Showing papers in "Annals of the New York Academy of Sciences in 1951"

Techniques for the preservaation of three-dimensional structure in preparing specimens for the electron microscope†

Abstract: Before examination of biological specimens can take place all volatiles must be removed. This presented paper details a method of sample preparation that reduces distortion and maintains 3-dimensional structure. Freeze drying disrupts cell structures as phase boundaries move through the specimen twice, first a solid boundary in the freezing process then a solid-vapor boundary during sublimation. To eliminate this the temperature of the ambient liquid is raised above its critical point. When it reaches the region where two phases cannot exist surface tension vanishes and fluid can escape without disrupting structures. Specimen preparation is given. Place droplet on a formvar-coated screen and fix with osmic acid vapor. Replace water with alcohol and alcohol with amyl acetate. Place specimen in a bomb and flood this with liquid carbon dioxide to replace the amyl acetate. Raise the temperature in the bomb to 35 Centigrade. Previous determinations show this to be above the critical point for carbon dioxide. Stereoscopic views of electron micrographs show three prepared specimens. There remains some minor distortion and flattening against the formvar screen. Outlines a method to retain cell structure in samples destined for the scanning electron microscope.

Patterned loss of hair in man; types and incidence.

Abstract: This account summarizes certain aspects of a study which is to be published in detail eisewhere and has the following aims: (1) To establish types or categories of scalp hairiness which can be used as standards for classitication and grading of the extent of common ba1dness.t (2) To survey the incidence of these scalp types in members of each sex throughout life, beginning with the first appearance of hair in the fetus. (3) To gain information regarding the relationship of scdp types to factors which influence the development of baldness, in particular to genetic, age, and endocrine factors. (4) To ascertain if bald men, as compared with men who did not become bald, have higher titers of urinary ketosteroids or a greater development of a secondary sex character, axillary hair, which can be measured quantitatively and used as an index of certain aspects of the endocrine status. This part af the study stems from the fact that common baldness is induced by androgenic stimulation (Hamilton, 1942). ( 5 ) To test if the tendency to acquire baldness of the scalp is associated with a disposition to baldness on another part of the body where alopecia is common, i e . , on the lateral surfaces of the legs.

The pharmacology of Flaxedil, with observations on certain analogs.

Abstract: Until as recently as 1946, the classical pharmacologic action of the natural curare alkaloids had had no counterpart in the many synthetic compounds examined in laboratories of pharmacology and physiology. True, Crum Hrown and Fraserl had described a paralytic action resulting from the yuaternization of the nitrogen atom of certain alkaloids, but this effect was soon proved to he characteristic for most quaternary amines and was recognized by physiologists as different in mechanism from the neuromuscular blockade produced by the natural curare alkaloids. In 1946, Bovet and his collaborators attempted to reproduce synthetically a simplified version of the d-tubocurarine molecule. They achieved the synthesis of a series of bis quinoline derivatives wherein the aromatic structures were connected through a methylene chain by ether linkages.‘ These compounds were actively curariform. Shortly thereafter, they examined simple mono and poly phenolic ethers of certain amino alcohols and found that these substances also possessed a striking curariform action.a In the latter series was the compound, triiodoethylate of Iris (triethylamino ethoxy) 1,2,3 benzene. This compound, named Flaxedil, exerted a potent curariform action in the rabbit. The following year! Barlow and In$ and I’aton and Zaimis5 reported that the paralytic action of quaternary amines could be intensified by the twinning of the aniine groups through polymethylene chains of varying lengths. This represented, in principle, the distant quaternary ammonium groups found in the molecule of d-tubocurarine. Most recently, Kimura et d6 described the potent neuromuscular blocking action that results from the twinning of two atropine molecules through an amyl chain. Thus, the principle was established by which compounds with strong neuromuscular blocking action could be synthesized by establishing at least two quaternary ammonium groupings a t an optimal intramolecular,distance. Of these compounds, two have had a considerable preliminary clinical trial in the practice of anesthesiology, namely, Flaxedil and decamethonium bromide, the bis trimethylammonium decamethylene compound. The present report is concerned with the pharmacologic properties of Flaxedil, particularly as they compare with those of d-tubocurarine. The onset and development of paralysis that follows the intravenous injection of Flaxedil into the intact cat is entirely like that occurring in this animal after an equipotent dose of d-tubocurarine. The order of events is such that the respiratory musculature is usually the last to succumb. As with other compounds of this nature, resulting paralysis of the muscles of respiration is not only the direct cause of death but the

The effect of insulin and pituitary hormones on glucose uptake in muscle.

Abstract: The purpose of this paper is to summarize the present state of our knowledge about two problems: first, the means by which insulin enhances glucose uptake by tissues; and second, the nature and loci of action of the anterior pituitary fractions which influence glucose uptake and utilization. Experiments with whole or eviscerated animals, with isolated tissues, and with cell-free enzyme systems will be considered. Because of limitations of time and space, I shall discuss principally experimental work by our own group* and will not undertake a complete literature review.

Regeneration and rate of growth of hairs in man

Abstract: The position of orifices of hair follicles was charted with reference to one to four small, permanent tattoos which were made in the skin with India ink. The tattoos were judged to be permanent if the ink could still be seen 48 hours after tattooing. At this time, the position of the tattoos and the orifices of follicles containing terminal hairs was drawn to scale as illustrated in FIGURE 1. Areas chosen for tattooing contained 6 to 12 hairs. The separately identified hairs were then plucked and preserved for microscopical study. A few hairs were observed to break upon plucking. If the stub could not be pulled immediately, it was removed after an interval of 7 days. Plucked areas were observed a t weekly intervals until the regeneration of hairs had been completed. A hair was considered to have regenerated when its tip projected above the skin. The time required for regeneration of a hair was calculated upon the number of days between plucking of an old hair and the appearance of a new hair above the skin, as observed a t intervals of 7 days. If a new

Radiation sensitivity of cells during mitotic and meiotic cycles with emphasis on possible cytochemical changes

Abstract: A number of recent reviews (Catche~ide,~~. 47 Dobson and Lawrence,s5 I ) r a ~ e r , ~ l Fano and Demerec,loM Giese,122 Goodspeed and Uber,130 Henshaw and Francis,14? Ho1laender,ls4 Lavedan,llYI Lea,201 Spear,32L Timofeeff-Ressovsky and Zimmer,345. 346 and various papers in Brit. Med. Bull. 4: 1, and Suppl. 1, Brit. J. Radiol., 1946) are concerned mainly with the effects of radiations on living cells, but, for the most part, they do not give adequate consideration to the problem of sensitivity changes or to the interrelationships between radiosensitivity and the various factors which may cause an increase or decrease in cell sensitivity. In the present review, particular emphasis will be given to the changes in radiosensitivity which occur during the meiotic and mitotic nuclear (or chromosome) cycles, and an attempt will be made to summarize the existing information on the basis of physiological, biochemical, or cytochemical factors which may seem pertinent to the general problem. Differences in the radiosensitivity of cells and tissues not only are of theoretical interest but are of considerable practical importance. Differences in susceptibility of neoplastic z's. normal tissue has long been utilized in X ray and radium therapy, but the practice is largely empirical, since the reasons for the difference are not well understood. This is not too surprising, however, since the fundamentals of the mechanism (or mechanisms) of the biological effect of radiations on living cells are likewise only partially understood. The interaction of X-ray photons, or other ionizing particles, with protoplasm is generally considered to be mediated by excitations and/or ionizations, either directly or indirectly. This is, however, only the first step in a chain of events which ends in a recognizable biological effect. The intermediate steps are probably, in most cases, a complex series of events or reactions which in some instances, e.g., mutations, result in a stable chemical change in certain protein or nucleoprotein constituents of the nucleus, and, in others, in unstable or degenerative changes. It is highly probable that most, if not all, species of organic molecules present in a cell suffer some change as a result of the energy transformations involved in the absorption of ionizing radiation. The effect on the biological functions of the cell, however, may not be proportional to the total number of all molecules affected but, rather, dependent upon the damage caused to particular molecular species or specific loci which are present within the cell in limited numbers and are involved in essential activities of cellular physiology or coordination. CYTOCHEMICAL CHANGES*

The keratinization of epidermis and its derivatives, especially the hair, as shown by x-ray diffraction and histochemical studies.

Abstract: The production of keratin appears to be the chief metabolic achievement of the epidermis and its derivatives. The keratins, as we know them today, are proteins which contain variable amounts of sulfur and may be associated with lipids. Their chemical differences have led to a separation of the keratins by Unna into the so-called A and B types.’ In turn, this has given rise to the concept of two corresponding processes of keratinization, i.e., “soft” and “hard” keratinbation.* In soft keratinization, the cells of the Malpighian layers become cornified after passing through a granular and a glassy stage, as may be seen in the epidermis, as well as in corns and callouses, the eponychium of nails, and the medulla of the An area of epidermis on the inner surface of the leg of the horse, the so-called horse burr, is thick enough to make possible a separation of the Malpighian from the cornified layer for chemical studies of soft keratinization. On the other hand, hard keratinization takes place by a progressive transformation of the Malpighian cells into cornified layers, through a transition or keratogenous zone without granular or glassy stages. Nails, horns, hooves, and claws, as well as the cortex and cuticle of the hair, are made up of hard Thus, the hair combines the two types of keratinization, since it consists of a ‘‘soft” medulla and a “hard” cortex and cuticle.2* Chemical Diferences between Malpighian and Corni$ed Layers of the Epidermis and Its Derivatives. Since Malpighian and cornified layers are common to both types of keratinization, it is instructive to ask how these layers differ from, or are similar to, one another. The histological differences are the most obvious, since Malpighian cells show all the attributes of active function (well formed nuclei, mitochondria, elc.) , while the cells of the cornified layers no longer show signs of vitality. Histochemical studies also show the predominance of active metabolites in the Malpighian zone. Desoxyribonucleic acid5* and small amounts of ribonucleic acid7 have been found in the cells of the Malpighian layers, but not in the cornified layers (see Dempsey’s paper in this monograph). Another difference was brought to light by the demonstration of the presence of ascorbic acid in Malpighian layers of soft and hard keratin structures (0.08 to 0.14 mg./gm.), while less than 0.01 mg./gm. could be found in the cornified layers.* Similarly, the leuco-fuchsin reagent, applied to frozen sections of skin to detect the combined aldehyde groups of plasmalogens, gave a positive reaction in Malpighian layers only.IO In studies on the distribution of alkaline phosphatase, the Malpighian layers of the epidermis gave a slight reaction,”-I3 while those of the hair follicle gave a pronounced

The hair cycle of the mouse and its importance in the study of sequences of experimental carcinogenesis

Abstract: This paper is the outcome of experiments made in 1937, 1938, and 1939 for the purpose of following sequences antecedent to tumor formations resulting from applications of 3,4benzpyrene and 20-methylcholanthrene to the skin of mice. My purpose is to present observations which I believe are of value for the interpretation and evaluation of similar published studies, many of which, fortunately for such purposes, are well illustrated by photomicrographs. I have seen very few that have not been objectively described previously. For my own understanding, I was forced into a study of the hair cycle of the mouse and found that consideration of the whole pattern was important, from the initiation of new follicle formation, resulting in a structure extending from the epidermis to the muscle panniculus, to the ascent of the completed hair, where its club end comes to rest close to the surface of the skin. Growth and atrophy are involved, and a knowledge of both sequences is essential for the interpretation of the pathologic results with which we are concerned. No feature of the microscopic pictures found in chemically treated skins can be regarded as static. I make no attempt to include cytological descriptions. I have excluded, as far as possible, complications resulting from trauma by companion mice, and from the presence of ectoparasites. Protection of areas by crust formation has also been considered. The Hair of the Mouse. Hair is the product of epithelium. The initial growth originates in buds composed of cells of the basal layer of the epidermis. Concurrently, a cluster of mesenchymal cells, the future papilla, may be seen. Which structure, epithelial or mesenchymal, is formed first, has not been determined. Stohr,' for human lanugo hair, gives lengthy consideration to this problem. A t the age of one day, in the first follicles to form, the papilla cells have invaginated the hair bulb, the hair matrix is cone-shaped, and the hair shaft is forming. At four days, the hair bulb has reached the subcutaneous muscle panniculus and the tips of the hair have penetrated the epidermis. At seven days, the internal sheath cells (layers of Huxley and Henle) have disintegrated and the hair canal has formed. At 11 to 14 days, growth of hair is about completed, the hair club has begun to form, and the cells of the matrix have begun to atrophy. At 22 to 23 days, the hair club has reached its final position in the dermis. Growth of the follicles of the first hair coat does not begin simultaneously. The larger covering hairs take the lead. According to Gibbs? in the first five days, there are four major waves of hair follicle development, but new follicles continue to form on the 6th, 7th, and

Metabolic effects of thyroxine in vitro.

Abstract: Studies of the mechanism by which the hormone of the thyroid gland exerts its metabolic effects must of necessity be designed to obtain information relevant to several different questions. First of all, it is necessary to learn the chemical nature of the metabolically active form of the hormone, and it is desirable to know which modifications of the structure can be made without loss of activity and which result in complete loss of activity. Secondly, it is necessary to learn the level of protoplasmic organization at which the hormone exerts its influence. The final question is, by what exact mechanism is the influence exerted? Biochemists, currently, want this answer in terms of effects of the hormone on enzymatically catalyzed reactions. The studies of Taurog and Chaikoffl and of Laidlaw* lead us to believe that thyroxine itself is the circulating form of the thyroid hormone. Whether thyroxine undergoes metabolic and structural changes within the cells it influences before it becomes the active hormone is still not known. Rather wide deviations from the structure of thyroxine are permissible without complete elimination of hormonal activity.8 Neimann and coworkers4 have interpreted the biological activitp of their synthetic isomers of thyroxine as indicating that only those structures capable of oxidation to a quinoid form have hormone activity. This renewed interest in the concept long championed by KendalP: that thyroxine participated in oxidationreduction systems. In regard to the level of organization required to demonstrate metabolic effects of the hormone, considerably more data are available. An increased rate of oxygen consumption has been observed in a number of different organs removed from animals which had previously been given relatively large large doses of thyroxine or thyroid substance. The response is still apparent in tissue slices and in several cases has been traced to an actual increase in the tissue content of certain enzymes. A considerable time interval is needed, following administration of the hormone, before such responses can be observed. When thyroxine is applied directly to surviving tissue in vitro, less consistent results are obtained. To cite an example, Davis, Da Costa, and Hastings7 found that the addition of thyroxine to excised, intact frog heart increased the rate of respiration, but if the heart was sliced no effect was obtained. Some workers80 have found extremely low concentrations of thyroxine to accelerate methylene blue reduction by minced muscle. The comparatively few reports of thyroxine accelerating oxygen consumption of minced tissue seem not to have been confirmed.'O As far as the mechanism of thyroxine's action on enzyme systems is concerned, everything remains to be discovered. Our experiments in this field began in 1942, when we attempted to confirm the report of Carter\" that thyroxine increased the respiration of rabbit spermatozoa. We found that

Types and distribution of the hair in man.

Abstract: Unlike other taxonomic criteria, hair can be used both to compare man to other primates, and to compare sub-groups of the genus Homo to each other. In the amount of hair, and the number of morphological types of hair, man differs from all other primates, while in the form, distribution, and development of the body hair, racial differences are great. It is not surprising, therefore, that most racial taxonomies have used hair form and distribution,' and some classiiications (like Deniker's) have made hair the principal criterion of race? As Weidenreich has pointed out, human taxonomies are unique in the importance given to hair: yet no other characteristic that has been employed is more suitable as a sorting criterion. Although the major racial differences in hair form and distribution have been known for a long time, our present knowledge of the form, structure, and distribution is largely limited to the hair of the face, head, and extremities. Until recently, few comparative studies had included data on the hair of. the trunk, and its patterns. Though physical anthropologists have rated hairiness, the categories have remained undefined, and the entire body was rarely included in such ratings. Recently, however, it has become practicable to examine and rate the nude subject, and the attention of anthropologists has therefore shifted from the face and head to the entire body. The pioneer quantitative study of body hair, conducted by Danforth and Trotter' over twenty years ago, has been followed by the recent investigation of Dupertuis, Atkinson, and Elftman,6 and studies by the author.6. 'I These investigations have developed standardized methods for rating body hair, both directly and from photographs. During this time, child-growth studies have contributed data on the growth and development of the adult hair pattern. The appearance of pubic hair, and the development of body hair a t puberty has been studied by Greulich in boyss and by Pryor in girlsQ and has been summarized by Stuart.'O Reynolds and Wines have considered the relationship between pubic hair development and maturation,\" while the relationships between body hair, physique, and sexual dimorphism in the adolescent and young adult have been treated by Bullen and Hardy,'2 Sheldon, Tucker, and st even^,'^ Bayley and Bayer,I4 and others. Since the studies mentioned have been conducted on draftees, adolescents, and college students in this country, published data is largely confined to young American whites. Now, due to the current interest in body-build, there are available extensive collections of somatotype photographs taken during medical and anthropological examinations, and these photographs are suitable for comparative racial studies of body hair, as well as investigations of hair changes in older age groups. Body-build photographs now on file include extensive series of American whites, Negroes, Chinese, Japanese,16 Navajo,*B Aleut,I7 and Micronesians.Is Reports on the body-

The results of x-ray diffraction studies on keratin fibers.

Abstract: Polypeptide Chain Configurations in Keratin Fibers. Animal hairs and other keratinous tissues have occupied a central place in the study of the fine structure of protein fibers. Much of this development is due to British investigators, who have introduced concepts and terminology widely encountered in the literature. The roles of side chains and backbones in the folding and unfolding of polypeptide chains are now almost classical parts of the thinking regarding these systems. According to the views of the British school, the polypeptide molecular chains of the better arranged (crystalline or fibrillar) portions of many fibers may exist in t h r g principal stages of contraction or extension, each characterized by a distinctive X-ray diffraction diagram (Astbury and Bell, 1939). These diagrams have been interpreted, in relation to other physical and chemical observations, as indicating that the following are the, three principal structural configurations available to the polypeptide chains (FIGURE 1). Normally, in such structures as mammalian hairs, the chains are in the somewhat contracted or a form. Under certain conditions, notably a t elevated temperatures in aqueous environments, the application of longitudinal tension results in an elongation (70 to 100 per cent), with transformation to an extended or 8 state. In similar environments (with possibly the help of reducing and/or hydrogen-bond relaxing agents), complete release of tension will eventually result in a third, or supercontracted, state, in which the fiber has contracted to considerably less than the original length (ca. 30 per cent). Early studies showed that supercontracted fibers may be in a condition exhibiting disoriented, &type dzractions. Subsequently, Rudall (1946), working largely with epidermal material, concluded that the chains are often thrown into long folds of specific type, the loops of which extend normal to the fiber axis (an exaggeration of the folds of a type shown in FIGURE la). The arms of the folds develop a structure much like the extended (parallel-8) form, except for predominant orientation of the mainchain segments normal to the fiber axis (the cross-8 configuration). Rudall found that saturated urea solution at room temperature is a particularly useful reagent for securing, under appropriate conditions of tension, reversal of the crossand parallel-8 forms back to the original a condition. Transformations of this sort, however, become more difficult if the fiber has previously been held in steam a t a given length, allowed to relax its tension spontaneously, and then permitted to become set in the new configuration. Speakman (1947), in particular, has defended the view that the processes of relaxation and set involve chiefly the interaction of side chains. During

Some Aspects of the Relationship Between Chemical Constitution and Curare-Like Activity

Abstract: Historical Background. Curarizing substances represent a group of pharmacodynamic agents whose effects reproduce those of different types of Indian curare and its active principles (d-tubocurarine, C-toxiferine, Ccurarine I). The precise meaning of the term, curarizing agents, has varied greatly. While, in the beginning, it served to denote those compounds which could produce in mammals an intoxication analogous to that of Indian curare (Crum-Brown,l Tillie2), the name “curarizing agent” was rapidly extended to cover a great number of substances which could block synaptic transmission in frog’s muscle. Thus, Santesson3 listed together such different compounds as quaternary ammonium bases, pyridine, quinoline, aconitine, delphinine, muscarine, and veratrine. An early attempt a t classification was made by Lapicq~e ,~ who grouped the products which block neuromuscular transmission according to their modification of nervous and muscular excitability. Although the mass of chemical and pharmacological research has shown the common properties of the group made up of natural curares and derivatives with quaternary ammonium function (Kiilz,6 Ing,6 Raventos,? etc.), the electrophysiological conception prevailed and, for many years, the terms “curarization” and “curarizing action” served to indicate the neuromuscular block, regardless of its mechanism and the dosage of the agent on the frog sciatic-gastrocnemius preparation. The introduction of curare in anesthesia and the researches made in attempts to find synthetic derivatives with analogous properties required a revision of our ideas in this field. The first result was the recognition of the connection between curarizing compounds and the group of cholinergic substances. We have recently shown* that, as a result of the recent progress in physiological it was advisable to give a definition of the whole group based upon the competitive antagonism which is exerted towards acetylcholine in striated muscle. From a strictly pharmacological viewpoint, we proposed12 to define curare-like agents on the basis of three groups of properties: (1) those substances for which a competitive antagonism towards acetylcholine is responsible for the neuromuscular block; (2) those which exhibited in mammals properties similar to those of d-tubocurarine; and (3) those for which there are no important secondary reactions (for example, either central or cardiovascular). All three points of view are equally important. Present Conceptions.

The development of pelage hairs and vibrissae from skin in tissue culture.

Abstract: Hair is recognized as one of the most sensitive indicators of bodily health in man and animals; but, although we know that many factors in heredity and environment affect the formation and growth of hair, we do not understand how they act. We need first of all to find out which effects are due to direct action on the skin and which are secondary to other physiological changes. For this reason, great interest centers on experimental methods of modifying the environment of skin. Skin grafting is a valuable tool in the analysis of hair follicle behavior, and use has been made of autografts,\" homografts,3 and even interspecific grafts.4* I t is not yet possible to obtain permanent homografts of adult skin.6 Two important advantages are obtained by removing the skin to an even more unnatural environment, a tissue culture chamber: first, the complexities of a continually changing blood supply are avoided, and second, the day by day observation of living follicles is made possible. Two kinds of hairs have received attention from those who attempted to cultivate skin and hair follicles in evitro. They are the tactile hairs, or vibrissae, which are found in most mammals on the face and a t other specific sites, and the pelage hairs, which cover the general body surface. The vibrissae are larger and more specialized hairs with a sensory function?' They are usually the first to develop in the embryo, and this gives them some advantages as material for tissue culture. Although intermediate forms do OCCUT,~ it is easy in practice to distinguish vibrissae from pelage hairs. It is well known that the tissues from embryos will differentiate more readily in vitro than will those of adults, and, for that reason, the study of hairs in tissue culture began with embryonic skin. Strangewayslo was the first to do this. She reported in a short note that pelage hair follicles from guinea pig embryos underwent a little development in tissue culture, but that vibrissa follicles gave more satisfactory results. Murray\" indicated in an abstract that she had cultivated the vibrissa follicles of rat embryos and obtained good differentiation and hair production. Both authorslo, Is were less successful with the later developing pelage hair follicles, and attributed their failure to the thickening and keratinization of the epidermis, which discouraged further development of the follicles. HardyI3 explanted skin from the trunk of mouse embryos, and this tissue underwent all the stages of normal follicle differentiation, which led to the production of keratinized pelage hairs. This development was observed in

Morphology and phylogeny of hair

Abstract: Hair is a structure found exclusively in mammals. With this in mind, Oken named the Mammalia, Trichozoa (hair animals), and Bonnet (1892) named them Piliiera (hair bearers). Of the many aspects of morphology and phylogeny of hair, only four will be discussed. These include (1) the principle of the arrangement of hairs in group patterns, (2) the types of hair and their relation to the principle of the group pattern, (3) a brief analysis of the structural elements of hair and their relation to the types of hair, and (4) the phylogeny of hair, with some remarks on (a) the relation of hair to the epidermal derivatives of other vertebrate classes and (b) aspects of the phylogeny of the hair and wool of sheep to illustrate that marked differences in hair coats exist between closely related animals. Hair is the subject of a voluminous literature. Toldt (1910, 1912, 1914, and 1935), Danforth (192Sa), Pinkus (1927), Pax and Arndt (1929-1938), Trotter (1932), Lochte (1938), Smith and Glaister (1939), and Stoves (1943a) discuss the problem of mammalian hair in general. Wildman (1940), von Bergen and Krause (1942), and the American Society for Testing Materials (1948) discuss the problem of fiber identification as applied to textiles.

β–GLUCURONIDASE AND THE ACTION OF STEROID HORMONES

Abstract: It may be desirable a t the outset to define the goals of research in the field of enzymes and the steroid hormones. In the first place, it is understandable that the explanation of the biological action of the sex steroids should be sought in the realm of enzymatic phenomena. Thus, as we know, the generalization that most biochemical reactions in the living organism are catalyzed by specific enzymes is widely held and accepted. Moreover, the success which has been realized in establishing the participation of various vitamins in essential specific enzyme systems of the cell has, in turn, led to the expectation that the steroid hormones may similarly be shown to be components of important enzyme systems. General Considerations. First, some of the concepts will be outlined which may apply to the participation of steroids in tissue enzyme systems. Reference will be made only to the estrogenic hormones presented in FIGURES 1 and 2. FIGURE 1 is a simplified picture of estrogen metabolism which indicates the main pathways of estrogen in the body. As can be seen, two forms of estrogen occur in the body, free and conjugated. The free estrogen may either be excreted mostly in the bile or be degraded oxidatively in the liver by non-specific oxidases. The conjugate of estrogen (either its glucuronide or sulfate) is excreted in the urine. Both free estrogen and its conjugates will stimulate growth processes in the secondary sex tissues. Accordingly, it is felt that the explanation of the action of the estrogens in terms of enzyme phenomena should be sought in these mechanisms labeled A and B, which may possibly be one and the same process. The utilization of estrogen as an integral component of an enzyme system is most simply represented in FIGURE 2. Enzyme X, which is the term signifying that the enzyme is hypothetical and as yet unidentified, should be the limiting factor in tissue growth stimulated by estrogen. If we may reason by analogy from experiences in the enzyme-vitamin field, all vitamin coenzymes which have been studied thus far are acidic in nature. It may not be too unreasonable to predict that, should the sex steroids be found to constitute coenzymes, these hormones will possess acid functions. Estrogen may participate in an enzyme system as a specific substrate, as in FIGURE 2. Perhaps the enzyme-substrate complex has a physiological function in growth which is distinct from its enzymological significance. It is necessary in a field as new and as confused as that constituting steroid-enzyme phenomena to distinguish between primary and secondary enzyme reactions resulting from hormonal action. A primary enzyme reaction of hormone-induced growth, in this regard, may be defined as one in which the steroid participates directly, either as coenzyme, substrate, activator, or inhibitor. Accordingly, secondary enzyme reactions of hor-

Analysis of mixtures based on rates of reaction

Abstract: The analysis, by conventional means, of mixtures of two constituents that have similar chemical properties is often difficult or impossible. Mixtures of two organic compounds that contain the same functional group (e.g., two esters or two aldehydes) are frequently encountered and present special difficulties to the analyst. For example, mixtures of homologous organic compounds or of certain orthoand para-isomers usually cannot be analyzed by classical chemical methods. Methods that depend on physical properties of the compounds are usually not suitable either. In illustration of this point, ultraviolet spectrophotometry cannot be used to analyze a mixture of homologous ketones because the spectrum of each ketone is determined chiefly by the carbonyl group and is affected only slightly by the nature of the alkyl group substituents. Infrared spectrophotometry, which is capable of distinguishing between homologous organic compounds, requires expensive equipment and is frequently not applicable if the sample is available only as a dilute solution in water or in certain other common solvents. (On the other hand, infrared analysis is ideal if the apparatus is available and if the sample is available in a suitable form.) I t frequently happens that such mixtures of organic compounds can be analyzed by a method based on differences in rates of reactions of the components of the mixture with a given reagent. The effect of a substituent on the rate of reaction of a reactive group with a particular reagent is usually pronounced. Propylene, for example, reacts with perbenzoic acid a t only one-thirtieth the rate a t which 2-butylene reacts (see below). Methyl alcohol reacts with hydrobromic acid nearly six times as rapidly as ethyl alcohol does (solvent phenol, SO').' It should be pointed out, however, that, if the substituents of the functional group are quite similar, as for example, n-butyl and n-amyl, the method of analysis based on reaction rate cannot be applied. Furthermore, the method is generally limited to mixtures of two components. Highly specific methods for the analysis of mixtures based on rates of reaction have been described previously in the literature?-' Most of these methods were developed for the investigation of specific physical chemical problems and are not convenient as general analytical procedures. They differ greatly from the proposed general method. In order to understand the principles underlying the proposed method of analysis, consider two compounds, A and B, that react with a reagent R a t different rates. Suppose that the reaction of A with R is faster than the reaction of B with R, a t a given constant temperature. Mixtures of A and B can be analyzed by the following procedure. A reaction solution is prepared in which the the total molar concentration of A + B is specified and in which the con-

An evaluation of experimental procedures used in a fundamental study of human locomotion.

Abstract: A cntical evaluation of an experimental study of locomotion should include a consideration of the following elements. First, why is such a study undertaken and of what use will be the information obtained from it? Second, what techniques may be utiiized, and what are the advantages, i i i t a tions, and shortcomings of the procedures employed? The final evaluation of an experimental procedure in respect to the abovementioned elements can only be reached after the techniques have been actually employed. Some of the techniques which we envisioned as yielding fundamental information have proved disappointing because of the failure to consider a11 factors before their employrnent. Other techniques which we felt would be of limited value were found to be singularly significant as a source of fundamental information. Because of our experience, we feel that a review of the techniques employed and a critical evaluation of the experimental procedures would prove of value to other investigators who might enter the field of human locomotion and assist in the interpretation of results from the work st i i i in progress. Remoias for the Study of Auman Locomoiion. The reasons for studying human locomotion may be divided into four main categories. (i) The orthopedic surgeon is called upon frequentiy to attempt surgical procedures in order to improve the function of the locomotor system in individuals who have suffered damage to it. This includes not only fractures, but damage to joints and muscles. T t is obvious that any attempted surgicai procedure with any hope of success must depend upon an accurate knowledge of the functions of the parts involved. (2) Tlie physiotherapist has definite need of similar information in order to provide adequate treatment and proper functional training of impaired parts. (3) ?%en portions of the locomotor system are irreparably injured, the surgeon must rely upon externa1 support. These supporting braces must be designed for the work demanded of them without restraining the remaining normal functions if they are to prove of value. (4) M'ith the loss of a part, as in the amputee, an attempt is made to replace the lost portion with a prosthesis. How poorly we have succeeded in duplicaiing nature is evidenced daily by the individual who is in contact with the amputee. It is apparent that any improvement, either in surgical and physiotherapeutic procedures, or in braces and prostheses, must depend upon better knowledge of the function of the locomotor system.

Measurement of the rate of proliferation of epidermis and associated structures

Abstract: It is widely known that the epidermis undergoes growth and replacement throughout life. Flemming, in 1884, discovered the presence of mitoses in the Malpighian layers of the human epidermis.’ He realized that the new cells produced by these mitoses exert a pressure which results in a movement of the cells to the region of least resistance, that is, toward the surface. It was soon found that epidermal derivatives, such as the hair and nail, also include a Malpighian layer where mitosis takes place, resulting in an outward displacement of the cells. In both epidermis and its derivatives, the Malpighian cells, on their way out, are transformed into a horny material forming the keratinized layers. This transformation may, however, occur in two different ways:* soft keratinization, as in the epidermis itself, in which the cornified cells are spontaneously desquamated and shed from the surface; or hard keratinization, as in nail and hair cortex, in which the cornified material is particularly hard and lengthens indefinitely. While the evolution of the cells of the epidermis and its derivatives has been known for a long time, much remains to be learned about the rate a t which this phenomenon proceeds. The measurements of the rate of proliferation, easily obtained in “hard keratin’’ structures, are rather difficult in “soft keratin.” After briefly discussing the former, most of this report will critically discuss the measurement of the rate of proliferation in cases of soft keratinization. Since “hard keratin” structures grow indefinitely, their rate of growth can be measured by estimating their increase in size over a definite period of time. Thus, direct measurement is possible in the case of the nail, where growth is cont inu~us.~ Giroud and Bulliard4 estimated the rate of growth of human nails. The maximum rate is observed from the age of 5 to 30. The growth rates vary in dillerent locations. Thus, the nails of the fingers grow faster than those of the feet, approximately 1 mm. per week in the former, compared with 0.25 mm. per week in the latter. Also, the different growth rates are related to the size of matrix. Where the matrix is broad and long, as in the thumb, the nail grows 1.20 mm. per week, compared with 0.90 mm. per week in the finger nails, where the matrix is short. Direct measurement is also possible with the hair: thus, the hairs of the leg grow a t the rate of about one and one half mm. a week,6 and those of the pubic and axillary region grow about 2.2 mm. a week after puberty.l. Hair growth is continuous only in a few cases, however, such as human scalp and sheep wool. Vsually, hair growth is cyclic, as it proceeds for some time until the hair falls and a new hair starts growing again.6. ’ Thus, Butcher Department of Anatonty, McCill University, Montreal, Canada

The Action of Podophyllin and its Fractions on Marine Eggs

Abstract: Podophyllum peltutum is called the Mandrake by those of classical leanings, or May-apple by those whose interest centers on its sweet, yellow fruit. The European mandrake (Mandragora: Solanaceae) has for centuries been held of value for certain delicate mythical propertieP and for very real toxic and narcotic potency. In the New World, the common name was applied to an entirely different herb in a different family (Berberidaceae). Modern interest in Podophyllum has taken a new trend. This stems directly or indirectly from a publication of Ka~lan ,2~ in which he revealed that podophyllin is strikingly effective in reducing venereal warts, condylomata acuminata, with 25 per cent podophyllin in oil, This simple and effective therapy met with enthusiastic acceptance in both hemispheres, judging from the literature that followed its introd~ct ion.~~ by sectioning biopsy material, showed that podophyllin attacks mitoses in both the condylomata and in normal skin. They were not prepared to say that this destruction of dividing cells is the mechanism of the cure, inasmuch as there is, in addition, a widespread degeneration of a nonspecific Common warts did not yield to 25 per cent podophyllin in oil, but 20 per cent podophyllin in 95 per cent alcohol destroyed 15 of a hundred verrucae vulgares.a6 B. J. Sullivan and Wechsler% found that plant mitoses also could be blocked, using a saturated aqueous podophyllin. Within the meristem of Allium cepa, prometaphases accumulated in the absence of a spindle to complete the division. The chromosomes shortened slightly, but remained attached a t the centromere. The picture is like that of a colchicine block, substantiating the similarity reported by King and Maurice Sullivan. Father T. D. Sullivan37 found a saturated solution of podophyllin useful for blocking mitoses in petunia leaves. With the addition of 0.05 per cent chloral hydrate, further shortening of the chromosomes could be obtained. In the meantime, successes with condyloma therapy inspired intensive work with malignant tumors in at least three separate laboratories. At the National Cancer Institute, Dr. Shear’s chemotherapy group obtained striking pictures of blocked mitoses peppering whole areas of tumor.27 The subsequent necrosis eliminated most of the tumor, but viable cells usually remained. Karyokinesis in normal mouse skin and intestine was also blocked by p0dophyllin.2~ In the chick, the cerebellum was damaged.28 Dr. Morris Belkin;? a t the Medical College of South Carolina, was able King and Maurice

Development of the pilary system and the replacement of hair in mammals

Abstract: The phenomenon of development attracts the attention of many biologists, who often seek rare materials for solving their problems when the skin offers many opportunities and is so easily observed. Much is known regarding the development of the pilary system. However, several problems remain to be solved. Some information undoubtedly will be presented on these problems in some of the subsequent papers, yet many questions will remain as an incentive for further work. The development of the pilary system in our most common laboratory animals, the rat and mouse, will be described first, since many extensive studies have been made on Hair germs become apparent in 17to 20-day fetal rats as a crowding of cells, with a slight convexity, in the deepest layers of the epidermis. These germs continue to form from the stratum germinativum from birth until the age of 10 days. The next stage in their development consists of an increase in their convexity and the appearance of a slight condensation of connective tissue, the prospective papilla, deep to them (FIGURE 1). Further development consista of an elongation of the epithelial bud, whose base is capped by the enlarged prospective papilla (FIGURE 2). In a slightly later stage of development, which occurs typically in the 2-day-old rat, the base of the epithelial portion has enlarged and invaginated to form the bulb of the hair, and the enlarged connective tissue papilla protrudes into the bulb (FIG-

Physically and Chemically Adsorbed Films in the Lubrication of Graphite Sliding Contacts

Abstract: When a graphite rod rubs against a spinning metal ring or cylinder (e.g., copper), small carbon fragments, usually thin enough to be transparent, are deposited upon the metal, where they tend to form a continuous graphitic sliding surface. This film, first isolated by microchemical means,’ was shown to have a representative thickness on unpolished copper of cm. Electron-diffraction patterns of similar films indicated a marked orientation2 in which the basal cleavage face of the graphite crystal tends to lie parallel to the plane of rotational motion. Electron microscopy further showed3 that the orientation was not complete but that a directional overlap persisted, according to the direction of the “stroke.” Many of the crystals were found by stereoscopic means to lie a t various forward angles to this plane, mostly below 45’ but some a t higher angles reaching nearly 90”. When the motion is reversed, a good deal of microscopic surface damage and upheaval may occur until the overlap has been reversed? All of this work proves the presence of a carbon layer interposed between the metal and the carbon rod, in most instances sufficiently thick to obscure or cover completely the adhesional forces of the underlying metal.* Evidently, when the opposing carbon surfaces of the rod and the ring are pressed together in rubbing contact, many islanded areas of basal cleavage plane surface (or carbon-ring networks) will be forced together, as well as some edge areas a t the outer boundaries of the crystals along the prismatic surfaces. The adsorbed films upon each of these will play a controlling part in their mutual cohesion, and thus in the friction. Because the separate contributions of these types of surfaces to the total friction are not known, we assume initially that each is involved. The friction of clean graphite in a vacuums has been shown to be high, the rod or brush dusting away with extreme speed when sliding against the spinning ring. Lubrication is effected instantly by any one of a number of vapors admitted to the friction apparatus a t low pressures. In the case of water vapor, lubrication is completed so as to produce minimum friction at a pressure of about 3 mm. mercury, apparently as the result of the coverage of the graphite surface by a physically adsorbed film. The vapors reduce the wear rate by a factor of 103 or more. High wear in a vacuum occurs even when the graphite is in the form of a crystalline platelet oriented with the cleavage face approximately parallel to the plane of rotational motion.6 This remarkable result shows that the frictional forces upon the clean cleavage face are considerable. This high wear result Introduction. The Carbon Film.

A review of the literature on the potential therapeutic significance of papain.

Abstract: The digestant action of the juice from papaya, a fruit of the melon tree, C U T ~ C U papaya, Linn., has been known for centuries.‘ The results of the experimental investigation of its action first appeared in 1874.2 In 1878, Wittmack in Germany also reported the digestive properties of the milky juice of the papaya3 When he saw these reports in 1879, Peckolt reexamined a precipitate he had made years before from the fresh juice of the unripe papaya in Brazil and confirmed the digestion of meat in a solution of that precipitate, “papay~tin.”~ Later in the same year, Wurtz and Bouchut5 also published their results of experiments on a puritied product from the sap of papaya, designated as “papain.” These well-controlled experiments have been referred to as the first scientific investigation of the enzyme.fi Since that time, the term papain has referred either to the crude dried powdered whole latex from the green papaya’s or to the same material after purification to various degrees by different methods. Other names, such as papaotin, Caroid, and papoid, have also been used for similar products by different manufacturers. The inadequacy of using the term papain to denote only the proteinase component of the whole preparations is made apparent by the thorough investigation of the complicated enzyme system in this preparation during recent years. The term papain used in this review, unless otherwise specified, will be restricted to designate the whole dried product from the latex from the unripe fruit of Carica papaya, which contains proteolytic enzymes and other possible components.

Histological structure of hair, with a brief comparison to other epidermal appendages and epidermis itself

Abstract: Hair plays a fundamental role in the maintenance of body temperature in mammals. Man, whose hair is no more than a symbol of strength or beauty, uses animal hair, such as fur or wool, to achieve the same end. *The remarkable properties of hair-heat-retaining capacity, durability, and resiliency-are due to its high content of a sulfur-containing protein, keratin.* Keratin is also present in epidermis and epidermal appendages, nails, claws, horns, feathers, elc. In all of these structures, the superficial layers, which are impregnated with keratin, arise from the transformation of the cells of the so-called Malpighian layers. Thus, Malpighian and keratinized layers make up the epidermis (FIGURE l), the hair (FIGURE 2), and the other appendages. The Malpighian layers present in all these structures take the form of stratified squamous epithelium, the basal cells of which are separated from the underlying connective tissue by a thin layer of fairly distinct reticular fibers (as can be seen, for instance, a t the limit between epidermis and derma, FIGURE 3). In areas of low biologic activity, such as the outer root sheath of the hair, the reticular fibers fuse to form a continuous basement membrane (FIGURE 4), whereas in areas of high activity, such as the Malpighian layer at the base of the hair follicle, reticular fibers are scarce or even absent (PIGURE S). These facts suggest a relationship between the thinness of the reticular layer and the intensity of the metabolic exchanges across such a layer from the subjacent connective tissue. The activity of the Malpighian layer is related to that of the subjacent tissue in many other ways. Thus it can be shown that the connective tissue beneathactively growing Malpighian layers, e.g., the hair papilla, is highly vascularized, contains many nuclei (FIGURE 7), and is rich in phosphatase' and metachromatic substance^,^ in contrast to the derma in general. The keratinized layers are formed by cells having a fairly homogeneous appearance and in which most cytological details are no longer recognizable. The keratin content is responsible for their low solubility and high resistance to many chemical agents. On the basis of histological appearance and chemical constitution, two types of keratin, namely, soft and hard, can be distinguished. Soft Keratin. The structures containing soft keratin, typically the epidermis, show a characteristic transition between the Malpighian and keratiniied layers. The cells in the upper part of the Malpighian contain irregular basophilic granules which more or less fill up the cytoplasm. This has led to the convention of subdividing the Malpighian layers into a

The relationship of the adrenal, thyroid, and pituitary glands to the growth of hair

Abstract: Since hair appears to be one of the most rapidly growing structures of the body, one might expect that it would serve as a sensitive indicator of the modifying action of hormones on general body growth. In this sense, alterations in the rate of growth of hair might be regarded solely as a reflection of any general metabolic changes induced by the hormones. On the contrary, it is possible that hormones modify the growth of hair in a way that is different from the effects which they elicit elsewhere in the body. In other words, is the response of hair to the action of these humoral agents so unique that the piliary system should be regarded as a special target organ? In the following presentation, we shall seek to analyze the effects of hormones on the piliary system in the light of these two alternatives. The r61e played by the secretions of the adrenal, thyroid, and pituitary glands in the regulation of the growth of hair has been investigated chiefly in two forms, the rat and man. Therefore, information which has been derived from study of the rat will be emphasized and an attempt made to correlate these findings with the more limited information which is available concerning the relationship of these glands to hair in man.