Commentary on "Subcellular Fractions of Adult and Developing Rat Cerebellum, by M. del Cerro, R. S. Snider and M. L. Oster, July 1969".

Subcellular fractionation by differential ultracentrifugation has allowed the study of the cell and its organelles from a morphological, physiological, and biochemical perspective. Combined with electron microscopy, and by using animals at different stages of postnatal development, these methods yielded useful results concerning the ontogeny of synaptosomes, mitochondria, and myelin and broadened the possibilities to investigate the molecular underpinnings of cerebellar histogenesis.

An avant-garde professorship of neurobiology in education: Christofredo Jakob (1866-1956) and the 1920s lead of the National University of La Plata, Argentina.

The interdisciplinary trend in "Mind, Brain, and Education" has witnessed dynamic international growth in recent years. Yet, it remains little known that the National University of La Plata in Argentina probably holds the historical precedent as the world's first institution of higher education that formally included neurobiology in the curriculum of an educational department, having done so as early as 1922. The responsibility of teaching neurobiology to educators was assigned to Professor Christofredo Jakob (1866-1956). In the present article, we highlight Jakob's emphasis on interdisciplinarity and, in particular, on the neuroscientific foundations of education, including special education.

Ramón y Cajal erroneously identified as Camillo Golgi on a souvenir postage stamp.

Focusing on a philatelic oddity that erringly identifies a picture of Santiago Ramón y Cajal as that of Camillo Golgi, this brief article examines official and unofficial stamp issues honoring the two great neuroanatomists, one from Spain and the other from Italy, who were early Nobel Prize winners in Physiology or Medicine.

Cajal on solar eclipse.

An impression that sculpted a lasting memory on the mind of the great neuroanatomist Santiago Ramón y Cajal, an 8-year-old boy at the time, was the total solar eclipse of 18 July 1860. This short article provides a translation of the relevant passage, found in a 1933 Buenos Aires schoolbook, and places the celestial event at the crossroads of neuroscience, astronomy and literature.

The structure of Lippmann heliochromes: Cajal and the 1908 Nobel Prize in Physics.

The 1908 Nobel Prize in Physics was awarded to Luxembourgeois Gabriel Lippmann (1848-1921), Professor of Mathematical and Experimental Physics at la Sorbonne, for his method of reproducing colors photographically based on the theory of wave interference. In the preceding several years, the eminent neurohistologist - and avid photographer - Santiago Ramón y Cajal (1852-1934) had been experimenting with Lippmann heliochromes, studying under the microscope the structure of the laminae of Zenker that produce mixed colors, and especially white. Those studies led to a series of technical papers by Cajal, the culmination being an article published 100 years ago in the Annual Report of the Board of Regents of the Smithsonian Institution in Washington, DC. A few years later, Cajal published Photography in Colors, his classic monograph on the physicochemical principles of the 'art of Daguerre,' bearing further testimony to his exuberant productivity, far-reaching interests, and scientific genius. The present article reflects on the workings of the mind of Cajal and his fundamental knowledge that was a precondition for his success in neurohistology. It highlights the links between the early photographic studies of Cajal and Lippmann, masters of the biological and physical sciences, respectively. Special emphasis is placed on Lippmann's discovery of heliochromes and the microscopic analyses performed on them by Cajal, including elements from relevant contemporary studies and discoveries.

Cajal's brief experimentation with hypnotic suggestion.

Spanish histologist Santiago Ramón y Cajal, one of the most notable figures in Neuroscience, and winner, along with Camillo Golgi, of the 1906 Nobel Prize in Physiology or Medicine for his discoveries on the structure of the nervous system, did not escape experimenting with some of the psychiatric techniques available at the time, mainly hypnotic suggestion, albeit briefly. While a physician in his thirties, Cajal published a short article under the title, "Pains of labour considerably attenuated by hypnotic suggestion" in Gaceta Médica Catalana. That study may be Cajal's only documented case in the field of experimental psychology. We here provide an English translation of the original Spanish text, placing it historically within Cajal's involvement with some of the key scientific and philosophical issues at the time.

Semicentennial tribute to the ingenious neurobiologist Christfried Jakob (1866-1956). 1. Works from Germany and the first Argentina period, 1891-1913.

This study, and the companion paper that follows, pays homage to the life and work of Christfried (also Christian or Christofredo) Jakob, a German-born neuropathologist who adopted Argentina as his country of vocation. Rated by von Economo and Koskinas among the three most important pre-1925 cortical neuro-anatomists, alongside Ramón y Cajal, Jakob is little known in the English literature. He has left an impressive record of publications, 30 richly illustrated monographs and 200 articles that span over a vast array of neurological themes, including cortical development and evolution, and the visceral brain. The present paper reviews works from his German years and the first visit to Argentina in 1899-1910. The companion paper covers his works (all in Spanish) during his 'second Argentina period', after 1913.

Semicentennial tribute to the ingenious neurobiologist Christfried Jakob (1866-1956). 2. Publications from the second Argentina period, 1913-1949.

Christofredo (also Christfried or Christian) Jakob is considered the father of neurology, neurobiology and forensic histopathology in Argentina, where he initially worked between 1899-1910 and then from 1913 onwards. He held professorships of neurobiology at the Faculty of Humanities and Educational Sciences of the University of La Plata and of anatomy and biology at the University of Buenos Aires, and established one of the most important neuropathological laboratories in South America. In the latter phase of his career, Jakob published important works on the pathological anatomy of neurological and neuropsychiatric disorders and formalized ideas on consciousness and neurophilosophy.

An ultrastructural study of the pathology of the retinal pigment epithelium, Bruch's membrane, and the choriocapillaris in the aged Fischer 344 rat.

PURPOSE: The neural retinal degeneration in the aging Fischer 344 (F344) rat has been previously characterized. Here we describe the ultrastructural changes that occur in the retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaris in the periphery of the aged Fischer 344 rat. METHODS: F344 eyes from 24-month-old animals (n = 4 animals, 8 eyes) were fixed and embedded for ultrastructural study. Serial mid-sagittal sections were taken from the superior peripheral retinas within 300 microm of the ora serrata. Pathology within the RPE, Bruch's membrane, and choriocapillaris was described. RESULTS: Progressive changes were seen in the RPE/Bruch's/choriocapillaris complex, increasing anteriorly as the ora serrata was approached. Early pathology of the RPE included increased number of basal infoldings, increased number of phagolysosomes and lipofuscin deposits, attenuation, inclusion of vasculature, vesicle formation, and whirling extensions of the basement membrane into the cytoplasm. Bruch's membrane showed spots of considerable thinning, but most prominent was the nodular thickening. The choriocapillaris was found to have severe endothelial degeneration and transformation to fibrous tissue in the most severely affected regions. Lipofuscin was also found in areas of degenerated choriocapillaris. CONCLUSIONS: Prior work focused on the neural retina, documented photoreceptor cell loss, and showed that Müller cell changes preceded that loss in the periphery of the F344 rat. It is now evident that the pathology in the RPE/Bruch's membrane/choriocapillaris complex may also be a critical component of the overall degenerative process. A possible mechanism for the extensive peripheral retinal degeneration in the F344 is presented.

An early work [1910-1913] in Biological Psychology by pioneer psychiatrist, criminologist and philosopher José Ingenieros, M.D. (1877-1925) of Buenos Aires.

One of the earliest recorded works in Biological Psychology was published in 1910 by Argentine psychiatrist José Ingenieros (1877-1925), Professor of Experimental Psychology at the Faculty of Philosophy and Letters of the University of Buenos Aires. Ingenieros, a multifaceted personality and prolific author and educator famous for his lapidary aphorisms, has been considered a 'luminary' for generations. Trained as a physician, he was the first scientist to establish a comprehensive psychological system in Latin America. His long list of publications includes more than 300 titles generally divided in two periods: studies in mental pathology and criminology (1897-1908) and studies in philosophy, psychology and sociology (1908-1925). His works were never made particularly available to English-speaking audiences, despite the fact that certain of his books are still best-sellers in the Spanish-speaking world. We present an overview of Ingenieros' life and work, and a detailed account of his profoundly interesting work Principios de Psicología Biológica, in which he analyzes the development, evolution and social context of mental functions. We also provide an English translation of the Introduction contributed by Nobel laureate Wilhelm Ostwald (1853-1932) to the 1922 German edition of the work, pertinent to the energetic principles Ingenieros used and the study of Psychology as a natural science. It is a hope, 80 years after Ingenieros' parting, to bibliographically resurrect this champion of reason, who, until now, has not been given his due placement in the international psychological and biomedical literature.

Posterior Segment Approach for Subretinal Transplantation or Injection in the Canine Model.

A posterior segment approach for cell transplantation or injection into the subretinal space of the dog has been developed. Controlled penetration to the subretinal space was achieved using a 29-gauge injection cannula, either blunted or with a 30° sharpened bevel, and partially ensheathed with moveable plastic tubing. Depending on the injection volume used, the retina detached, and the fluid was reabsorbed within 1 - 3 weeks, although for smaller volumes the retina reattached within a matter of days. The optimal injection volume used was between 100 and 150 µl, or two injections of 55 µl each. By ophthalmoscopy following the surgery, it was possible to serially monitor the injection site and retinal bleb through fundus photography. Light microscopy demonstrates the distribution of stable, viable RPE cells in the subretinal space up to 6 months. The transplantation technique developed for the dog is atraumatic and free from any major surgical or clinical complications. It can be readily used to deliver cells or fluids to localized regions of the subretinal space.