M100907 and clozapine, but not haloperidol or raclopride, prevent phencyclidine-induced blockade of NMDA responses in pyramidal neurons of the rat medial prefrontal cortical slice

Antiserum to leucokinin I, a neuropeptide originally isolated from the cockroach Leucophaea maderae, was used for immunocytochemical labeling of neurons in the brain and ventral ganglia of the moth Spodoptera litura during postembryonic development. In the ventral ganglia, leucokinin-like immunoreactivity begins to occur in the abdominal ganglion A3 to A7 of first instar larva. One to two weakly labeled pairs of bilateral LK-LI cell bodies are located in the subesophageal ganglion of fourth to sixth instar larvae and in the abdominal ganglia A1 to A7 of second to sixth instar larvae. The abdominal ganglion A1 of fourth to sixth instar larvae and A8 of sixth instar larva each contain one weakly labeled pair of median LK-LI cell bodies. Two strongly labeled pairs of bilateral LK-LI neurons are found in A3 to A7 of third to sixth instar larvae. Abdominal ganglia A1 to A8 of prepupa, pupa and adult contain one to three weakly labeled pairs of bilateral LK-LI neurons. Two strongly labeled pairs of bilateral LK-LI neurons in each of the abdominal ganglia of larva, prepupa, pupa and adult send axons to the neuropil, and then each axon bifurcates into two axonal branches. Theses axonal branches from two bundles. From each of the two pairs of neurons an axon exits through the posterior ventral nerve (N2) which runs to the transverse nerve of the next posterior segment. In larval brains, 2-16 pairs of bilateral LK-LI cell bodies can be found together with LK-LI processes in the central neuropil. The larval brains show large changes in the number of LK-LI neurons throughout postembryonic development. The number of LK-LI cell bodies are reduced in number from sixth instar larval brain. Therefore, prepupal, pupal and adult brains contain a smaller number of LK-LI cell bodies. Two pairs of LK-LI median neurosecretory cells located immediately beside the pars intercerebralis in larval brains increase to three pairs in the 7-day-old pupal brain. In the adult, however, LK-LI median neurosecretory cells decrease to one pair.     

Exaggerated precocious centromere separation in cells of a human breast cancer line treated with a green tea extract

In a breast cancer cell line, MDA-MB-468, established in our laboratory, an average of 3% of the mitotic cells exhibited a phenomenon known as centromere splaying, which is a characteristic feature of cells of patients with Roberts syndrome. However, centromere splaying in cells of Roberts syndrome patients is limited to i) the centromere region and ii) chromosomes with large amounts of heterochromatin. When the breast cancer cells were treated with an extract of green tea GTE-TP91, up to 45% of the metaphases were observed to exhibit this behavior; and the precocious centromere separation was highly exaggerated, affecting all chromosomes in such metaphases. Apparently, as the sister centromeres continued to pull apart, they carried the chromatids with them, except for the telomere regions, giving a ring-like configuration. Eventually, the sister chromatids became completely separated. Whether this bizarre phenomenon was induced by the polyphenols contained in this green tea extract GTE-TP91 is not known, but this phenomenon, upon further investigation, may throw some light on chromosomal proteins, centromere behavior, telomere behavior and related questions.     

Developmental changes in the precedence effect: estimates of minimum audible angle

The precedence effect refers to an auditory phenomenon which occurs when two similar sounds are presented from different locations with a brief delay, and only one sound is heard whose perceived location is dominated by the first source. Although the lagging source si not localized as an independent event, under some conditions, adults are able to extract its directional cues. Developmental studies suggest that this ability changes during the development. However, those studies have used stimulus configurations which minimize the measurement of that ability. In the present study adults were first tested under several conditions, and the one which produced optimal performance was chosen for testing children. Using the minimum audible angle (MAA) task in the azimuthal plane, performance was compared for a single-source condition and two precedence conditions: in lag discrimination the lagging source changed location while the lead remained at midline, and in lead discrimination the reverse occurred. Subjects were 18 months old, 5 years old, and adult. Significant improvements in MAA occurred with an increase in age, especially in the precedence conditions. Within each group, performance was significantly better in single-source condition, followed by the lead and the lag discrimination.     

Nonlinear stress analysis for thin spherical vessels with local non-axisymmetric imperfections

On a thin spherical shell with a local and non-axisymmetric imperfection, the magnitude of the strain concentration occurring around the imperfect region was investigated by means of a finite element method, and the quantitative determination method of it was theoretically studied. In a stress analysis of the thin shell structures, a large deformation analysis considering geometrical nonlinearity of the imperfect regions was practically necessary and important, as reported previously in detail (Ohtani et al., Int. J. Pres. Ves. & Piping, 45 (1991) 3–21). As a result of this analysis, it was seen that the imperfection induced a considerably high strain concentration, even if the amplitude of imperfection was very small, and that a tendency of strain concentration due to loading of internal pressure apparently showed a nonlinearity to the pressure. Furthermore, from a comparison of the present results for the local non-axisymmetric imperfection with the previous ones for the banded axisymmetric imperfection, which deformed uniformly on circumferential direction, it was found that a tendency of strain concentration due to this kind of local imperfection was basically similar to that of the uniform axisymmetric one. Therefore, it was clarified that the magnitude of strain in the local non-axisymmetric imperfection was calculated in practical accuracy by using the formulae presented in the previous paper for the axisymmetric one.     

cAMP-signaling pathway acts in selective synergism with glucose or tolbutamide to increase cytosolic Ca2+ in rat pancreatic beta-cells

The effect of repeated cocaine administration on serotonin2 (5-HT2) receptor function was examined in male rats. Rats were fitted with indwelling jugular catheters and subsequently received cocaine (15 mg/kg, i.p., b.i.d.) or saline for 7 days. Rats were challenged with the 5-HT2 agonist DOI (25, 100, 400 micrograms/kg, i.v.) or saline 42 hr and 8 days after cessation of chronic treatment. Serial blood samples were collected at various times after DOI challenge and analyzed for prolactin levels. DOI-induced head shakes and skin jerks were examined concurrently in the same subjects. After 42 hr of withdrawal, the stimulatory effects of DOI on prolactin release and shaking behavior were significantly enhanced in cocaine-treated rats. Conversely, the skin jerk response to DOI was not altered by prior cocaine exposure. After 8 days of withdrawal, the prolactin and head shake responses to DOI were still potentiated in cocaine-treated rats, but this effect was no longer statistically significant. The data indicate that chronic cocaine enhances the sensitivity of 5-HT2 receptor mechanisms. Our findings further suggest the possibility that altered 5-HT2 receptor function may be involved in the mood disturbances experienced by abstinent cocaine addicts.     

Nitric oxide acts directly in the presynaptic neuron to produce long-term potentiation in cultured hippocampal neurons

Nitric oxide (NO) has been proposed to act as a retrograde messenger during long-term potentiation (LTP) in the CA1 region of hippocampus, but the inaccessibility of the presynaptic terminal has prevented a definitive test of this hypothesis. Because both sides of the synapse are accessible in cultured hippocampal neurons, we have used this preparation to investigate the role of NO. We examined LTP following intra- or extracellular application of an NO scavenger, an inhibitor of NO synthase, and a membrane-impermeant NO donor that releases NO only upon photolysis with UV light. Our results indicate that NO is produced in the postsynaptic neuron, travels through the extracellular space, and acts directly in the presynaptic neuron to produce long-term potentiation, supporting the hypothesis that NO acts as a retrograde messenger during LTP.     

Factors affecting young children's mental development and their significance in intervention

Factors affecting their developmental quotients (DQ) in 48 normal young children, who were involved in regular development assessments at child health care outpatient visits and whose parents received child-rearing guidance at Chaoyangmen Subdistrict of Dongcheng District, Beijing, and 43 controls aged 36 months were analyzed. Factors, such as their parents' receiving child-rearing guidance, paternal education, maternal education, paternal occupation, type of nursery schools, home environment quality score (HEQS) at 24 and 36 months of age, and mothers' knowledge of child-rearing were associated with children's DQ at their age of 36 months, with statistical significance at a level of 0.05 in univariate analysis. With multiple regression analysis, HEQS at the age of 36 months, family size at the age of 24 months, paternal education, children's sex, and mothers' age had influences on DQ at age of 36 months with statistical significance, and the degree of correlation of HEQS with DQ at 36 months was much higher than that of other factors, and it suggested that HEQS was an important link in child developmental intervention.