Thy28 protects against anti-CD3-mediated thymic cell death in vivo

Apoptotic cell death plays a pivotal role in the development and/or maintenance of several tissues including thymus. Deregulated thymic cell death is associated with autoimmune diseases including experimental autoimmune encephalomyelitis (EAE), a prototype murine model for analysis of human multiple sclerosis. Because Thy28 expression is modulated during thymocyte development, we tested whether Thy28 affects induction of EAE as effectively as antigen-induced thymocyte deletion using Thy28 transgenic (TG) mice. Thy28 TG mice showed partial resistance to anti-CD3 monoclonal antibody (mAb)-induced thymic cell death in vivo, as assessed by annexin V-expression and loss of mitochondrial membrane potential. The resistance to anti-CD3 mAb-induced cell death in Thy28 TG mice appeared to correlate with a decreased c-Jun N-terminal kinase phosphorylation and reduced down-regulation of Bcl-xL. Moreover, thymic hyperplasia was detected in Thy28 TG mice, although thymocyte development was unaltered. Development of peripheral lymphoid tissues including spleen and lymph nodes was also unaltered. Thy28 TG spleen T cells showed an increased production of IFN-γ, but not IL-17, in response to both anti-CD3 and anti-CD28 mAbs. Finally, Thy28 TG mice displayed accelerated induction of EAE as assessed by disease incidence, clinical score, and pathology following immunization with myelin oligodendrocyte glycoprotein compared with control WT mice. These findings suggest that modulation of Thy28 expression plays a crucial role in the determination of thymic cell fate, which may contribute to the development of EAE through proinflammatory cytokine production.

Search for nucleon decay via n→ν[over ¯]π0 and p→ν[over ¯]π+ in Super-Kamiokande

We present the results of searches for nucleon decay via n→ν[over ¯]π0 and p→ν[over ¯]π+ using data from a combined 172.8  kt·yr exposure of Super-Kamiokande-I,-II, and-III. We set lower limits on the partial lifetime for each of these modes: τn→ν[over ¯]π0>1.1×10(33) years and τp→ν[over ¯]π+>3.9×10(32) years at a 90% confidence level.

Search for dinucleon decay into kaons in Super-Kamiokande

A search for the dinucleon decay pp → K+ K+ has been performed using 91.6  kton·yr data from Super-Kamiokande-I. This decay provides a sensitive probe of the R-parity-violating parameter λ112''. A boosted decision tree analysis found no signal candidates in the data. The expected background was 0.28±0.19 atmospheric neutrino induced events and the estimated signal detection efficiency was 12.6%±3.2%. A lower limit of 1.7×10(32)  years has been placed on the partial lifetime of the decay O16 → C14K+ K+ at 90% C.L. A corresponding upper limit of 7.8×10(-9) has been placed on the parameter λ112''.

Evidence for the appearance of atmospheric tau neutrinos in super-Kamiokande

Super-Kamiokande atmospheric neutrino data were fit with an unbinned maximum likelihood method to search for the appearance of tau leptons resulting from the interactions of oscillation-generated tau neutrinos in the detector. Relative to the expectation of unity, the tau normalization is found to be 1.42 ± 0.35(stat)(-0.12)(+0.14)(syst) excluding the no-tau-appearance hypothesis, for which the normalization would be zero, at the 3.8σ level. We estimate that 180.1 ± 44.3(stat)(-15.2)(+17.8) (syst) tau leptons were produced in the 22.5 kton fiducial volume of the detector by tau neutrinos during the 2806 day running period. In future analyses, this large sample of selected tau events will allow the study of charged current tau neutrino interaction physics with oscillation produced tau neutrinos.

Search for differences in oscillation parameters for atmospheric neutrinos and antineutrinos at Super-Kamiokande

We present a search for differences in the oscillations of antineutrinos and neutrinos in the Super-Kamiokande-I, -II, and -III atmospheric neutrino sample. Under a two-flavor disappearance model with separate mixing parameters between neutrinos and antineutrinos, we find no evidence for a difference in oscillation parameters. Best-fit antineutrino mixing is found to be at (Δm2,sin2 2θ)=(2.0×10(-3)  eV2, 1.0) and is consistent with the overall Super-K measurement.

Anti-IgM-induced down-regulation of nuclear Thy28 protein expression in Ramos B lymphoma cells

We recently cloned mouse Thy28 cDNA (mThy28), which is highly conserved among vertebrates and plants. The mThy28 mRNA is highly expressed in testis, liver, kidney, brain, with moderate expression in thymus, spleen, and heart. In the present study, characteristics of mouse Thy28 protein expression were examined using rabbit anti-mThy28 polyclonal antibody (Ab). Levels of mThy28 protein expression were highest in testis, with moderate expression in liver, spleen, and thymus. The Thy28 protein was mainly located in the nucleus, which was revealed by immunofluorescence microscopy and Western blotting using anti-mThy28 Ab, and transient expression of the mThy28/EGFP fusion gene. Engagement of membrane immunoglobulin with anti-IgM induced down-regulation of human Thy28 expression at both mRNA and protein levels, accompanied by induction of apoptosis in Ramos B lymphoma cells. Expression of protein and mRNA and induction of apoptosis were evaluated by flow cytometry/Western blotting, reverse transcription-polymerase chain reaction, and propidium iodide staining, respectively. Anti-IgM also down-regulated the promoter activity of the mThy28 gene, as demonstrated by luciferase assay. Thus, the anti-IgM-induced down-regulation of the nuclear Thy28 expression appears to correlate with the induction of apoptosis in Ramos B lymphoma cells.

Etoposide-mediated sensitization of squamous cell carcinoma cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced loss in mitochondrial membrane potential

Squamous cell carcinoma (SCC) cell lines (MIT7-x(L), MIT8, and MIT16) that overexpress Bcl-x(L) have been demonstrated to show resistance to multiple chemotherapeutic drugs. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), which belongs to the TNF family of proteins, induces apoptosis in tumor, but not in normal, cells. In the present study, we examined whether etoposide sensitizes tumor cells with multiple-drug-resistance to TRAIL-induced apoptosis. Sequential treatment with etoposide and TRAIL resulted in a synergistically induced cell death in the two resistant lines (MIT7-x(L) and MIT16) but not MIT8, as assessed by WST-8 assay. As expected, MIT7 cells (a drug-sensitive line) were sensitive to the combined treatment. The cell death caused by both etoposide and TRAIL appears to involve apoptosis, since the combined treatment caused a loss in mitochondrial membrane potential (DeltaPsim), which is closely associated with apoptosis induction. The density of the TRAIL-receptors (TRAIL-Rs) was not appreciably modulated by the etoposide treatment, suggesting that etoposide targets molecule(s) downstream of the TRAIL-Rs. Regardless of the molecular mechanisms underlying the cell death, sequential treatment with etoposide and TRAIL could be useful in the design of treatment modalities for patients with SCC, especially those with elevated levels of Bcl-x(L).

Bcl-x(L) confers multi-drug resistance in several squamous cell carcinoma cell lines

Carboplatin (CBDCA) alone or in combination with irradiation and other chemotherapeutic agents has been used for the treatment of oral squamous carcinoma. However, there are some limitations for such therapy because of inherent or acquired resistance to CBDCA. To gain some insights into the association of CBDCA resistance with Bcl-2 family level or p53 status, we established eight carcinoma cell lines, consisting of two resistant (MIT8, MIT16), two sensitive (MIT6, MIT7), and four intermediate lines. All of the five cell lines with p53 mutation belonged to the resistant approximately intermediate group, whereas two of three other lines with wild-type p53 were in the sensitive group. Interestingly, both of the two resistant cell lines showed elevated levels of Bcl-x(L), almost double that of sensitive line (MIL5), whereas either Bcl-2 or Bax-alpha level did not correlate with the CBDCA-resistance. To further verify the association between the Bcl-x(L) level and the drug resistance, two transformants (x(L)-3, x(L)-6) overexpressing Bcl-x(L) in the CBDCA-sensitive cell line MIT7 were established using the gene transfer method. Both clones showed resistance to multiple chemotherapeutic agents, including CBDCA, actinomycin D, etoposide, and mitomycin C. Moreover, MIT8 and MT16 also displayed cross-resistance to these agents. These findings suggest that Bcl-x(L) may function as one of the key components conferring multiple drug-resistance in squamous cell carcinomas.

Changes in the constraints of semantic and syntactic congruity on memory across three age groups

20 college undergraduates, 25 sixth-grade, and 31 second-grade students studied targets embedded in three types of sentence contexts and then performed free recall and cued recall tests. Although there were no differences in performance of free recall among sentence types within each age group, the differences in cued recall among sentence types were observed. For sixth graders and undergraduates, both semantically congruous/syntactically congruous sentences and semantically incongruous/syntactically congruous sentences led to a better cued recall of targets than semantically incongruous/syntactically incongruous sentences. Second graders performed better in a cued recall of targets in semantically congruous/syntactically congruous sentences than for the other two sentence types. The results were interpreted as indicating changes across age groups in constraints of semantic and syntactic congruity on the spreading activation of targets in memory.

Prevention of anti-IgM-induced apoptosis accompanying G1 arrest in B lymphoma cells overexpressing dominant-negative mutant form of c-Jun N-terminal kinase 1

A family of mitogen-activated protein (MAP) kinases comprising the extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs), and p38 MAP kinases are involved in proliferation and apoptosis. However, there are some arguments concerning the role of these kinases in Ag-induced B cell apoptosis. Two of the B lymphoma cell lines (CH31 and WEHI-231) susceptible to anti-IgM-induced apoptosis were used as a model. To address these issues, we examined the kinetics of anti-IgM-induced activation of MAP kinases and established cell lines overexpressing a dominant-negative (dn) mutant form of JNK1 (dnJNK1). Anti-IgM induced a sustained JNK1 activation with a peak at 8 h, with a marginal activation of ERK1/ERK2 in CH31 cells. The sustained JNK1 activation was not a secondary event through a caspase activation. The peak point of the JNK1 activation was just before the onset of a decline in mitochondrial membrane potential, which preceded anti-IgM-induced cell death. Following anti-IgM stimulation, dnJNK1 prevented a decline in mitochondrial membrane potential at 24 h, with a prolonged inhibition up to 72 h in WEHI-231, although it did so only partially during a later time period in CH31. The dnJNK1 cells also demonstrated diminished procaspase-3 activation and a decreased rate of apoptosis upon anti-IgM stimulation, with a concomitant increased arrest in G(1) phase, which could be explained by enhanced levels of cyclin-dependent kinase inhibitor p27(Kip1) protein. Thus, anti-IgM-induced JNK activation might be implicated in cell cycle progression as well as in apoptosis regulation, probably involving p27(Kip1) protein.

Changes in the semantic constraint of spreading activation of memory across three age groups

28 undergraduate, 34 sixth-grade, and 36 second-grade students studied target words embedded in interchangeable or noninterchangeable sentences, and then performed free recall tests. In an interchangeable sentence the word which was to be remembered and its associated word fitted sensibly, whereas in a noninterchangeable sentence the target word fitted sensibly but its word associate did not. Undergraduates recalled the target words in noninterchangeable sentences better than sixth or second graders for whom a difference was not observed (undergraduates > sixth graders = second graders). In interchangeable sentences undergraduates recalled more targets than sixth or second graders, and sixth graders recalled more than second graders (undergraduates > sixth graders > second graders). The results were interpreted as indicating changes across age groups in the semantic constraint of spreading activation of target words in memory.

The self-choice elaboration effects on incidental memory of Japanese historical facts

The subjects performed an orienting task involving 3 conditions, followed by unexpected tests which included free recall, name-matching and name-selec tion. Conditions were designed to force self-generated elaboration, self-choice elaboration, and experimenter-provided elaboration. In the self-generated elaboration condition, subjects were presented target sentences, e.g., Nobunaga ODA burned down ENRYAKUJI Temple, and asked to answer an elaborative interrogation, e.g., Why did Nobunaga ODA burn down ENRYAKUJI Temple? about each sentence. In the self-choice elaboration condition, subjects selected one of the alternative answers to an elaborative interrogation about each sentence. In the experimenter provided elaboration condition, subjects were presented an answer which they rated for congruity as the correct answer to the elaborative interrogation. In the free recall test, self generated elaboration led to better performance than the other two conditions for which no difference was observed. However, in the name-matching and name-selection tests, scores were better for self choice elaboration and self-generated elaboration than for experimenter-provided elaboration. These results were interpreted as demonstrating that self choice elaboration, in addition to self-generated elaboration, led to effective encoding in memory.

Histamine H1 receptor binding capacities in the amygdalas of the amygdaloid kindled rat

The histamine H1 receptor binding capacity of the amygdalas of amygdaloid kindled rats was studied. In the kindled nonstimulated amygdala, significant decreases in K(D) and B(max) values compared with those of control amygdala were found 1 week after the last kindled seizure. One month after the last kindled seizure, the decreased K(D) value was sustained in the kindled nonstimulated amygdala. This decreased Bmax value 1 week after the last kindled seizure in nonstimulated amygdala may partly and transiently contribute to kindled seizure susceptibility. The decreased K(D) value in nonstimulated amygdala observed until 1 month after the last kindled seizure indicates the long-lasting increment of binding affinity of the pyrilamine binding site of the histamine H1 receptor in the steady state of kindled seizure susceptibility.

Effects of the acute and chronic restraint stresses on the central histaminergic neuron system of Fischer rat

The effects of acute and chronic restraint stresses on the brain histamine level and histamine N-methyltransferase activity in Fischer rat brain were studied. The acute restraint stress increased the histamine levels in the diencephalon and nucleus accumbens, and increased the histamine N-methyltransferase activities in the nucleus accumbens and striatum. The chronic restraint stress also increased histamine N-methyltransferase activities in the nucleus accumbens and striatum. These results indicate that the acute and chronic restraint stresses increase the brain histamine turnover, which may partly relate to the vulnerability for stress-induced anxiety and depression.

Ramp-rate dependent external work during ramp-load release in cardiac muscle

When the load of frog cardiac muscle was decreased linearly from the maximum force to the resting force (ramp-load release), the muscle shortened with various velocities calculated from the instantaneous lengths, which showed the instantaneous force-velocity relationship. These velocities increased with the increase of the ramp rate. To study these dependency of ramp rate, the parameters obtained from Huxley model in 1957 during quick load-release were fixed throughout the calculations, but even if the shortening of the series elastic component (SEC) was taken into account, the model did not seem to explain these velocities. If the ramp rate was reduced, velocities were more decreased as expected, especially at smaller load, which suggested that the cross-bridges should bear some extra load. Thus the internal load was added in calculation. The velocities in the modified model well explained those measured even the ramp rate varied widely, especially in higher force. At lower force, the calculated velocities increased rapidly than those measured, mainly due to the shortening of SEC which were calculated from the initial shortening of quick release. On the force-sarcomere length plane, the calculated sum-force (internal-plus external-load) was almost linearly decreased versus length with the initial slope of 2.66 (mean). Adding the original dependency (= 1), the value of 3.66 was similar to 3.5 in skeletal muscle. The external work during the ramp-load release was also calculated and decreased with the increase of ramp rate, and showed the peak or plateau, which suggested the existence of optimal work.

Decreased central histamine in the amygdaloid kindling rats

This study was conducted to elucidate the role of central histamine (HA) in seizure susceptibility. We stimulated the left amygdala of rats to produce amygdaloid kindling. We sacrificed rats 1 h, 1 week and 1 month after the last kindled seizure, and measured the histamine contents and the histidine decarboxylase (HDC) activities of various brain regions. One hour after the last kindled seizure, we found significant decreases in HA levels in the bilateral amygdala, hippocampus and diencephalon in the kindled group. The HDC activities of the bilateral amygdala and diencephalon were lower in the kindled group than in the control group. One week after the last kindled seizure, we also found a significant decrease in the HA level in the bilateral amygdala. No significant change was found in HA content or HDC activity 1 month after the last kindled seizure. These results suggest that kindling suppresses HA synthesis and that the reduced HA content is maintained until 1 week after the last kindled seizure. The reduced HA may play a role in the acquired kindled seizure susceptibility.

[Effect of information generation on incidental memory of words]

The present study was carried out to investigate the effect of information generation on incidental memory of words. Subjects in the subject-generated group were asked to generate a converging associate of three targets in each triplet. Subjects in the experimenter-provided group were asked to rate the relation between targets and a paired-presented word on 5-point scale. Each subject in both groups were given an unexpected free recall test. Recall performance for targets in each unrelated triplet in the subject-generated group was higher than in the experimenter-provided one. Conditional probability of recalling targets given relational information was an index of effectiveness of within-item elaboration. This index was higher in the subject-generated group. These results were interpreted as showing that the effect of information generation was caused by the effectiveness of within-item elaboration.

The staircase phenomenon and the strength-interval relationship of contractions in cultured cells of chicken embryonic ventricles

The staircase phenomenon and the relationship between contraction strength and stimulation interval were investigated in single or aggregated cells cultured from 5-, 12-, and 19-d-old chicken embryonic ventricles. Within 24 h after start of cultivation was begun, the cells were separated and spontaneously inactive. However, they contracted when electrical stimulation was applied. The modes of a staircase phenomenon and a strength-interval relationship varied, depending on a few conditions such as the ages of the embryos, the presence of spontaneous activities and the composition of the bathing solution. The 19-d-old cells, which formed an aggregate and exhibited spontaneous activities, showed a negative staircase phenomenon and the negative strength-interval relationship when they were bathed in a culture medium containing bovine serum. The 12-d-old cells demonstrated a less distinct staircase and a flat strength-interval relationship. Both 19- and 12-d-old cells showed a positive relationship, if they were cultured for less than 48 h and were spontaneously inactive, or if they were bathed in Tyrode solution during the experiments. The 5-d-old cells showed the positive staircase whether they were spontaneously active or not. The developmental change in the interval-dependency of contraction can be explained by the functions of the sarcoplasmic reticulum (SR), although Ca2+ current and the Na(+)-Ca2+ exchange mechanism should be involved. The function of the SR develops progressively during the embryonic stage and plays an important role in regulation of the contraction-relaxation cycle at the late stage before hatching.

[Effects of between-item elaboration on incidental memory]

The present study was carried out to investigate the effect of between-item elaboration on incidental memory of words. Between-item elaboration refers to the encoding of relational information to each target item. Forty-four college students were asked to generate free associates to each target in the orienting task which was followed by unexpected recognition and recall tests. Triplets of targets which was known to elicit a converging associate were used. Targets of such a triplet were presented in massed or spaced fashion. Frequency of converging associates generated in the orienting task (free association) was used as an index of between-item elaboration. The proportion of targets correctly recalled for which the converging associates were generated was higher than that of the opposite cases. The above result suggested that the between-item elaboration was effective in retrieval of targets. No effect of types of presentation on free recall performance was observed.

Substrate Specificity of Tea Leaf Hydroperoxide Lyase

Substrate specificity of tea leaf fatty acid hydroperoxide lyase was systematically investigated using an entire series of ω 6-(5)-hydroperoxy-C14-C24 dienoic and trienoic acids as substrates. Unexpectedly, the hydroperoxides of C22 but not natural substrates, i.e., those of C18, showed the highest reactivities for the lyase. The reactivities of the hydroperoxides of trienoic acids were always four to ten times higher than those of the dienoic acids.

Comparison of the Substrate Specificities of Lipoxygenases Purified from Soybean Seed, Wheat Seed, and Cucumber Cotyledons

Lipoxygenases were highly purified from soybean seed, wheat seed and cucumber cotyledons. Substrate specificities of these lipoxygenases were studied by using an entire series of (ω6Z ,ω9Z )-C13~C24-dienoic acids as synthetic substrate analogues. Soybean lipoxygenase-1 and cucumber lipoxygenase showed broad specificities for these substrates while wheat lipoxygenase showed narrow specificities. Position of dioxygenation to each substrate was analyzed by high performance liquid chromatography. With soybean lipoxygenase-1 elongation of the distance between the terminal carboxyl group and the site of hydrogen removal in a substrate decreased the positional specificity of dioxygenation, while, with cucumber lipoxygenase, shortening the distance decreased the specificity. It was suggested that cucumber lipoxygenase and soybean lipoxygenase-1 recognized the terminal carboxyl group of a substrate to arrange it only in one orientation at the reaction center. In case of wheat lipoxygenase, recognition of the carboxyl group was thought to have crucial and essential role to secure the activity.

[A case report of anterior crowding treated without extraction]

In orthodontic diagnosis, one of the most important factors is to decide whether or not to extract permanent teeth. There are many so-called borderline cases. In analyzing and determining whether or not to extract, discrepancy, profile, growth, and the patient's understanding and cooperation must be considered. We treated a borderline case without extraction, and established good occlusion and profile. Soft tissue changes are chiefly discussed.

[Case of bimaxillary protrusion and lip evaluation on cephalogram]

One of the goals of orthodontic treatment is to obtain the best balance and harmony of facial lines, especially it is important to retract the lip in bimaxillary case. A 12-year and 4-month-old boy was first seen with the chief complaint of excessive lips protrusion. We treated him by the edgewise method for 34 months, and evaluated the change of facial profile. Excessive lip protrusion was eliminated, and arch leveled. Overjet and overbite were reduced. Mandibular growth increased the prominence of the chin, and reduce the protrusion of the lower lip.

[Effects of types of sentence frame on elaboration in memory]

Two experiments were carried out to investigate the effects of types of sentence frame on elaboration in incidental memory. Subjects were asked to rate whether the target word would fit into sentence frame with five point scales followed by an unexpected free recall test. In Experiment I, three types of sentence frame (CA, CN and II) were used. The target words fitted into CA and CN sentence frames, but did not into II ones. In a CA sentence frame, two associates of the target word were involved, whereas in a CN one were not. CA and CN sentence frames led to a better recall than II ones, but the difference between the former two sentence frames was not observed. In Experiment II, three types of sentence frames were used: Semantic and Syntactic Congruous (CC) Semantic Incongruous and Syntactic Congruous (CI) and Semantic and Syntactic Incongruous (II). CC and CI sentence frames led to a better recall than II, but the difference between the former two sentence frames was not observed.

Differentiation of inotropic action from chronotropic action of sympathetic agents in cultured cells of chick embryonic ventricles

The rate of the spontaneous activity of cultured cells from the chick embryonic ventricle was only slightly increased by norepinephrine (NE) or epinephrine (EP), even if it was applied close to the cell. On the other hand, the amplitude of contraction, measured from the shortening of the diameter of the cell aggregate, was clearly augmented by up to 50%. Intracellularly injected cAMP also potentiated contraction. Namely, NE, EP, or cAMP showed positive inotropic action but slight chronotropic action on cultured ventricle cells. NE produced an increase in the action potential amplitude, shortening of action potential, and slight hyperpolarization in 17- to 19-day-old but not in 7- to 9-day-old embryo. If NE was applied to the cells whose plateau potential was inhibited by the previous treatment with nifedipine, NE recovered the plateau level to the control. Iontophoretically injected cAMP also recovered the plateau level once it had been inhibited by nifedipine or verapamil. In some cells, the membrane was transiently depolarized after the end of injection and turned back to the control level. This transient depolarization took place spontaneously again. It was suggested that the Ca2+-induced Ca2+ release mechanism from the sarcoplasmic reticulum was involved in the cyclic depolarization.

Relationship between contraction strength and stimulation frequency in cultured chick embryonic heart cells

Membrane potential and contraction were investigated in cultured chick embryonic heart cell aggregate. The cells were stimulated through the intracellular microelectrode, and the contraction of the cell aggregate was measured from the shortening of the diameter. The contraction decreased if the stimulation frequency was raised in the range between 20/min and 100/min; namely, the negative relationship between contraction strength and stimulation frequency. The peak action potential or plateau duration was not affected by the change in the stimulation frequencies unless they exceeded 60/min, but they were shortened at frequencies higher than 75/min. In the latter case, the decrease of contraction strength was related to the shortening of plateau duration. If the stimulation frequency was lowered suddenly, the following contraction was transiently increased without any noticeable change in the shape of the action potential. When TTX was added (3-10 x 10(-6) M), the rate of the spontaneous activity was reduced, which made it possible to study the contraction strength at low stimulation frequencies. In TTX medium, similar to the observations in the control medium, the relationship between contraction strength and stimulation frequency was also negative. In the medium containing TTX plus verapamil (5-9 x 10(-7) M), the peak action potential was inhibited during the repetitive stimulation dependently on the stimulation frequency, accompanied by the concomitant decrease of contraction strength. These results suggest that the negative inotropic effect of the stimulation frequency is caused in part by the change in Ca2+ inflow.

[Developmental changes in attributes of memory in children]

The present study investigated the developmental changes in dominance of memory attributes between second and sixth graders. Subjects studied a familiar word list followed by a recognition test; dominance was inferred from the types of false recognition error (semantic and acoustic) on the test. The results showed dominance of the semantic attribute for sixth graders, but no difference of dominance level between the semantic and the acoustic attribute for second graders. The evidence also indicated no effect of the stimulus mode on dominance of memory attributes for both graders.