Learning a novel grapheme: effects of positional and phonemic context on children's spelling.

Two experiments explored how children who encounter a new spelling for a phoneme generalize it to novel items. Children ages 5 1/2 to 9 (N = 123) were taught a CVC (consonant-vowel-consonant) nonword containing a new vowel spelling in the middle position (e.g., /gaik/ is spelled as giik). They were then asked to spell other nonwords containing the vowel or to judge spellings that had supposedly been produced by younger children. Children were sensitive to position in the spelling production task, being more likely to use the novel grapheme when the vowel appeared in the middle of a CVC target than when it appeared in word-initial or word-final position. Children were not significantly more likely to use the novel grapheme when the target shared the vowel and final consonant (rime) of the training stimulus than when it shared the initial consonant and vowel. Implications for views of spelling development are discussed.

Double-blind study of adjuvant buspirone for fluoxetine-treated patients with obsessive-compulsive disorder.

In a double-blind, crossover study, 13 fluoxetine-treated patients with obsessive-compulsive disorder were given adjuvant buspirone and placebo for 4 weeks each. There were no significant differences between buspirone and placebo in obsessive-compulsive, depressive, or anxiety symptoms.

A double-blind, placebo controlled study of trazodone in patients with obsessive-compulsive disorder.

Patients with obsessive-compulsive disorder (OCD) have been shown to be preferentially responsive to serotonin (5-HT) uptake-inhibiting antidepressants including clomipramine, fluoxetine, fluvoxamine, and sertraline. The nontricyclic antidepressant, trazodone, also possesses serotonin reuptake inhibiting properties and has been reported to be efficacious in OCD in several case reports and open trials. In order to investigate trazodone's potential antiobsessive efficacy in a controlled fashion, 21 patients with OCD were entered into a double-blind, parallel design comparison of trazodone and placebo. There were no significant differences in baseline rating scores of OCD or depressive symptoms between those who entered the trazodone phase (N = 13) versus those who entered the placebo phase (N = 8). As measured by standardized OCD and depression rating scales, there was no significant difference in OCD or depressive symptoms in the 17 patients who completed 10 weeks of trazodone (N = 11, mean daily dose, 235 +/- 10 mg) versus 10 weeks of placebo (N = 6) administration. In comparison to clomipramine and fluoxetine treatment which we have found to be associated with greater than 95% reduction in platelet 5-HT concentration, there was only a 26% mean reduction in platelet 5-HT concentration after 10 weeks of trazodone administration. These results indicate that trazodone lacks substantial antiobsessive effects and is associated with only modest reductions in platelet 5-HT concentrations.

A double-blind study of adjuvant buspirone hydrochloride in clomipramine-treated patients with obsessive-compulsive disorder.

In this study, 14 patients with obsessive-compulsive disorder (OCD) who had received at least 3 months of treatment with clomipramine were treated with the anxiolytic agent buspirone in a 10-week, double-blind study. Before the addition of buspirone, these patients as a group had shown a partial but incomplete reduction (averaging 28%) in OCD symptoms during clomipramine treatment alone. Because buspirone has been reported to be efficacious as a sole agent and as an adjunct agent in combination with fluoxetine in patients with OCD, we were interested in assessing whether buspirone added to clomipramine treatment would be associated with further significant reductions in OCD or depressive symptoms. Although adjuvant buspirone treatment was well tolerated in most subjects, mean OCD and depressive symptoms, as evaluated by standardized rating scales, did not significantly change from baseline scores achieved on clomipramine treatment alone, either after the addition of placebo for 2 weeks or buspirone (57 +/- 7 mg/day) for an additional 10 weeks. However on an individual basis, 4 (29%) of the 14 patients did have an additional 25% reduction in OCD symptoms after adjuvant buspirone treatment. This double-blind study suggests that adjunctive buspirone therapy is not generally associated with significant further clinical improvement in OCD or depressive symptoms compared with clomipramine monotherapy, but that there may be a subgroup of patients who do benefit from adjuvant buspirone therapy.

A controlled comparison of adjuvant lithium carbonate or thyroid hormone in clomipramine-treated patients with obsessive-compulsive disorder.

In this study, 16 patients with obsessive-compulsive disorder (OCD) who had partially improved during at least 6 months of treatment with clomipramine were sequentially treated with triiodothyronine and lithium carbonate in an 8-week double-blind cross-over study. Both triiodothyronine and lithium carbonate have been reported to be efficacious in open trials as adjunctive agents when combined with tricyclics in the treatment of OCD and depressed patients. However, in our controlled study, OCD and depressive symptoms, as assessed by standardized rating scales in the patient group as a whole, did not significantly change after either adjuvant treatment. Further analysis on an individual patient basis revealed that neither adjuvant medication was associated with a clinically meaningful change (greater than 25%) in OCD symptoms. However, lithium, but not triiodothyronine, adjuvant therapy was associated with a 25% or greater reduction in depression scores in 44% of the patients. This controlled study lends further support to the contention that OCD may represent a disorder with characteristics distinct from affective disorders.

Metergoline blocks the behavioral and neuroendocrine effects of orally administered m-chlorophenylpiperazine in patients with obsessive-compulsive disorder.

The pharmacological probe, meta-chlorophenylpiperazine (m-CPP), administered orally to patients with obsessive-compulsive disorder (OCD) has been shown to induce an acute exacerbation in OCD symptoms as well as an exaggerated anxiogenic response in comparison with controls. The mechanism of m-CPP's behavioral effects in humans remains controversial. To further study m-CPP's actions in OCD patients, we completed a series of double-blind pharmacological challenges in 12 OCD patients. Six OCD patients received four separate challenges: placebo, metergoline, m-CPP, and metergoline plus m-CPP; the second group (n = 6) received metergoline and metergoline plus m-CPP in separate challenges. OCD patients receiving placebo or metergoline alone failed to show evidence of significant changes on any of the behavioral rating scales, in contrast to the patients who received m-CPP alone who exhibited significant increases in anxiety and OCD symptoms. However, the 12 OCD patients who received pretreatment with metergoline before m-CPP experienced no significant changes from baseline OCD symptoms or other behavioral changes. m-CPP's ability to elicit elevations in plasma prolactin was blocked by metergoline pretreatment. Metergoline's ability to block m-CPP's effects on behavior and plasma prolactin lends further support to a serotonergic mediation of m-CPP's effects, including its elicitation of OCD symptoms.

Controlled comparisons of clomipramine and fluoxetine in the treatment of obsessive-compulsive disorder. Behavioral and biological results.

Treatment with fluoxetine hydrochloride was compared with treatment with clomipramine hydrochloride in two groups of patients with obsessive-compulsive disorder using two different experimental designs. In the first group of 11 patients with obsessive-compulsive disorder studied using a randomized, double-blind, crossover design, treatment with fluoxetine for 10 weeks was found to produce therapeutic effects similar to treatment with clomipramine for 10 weeks. There were significantly fewer total side effects reported during fluoxetine than clomipramine treatment. Drug tapering and placebo substitution in the 4-week crossover interval phase led to substantial relapses in obsessive-compulsive disorder symptoms and depression. Furthermore, responses to the second drug took as long to occur as responses to the first drug, although both drugs are thought to act by a common mechanism, serotonin uptake inhibition. A second group of 21 patients with obsessive-compulsive disorder that had been previously stabilized on clomipramine treatment with at least partial benefit were crossed over to fluoxetine treatment in a double-blind fashion. After 10 weeks of fluoxetine administration, most patients manifested behavioral rating scores of obsessive-compulsive disorder and depressive symptoms that were comparable with precrossover ratings completed during clomipramine treatment. A significant exacerbation in obsessive-compulsive disorder and depression ratings as well as a similar lag in therapeutic efficacy were also noted in this second cohort of patients with obsessive-compulsive disorder. Platelet 5-HT concentrations were reduced 95% during both clomipramine and fluoxetine treatment periods. These results suggest that fluoxetine may represent a viable alternative to clomipramine in the treatment of obsessive-compulsive disorder, although further studies with larger sample sizes are needed.

Bone marrow replacement in the treatment of hemolytic disease in mice.

Bone marrow replacement therapy following whole-body x- or gamma-irradiation has until now proven to be of limited value in the treatment of individuals with hemolytic disease. The large doses of radiation required for destruction of defective erythropoietic tissues coupled with their resultant high mortality appears to limit its usefulness. Techniques have been developed by the authors to limit the extent of exposure and to improve survival following irradiation. These techniques include shielding of all parts of the body except the hind limbs, prophylactic use of antibiotics, and preparatory blood transfusion to suppress the development of indigenous defective erythrocytes. Using these combined techniques we were able to establish high rates of survival, successful engraftment, and long-term clinical improvement in mice with several hemolytic disorders emanating from hereditary defects in spectrin production and incorporation. Evidence is presented indicating that complete bone marrow replacement occurs even in nonirradiated portions of the erythron and that only donor type red blood cells appear in the circulation.

Impaired echinocytic transformation of ankyrin- and spectrin-deficient erythrocytes in mice.

The membrane skeleton of the red blood cell plays an important role in the determination of cell deformability and cell shape. Under various in vitro conditions, red blood cells undergo an echinocytic or stomatocytic shape transformation. The mechanism of this fundamental process is not well understood. We have studied the red cell shape transformation in normoblastic anemia mice (nb/nb) and spherocytic anemia mice (sph/sph), which are deficient in ankyrin and spectrin, respectively. We found that both ankyrin-deficient cells (nb/nb) and spectrin-deficient cells (sph/sph) have a reduced capacity to undergo echinocytic transformation with various echinocytogenic treatments, that is, incubation with sodium salicylate (40 and 120 mM), calcium loading (50 microM A23187 + 2.2 mM Ca2+), or metabolic depletion (24 hr at 37 degrees C). These results suggest that the functional integrity of the membrane skeleton is essential for the maintenance and transformation of the red cell shape.

Evaluation of stem cell reserve using serial bone marrow transplantation and competitive repopulation in a murine model of chronic hemolytic anemia.

Serial transplantation and competitive repopulation were used to evaluate any loss of self-replicative capacity of bone marrow stem cells in a mouse model with increased and persistent hemopoietic demands. Congenic marrows from old control and from young and old mice with hereditary spherocytic anemia (sphha/sphha) were serially transplanted at 35-day intervals into normal irradiated recipients. Old anemic marrow failed or reverted to recipient karyotype at a mean of 3.5 transplants, and young anemic marrow reverted at a mean of 4.0 transplants, whereas controls did so at a mean of 5.0 transplants. In a competitive assay in which a mixture of anemic and control marrow was transplanted, the anemic marrow persisted to 10 months following transplantation; anemic marrow repopulation was greater if anemic marrow sex matched with the host. It is possible that lifelong stress of severe anemia decreases stem cell reserve in the anemic sphha/sphha mouse marrow. However, marginal differences in serial transplantation number and the maintenance of anemic marrow in a competition assay would suggest that marrow stem cells, under prolonged stress, are capable of exhibiting good repopulating and self-replicating abilities.

Monoconjugated bilirubin is a major component of hemolysis-induced gallstones in mice.

The role of bilirubin conjugates in the formation of pigment gallstones is not known. In this study, we completely solubilized and then analyzed by high-performance liquid chromatography specimens of black pigment gallstones from eight nb/nb mice with hereditary hemolytic anemia. Each dried gallstone specimen of about 200 micrograms was dissolved in 5 ml of dimethyl sulfoxide/0.15 M HCI/50 mM disodium-EDTA (8:1:1 by volume) at room temperature. Stone dissolution was complete by 30 min as monitored by the A456 and direct observation, and no oxidative products of bilirubin were observed in the visible spectrum, 350 to 750 nm. By high-performance liquid chromatography, the intact tetrapyrroles were separated as diconjugated and monoconjugated bilirubins; unconjugated bilirubin was resolved as XIII, IX and III alpha-isomers. The isocratic solvent system used was 0.1 M di-n-dodecylamine acetate/0.1 M di-n-octylamine acetate (4:1, v/v) in methanol, pH 7.4, at a flow of 1 ml per min. Diconjugated bilirubin accounted for 6.0 +/- 2.4 molar % (mean +/- S.E.), monoconjugated bilirubin for 37.4 +/- 8.4% and unconjugated bilirubin for 56.3 +/- 8.9% of the solubilized pigments. The IX alpha-isomer represented 96 +/- 1.9% of the unconjugated bilirubin. The presence of bilirubin conjugates in gallstones was confirmed by ethylanthranilate diazotization: the conjugated azodipyrrole in stone had the same retention time as that of conjugated azodipyrrole from rat and mouse bile. A majority of the bilirubin conjugates was sensitive to beta-glucuronidase of liver origin, indicating that the C-1 glucuronide ester was present.(ABSTRACT TRUNCATED AT 250 WORDS)

Hereditary hypotransferrinemia with hemosiderosis, a murine disorder resembling human atransferrinemia.

A newly reported spontaneous mutation in mice resembles human atransferrinemia. Both the human and murine forms have a Mendelian recessive mode of inheritance, and both are early onset lethal diseases in which homozygotes have refractory iron-deficient hypochromic anemia. Their plasma transferrin levels are less than 4 mg/dl, and extensive deposits of iron are found in the livers and other organs of afflicted individuals. Although heterozygotes are not anemic, they have half normal levels of circulating transferrin, and they become siderotic late in life. In the mouse, weekly injections of mouse or human serum, or of highly purified transferrin, permit survival and alleviate the anemia. The pattern of inheritance, clinical features, time course and distribution of parenchymal iron, and nature and stability of the endogenous transferrin are presented. The data indicate that the gene hpx produces wholly normal strain-specific transferrin but in small amounts. The hpx gene is closely linked with the transferrin locus, Trf, on chromosome 9.

Long-term administration of massive doses of Sn-protoporphyrin in anemic mutant mice (sphha/sphha).

The effects of long-term administration of very large doses of Sn-protoporphyrin on hematological indices, histological changes, plasma bilirubin levels, tissue heme oxygenase activity, and activities of heme biosynthetic enzymes, were examined in genetically anemic mutant mice with hemolytic anemia (sphha/sphha). Long-term weekly treatment with Sn-protoporphyrin (100 mumol/kg body weight for 32 wk) did not alter hematological indices, histological findings, or enzyme activities related to heme biosynthesis, even though it resulted in sustained decreases in microsomal heme oxygenase activity in the liver, kidney, and spleen, and a prolonged decrease in plasma bilirubin concentration. Inhibition of heme oxygenase did not alter the level of cytochrome P-450 in the liver and the kidney. The results indicate that long-term treatment with massive doses of Sn-protoporphyrin suppresses bilirubin formation but does not produce significant histopathological changes or appreciably interfere with heme synthesis, in this strain of genetically anemic mice. These findings provide further support for the idea that suppression of heme degradation to bile pigment by the inhibition of heme oxygenase may prove useful to the prevention of severe hyperbilirubinemia in humans.

Interaction of hemolysis and genotype on ionized calcium in bile of mice with hemolysis-induced gallstones.

In this study, we used an ion-selective membrane electrode to measure ionized calcium in hepatic bile of control +/+ mice and nb/nb mice with hereditary hemolytic anemia. We found that biliary concentrations of ionized, bound, and total calcium were significantly higher (p less than 0.001) and magnesium was significantly lower (p less than 0.001) in nb/nb mice than in control +/+ mice. To separate the hemolytic process from genotypic influences, we transplanted genetically defective bone marrow from nb/nb mice into histocompatible nonhemolytic recipients (W/Wv). After successful engraftment, transplanted W/Wv mice had significantly higher biliary concentrations of ionized calcium than their untreated W/Wv counterparts (p less than 0.001); but bound and total calcium and magnesium concentrations were not different from untreated W/Wv controls. When compared with nb/nb mice, transplanted W/Wv mice had lower ionized calcium (p less than 0.001) and higher bound calcium concentrations (p less than 0.001) in their biles. These data indicate that ionized calcium in hepatic bile is significantly influenced by genotypic factors and subsequently increased in chronic hemolysis; and further, that increased ionized calcium in bile of mice with hemolysis is a risk factor, but of limited predictive value for hemolysis-induced gallstone formation.

Normal content of brain spectrin-like protein in sph/sph mice.

In the erythrocytes of WBB6F1-sph/sph mice spectrin constitutes only approximately 1% of the total sph/sph membrane protein compared to approximately 23% in WBB6F1-+/+ controls. No increase in proteolytic degradation of spectrin in sph/sph erythrocyte membranes could be detected with antibodies directed against mouse erythrocyte spectrin or mouse brain spectrin-like protein. As attachment of normal spectrin to the erythrocyte membrane of these animals appeared to be normal, and as spectrin is not detected when whole sph/sph erythrocytes are solubilized in SDS for SDS PAGE, the deficient erythrocyte spectrin was probably due to diminished production. Brain spectrin-like protein, a nonerythroid spectrin analogue, is antigenically, morphologically and functionally related to erythrocyte spectrin, but appears by peptide mapping analysis to be a distinct gene product. It was found by protein- and antibody-staining of brain membranes to be present in normal concentrations in sph/sph animals. Indirect immunofluorescence of mouse brain tissue with anti-brain spectrin-like protein IgG or anti-erythrocyte spectrin IgG indicated that the distribution of brain spectrin-like protein was normal in sph/sph brain. Therefore the mutation causing diminished production of sph/sph erythrocyte spectrin does not affect the expression of this nonerythroid spectrin analogue.

A spectrin-like protein from mouse brain membranes: phosphorylation of the 235,000-dalton subunit.

A mouse brain spectrin-like protein, which was an immunoreactive analogue of erythrocyte spectrin, has been isolated from demyelinated membranes. This spectrin analogue was a 10.5 S, 972,000 molecular weight (Mr) (alpha beta)2 tetramer containing subunits of 240,000 (alpha) and 235,000 (beta) Mr. We demonstrated that in vivo only the 235,000 Mr beta subunit of the mouse brain spectrin-like protein was phosphorylated, which was an analogous situation to mouse erythrocyte spectrin in which only the 220,000 Mr beta subunit was phosphorylated. Incubation of isolated membrane fractions with [gamma-32P]ATP +/- adenosine 3',5'-cyclic monophosphate (cAMP) indicated that mouse brain spectrin-like protein, mouse erythrocyte spectrin, and human erythrocyte spectrin's beta subunits were all phosphorylated in vitro by membrane-associated cAMP-independent protein kinases.

Tin-protoporphyrin suppression of hyperbilirubinemia in mutant mice with severe hemolytic anemia.

Tin-protoporphyrin is a potent competitive inhibitor of heme oxygenase both in vivo in animals and in vitro in isolated enzyme preparations, and when administered to neonatal rats, prevents the development of postnatal hyperbilirubinemia. In this study we examined the effect of the metalloporphyrin on the activity of heme oxygenase in liver, kidney, and spleen, and on the level of bilirubin in plasma in three types of anemic mutant mice with severe hemolytic diseases. We report that the administration of tin-protoporphyrin to anemic mutants homozygous for severe hemolytic disease results in substantial inhibition of heme oxidation in liver, spleen, and kidney and in significant reduction of plasma bilirubin levels. Tin-protoporphyrin thus has the capacity to significantly inhibit in vivo heme degradation and to concurrently diminish plasma bilirubin levels in severe chronic hemolytic disorders.

Interaction of hemolytic anemia and genotype on hemolysis-induced gallstone formation in mice.

We previously reported that nb/nb mice with hereditary hemolytic anemia spontaneously developed calcium bilirubinate pigment gallstones. To assess the extent to which gallstone formation and bile composition is gene dependent, we transferred the hemolytic process by transplanting bone marrow from nb/nb mice into a nonhemolytic, but histocompatible genotype, W/Wv mice. Hematologic parameters of transplanted W/Wv mice were nearly identical to those of nb/nb mice. Like nb/nb mice, the percentage of transplanted mice with gallstones increased with the duration of the hemolysis and occurred twice as often in female mice as in male mice (37% vs. 19%; p less than 0.05). However, the rate of gallstone formation in transplanted mice was one-third less than that in nb/nb mice (3.6% per month vs. 5.5%; p less than 0.05). Analysis of hepatic bile revealed that (a) marrow-transplanted mice had higher concentrations of unconjugated bilirubin due to hemolysis (p less than 0.05) and of total bile acids determined by the W/Wv genotype (p less than 0.001) than their respective nb/nb counterparts and (b) transplanted mice with stones had a significantly lower proportion of cholic acid (p less than 0.005) and higher proportion of keto-bile acids (p less than 0.005) than transplanted mice without stones, suggesting that the cholic acid concentration may retard stone formation. These data indicate that the hemolytic process is the primary determinant of pigment gallstone formation in these mice and is influenced by the following factors: (a) duration of the hemolytic process, (b) gender, and (c) the genotype that regulates the composition of biliary components like bile acids.