Transplantation of neural tissues in the brains of laboratory mammals: Technical details and comments

Summary Various technical details on the transplantation of the embryonic neural tissues in the brains of the neonatal and adult rats are presented. Conditions determining successful or leading to unsuccessful survival, growth and differentiation of these transplants are critically examined.Supported by Research grants NS. 08817 and CA. 14650 from N.I.H.     

Latency of taste nerve signals in frog (Rana catesbeiana).

The latency of frog gustatory neural impulses to 1.0 M NaCl was a mean of 86 msec. Electrical stimulation of taste cell membranes produced gustatory neural impulses with the mean 5 msec latency. It is concluded that most of the 86 msec latency of taste nerve responses to 1.0 N NaCl is due to the latency of taste receptor potential following the onset of gustatory stimulation.     

Freezing and transplantation of brain tissue in rats

Summary Neocortical tissue obtained from rat embryos was frozen and stored at –70°C for 6 h prior to transplantation into the cerebellum of neonatal rats. Growth, differentiation, and integration of this tissue within the host brain was comparable to that obtained from freshly dissected and transplanted tissue. It is suggested that freezing to low temperatures does not adversely effect the viability or transplantability of the neural tissue.Supported by N.I.H. research grants Nos NS-08817 and CA-14650.     

Transplantation of neural tissues in the brains of laboratory mammals: technical details and comments.

Various technical details on the transplantation of the embryonic neural tissues in the brains of the neonatal and adult rats are presented. Conditions determining successful or leading to unsuccessful survival, growth and differentiation of these transplants are critically examined.     

Does an initial phasic response exist in the receptor potential of taste cells?

The depolarizing receptor potentials to 0.5 M NaCl recorded from frog taste cells did not exhibit any phasic response, even when the rectangular waveform of stimulus onset was employed. The quickest depolarizations recorded reached the peak in 50 msec. On the other hand, the gustatory neural response showed initial overshoot of the impulse discharge even when 0.5 M NaCl was delivered at the slower rate of 0.06 ml/sec. It is concluded that the initial neural response may be associated with the rate of rise of the receptor potential before its plateau level is reached.     

Effects of oral contraceptive steroids (norethisterone/mestranol) on the activities of hepatic drug-metabolizing enzymes in iron-deficient anemic rats

Either oral contraceptive steroid (norethisterone/mestranol; N/M) treatment or iron-deficiency (Fe(-] anemia alone caused an increase in NADPH cytochrome c reductase and in three hepatic microsomal mixed-function oxidase activities in female rats. When N/M treatment and the Fe(-) diet are combined, no further change in hepatic enzyme activity is seen compared with that with either treatment alone.     

Role of adenosine A1 and A2 receptors in the regulation of aldosterone production in rat adrenal glands

To investigate the roles of adenosine A1 and A2 receptors in the regulation of aldosterone production, we examined the effects of adenosine and adenosine agonists (N6-cyclohexyl adenosine; selective adenosine A1 receptor agonist and 5'-N-ethylcarboxamine adenosine; selective adenosine A2 receptor agonist) on aldosterone and cyclic AMP production in rat adrenal capsular cells. Neither adenosine nor 5'-N-ethylcarboxamine adenosine caused significant effects on basal aldosterone or cyclic AMP production. Also, adenosine (10(-3) M) showed no consistent effects on aldosterone and cyclic AMP production induced by ACTH. On the other hand, N6-cyclohexyl adenosine exhibited a significant inhibition of basal aldosterone and cyclic AMP production at doses of 10(-4) M and 10(-3) M; furthermore, 10(-3) M N6-cyclohexyl adenosine inhibited aldosterone and cyclic AMP production stimulated by ACTH. These results suggest that adenosine A1 receptors are coupled to and inhibit adenylate cyclase and may be involved in the inhibition of aldosterone production.     

A protective mechanism for the tongue: Suppression of genioglossal activity induced by stimulation of trigeminal proprioceptive afferents

Zusammenfassung Die Reflexaktivität des Protrudors der Zunge (M. genioglossus) wurde durch die Aktivierung propriozeptischer afferenter Fasern im N. trigeminus bedeutend herabgesetzt. Polysynaptische Reflexe zum M. genioglossus wurden entweder durch Reizung des N. lingualis oder des N. glossopharyngicus ausgelöst. Bedingende elektrische Reizung der Nerven verschiedener Kaumuskeln induzierte eine bis zu 500 msec andauernde Hemmung dieser Reflexe.     

iPSC-derived neural precursor cells: potential for cell transplantation therapy in spinal cord injury

A number of studies have demonstrated that transplantation of neural precursor cells (NPCs) promotes functional recovery after spinal cord injury (SCI). However, the NPCs had been mostly harvested from embryonic stem cells or fetal tissue, raising the ethical concern. Yamanaka and his colleagues established induced pluripotent stem cells (iPSCs) which could be generated from somatic cells, and this innovative development has made rapid progression in the field of SCI regeneration. We and other groups succeeded in producing NPCs from iPSCs, and demonstrated beneficial effects after transplantation for animal models of SCI. In particular, efficacy of human iPSC–NPCs in non-human primate SCI models fostered momentum of clinical application for SCI patients. At the same time, however, artificial induction methods in iPSC technology created alternative issues including genetic and epigenetic abnormalities, and tumorigenicity after transplantation. To overcome these problems, it is critically important to select origins of somatic cells, use integration-free system during transfection of reprogramming factors, and thoroughly investigate the characteristics of iPSC–NPCs with respect to quality management. Moreover, since most of the previous studies have focused on subacute phase of SCI, establishment of effective NPC transplantation should be evaluated for chronic phase hereafter. Our group is currently preparing clinical-grade human iPSC–NPCs, and will move forward toward clinical study for subacute SCI patients soon in the near future.     

Modulation of carcinoembryonic antigen release by HT-29 colon carcinoma line in the presence of different agents

In this study we followed the effects of various differentiating agents on the expression of carcinoembryonic antigen (CEA) released into the medium by a colon carcinoma cell line HT-29. Butyric acid 1 mM markedly increased the level of CEA (12-fold in comparison to control levels). 12-O-tetradecanoyl-phorbol-13-acetate (TPA) 50 ng/ml and 5-azacytidine 4 x 10(-6) M increased the amount of CEA, 2- and 1.5-fold respectively. On the other hand retinoic acid 10(-5) M, N methyl-formamide 1% and N,N hexamethylene bisacetamide 2.5 mM decreased CEA 2-, 4- and 3-fold respectively. Our results emphasize that various differentiating agents affect CEA levels differently. Thus changes in CEA levels appear not to be reliable as a marker of a more differentiated phenotype.     

Gustatory sensitivity of an anuran to cantharidin

Glossopharyngeal nerve stimulation of the bullfrog, Rana catesbeiana, revealed responsiveness to low levels of cantharidin (1.3 x 10(-6) M), providing a first demonstration of neural gustatory sensitivity of an animal to this defensive chemical from blister beetles (Meloidae).     

Alkaloids of apocynaceae IV. Dregamine,a new alkaloid fromVoacanga dregei E. M.

Zusammenfassung Dregamine, ein neues Alkaloid aus der ApocynaceaeVoacanga dregei E. M. wurde isoliert und charakterisiert. Diese Verbindung stellt einen neuen Vertreter der Klasse der 2-Acyl-indole dar.

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Alkaloids of Apocynaceae III,M. Gorman, N. Neuss, J. A. Deyrup, andN. J. Cone, J. Amer. chem. Soc. (1959), in press.     

Modulation of carcinoembryonic antigen release by HT-29 colon carcinoma line in the presence of different agents

Summary In this study we followed the effects of various differentiating agents on the expression of carcinoembryonic antigen (CEA) released into the medium by a colon carcinoma cell line HT-29. Butyric acid 1 mM markedly increased the level of CEA (12-fold in comparison to control levels). 12-O-tetradecanoyl-phorbol-13-acetate (TPA) 50 ng/ml and 5-azacytidine 4×10^–6M increased the amount of CEA, 2- and 1.5-fold respectively. On the other hand retinoic acid 10^–5M, N methyl-formamide 1% and N,N hexamethylene bisacetamide 2.5 mM decreased CEA 2-, 4- and 3-fold respectively. Our results emphasize that various differentiating agents affect CEA levels differently. Thus changes in CEA levels appear not to be reliable as a marker of a more differentiated phenotype.     

Gastrin stimulated H+ secretion in amphibian gastric mucosa: Effect of tetrodotoxin

Summary The role of neural mechanisms in gastrin stimulated H⁺ secretion was studied using amphibian gastric fundic mucosa. Spontaneously secreting mucosae were converted to resting state (zero H⁺ secretory rate) using Burimamide. Following removal of burimamide, 3×10^–6 M tetrodotoxin did not block gastrin stimulation of H⁺ secretion indicating that neural mechanisms are not required.This work was supported by U.S. Public Health Service NIH Grant AM17315 and by the Medical Research Service of the Veterans Administration.     

Inhibitory effect of cytokinins on PHA-induced human lymphocyte stimulation.

The inhibitory effect of various purine derivatives on PHA-induced human lymphocyte blast formation was studied. Two nucleoside cytokinins, N6-benzyladenosine and N6-isopentenyladenosine, inhibited blast formation at concentrations as low as 10(-6) M. However, the other cytokinins, which lacked the ribosyl residue at N9 position, had to be at the higher molar concentration of 10(-4) before they could induce the same inhibitory effect.     

Further characterization of the effects of ultraviolet irradiation of the amphibian egg

Summary UV-irradiation of the vegetal hemisphere of amphibian eggs leads to developmental abnormalities in neural morphogenesis. The possibility that the egg's transient sensitivity to irradiation could be due to pigmentation changes was examined in albino eggs. The tissue specificity of the effects of irradiation was analyzed by exchanging the ectoderm between irradiated and control embryos.The N.S.F. (PCM 77-04457), Fulbright-Hags Commission, and Busan National University are gratefully acknowledged for financial support.     

Genetic control of malate dehydrogenase inNicotiana suaveolens andN. glutinosa

Summary The study of malate dehydrogenase patterns in leaves ofNicotiana suaveolens, N. glutinosa and their interspecific hybrid has been carried out, in order to propose a model of its genetic control. Two possible explanations for the genetic control of malate dehydrogenase have been postulated forN. suaveolens, and at least two loci appear to be implicated in the control of this system inN. glutinosa.Acknowledgments. The authors thank Dr M. Pérez de la Vega for his valuable advice.     

Molecular study in polyacrylamide gel of polypeptides of several strains of rabies virus

Comparative study of structural polypeptides of five rabies virus strains (serotype 1) and one serotype IV, demonstrates difference in molecular weight of the envelope polypeptides M1 and G of all strains. There is little difference between the structural polypeptides N, M2 and probably L. Some purified strains have been treated by trypsine to localize the position of polypeptides. There was no difference between the four major polypeptides of complete and defective virus. Pasteur strain cultivated on different cells shows very little difference in molecular weight of the four major polypeptides.     

Gustatory sensitivity of an anuran to cantharidin

Summary Glossopharyngeal nerve stimulation of the bullfrog,Rana catesbiana revealed responsiveness to low levels of cantharidin (1.3×10^–6M), providing a first demonstration of neural gustatory sensitivity of an animal to this defensive chemical from blister beetles, (Meloidae).Acknowledgments. Study supported in part by grant AI 02908 from NIH.