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Notes: Summary A case of congenital peripheral medullo-epithelioma arising in the sciatic nerve of a 6-month-old boy is reported. Histologically, areas of primitive neural tumor merged with areas showing differentiation into ependymoma, astrocytoma, oligodendroglioma, and ganglioneuroma. These lines of differentiation were confirmed by electron microscopy and immunohistochemistry. Despite the malignant nature of the tumor, 7 years after amputation of the affected leg, the child is alive without recurrence.

Notes: Summary The distribution and ultrastructure of Alzheimer's neurofibrillary tangles (ANT) in the brain stem, hypothalamus, and Ammon's horn were studied in four patients with postencephalitic parkinsonism of Economo type (PEPE). The distribution of ANT was as previously reported; the pattern of distribution resembled to that of amine-containing nerve cells. Ultrastructurally, ANT revealed twisted tubules (TT), but straight tubules (ST) of 150 Å width were also found in the locus ceruleus of three cases; sometimes, TT and ST were mixed in a single neuron. Whether the coexistence of TT and ST in the locus ceruleus is a characteristic ultrastructural feature of ANT in PEPE or a regional peculiarity could not be determined. Ultrastructurally, ANT in PEPE were identical to those found in the brains of patients with Alzheimer's disease or senile dementia.

Notes: Summary Tissue from seven patients with tuberous sclerosis and subependymal giant-cell tumors was examined with special stains, immunohistochemistry, and electron microscopy. Immunoreactive glial fibrillary acidic protein (GFAP) was not found in the giant cells of four tumors, but was present in some tumor cells in the other three. Immunoreactive S-100 protein was present in tumor cells of six cases; it was also seen in more tumor cells than was GFAP. Electron microscopy was similar in all cases and showed that the tumor cells had numerous organelles — many dense bodies thought to be primary lysosomes, swollen mitochondria, Golgi complexes, rough and smooth endoplasmic reticulum, free ribosomes, and sparsely distributed intermeadiate filaments. In one case, neurosecretory granules, microvilli, and synapses were observed. In another subject, prominent, thick bundles of glial filaments were seen. These findings suggest that the tumor is made up of unique cells in addition to cells with recognizable neuronal or astrocytic features.

Notes: Summary Neurons found in the medial bulbar reticular formation were activated by stimulation of the orbital gyms and responded with antidromic spike potentials to selective stimulation of either the masseter or anterior digastric motoneuron pool in the trigeminal motor nucleus in cats anesthetized with α-chloralose. These two kinds of reticular neurons were assumed to be inhibitory neurons projecting to masseter motoneurons (IM neurons) and excitatory neurons projecting to anterior digastric motoneurons (ED neurons), involved in the effects of stimulation of the orbital gyrus on trigeminal motoneurons: inhibition of masseter motoneurons and excitation of anterior digastric motoneurons. Input-output properties of IM and ED neurons were studied intracellularly with the following results: (1) stimulation of the orbital gyrus evoked EPSPs in im and ED neurons with mono- and polysynaptic latencies; and (2) stimulation of the lingual nerve evoked a spike potential in a few IM and ED neurons after a rather long latency, indicating that the pathways involved in the cortical control of trigeminal motoneurons via IM and ED neurons were basically separate from those responsible for the reflex control by the peripheral inputs Intracellular injection of horseradish peroxidase revealed that both IM and ED neurons were small or medium in size and the former were smaller than the latter, while none of the large reticular neurons directly projected to the trigeminal motor nucleus. This suggests a possible functional differentiation among bulbar reticular neurons according to cell size.

Notes: Summary Spatio-temporal patterns of pre- and postsynaptic inhibition were studied in the trigeminal spinal nucleus oralis of cats by means of systematic electrical stimulation of the facial skin. Stimulation of the facial skin induced an EPSP-IPSP sequence in trigemino-thalamic relay cells (TRC). The IPSP was depressed by picrotoxin but was resistant to strychnine. The largest IPSP was evoked from the center of the excitatory area, where stimulation induced the largest EPSP and spike potentials at the lowest intensity in the same TRC. The amplitude of the IPSP decreased with increasing distance from the center in parallel with that of the EPSP. In the great majority of trigeminal primary afferent fibers, the largest primary afferent depolarization (PAD) was not evoked from the center of the excitatory area, where the threshold for spike generation was lowest, but from the adjacent points on the face. Spike activities in a trigeminal primary afferent fiber did not evoke any detectable PAD in itself. The duration of the PAD was definitely longer than the IPSP in TRC. However, the temporal distribution of the peak of PADs was very similar to that of the EPSP in TRC. Inhibition was evoked in glutamate-induced spike discharges of TRC by stimulation of the points on the face, which were located close to the center of the excitatory area of the TRC. However, the afferent inhibition of both spontaneous and peripherally induced spike discharges of TRC outlasted the postsynaptic inhibition. Thus, the late phase of the afferent inhibition is most probably due to presynaptic inhibition. Presynaptic inhibition, together with postsynaptic inhibition, would be involved also in the early phase of afferent inhibition through its mutual inhibitory organization.

Notes: Summary Chromatographic behavior of 51 inorganic ions has been systematically studied on layers of sulfoethyl (SE) cellulose, a strongly acidic exchanger, in hydrochloric acid and in acid-ammonium thiocyanate media. The sorption of most of the ions on he SE-cellulose decreases with increasing concentration of the acid and the thiocyanate. The characteristic retention of some metal ions of SE-cellulose layer can be recognized over a low concentration of the acid or the salt. Feasibilities for separations of analytical interest are also presented in both systems.

Notes: Gelation velocity and reaction rate for the acid-catalyzed condensation reaction in the aqueous solution (10-22%) of partially N-methylolcarbamoylethylated polyvinyl alcohol (about 20 mole-% degree of methylolcarbamoylethylation) have been investigated by the falling ball viscosity method and the chemical analysis of methylol groups including the effects of kinds of acid, concentrations of acid and polymer, and temperatures of reaction. For the reciprocal gel point, 1/tg, and the hydrogen ion concentration, [H+], the following equation holds: \documentclass{article}\pagestyle{empty}\begin{document}$ 1/t_g = c[{\rm H}^ +]^\alpha $\end{document} where α and c are constants independent of the kind of acid; also α is independent of temperature and polymer concentration, while c increases with increasing temperature or polymer concentration. The 1/tg is approximately proportional to the concentration of polymer in the range of a concentrated polymer solution above about 15% by weight. From this fact, it is suggested that, in a concentrated polymer solution, the intermolecular crosslinking proceeds predominantly as a bimolecular reaction with respect to methylol groups. Assuming that the increase of the apparent viscosity of the reacting system is mainly due to that of the structural viscosity which should be increased by a bimolecular crosslinking reaction, the following expression was derived for the gelation velocity: \documentclass{article}\pagestyle{empty}\begin{document}$ \eta _0 /(\eta _t - \eta _0) = A(1/i - 1/t_g) $\end{document} in which, \documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{*{20}c} {A/t_g = 1 - x_g /a} & {{\rm and}} & {k = x_g /(a^2 A)} \\ \end{array} $\end{document} where η0 and ηt are the apparent viscosities at time 0 and t, respectively, A is a measure of gelation velocity, a is the initial number of methylol groups, xg is the number of crosslinked methylol groups at the gel point, and k is the bimolecular rate constant. The experimental results of viscosity changes have shown a fairly good agreement with the above expression except in the early stage of condensation. The extent of reaction at the gel point (xg) has been estimated to be about 0.03-0.05 regardless of concentration of polymer and acid, kinds of acid, and temperature. Also, it has been observed that the rate constant of reaction is independent of the concentration of polymer and is proportional to the concentration of hydrogen ions. The above expression and estimation have been verified by the chemical analysis of methylol groups in the condensation processes. However, the extent of reaction at the gel point is about ten times that predicted by Flory's theory. This discrepancy may presumably be attributed to the fact that all of the methylol groups on the polymer chains which are coiled, entangled, and strongly solvated prior to the crosslinking are not equally reactive sterically and a certain extent of intramolecular crosslinking occurs. The activation energy of reaction has been estimated to be about 21 kcal./mole.

Notes: The effect of polymer dilution on the acid-catalyzed gelation of partially N-methylolcarbamoylethylated polyvinyl alcohol has been studied viscometrically and chemically. The result that the higher the degree of dilution the greater the extent of reaction at gelation, especially in the polymer concentration below 15% by weight, indicates that a certain increase of intramolecular crosslinking with dilution occurs. However, sufficient agreement with Kilb's theory could not be found. Also, even when the extent of reaction at gelation was extrapolated to infinite concentration of polymer, it was far greater than that obtained from Flory's theory. The discrepancy may presumably be attributed to the fact that in addition to the intramolecular crosslinking, all the methylol groups on the polymer chains which are coiled, entangled, and strongly solvated prior to crosslinking are not equally reactive sterically.