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Biomedical subjects

E Schwartz

Publications and source records attributed to E Schwartz.

At least 361 records · Page 20Linked to original sources
PubMed1979

Hereditary spherocytosis with normal osmotic fragility after incubation. Is the autohemolysis test really obsolete?

Two patients in two families had hereditary spherocytosis but lacked a population of RBCs with increased osmotic fragility after incubation. The diagnosis in each patient was confirmed by the presence of splenomegaly, spherocytosis, reticulocytosis, and abnormal autohemolysis corrected by glucose. Sodium flux studies showed increased sodium permeability of the RBC membrane in one patient and normal permeability in another. Hereditary spherocytosis was also present in three other family members of patient 2. The autohemolysis test is of value in confirming the diagnosis in patients with hereditary spherocytosis and normal incubated osmotic fragility.

Child↗
PubMed1979

Spin-label studies of membrane-associated denatured hemoglobin in normal and sickle cells.

A maleimide spin label (N-(1-oxyl-2,2,5,5-tetramethylpyrrolidinyl)-maleimide) was reacted with oxyhemoglobin-free cell stromata of normal and sickle cells. The EPR spectrum of spin-labeled red cell membranes showed that the spin labels are attached to at least two different binding sites. There was a major signal, A, which characterized a strongly immobilized environment and a minor signal, B, which characterized a weakly immobilized environment. Quantitative EPR measurements using equal amounts of Hb AA and Hb SS red blood cells demonstrated that Hb SS red cell membranes had an approximately four times higher EPR signal intensity than Hb AA red cell membranes ((7.98 +/- 1.14 . 10(5) and (2.2 +/- 1.2) . 10(5) spin labels/cell, respectively). Moreover, the ratio of signal intensities A and B are different in these cells. Comparative spectrophotometric studies of membrane-associated denatured hemoglobins of Hb AA and Hb SS red cell membranes suggested that the EPR signal A is derived from spin labels attached to membrane-associated denatured hemoglobin, while signal B is mainly from spin labels attached to membranes. The combination of EPR spectrum of Hb AA membranes pretreated with N-ethylmaleimide and that of spin-labeled precipitated hemoglobin further strengthened this conclusion.

Anemia, Sickle Cell↗
PubMed1979

Help-agents' views about clinical interactions with acting-out children.

A scale to measure nonprofessional child-aides' views about, and practices in, working primarily with acting-out children is described. The scale was used as part of an overall evaluation of a program to teach the aides Ginottian limit-setting approaches for work with such children. A prior study had shown that the training was followed by significantly more favorable treatment outcomes. Compared to 44 nontrained child-aides, the 19 trained aides had significantly higher postprogram scale scores on opinions and beliefs about acting-out children, changes in feeling about working with them, and actual observed changes in their playroom behaviors. Item analysis indicated that, following training, aides felt more comfortable with and had a richer repertoire of techniques for dealing with acting-out children. Specifically, they found it easier to set limits and to deal with overtly aggressive behaviors. Those changes may be key factors in explaining the significantly greater effectiveness of the trained aides working with acting-out children.

Acting Out↗
PubMed1979

Ankle arthrodesis. Long-term follow-up with gait analysis.

A functional assessment of twelve patients after ankle arthrodesis for post-traumatic arthritis was carried out by means of an extensive clinical evaluation and gait analysis after an average follow-up of eight years. A weighted point system was developed to grade ankle function clinically. The data on gait analysis were examined to determine the effect of arthrodesis of the ankle on the over-all pattern of walking. Under conditions of normal daily living while wearing shoes, all patients functioned well after arthrodesis. The gait-analysis data obtained with the patients wearing shoes showed excellent gait characteristics, and the ankle motion that had been lost was compensated for by: (1) motion of the small joints of the ipsilateral foot; (2) altered motion of the ankle in the contralateral limb; and (3) appropriate footwear. While the patients were walking barefooted, some adverse effects of fusion of the ankle were evident. Velocity of gait was slowed and the length of stride was shortened in all twelve patients. One patient whose ankle had been fused in an equinus position had a back-knee deformity during stance phase, and another walked only on his toes when he was without shoes. The gait patterns of all patients were markedly improved when they were wearing shoes with appropriate heel heights.

Activities of Daily Living↗
PubMed1979

The quiet carrier of beta-thalassemia.

Heterozygosity for beta-thalassemia is usually characterized by hypochromia, microcytosis, mild anemia, and increased percentage of Hb A2, and normal or mildly increased Hb F. We have studied an unusual type of beta-thalassemia with typical morphologic abnormalities but normal levels of Hb A2 and Hb F, with diagnosis confirmed by globin synthesis studies. The results indicate that globin synthesis studies may be necessary when the cause of hypochromia and microcytosis cannot be clearly determined by hemoglobin quantitation and electrophoresis and other standard clinical tests.

Child, Preschool↗
PubMed1978

Stabilizing effect of various organic solvents on protein.

The rate of denaturation of hemaglobin and other proteins by mechanical shaking is strongly affected by organic solvents. A group pf solvents,including alcohols and ketones, was found to stabilize proteins at low concentrations, although these same organic solvents denatured proteins at high concentrations. The stabilizing effect of alcohols increased with increasing chain lenghts. The second group of solvents, including toluene and chloroform, showed only a destabilizing effect, while the third group of solvents such as formamide and pentane had no effect over a wide range of concentrations. Organic solvents may be used to protect or denature a specific protein in solutions containing various proteins.

Alcohols↗
PubMed1978

Comparative studies of Hb Lepore Boston, Hb A2, and Hb A.

Several functional tests were performed to compare Hb A, Hb A2, and Hb Lepore Boston, which has a delta-beta crossover in the region of residues 87 to 116. Oxygen equilibrium curves determined by an automatic apparatus in 0.1 M potassium phosphate buffer, pH 7.0, at 20 degrees showed that the p50 was 5.8 mm Hg for Hb Lepore Boston, in contrast to 8.1 and 10.3 mm Hg for Hb A2 and Hb A, respectively. The n values (Hill coefficinets) of Hb Lepore Boston and Hb A2 were slightly smaller than that of Hb A. The effect of 2,3-diphosphoglycerate and inositolhexophosphate on the p50 of Hb Lepore Boston and Hb A2 was less than that on the p50 of Hb A. The molecular stability to mechanical shaking of Hb Lepore Boston and Hb A2 showed that the oxy forms of Hb Lepore Boston and Hb A2 denatured at a rate 3 times faster than that of Hb A. MetHb Lepore Boston was more unstable than MetHb A2 to mechanical shaking. These results indicate that, although the molecular stability of Hb Lepore Boston is more similar to that of Hb A2 than that of Hb A, the oxygen-binding properties of Hb Lepore differ from both Hb A and Hb A2.

Carboxyhemoglobin↗
PubMed1978

Iron chelation therapy with deferoxamine in Cooley anemia.

The iron-chelating agent, deferoxamine, was studied in 16 patients with thalassemia major. Urinary excretion of iron in response to 0.75 gm of deferoxamine, intramuscularly, ranged from 2.2 to 44.8 mg Fe/24 hours. In response to a subcutaneous infusion of 1.5 gm deferoxamine for 18 hours, iron excretion increased by an average of 240%. The intravenous infusion of large doses of deferoxamine for 18 hours resulted in the highest rate of iron excretion, as much as 447.5 mg Fe/24 hours in response to 16 gm of deferoxamine. Administration of vitamin C increased chelation-induced excretion of iron in most patients more than five years of age. Preliminary evidence suggests that further iron accumulation can be prevented and excessive iron stores can be depleted by the intramuscular, subcutaneous, or intravenous administration of deferoxamine.

Adolescent↗
PubMed1978

Excretion of iron in response to deferoxamine in sickle cell anemia.

Iron chelation with deferoxamine was studied in ten patients with sickle cell anemia who had received 2 to 37 liters of red blood cells. Urinary excretion of iron in response to 1.5 gm of deferoxamine administered intravenously ranged from 5.9 to 28.7 mg/24 hours and was closely related to the amount of iron acquired from transfusions. Administration of ascorbic acid did not improve deferoxamine-induced excretion of iron. Urinary excretion of iron in response to 0.75 gm of DFO intramuscularly was 4.7 to 6.9 mg/24 hours in three patients who had received 15 to 37 liters of red cells. The data indicate that measurement of DFO-induced excretion of iron is of value in detecting increased iron stores in children with sickle cell anemia who have received repeated transfusions and that chelation therapy will retard the accumulation of iron.

Adolescent↗
PubMed1978

A simple test for detection of sickle hemoglobin in the neonatal period.

The ease of denaturation by shaking of a solution of oxyhemoglobin S (oxy-Hb S) forms the basis for a simple and reliable test for confirmation or rapid detection of Hb S in children and adults. Comparison of results of this test with those from agar gel electrophoresis in capillary blood samples from 187 black neonates at 2 to 7 days of life showed no overlap of the amounts of hemoglobin precipitated between the group of neonates with Hb S (5.7--12.0%) and that without Hb S (0--4.7%). These results indicate that the shaking test, by virtue of being simple, reliable and inexpensive, may be used to detect and confirm Hb S in large numbers of neonates before their discharge from the nursery.

Anemia, Sickle Cell↗