Del Rio Hortega Research Articles

Melanoblasts of the normal human choroid; study with silver carbonate and silver nitrate.

THE MELANOBLASTS constitute an important element of the choroid of the human eye, but their morphology and physiology have attracted little attention; they are generally considered as elements without particular function and of limited biologic significance, destined only to fill out the space. That such a view is not justified can be demonstrated with modern silver methods, which disclose an intricate relationship between the melanoblasts and other elements of the choroid; this relation suggests that these pigmented cells have important functions. MATERIAL AND METHODS The tissue examined was that of normal human eyes. Figures 1 to 7 were prepared with the silver carbonate method of del Rio Hortega without reduction (Scharenberg and Zeman 1 ). This technique permits a complete impregnation also of those segments of processes of the melanoblasts that, according to Lauber, 2 contain only colorless premelanotic pigment. This substance stains black with colloid silver, so that all parts

A comparison of deformalinizing technics.

Five methods of removing bound formalin from tissues were studied with the Cajal, Del Rio-Hortega, and Feulgen technics used as indicators of efficiency of removal. The tissues had been fixed in 10% formalin for varying periods from one week to several years. The most effective means of eliminating the effects of formalin on staining was two 24-hour changes of 20% aqueous chloral hydrate. Tissue so treated (in the block) gave good results with both the Feulgen and Cajal technics. The Del Rio-Hortega silver carbonate method did not differentiate microglia and oligodendroglia, although astrocytes, unstained in untreated material, stained well after deformalinizhig.

XIII.—A Comparative Study of the Cytoplasmic Components during the Oogenesis of Dog, Cat, and Rabbit

The present paper gives an account of the behaviour of the Golgi material, mitochondria, and nucleolar extrusions during the oogenesis of dog, cat, and rabbit. So far as the writer is aware there is no previous detailed work on the cytoplasmic components of the female germ-cells of the animals investigated.R. Vander Stricht (1911) dealt with the oogenesis of the cat; O. Vander Stricht (1923) has made a comparative study of oogenesis of mammals, including the dog and the cat; P. del Rio Hortega (1913) described the behaviour of the Golgi material, and H. von Winiwarter (1900) studied the nuclear changes during oogenesis of the rabbit; H. von Winiwarter and G. Sainmont (1909) dealt with nuclear metamorphosis during the oogenesis of the cat; finally J. Nihoul (1926), in his paper on the rabbit, described the Golgi material during oogenesis. All the papers quoted, apart from those which deal with the nuclear changes, are either incomplete surveys, or the methods used are insufficiently delicate to reveal changes shown by modern techniques.

THE RELATIONSHIP BETWEEN THE SECRETORY CELLS OF THE PARS NERVOSA OF THE HYPOPHYSIS AND CLASSICAL NEUROGLIA

BY THE USE of methods which stain oligodendroglia and microglia, Bucy (1, 2,)demonstrated the presence of characteristic neuroglial cells in the infundibular stalk and process of the bovine pituitary. These cells he termed pituicytes. The pituicytes vary greatly in shape and size but have two characteristics in common: firstly, the cell body is drawn out into a variable number of cytoplasmic processes, one or more of which are attached by foot plates to connective tissue (either in the form of pia, septa, or that around blood vessels), and secondly, the cells are all well impregnated by Penfield's (3) second modification of the del RioHortega (4) silver carbonate technic for oligodendroglia. This modification stains both oligc dendrocytes and microglia. The pituicytes are distributed diffusely throughout a rich plexus of unmyelinated nerve fibers which make up the main mass of the gland. The supraoptic and to some extent the

GLIOMA OF THE OPTIC NERVE

While 1 or 2 cases of primary glioma of the optic nerve are reported each year in the literature, it is the clinical aspect that almost always predominates in these reports. Relatively little has been said regarding the pathologic study and classification of these tumors1since the introduction of the impregnation methods of Cajal and del Rio-Hortega. Save for Dandy's paper2in 1922, there has been no critical evaluation of the surgical procedures. It is, then, with the pathologic aspect and also with the operative approach that this paper is chiefly concerned. In general, these tumors are divided into two large groups : (1) the dural endotheliomas or meningiomas, which arise from the fibrous sheath of the nerve, and (2) the gliomas, which arise from the neuroglial elements within the nerve itself. Clinically, the meningiomas seem to be more malignant than the gliomas, a fact recognized by Hudson3

GENESIS OF MICROGLIA IN THE HUMAN BRAIN

The existence of microglia as a cell group in the central nervous system was first described by del Rio Hortega in 1919 and has been universally accepted. However, the origin of these cells and their relation to neuroglia1has remained controversial. Certain authors have maintained that microglia and neuroglia have a common origin from the neuroepithelium of the primitive medullary canal. On the other hand, Hortega and many others have expressed the belief that microglia cells are derived from mesenchymal cells and have no direct genetic relationship to astrocytes and oligodendroglia cells. This difference is fundamental and of great significance in understanding the biologic functions of these cells. With few exceptions, all previous embryologic studies on microglia have been made on laboratory animals. In the present work, the origin and evolution of these cells were traced in a series of human embryos. It was possible to demonstrate that microglia

International Cancer Congress

THE second International Congress of the Scientific and Social Campaign against Cancer will be held in Brussels on September 20-26. The Congress is under the patronage of His Majesty the King of the Belgians and of Her Majesty Queen Elizabeth, and has the support of the Government. The National Executive Committee consists of Dr. Lerat (chairman), president of the Belgian National League against Cancer, Profs. Delrez, Dustin, Goormaghtigh and Maisin, directors of the Anti-Cancer Centres of Liege, Brussels, Ghent and Louvain respectively; Dr. Sluys, president of the Belgian Society for Radiology; Dr. Timbal, director-general of the Government Department of Hygiene; Mr. H. Marchal, treasurer, and Mr. W. Schraenen, general secretary of the Belgian National League against Cancer and of the Congress. The programme of the Congress has been divided into two main groups, embracing the scientific campaign and the social campaign against cancer, and the subjects on which official reports will be prepared and upon which individual communications are invited are grouped together under the following headings: (1) The experimental investigation of cancer, which comprises the study of carcinogenic substances, transmissible agents and viruses, growth substances, and factors of predisposition and resistance such as heredity, metabolism and immunity; (2) the diagnosis of cancer by histological, radiological and serological methods; (3) the treatment of cancer by surgical, medical and radiological methods. In the second group, on the social campaign against cancer, the subjects dealt with are: (1) Access of patients to diagnosis and treatment; (2) medico-social assistance to incurable cases; (3) cancer and demography including statistics and racial incidence. The list of official rapporteurs is not yet complete, but among those who have agreed to present reports are: M. Borst, J. W. Cook, W. Cramer, H. F. Deel-man, L. Dublin, A. P. Dustin, J. Ewing, W. E. Gye, H. Holthusen, E. L. Kennaway, J. Maisin, M. Nagayo, F. Pentimalli, Cl. Regaud, P. del Rio Hortega, G. Roussy, C. Rowntree, H. Schinz, F. Carter Wood. Further particulars may be obtained from Mr. W. Schraenen, General Secretary to the Congress, 13 rue de la Presse, Brussels, Belgium.

A STAIN FOR NEUROGLIA IN FORMALDEHYDE-FIXED PARAFFIN SECTIONS

The difficulty of obtaining fresh, properly fixed tissue has unfortunately limited the usefulness of the gold and silver impregnation methods of Ramon y Cajal 1 and del Rio-Hortega 2 for demonstration of the neuroglia cells, particularly in the study of old formaldehyde-fixed material and of brains hardened intact in formaldehyde before sectioning. The deformalization and bromination proposed by Globus 3 have given only partly satisfactory results in our hands. The necessity for using frozen sections with most previously employed metallic staining methods has also been a distinct disadvantage at times. With many friable neoplastic tissues the difficulty of cutting satisfactorily thin and uniform sections on the freezing microtome and carrying them through many different solutions off the slides has diminished the value of the methods. We have previously, on the advice of Bailey, 4 employed Perdrau's 5 method for silver impregnation of reticulin for paraffin sections, but this is the

A SIMPLE ROUTINE PROCEDURE FOR STAINING THE NEURONS AND GLIA OF THE NERVOUS SYSTEM

A great step forward in the study of the elements of the nervous system and their pathologic alterations was made by the Spanish school of histologists, particularly Ramon y Cajal 1 and del Rio Hortega, 2 with the introduction of the gold and silver methods now in use. Because they necessitate the use of fresh material in small sections for the proper penetration of special and diverse fixatives and the staining of the tissues within short prescribed periods of time, difficulties are encountered, excellent as these methods are. Since it is often impossible to fix the nerve tissue shortly after death and it is frequently advantageous to study the hardened brain grossly before sectioning is undertaken, a routine fixative must be used which will meet these requirements. Not only are special fixatives required, but numerous stains are necessary to complete a satisfactory study of the tissues. In addition, many times,

The Impregnation of Glioma Sections from Paraffined Tissue with Hortega's Silver Carbonate (Lithium) Solution

The staining methods of S. Ramon y Cajal and his pupils, P. del Rio Hortega and N. Achucarro, have been used by Bailey and Cushing, Penfield, Globus and Strauss, as well as others in studying neuropathology. From their work and the contributions of Mallory, Spiller, Rosenthal, Ribbert, and others, there has developed a working classification of the glioma growths. In a histologic study of the “glioma cases” from the neurosurgical service of Dr. Ernest Sachs 1 several years ago, considerable difficulty was encountered in staining glioma sections cut from old tissue. Inasmuch as the microscopic diagnosis depended somewhat upon individual cell study, a method for staining the glial and neural elements in their entirety was desirable. In a number of the cases the only available tissue was that which had been removed at operation for diagnosis. This tissue, fixed either in Zenker9s fluid or formalin, had been embedded in paraffin. Sections cut from these blocks and stained according to the modification described here gave very satisfactory microscopic detail. It was then decided to embed tissue in paraffin that had been long preserved in solutions which did not permit specific gold or silver impregnation. The procedure was subsequently extended to include tissue which did not lend itself to satisfactory frozen sectioning. Clear cut pictures of the individual cells and their processes were possible in every instance, though in some sections rather trying repetition was necessary before satisfactory sections were obtained.

ORIGIN AND DEVELOPMENT OF GIANT CELLS IN GLIOMAS

The study of gliomatous tumors has been considerably advanced in recent years by the development and perfection of neuroglial staining methods. The credit for this should be given to the Spanish school of neurohistologists, notably Cajal and del Rio-Hortega. The methods of using gold and silver solutions of the former and the technic of silver carbonate staining with all its variations of the latter have brought to light many details of importance in the furtherance of knowledge of the structure of the neuroglia. To Cajal and his school is due much of the present knowledge of the histogenesis and structure of the astrocytic neuroglia, while del Rio-Hortega has demonstrated clearly the histogenesis, morphology and pathologic variations not only of the oligodendroglia, but also of the other constituent of the third element, the microglia or mesoglia. These studies have clarified remarkably the knowledge of the normal structure of the neuroglia and

A NEW DEMONSTRATION OF HORTEGA CELLS

Since del Rio Hortega published his silver carbonate method for the demonstration of the neuroglia cell which now carries his name, there have been complaints from research workers and technicians that the method simply does not always work. I have been interested in silver methods for histologic purposes since the same attitude has arisen as regards their application to Spirochaeta pallida . Experimentation with spirochetes resulted in the presentation of my colloidal method for demonstrating them in single microscopic sections. 1 Following this work, I applied certain modifications of the procedure to the Hortega cells and, as is common experience with silver methods, there was obtained, through certain mysterious incidences, the best demonstration of rod cells in dementia paralytica that I had seen. The inconstant results, however, were as discouraging as with Hortega's original method, and I accordingly dropped the investigation in spite of the occasional exceptionally excellent pictures resulting with

MULTIPLE GLIOMAS OF THE BRAIN

Gliomas of the brain are common enough but since the works of Achucarro, Ramon y Cajal and del Rio Hortega, of Spain, and of Percival Bailey, Harvey Cushing, Wilder Penfield and J. H. Globus, in this country, much histologic interest has been aroused in these tumors. Bailey and Cushing1and Bailey2have made detailed clinicopathologic studies of the tumors of the glioma group. In contrast to solitary gliomas, multiple gliomas have been observed but rarely. Because of this, the case of multiple gliomas of the brain presented is of interest. REPORT OF CASE Clinical History. —M. A., a cattle dealer, aged 44, was admitted, in 1928, to the service of Dr. George S. Amsden, Albany Hospital, as suffering from mental disease. His wife, a son and two cousins gave the information that the patient had been in an automobile accident a little over four weeks before. He was

ON THE DEVELOPMENT OF THE SENILE PLAQUE IN ALZHEIMER'S DISEASE AND OTHER SENILE CEREBRAL DISEASES EXAMINED BY APPLYING DEL RIO HORTEGA'S METHOD OF IMPREGNATION

Acta Psychiatrica ScandinavicaVolume 4, Issue 4 p. 399-411 ON THE DEVELOPMENT OF THE SENILE PLAQUE IN ALZHEIMER'S DISEASE AND OTHER SENILE CEREBRAL DISEASES EXAMINED BY APPLYING DEL RIO HORTEGA'S METHOD OF IMPREGNATION DR. W. J. C. VERHAART, DR. W. J. C. VERHAART LABORATORY OF THE MENTAL HOSPITAL ROSENBURG AT LOOSDUINEN (THE HAGUE).Search for more papers by this author DR. W. J. C. VERHAART, DR. W. J. C. VERHAART LABORATORY OF THE MENTAL HOSPITAL ROSENBURG AT LOOSDUINEN (THE HAGUE).Search for more papers by this author First published: December 1929 https://doi.org/10.1111/j.1600-0447.1929.tb03557.xCitations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume4, Issue4December 1929Pages 399-411 RelatedInformation

THE ORIGIN OF OLIGODENDROGLIA

The origin of the oligodendroglia is still a debated question. This cell, which Cajal called the third element of the brain, apparently has an origin different from that of the microglia. Del Rio Hortega is an advocate of the mesodermic origin of the microglia, although his view is not yet entirely accepted. With the new conception of the ectodermic origin of the meninges, the question of the embryologic derivation of the microglia again comes to the fore and will certainly be the subject of new investigations. I may anticipate my observations by the statement that in my investigations of the meningiomas I have found numerous microglia cells in the tumors themselves. This fact might be considered as in support of the mesodermic origin of the microglia, as well as an argument against it if other elements of ectodermic origin are to be found in the same tissue. In regard to

STAINING OF TISSUES OF THE CENTRAL NERVOUS SYSTEM WITH SILVER

In studies of the so-called staining methods, emphasis has usually been laid on the role of the fixative and on the nature of the silver solution, while relatively little attention has been paid to the action of the reducing agent. Perhaps the first investigator to make use of wide variations in this step was del Rio-Hortega. In the gradual development of his method of staining microglia, he parted from the traditional reduction with 10 or 20 per cent commercial formaldehyde solution and found that selective staining of the cells could be secured by immersing the silver-impregnated sections, without washing, directly into a formaldehyde solution of only 1 per cent (1 cc. of concentrated liquor formaldehydi—approximately 37 per cent—in 100 cc. of distilled water). He also made certain interesting observations on reduction after a variety of intervening washes with, for example, alcohol, pyridine and other liquids. These observations, which I

THE AMMONIACAL SILVER SOLUTIONS USED IN NEUROPATHOLOGY

The methods of staining with silver salts, developed so largely by Fajersztajn and Bielschowsky in Germany, and by Ramon y Cajal and Del Rio-Hortega in Spain, are receiving increasing attention. Several procedures have been described for preparing the ammoniacal silver solutions which are used in these methods, and selective staining results have been attributed to each. The conflicting claims have led at times to actual controversy, and the present investigation aims to clarify this subject.1 (1) The method of Fajersztajn,2described in 1901, is of both historical and theoretical interest (as will be shown later). To a weak solution (exact concentration not given) of silver nitrate (AgNo3), Fajersztajn added until the brown precipitate which formed at first had completely redissolved. He then added more silver nitrate until a precipitate began to form again; the solution, supposedly freed of excess ammonia in this way, was filtered through

THE CAJAL AND HORTEGA GLIA STAINING METHODS

Formaldehyde is still the ideal fixation medium for the preservation of brain tissue. It hardens such material in bulk rapidly and uniformly; it is of great service in the study of changes in the central nervous system, for it offers an opportunity to retain the specimen in its uncut and undisturbed shape for gross morphologic studies before it is dismembered for finer cytologic observations. There is, however, one difficulty—and that is, because of the great assortment of methods devised for a better display of the various components of the nerve tissue and their numerous pathologic changes, there is need of a large variety of fixatives. This holds true for the many methods of staining neuroglia, and it is particularly essential for Cajal's1gold chloride and sublimate method as well as for its more recent modifications introduced by Achucarro and Del Rio Hortega.2 Cajal's staining method demands that fresh

ACUTE SWELLING OF OLIGODENDROGLIA

The introduction of a cytologic method which throws new light on anatomic structure is often the preliminary step toward a further knowledge of pathologic changes. Del Rio-Hortega's description of oligodendroglia 1 by the use of his silver carbonate method has made possible the following study which shows that these cells undergo a specific alteration which is often the only evidence of a pathologic process in the central nervous system. CLASSIFICATION OF THE INTERSTITIAL CELLS Under the heading of interstitial cells are included neuroglia and microglia cells. The most concise and complete modern description of neuroglia astrocytes is to be found in a publication by Cajal 2 in 1913. Much of this description was, of course, not new but the gold chloride method which he devised led him to certain definite conclusions. He gave a clearer picture of the fibrous astrocytes of the white matter and the protoplasmic astrocytes of

THE CAREER OF RAMÓN Y CAJAL

DON SANTIAGO RAMON Y CAJAL It has been said many a time that the problem of Spain is a problem of culture. It is necessary in fact, if we would enroll ourselves with the civilized peoples, that we cultivate intensively the deserts of our land and brain thus rescuing by prosperity and mental vigor all those national riches that have been lost in the sea and all those talents which have been lost in ignorance. These words were scrawled in Spanish across the portrait of Ramon y Cajal. I had been conscious of keen eyes looking down from out that portrait during my first day of work in the laboratory of Pio del Rio-Hortega, and finally stopped to decipher the scrawl. Before coming to Spain I had learned much of the scientist Cajal, the great master of the Spanish school of neurology, from his scientific publications. But the writer