HPLC/RIA analysis of bioactive methionine enkephalin content in the seizure-susceptible El mouse brain

We previously reported a deficit of methionine enkephalin-like immunoreactivity (ME-LI), in the cerebral cortex, septal area, hippocampus, and striatum and the abnormal metabolism of opioid peptides in the hippocampus and striatum of seizure-susceptible El mice, which are involved in the pathogenesis of seizures. However, these findings suggest that the ME-LI does not necessarily reflect the bioactive methionine enkephalin (ME). Herein, we measured the biologically active peptide, ME excluding cross-reactive substances by using HPLC coupled with radioimmunoassay to clarify the abnormal function of enkephalinergic neurons in the El mouse brain. The ME content in 25-day-old El mice that had no seizures was significantly decreased in the hippocampus and septal area, as compared with corresponding regions in ddY mice (seizure-nonsusceptible; the mother strain of El). At the age of 50 days when El mice displayed abortive seizures, this content in both stimulated El[s] and nonstimulated El[ns] was significantly reduced in the septal area and cerebral cortex. At the age of 150 days when El mice exhibit tonic-clonic seizures, this content in both El[s] and El[ns] was significantly reduced in the septal area, cerebral cortex and striatum. These findings were generally compatible with our previous findings. This study further supports our hypothesis that a deficit of anticonvulsant endogenous ME, in the cerebral cortex, septal area, and hippocampus of seizuresusceptible El mice play an important role in the pathogenesis of seizures.     

Adenovirus infection and specific secretory IgA responses in the intestine of infants.

We investigated adenovirus (Ad) infection of the intestine and Ad group-specific fecal IgA antibody responses in seven infants who were followed up from birth to 16 months to seven years of age. We isolated in tissue culture from fecal samples not only enteric Ad type 41 but also other Ads (types 2, 3, 5, 6, and 12). We also detected Ad antigens in the feces by ELISA at the times of infection with even non-enteric Ads, suggesting that a large amount of antigens were produced in the intestine. We found that repeated Ad infections with different serotypes were occurring and there were good fecal IgA antibody responses at each time. The infection seemed usually mild or asymptomatic: only one out of 23 occasions of the detected infections required hospitalization.     

Induction Kinetics of Millisecond-Delayed Luminescence in Intact Bryopsis Chloroplasts

The induction curve of delayed luminescence emitted from 0.5to 2.5 ms after excitation of dark-adapted intact chloroplastsof the green alga, Bryopsis maxima, showed three transient peaks,L₁, L₂ and L₃ (in order of appearance), at about 0.1, 1 and5 s after theonset of intermittent illumination. Intact chloroplastswere needed for L₂ to appear, whereas L₁ and L₃ were presentin hypotonically treated chloroplasts. L₁ and L₂ are related to the electric field generated acrossthe thylakoid membranesbecause the two peaks parallelled theappearance of the first and second peaks of electrochromic absorptionchanges at 560 nm and they were totally abolished by valinomycinand CCCP. A smaller contribution to the L₁ and L₂ of the protonactivity gradient across the membranes, or of pH changes insideor outside the membranes, was suggested by the partial suppressionof the transient by NH₄CI. L₃ is related to the proton gradient or pH changes because thetransient was inhibited by NH₄CI and CCCP but enhanced by N,N'-dicyclohexylcarbodiimide.In the presenceof valinomycin, which somewhat lowered the peakheight of L₃, the kinetics of delayed luminescence parallelledthat of fluorescence. Electrogenic reactions which occur sequentiallyduring the dark to light transition of the photosynthetic machineryin intact chloroplasts is discussed in connection with transientchanges in delayed luminescence. (Received November 8, 1982; Accepted May 21, 1983)     

Comparison of mauthner cell size in sexually developed and undeveloped male red-bellied newts

Differences in Mauthner (M) cell size were examined in sexually developed and undeveloped male red-bellied newts, Cynops pyrrhogaster. The mean areas of nuclei and cell bodies of M cells and mean maximum and minimum diameters of the cell bodies in the sexually developed males were significantly larger than those in the sexually undeveloped ones. In the hypophysectomized male newts, all these parameters were not significantly different from those in the sexually undeveloped ones. These values were significantly increased by treatment with both bovine prolactin and human chorionic gonadotropin every other day for 3 weeks after hypophysectomy, and these measures were comparable to those in the sexually developed males. These findings suggest that differences in M cell size between sexually developed and undeveloped male newts are due to alteration in hormonal milieu. © 1995 John Wiley & Sons, Inc.     

Identification of group A coxsackieviruses by immune adherence hemagglutination

We investigated to find whether the immune adherence hemagglutination (IAHA) test could be used for identification of group A coxsackieviruses (Cox. A). By using homogenate of suckling mouse torsos infected with each of nine prototype viruses (Cox. A 2, 3, 4, 5, 6, 8, 9, 10 and 16) and 46 isolates as antigens and hyperimmune mouse ascitic fluids to the prototype viruses, we compared IAHA with complement fixation (CF) for serotyping of these viruses. The results of identification tests by IAHA were the same as those by combined use of CF and neutralization tests on all the 46 strains. By CF alone, however, six of 46 strains were not identified because of lower antigen titers; IAHA antigen titers were generally higher by 16-fold or more than CF tests. Furthermore, IAHA had a higher type-specificity than CF; a weak cross-reaction was found by IAHA only between Cox. A 3 and Cox. A 8. Nonspecific reactions encountered in IAHA were reduced more readily by kaolin than fluorocarbon treatment of the torso homogenates. From these results, we conclude that IAHA is an alternative method to CF and neutralization for serotyping of Cox. A viruses.     

Histochemistry of acetylcholine receptors and acetylcholinesterase during the formation of neuromuscular junctions in the urodele Hynobius nigrescens

The development and structure of neuromuscular junctions (n-m-js) in stylopodia of forelimbs of larvae and adults of Hynobius nigrescens were histochemically investigated for acetylcholine receptors (AChRs) and acetylcholinesterase (AChE) activity. In larvae, the tetramethyl rhodamine-labelled α-bungarotoxin (TMR-αBT) positive areas appeared either as small fluorescent spots or fluorescent plates of various sizes. The mature fluorescent plate was found to be formed by the successive addition of spots, and the plates thus established were arranged linearly parallel to the axes of muscle fibers. AChE activity occurred almost exactly at TMR-αBT-positive sites. In adults, plate assemblies were often seen as a single dotted line (type A form) for both AChR binding and AChE reaction, in contrast to larval n-m-js in which AChE activity appeared as a continuous line. By applying the TMR-αBT method, two other forms of adult n-m-js were observed: type B, a long dotted line several plates wide; and type C, with a cluster of plates randomly dispersed over the whole width of the muscle fiber. It seems that protoforms of the latter two forms of n-m-js appear in the muscles just before and after metamorphosis.     

Parallel time courses of electrochromic shifts of carotenoids and cytochrome f photooxidation in intact Bryopsis chloroplasts

Light-induced absorbance changes at 560 nm, and electrochromicshifts in absorption of carotenoids responding to membrane potentialacross the thylakoid membrane, were studied, comparing themwith the kinetics of cytochrome f photooxidation, in the dark-adaptedintact chloroplasts of the green alga Bryopis maxima. The 560nm changes showed transient variations, characterized by a sharpinitial peak followed by a second, lower peak, within a fewseconds of illumination. The time course of the 560 nm changesis parallel to that of light-induced transient changes of cytochromef. Inhibitors and redox substances which selectively influenceddifferent transient phases of the cytochrome f induction alsospecifically affected corresponding transient phases of the560 nm changes. These results indicate that the two inductionphenomena are closely related to each other and that the inductionof the 560 nm change is due to light-dependent changes in electrontransfer on the reducing side of photosystem I. A possible mechanismfor the electric field formation by electron transfer associatedwith photosystem I will be discussed. (Received May 9, 1977; )