobin's AA, SS. It thus appears that lower brain oxygen saturation in sickle cell anaemia patients is related to impaired oxygen carrying capacity or delivery by sickle haemoglobin.

Effect of transfusion on cerebral oxygenation, flow velocity in a patient with sickle cell anemia and Moyamoya disease: a case report.

Vascular occlusive diseases affect brain blood flow, brain metabolism and are associated with arterial ischemic stroke. This study was designed to measure the brain blood flow velocity, brain oxygenation, hemoglobin concentrations, hematocrit, and cell free hemoglobin at pre- and post-exchange red cell transfusion in an 18 year old male patient with sickle cell disease and moyamoya syndrome (MMS). Exchange transfusion increased cerebral oxygen saturation 12%, total hemoglobin concentration 2%, hemoglobin AA 80%, and reduced sickle (SS) hemoglobin 12%, arterializations 33%, and cell free hemoglobin 33%. Brain blood flow velocity values were unaffected by transfusion. These observations suggest that exchange transfusion increases the hemoglobin carrying capacity and reduces sickle hemoglobin and shunting of blood, which may improve the peripheral and cerebral oxygenation. Transfusion did not affect the brain blood flow in this patient. Therefore the risk of transient ischemic attack and arterial ischemic stroke from mms still exist.

Cerebral oximetry in patients with sickle cell disease.

BACKGROUND: There is limited information concerning the brain's oxygen supply and demand in patients with sickle cell disease. DESIGN: We measured near-infrared spectroscopy of brain oxygenation in 27 patients with sickle cell disease regardless of vaso-occlusive crisis, 14 normal healthy controls, and five anaemic patients without sickle cell disease. We also measured pre- and post-transfusion cerebral oximetry in 14 additional sickle cell disease patients who were on transfusion programmes. RESULTS: The mean cerebral oxygen saturation in the combined steady-state and vaso-occlusive crisis population was found to be significantly lower than that in the controls and in anaemic patients without sickle cell disease (47.7% vs. 61.3%, 59.8%, P < 0.0001). Cerebral oxygen saturation failed to correlate with the haemoglobin concentration (r = 0.51, P > 0.5). However, cerebral oxygen saturation increased from 40.4% to 49.6% (P = 0.01) and correlated significantly with the haemoglobin level (r = 0.553, P = 0.003) in 14 subjects studied before and after transfusions. In seven subjects who received simple transfusions, cerebral oxygen saturation correlated strongly and positively with the haemoglobin level (r = 0.811, P = 0.001) and with percent normal haemoglobin (r = 0.786, P = 0.002), and negatively with abnormal sickle haemoglobin (r = -0.775, P = 0.003). None of these correlations was found to be statistically significant in the seven subjects given exchange transfusions. Cerebral oxygen saturation measured in the sickle cell disease subjects after transfusions was still significantly lower than in the anaemic subjects without sickle cell disease and in the normal controls (49.6% vs. 59.8% and 61.3%, P = 0.001). CONCLUSIONS: We found that patients with sickle cell disease have subnormal values of cerebral oxygen saturation. Red cell transfusions significantly increased the brain oxygenation in these patients. Cerebral oximetry may be a useful, noninvasive method for assessing the effect of circulating normal red cells in sickle cell patients after transfusions.

Deoxyribonucleic acid, ribonucleic acid, and protein in the placentas of normal and selected complicated pregnancies.

Placenta from uncomplicated term pregnancies resulting in the birth of male infants weighing between 2900 and 3800 grams were analyzed for deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein content. The mothers of the infants all had pre-pregnancy weights within +/- 15 percent expected body weight for body frame, according to the Metropolitan Life Tables. There were no significant differences, as regards the content of DNA, RNA and protein, between the placental cotyledons. Nine placenta from mothers giving birth to growth retarded infants were analyzed along with the placenta from six mothers with insulin dependent diabetes mellitus. A trend suggesting less DNA in the placenta of the severely growth retarded (symmetric) infants when compared with placenta from the normal pregnancies was not noted in the less severely growth retarded (asymmetric) infants. The placenta from the infants of diabetic pregnancies contained DNA and RNA in amounts similar to that found in normal pregnancy placenta but the protein content was greater.

Facilitory role of thyroid hormone in vitamin A uptake in the rat testes.

The inter-relationship of hormones and retinol (vit. A) metabolism is under investigation in our laboratory. The investigation is designed to study the role of thyroid hormone (tetraiodothyronine, T4) in the uptake of vit. A in various rat tissues. Adult male thyroidectomized (Tx) rats, partially vit. A deficient, were administered intragastrically tritium-labeled vit. A. Twenty-four hours later, the level of radioactivity was measured in the blood plasma, liver, kidneys, testes and urine collected for 24 hrs. The data showed that in Tx rats, there was a significant decrease (P less than .01) in the level of radioactivity in the kidneys, testes and urine; in blood plasma and the liver, there was a significant increase (P less than .01). In Tx rats, treatment with T4 restored 50-70% of the radioactivity lost in the kidneys, testes and urine. The endogenous vit. A level in Tx rats treated without and with T4 followed essentially the same pattern. The capacity of cellular retinol binding protein (CRBP) to bind exogenously added vit. A was examined. The data showed a decrease in the binding capacity of CRBP in Tx rats. We conclude that T4 facilitates the uptake of vit. A in the target tissues by regulating CRBP synthesis or degradation.