Strategies that reduce Stroop interference.

A remarkable example of reducing Stroop interference is provided by the word blindness post-hypnotic suggestion (a suggestion to see words as meaningless during the Stroop task). This suggestion has been repeatedly demonstrated to halve Stroop interference when it is given to highly hypnotizable people. In order to explore how highly hypnotizable individuals manage to reduce Stroop interference when they respond to the word blindness suggestion, we tested four candidate strategies in two experiments outside of the hypnotic context. A strategy of looking away from the target words and a strategy of visual blurring demonstrated compelling evidence for substantially reducing Stroop interference in both experiments. However, the pattern of results produced by these strategies did not match those of the word blindness suggestion. Crucially, neither looking away nor visual blurring managed to speed up incongruent responses, suggesting that neither of these strategies is the likely underlying mechanism of the word blindness suggestion. Although the current results did not unravel the mystery of the word blindness suggestion, they showed that there are multiple voluntary ways through which participants can dramatically reduce Stroop interference.

Oral sodium phenylbutyrate therapy in homozygous beta thalassemia: a clinical trial.

Butyrate analogues have been shown to increase fetal hemoglobin (HbF) production in vitro and in vivo. Sodium phenylbutyrate (SPB), an oral agent used to treat individuals with urea-cycle disorders, has been shown to increase HbF in nonanemic individuals and in individuals with sickle cell disease. We have treated eleven patients with homozygous beta thalassemia (three transfusion dependent) and one sickle-beta-thalassemia patient with 20 g/d (forty 500-mg tablets) of SPB for 41 to 460 days. All patients showed an increase in the percent of F reticulocytes associated with treatment, but only four patients responded by increasing their Hb levels by greater than 1 g/dL (mean increase, 2.1 g/dL; range, 1.2 to 2.8 g/dL). None of the transfusion-dependent thalassemia subjects responded. Increase in Hb was associated with an increase in red blood cell number (mean increase, 0.62 x 10(12)/L), and mean corpuscular volume (mean increase, 6 fL). Changes in percent HbF, absolute HbF levels, or alpha- to non-alpha-globin ratios as measured by levels of mRNA and globin protein in peripheral blood did not correlate with response to treatment. Response to treatment was not associated with the type of beta-globin mutation, but baseline erythropoietin levels of greater than 120 mU/mL was seen in all responders and only two of eight nonresponders to SPB. Compliance with treatment was greater than 90% as measured by pill counts. Side effects of the drug included weight gain and/or edema caused by increase salt load in 2/12, transient epigastric discomfort in 7/12, and abnormal body odor in 3/12 subjects. Two splenectomized patients who were not on prophylactic antibiotics developed sepsis while on treatment. We conclude that SPB increases Hb in some patients with thalassemia, but the precise mechanism of action is unknown.

Comparison of a transfusion preparation of newly formed red cells and standard washed red cell transfusions in patients with homozygous beta-thalassemia.

BACKGROUND: Previous studies of transfusions of newly formed red cells (neocytes) demonstrated modest extensions of transfusion interval in patients with homozygous beta-thalassemia. STUDY DESIGN AND METHODS: The clinical benefits of a new system of neocyte preparation (Neocel, Cutter Biological, Berkeley, CA), reported to combine ease of preparation with reduction in the transfusion requirements of thalassemia patients, were evaluated. Sixteen thalassemic patients who had undergone splenectomy received eight consecutive, standard, automated, washed red cell transfusions (standard transfusions), followed by eight transfusions with the neocyte preparation (neocyte transfusions). In each arm of the study, mean pretransfusion hemoglobin and mean red cell mass transfused were carefully controlled and were similar. RESULTS: A significant (p < 0.0001) extension of transfusion interval was observed in patients receiving neocyte transfusions (mean +/- SD; 38.7 +/- 34 days; range, 35.0-44.5), over that in those receiving standard transfusions (32.9 +/- 2.5 days; range, 29.6-38.5). The mean prolongation of transfusion interval by neocyte transfusion corresponded to a mean reduction of 25 mL in packed red cells transfused per kg of body weight per patient per year and a mean reduction in transfused iron of 15 percent per year per patient. During neocyte transfusions, blood preparation costs were considerably increased and donor exposure was significantly (p < 0.0005) higher than during the standard transfusion period. CONCLUSION: These data demonstrate that extension of the transfusion interval, and reduction in transfused iron, may be achieved in thalassemic patients by use of the Neocel system. These benefits are achieved, however, with substantial increases in donor exposure and in component preparation costs.

Iron-balance and dose-response studies of the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in iron-loaded patients with sickle cell disease.

Several life-threatening complications of the common disorder sickle cell disease require management with red blood cell transfusions and, hence, long-term iron-chelating therapy. The efficacy of the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) has not previously been determined in patients with sickle cell disease. We compared the efficacy of L1 to that of standard-dose subcutaneous deferoxamine in four regularly transfused patients with homozygous sickle cell disease, who had evidence of severe iron overload and a history of poor compliance with deferoxamine. Determination of 24-hour urinary iron excretion conducted over 5 days immediately after transfusion showed that the mean daily urinary iron excretion induced by L1 at 75 mg/kg/d (0.48 +/- 0.23 mg/kg) was equivalent to that induced by deferoxamine at 50 mg/kg/d (0.39 +/- 0.06 mg/kg). In two of three patients studied, a significant (P < .025) increase in mean daily urinary iron excretion was achieved when the dose of L1 was increased to 100 mg/kg/d. Total iron balance studies, which quantitated both urinary and stool iron excretion on L1 and deferoxamine, determined that mean total daily iron excretion induced by deferoxamine (0.88 +/- 0.05 mg/kg) was significantly greater (P < .05) than that induced by L1 (0.53 +/- 0.17 mg/kg), attributable to the significantly greater stool iron excretion during deferoxamine treatment (0.50 +/- 0.16 mg/kg/d) compared with that measured during L1 treatment (0.12 +/- 0.08 mg/kg/d, P < .01). Stool iron excretion accounted for a significantly greater percentage of total iron excretion during deferoxamine treatment (59% +/- 20%) than during L1 treatment (23% +/- 14%, P < .01). These iron balance studies are the first to compare total iron excretion induced by L1 with that achieved by deferoxamine. They demonstrate that the mean total daily iron excretion during L1 treatment (0.53 +/- 0.17 mg/kg) is sufficient to maintain net negative iron balance in most regularly transfused patients with sickle cell disease. Because long-term compliance with L1 has been shown previously to be superior to that with deferoxamine in patients with homozygous beta-thalassemia, the use of L1 should increase the long-term effectiveness of iron chelation in patients with sickle cell disease.

A study on children's condition thalassemia using neutron activation analysis and other techniques.

In this study, 50 thalassemia patients were tested using dual-energy X-ray absorptiometry (DEXA) and in vivo neutron activation analysis (IVNAA) to determine their bone mineral status. Both techniques were suitable for this purpose. Lower age was found to correspond to lower liver iron content and higher bone mineral content in the normal range. Patients undergoing treatment with transfusion had higher bone mineral content. Osteopenic patients had higher hepatic iron content than those with normal bone status. In the case of DEXA, bone mineral content (BMC) divided by height cubed was found to be a better indicator of bone mineral status than the BMD usually given. Liver density as determined by DEXA correlates well with hepatic iron.

Phonological priming of lexical retrieval in speech production.

We report a series of three experiments exploring phonological priming effects in speech production. In all cases, subjects repeated aloud auditorily presented primes and then named picture targets. Experiment 1 showed that targets were named faster when prime and target shared phonemes but only when these occupied the same word or syllabic positions. Experiment 2 showed that the degree of facilitation was unaffected by the lexicality of the prime or whether shared phonemes occurred early or late in the syllable. Experiment 3 examined the effect of the lexicality of the prime at different intervals between response and prime in an attempt to tease apart contributions to the effect from automatic and strategic processes. The results are considered in relation to current accounts of lexical retrieval.