Practice and serial reaction time of adolescents with autism

This study examined effects of practice on timing of serial reactions by 7 adolescents diagnosed with autism by using a task requiring they track a series of timed lights. The adolescents showed significantly slower and more variable mean simple reaction time than 10 normal control subjects of the same age. On a task of tracking a serial light stimulation for 4 days, on the other hand, significant effects of practice on timing of serial reactions were observed for mean serial reaction times of them. In addition, from individual variations in reaction times and anticipatory reaction times, four of seven subjects with autism showed significant effects of practice. Analysis suggested that these autistic adolescents may be chunking together the whole series of responses and are unable to coordinate the timing of individual responses with individual stimuli. Our data indicate that at least some adolescents with autism are able to form and utilise a motor program with practice.

Simple reaction times and timing of serial reactions of middle-aged and old men

The timing control of serial reactions in 20 middle-aged (38-43 years) and 20 older men (57-63 years) was examined by using a task of tracking serial-light stimuli with and without the previous learning (Exps. III and II, respectively). In Exp. I, a control group of 20 college students (19-22 years) had significantly faster and less variable mean simple reaction times than the two other groups. For the serial reaction times (Exps. II and III), the control group had significantly faster mean reaction times than the other groups who did not differ. In Exp. III, there was no difference between the serial reaction times and the simple reaction times in the contrasting groups. In Exp. II, however, although the serial reaction times were significantly slower than the simple reaction times in the older group, the serial reaction times did not differ from the simple reaction times in the middle-aged group. The difference between these groups appeared to be due to the task in Exp. II being more difficult than that in Exp. III, suggesting the more complex the movement to be made, the slower the responses of older people. Advancing age seems to have a greater effect on central processing components than on the perceptual and motor output components of serial reactions.

Transfer to changed serial position in a task of tracking a sequence of light stimuli

This study examined transfer when different serial positions are changed in a task of tracking a sequence of light stimuli. Thirty subjects were divided into three groups, and all tracked a serial pattern of six movements for 20 acquisition trials. Then, on 20 more transfer trials, the last two movements were reversed for Group I, the second two movements reversed for Group II, and the first two movements reversed for the Group III. Performance during the transfer trials improved over performance during the acquisition trials for Groups I and II but not Group III. Thus, there appeared to be positive transfer when the last and middle parts of the serial pattern were changed. However, there was no positive transfer when the first part of the serial pattern was changed. This indicated a contextual interference effect dependent upon serial position in the performance of a serial tracking task.

Analysis of CA repeats in first intron of class I ADH gene in Long-Evans Cinnamon rats developing fatal intoxication after ethanol intake

The Long-Evans Cinnamon (LEC) rat is a mutant strain established from Long-Evans rats that displays spontaneous hepatitis and liver cancer. We previously demonstrated that LEC rats died of acute ethanol intoxication after being fed a liquid diet containing 5% ethanol. Furthermore, we found that both alcohol dehydrogenase (ADH) and aldehyde dehydrogenase activities were remarkably suppressed in the liver of LEC rat, compared with Wistar rats. In the present study, we further investigated ethanol metabolism in the non-ADH pathway and what caused the decrease of liver ADH activity in LEC rats. Blood ethanol concentration 5 hr after intraperitoneal administration of ethanol in LEC rats was higher than in the Wistar rats, indicating that ethanol oxidation was impaired in LEC rats. The expression of liver cytochrome P-450IIE1 in the LEC rat was as much as that in Wistar rats. Regarding decreased ADH activity in the liver of LEC rats, we examined an alternating purine-pyrimidine (CA) repeat-length polymorphism in the first intron of a class I ADH gene that would play a role in altering ADH activity. A polymerase chain reaction method was used to amplify the CA repeat in the first intron of this class I ADH gene, a nine CA repeat insertion and a point mutation were detected in LEC rats. These results suggest that this alternating sequence would modify transcription of the class I ADH gene in LEC rats. Thus, LEC rats have abnormal ethanol metabolism in the ADH pathway.

Detection of activity in the conditioned medium of ethanol-treated HepG2 cells which stimulates collagen synthesis in IMR-90 cells

Hepatic fibrosis often occurs in alcoholic liver diseases without accompanying tissue necrosis or inflammation. However, the precise mechanism of this fibrosis has not been fully clarified. In the present study, using the hepatoblastoma cell line HepG2 as a model for hepatocytes, we identified a factor that stimulates collagen synthesis of fibroblasts in a conditioned medium of HepG2 cells after treatment with ethanol. Type 1 procollagen peptide (PIC) in a culture of human fibroblast IMR-90 markedly increased after incubation with the conditioned medium of ethanol-treated HepG2 cells. The stimulating activity on the production of PIC by IMR-90 remained after the dialysis and evaporation of the conditioned medium of HepG2 cells, indicating this factor was not as volatile from low molecular substances such as acetaldehyde, acetate, or lactate. The activity of this factor diminished with heat or trypsin treatment. A gel chromatographic analysis disclosed that the molecular weight of this factor was approximately 8000 Da. These results suggest that a polypeptide factor secreted from HepG2 cells by treatment with ethanol stimulates collagen synthesis of fibroblasts.

Simple reaction times and timing of serial reactions of adolescents with mental retardation, autism, and Down syndrome

The purpose of this study was to examine the serial information processing in adolescents with mental retardation, autism, and Down syndrome by using a serially patterned tracking task. Analyses indicated that 7 adolescents with mental retardation, 8 with autism, and 3 with Down syndrome had significantly slower and more variable simple reaction times than did 10 college students. Also, the autistic adolescents had significantly faster mean simple reaction time than those with Down syndrome. On a task of tracking serial light stimulation, mentally retarded adolescents had significantly faster reaction time than college students. The autistic subjects excessively had faster anticipatory reaction time than did the subjects in the other three groups. On the other hand, adolescents with Down syndrome had markedly slower and more variable reaction time than did adolescents with non-Down-syndrome mental retardation. As for motor organization of keystrokes on the tracking task, mentally retarded adolescents responded with six movements, in which these individuals pressed a series of keys 1, 2, 3, 4, 5, and 6, as a chunk, as exhibited by college students. Adolescents with autism and Down syndrome, however, did not produce this movement-output chunking.

[A case of eosinophilic pneumonia associated with Mycobacterium avium infection]

A 54 year-old woman was admitted with cough and high fever. Computed tomographic scan of the chest showed bilateral patchy infiltrates, predominantly in the upper lobes. Eosinophils in the bronchoalveolar lavage fluid (BALF) accounted for 19% of BALF cells. Furthermore, Mycobacterium avium was isolated from a bronchial washing from the upper area of the right lung (S3) and a sample of sputum which had been submitted for microbial examination about 1 month before admission by another clinic. Based on these finding's the diagnosis of eosinophilic pneumonia associated with Mycobacterium avium infection was established. The infiltrates of the lung rapidly decreased after administration of antituberculous agents. The simultaneous presentation of eosinophilic pneumonia and Mycobacterium avium infection has not been previously reported. Because of the efficacy of antituberculous agents in this case, we concluded that Mycobacterium avium was a cause of eosinophilic pneumonia.

Genetic variations in baseline and ultraviolet light-induced sister chromatid exchanges in peritoneal lymphocytes among different mouse strains

The variation in the induction of sister chromatid exchanges (SCEs) in the peritoneal lymphocytes of different mouse strains was investigated. For the baseline SCEs, BALB/c and outbred ICR showed the lowest frequency and DBA/2 and C57BL/6 the highest. BDF1 (C57BL/6 x DBA/2) was ranked among the highest, while CDF1 (BALB/c x DBA/2) was intermediate between the parental strains. Regarding UV-induced SCEs, BALB/c was less susceptible as compared to DBA/2 and C57BL/6. Both BDF1 and CDF1 showed values significantly higher than BALB/c, but not significantly different from DBA/2 or C57BL/6. ICR was ranked in the susceptible group. For the baseline SCEs of bone marrow cells, the overall ranking among strains was essentially the same as that for the baseline, but different from that for the UV-induced, SCEs in peritoneal lymphocytes. The present results can be explained by assuming that the major genetic factor contributing to the strain-dependent difference in the baseline SCEs is due to a codominant trait of a single allele, but that the UV-induced SCEs are complicated by other genetic factor(s).

Mouse strain differences in induction of micronuclei by base analogues and nucleosides

The frequency of induced micronucleated polychromatic erythrocytes (MNPCEs) was compared in BALB/c, C57BL/6, and DBA/2 mice after intraperitoneal (i.p.) injection of 5-bromodeoxyuridine (BUdR), 5-fluorodeoxyuridine (FUdR), cytosine arabinoside (Ara-C), 6-mercaptopurine (6-MP), 5-bromouracil (5-BU), thymidine (TdR), uridine (UdR), adenosine (AdR) and guanosine (GdR). The experimental procedure was a single i.p. injection followed by harvest at 30 h. The frequency of MNPCEs was significantly increased in all strains by treatment with BUdR, FUdR, Ara-C and 6-MP compared to vehicle control. TdR and UdR induced MNPCEs slightly in BALB/c mice but showed no effect on C57BL/6 and DBA/2 mice. 5-BU, AdR, and GdR did not increase the frequency of MNPCEs in any mouse strain used. These results suggest that BALB/c mice are more susceptible to induction of MNPCEs by clastogenic base analogues and nucleosides than are C57BL/6 or DBA/2 mice.

Acrylamide; induction of DNA damage, chromosomal aberrations and cell transformation without gene mutations

The genotoxic potential of acrylamide monomer (AA), a compound familiar as a raw material of polyacrylamide electrophoresis gel, was extensively investigated in vitro. The results were clear cut: AA did not induce any gene mutations in Salmonella/microsome test systems (TA98, TA100, TA1535, TA1537), Escherichia coli/microsome assay (WP2 uvrA-) up to a dose of 50 mg AA/plate, or in HPRT-locus in Chinese hamster V79H3 cells (AA, 1-7 mM, 24 h treatment). On the other hand, AA showed a strong positive response: (a) in a Bacillus subtilis spore-rec assay (DNA damage) at 10-50 mg/disc, (b) to a chromosomal structural change test (AA, 2-5 mM, 24 h treatment), (c) to a polyploidy test (AA, 1-5 mM, 24 h treatment) in Chinese hamster V79H3 cells, (d) to a cell transformation assay in mouse BALB/c3T3 cells (AA, 1-2 mM, 72 h treatment). Sister chromatid exchange was also weakly but significantly induced by AA (AA, 1-2.5 mM, 24 h treatment) in Chinese hamster V79H3 cells. Carcinogenic potential of AA was reported in mice and rats several years ago. AA thus seems to be a typical clastogenic rodent carcinogen without any gene mutation potential. Furthermore, this experiment showed for the first time positive response of AA to a microbial test system (B. subtilis spore-rec assay).

Abnormal ethanol metabolism in Long-Evans Cinnamon rats, a mutant strain developing spontaneous hepatoma

The Long-Evans Cinnamon (LEC) rat is a mutant strain established from Long-Evans rats. LEC rats display hereditary hepatitis and spontaneous hepatocellular carcinoma (HCC). We first tried to examine effects of ethanol consumption on the development of HCC, and fed a Lieber's liquid diet containing 5% ethanol to LEC rats. However the rats died within 2 weeks because of acute alcohol intoxication. In LEC rats, the concentration of ethanol and acetaldehyde in blood was significantly higher, and liver alcohol dehydrogenase activity was slightly lower and acetaldehyde dehydrogenase activities were remarkably suppressed compared to those of Wistar rats. These results suggest that LEC rats have hereditary deficiencies of ethanol and acetaldehyde metabolizing enzymes.

Inhibitory effects of antipromoters and radical scavengers on the promotion process in two-stage cell transformation

To find the mechanism of promotion process, we have investigated the antipromoting effects of radical scavengers and specific inhibitors for phospholipid metabolism and for protein kinase C using a two-stage transformation assay system in BALB/3T3 cells. All radical scavengers and inhibitors tested showed the antipromoting effects on 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted transformation. Diacylglycerols, activators of protein kinase C, showed promoting effects in vitro and the promoted-transformation by them was suppressed by radical scavengers employed. By an electron spin resonance (ESR) spin-trapping method, inhibitors, which suppressed promoted-transformation by TPA markedly, had .OH scavenging action. It was found using a ESR spin-trapping method that treatment of TPA on BALB/3T3 cells generates .OH in a dose-dependent manner. These results suggest that generation of oxygen radicals, especially .OH, which occurs in the processes of phospholipid metabolism as well as activation of protein kinase C, is essential to the promotion process.

Inhibitory effects of radical scavengers on diacylglycerol-promoted transformation in BALB/3T3 cells

To discover the relationship between the activation of protein kinase C and the generation of reactive oxygen in the tumor promotion process, we investigated the effects of radical scavengers on diacylglycerol-promoted transformation in BALB/3T3 cells. Superoxide dismutase (SOD) showed inhibitory effects on both 1-oleoyl-2-acetylglycerol (OAG)-promoted and diolein-promoted transformation. Catalase (CT) suppressed the promoting effects of diolein by up to 70%. Mannitol (MT), a hydroxyl radical (.OH) scavenger, inhibited diacylglycerol-promoted transformation dose-dependently. These results suggest that activation of protein kinase C alone is insufficient and that generation of reactive oxygen accompanied by activation of the enzyme is essential to the promotion process in BALB/3T3 cells.

A comparison of micronucleus induction in 3 mouse strains with representative clastogens

The frequency of micronucleated polychromatic erythrocytes (MNPCEs) was compared in BALB/c, C57BL/6 and DBA/2 mice after the intraperitoneal injection (i.p.) of methyl methanesulfonate (MMS), potassium chromate (K2CrO4), colchicine (COL), cycloheximide (CYH), 4-nitroquinoline-1-oxide (4-NQO) and 5-fluorouracil (5-FU). In BALB/c mice, the frequency of MNPCEs was significantly increased by all the chemicals tested, as compared to the vehicle control. In both C57BL/6 and DBA/2 mice, MMS, K2CrO4, COL and 4-NQO significantly increased MNPCEs, but CYH and 5-FU only slightly increased the MNPCEs in C57BL/6 and had no effect on DBA/2 mice. These results suggest that BALB/c mice are more sensitive to the induction of MNPCEs with a wider spectrum of chemicals than C57BL/6 or DBA/2 mice.

Effects of activators and inhibitors of protein kinase C on two-stage transformation in BALB/3T3 cells

To determine the relationship between protein kinase C and the promotion of carcinogenesis, we investigated the effects of activators and inhibitors of protein kinase C on two-stage transformation in BALB/3T3 cells. Diacylglycerols, which are activators, and specific inhibitors, such as palmitoyl-DL-carnitine chloride (PC), 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), and staurosporine (ST) were used. Treatment with diacylglycerols enhanced focus formation in 3-methylcholanthrene (3-MC)-initiated cells, but not as much as 12-O-tetradecanoylphorbol-13-acetate (TPA). PC and H-7 inhibited TPA-enhanced transformation by 76 and 79%, respectively. ST, the most potent inhibitor of protein kinase C, had a low inhibitory effect on transformation at non-toxic doses (33% inhibition). The results suggest that protein kinase C may play an important role in the process by which transformation is promoted in BALB/3T3 cells.

Inhibition of 12-O-tetradecanoylphorbol-13-acetate-enhanced transformation in vitro by inhibitors of phospholipid metabolism

The effects of some inhibitors of phospholipid metabolism were studied using a two-stage transformation assay system in vitro with 3-methylcholanthrene (3-MC) initiation and 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion in BALB/3T3 cells. Inhibitors of phospholipid metabolism such as hydrocortisone (HC), p-bromophenacyl bromide (BPB), nordihydroguaiaretic acid (NDGA), quercetin and indomethacin (IM) were used. They were demonstrated to inhibit strongly TPA-promoted transformation. In particular, HC at 1 microgram/ml inhibited the in vitro transformation completely. All the inhibitors used inhibited transformation in a dose-dependent manner. The results suggest that phospholipid metabolism is important for the promotion stage of transformation in BALB/3T3 cells.

[Olivocerebellar, corticonuclear and nucleocortical projections in the "four limbs area" of the paramedian lobule in the cat: a combined electrophysiological and HRP study]

The present study examined the olivocerebellar, corticonuclear and nucleocortical projections in the medial and lateral parts of the "four limbs area" of the paramedian lobule in the cat. Each part of the area could be identified electrophysiologically on the basis of their climbing fiber input. A small volume of 20% horseradish peroxidase (HRP) was injected iontophoretically into the center of an identified area. Results obtained are as follows: 1) Labeled cells were found in the rostral one-third of the medial accessory olive (MAO) of the inferior olive following injections of HRP in the four limbs area of the paramedian lobule. 2) The central MAO projects to the medial and lateral parts of the four limbs area in the caudal folium of the rostral part of the paramedian lobule. 3) The lateral and central MAO project to the medial part of the four limbs area in the intermediate part of the paramedian lobule, and the medial and central MAO project to the lateral part of the four limbs area in the intermediate part of the paramedian lobule. 4) The posteromedial three-fifths of the ipsilateral nucleus interpositus posterior (NIP) receive the corticonuclear projections from the four limbs area. 5) The medial two-fifths of the ipsilateral NIP project to the four limbs area. No strict point-to-point reciprocal relationship was found between corticonuclear and nucleocortical projections.

DNA damage induced in mouse peritoneal exudate cells after in vivo administration of chemical and physical agents as determined by alkaline elution

The alkaline elution technique for detecting DNA strand breaks has been applied to the study of DNA damage in mouse peritoneal exudate cells resulting from the in vivo administration of chemical and physical agents. The direct methylating agents methyl methanesulphonate and N-methyl-N-nitrosourea induced extensive breakage in samples taken 2 h after administration. The direct ethylating agents ethyl methanesulphonate and N-ethyl-N-nitrosourea also induced DNA strand breaks, but to a lesser extent than the methylating agents. The indirect methylating agent dimethylnitrosamine showed hardly any effect in this system. A weak but positive response was observed upon treatment with the anti-neoplastic alkylating agent procarbazine hydrochloride. The whole-body irradiation of mice with 60Co gamma-rays also induced DNA strand breaks. The elution profiles for gamma-ray irradiation were different from those of alkylating agents, and indicate that alkylating agents produce many more secondary lesions leading to DNA strand breaks than gamma-rays. N-methyl-N-nitrosourea produced slightly more DNA strand breaks in mutagen-sensitive mice, which are derived from the CD-1 strain, than in ICR mice.

A comparison of intraperitoneal injection and oral gavage in the micronucleus test with mitomycin C in mice

Intraperitoneal (i.p.) injection and oral (p.o.) gavage were evaluated in the mouse micronucleus test with mitomycin C (MMC). The tests were carried out in 2 laboratories with the MS/Ae and CD-1 mouse strains. On the basis of a small-scale acute toxicity study and a pilot experiment, the full-scale micronucleus test was performed with a 24-h sampling time at doses of 1, 2, 4, and 8 mg/kg for both treatment routes. In both strains, a clear positive dose-response relation was shown by both routes. Although the frequency of micronucleated polychromatic erythrocytes (MNPCEs) was higher with i.p. on a mg/kg basis, this tendency was reversed when dose was expressed as a percentage of the LD50.

Effects of diesel exhaust particles on chromosome aberration, sister chromatid exchange and morphological transformation in cultured mammalian cells

The ability of diesel exhaust particles (diesel tar) from light-duty (LD) and heavy-duty (HD) engines to induce chromosome aberrations, sister chromatid exchanges (SCEs) and morphological transformations is examined. Chinese hamster V79 cells were treated with LD and HD diesel tar for 3 h in order to analyze chromosome aberrations and SCEs. BALB/c 3T3 cells were used for the morphological transformation test. LD tar induced significant numbers of chromosome aberrations, whereas HD did not. Both LD and HD samples increased the number of SCEs in a dose-dependent fashion, with LD being more potent. In the transformation test, LD tar also induced a significant number of Type III foci, while HD was only weakly active. The transformed cells isolated from these Type III foci produced tumors when injected into nude mice. These results show that LD possesses clear clastogenic and transforming capabilities but that HD is weaker in this regard.

Mouse strain differences in the induction of micronuclei by polycyclic aromatic hydrocarbons

The frequency of micronucleated erythrocytes (MNE) in 3 inbred mouse strains and 2 of their hybrids (C57BL/6, BALB/c, DBA/2, BDF1 and CDF1) were examined after polycyclic aromatic hydrocarbons (PAHs; 7,12-dimethylbenz[a]anthracene (DMBA), 3-methylcholanthrene (3-MC), benzo[a]pyrene (BaP), benzo[e]pyrene (BeP) and anthracene (ANT] were injected i.p. PAHs are thought to form active metabolites after being administered to mammals. In mouse strains with inducible PAH activating enzymes, such as C57BL/6 or BALB/c, MNE were significantly induced, as compared to control mice, 48 h after DMBA, BaP, or 3-MC was injected. No increase in the frequency of MNE occurred in the DBA/2 strain which cannot induce the activating enzymes. BeP and ANT did not increase the frequency of MNE in any mouse used. The levels of MNE induction in BDF1 or CDF1 hybrids were similar to those in C57BL/6 or BALB/c. These results support the view that the genetic capacity to metabolize PAHs is strongly associated with micronucleus induction as in the case of PAH carcinogenesis.

Inhibition of 12-O-tetradecanoylphorbol-13-acetate-enhanced transformation in vitro by radical scavengers

The inhibitory effects of some scavengers of oxygen radicals were studied, using a two-stage transformation assay system in vitro 3-methylcholanthrene (3-MC)-initiation and 12-O-tetradecanoylphorbol-13-acetate-(TPA)-promotion in Balb 3T3 cells. Mannitol, a scavenger for hydroxyl radicals, strongly inhibited the TPA-enhanced transformation in a dose-dependent manner. Superoxide dismutase (SOD) and catalase, which are specific scavengers for O2-. and H2O2, respectively, also inhibited the transformation. These results suggest that oxygen radicals may play an important role in the TPA-enhanced transformation in Balb 3T3 cells.