摘要:

AbstractThe determination of the spatial positions, with respect to a head holder reference, of anatomic structures within the brains of experimental animals, based on measurements of coordinates of ventricular and internal cranial landmarks, is described. If “appropriate” landmark arrays are employed, the uncertainty in coordinate values for prechosen anatomic sites in cat brain, determined by the methods outlined in the paper, is reduced by a factor of the order of five compared to the deviations experienced when the Horsley‐Clarke landmarks are employed. The instrumentation system developed for implementing the entire procedure, including precision x‐ray contrast ventriculography, and the atlas and roentgenographic data used to obtain the desired coordinate information are illu

ISSN:0003-276X    

DOI:10.1002/ar.1091470202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractAdult mice of the A/Jax strain were given injections of thymidine‐H3at proestrus and injections of estrogen at one day intervals thereafter, up to eight days. Mice were killed at daily intervals and longitudinal sections of vagina were radioautographed. Cells which were immediately above the basal layer at proestrus, and which would have given rise to the mucous, nucleated cell layer, eventually produced an interruption in the otherwise continuous cornification of the surface layers. A similar experiment, begun at late metestrus, produced comparable results, except that the interruption of cornification was more pronounced.Mice which had been ovariectomized two weeks previously were given injections of estradiol and thymidine‐H3. Cells at the surface continued to show a low frequency of mitotic activity and retained their nuclei after estradiol treatment. They were finally sloughed by the squamous transformation of underlying cells. The latter were derived originally from the basal layer under the influence of estradiol, which led to greatly accelerated mitotic activity in that layer. It is concluded that the course of cellular differentiation in these migrating cells is fixed when they are produced by mitosis of basal cells. This differentiation can only be modified, not reversed, by subsequent estradiol treatment even when the cells involved are still capable of undergoing mito

ISSN:0003-276X    

DOI:10.1002/ar.1091470203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractThe different anatomic properties of the three major coronary arteries of the dog were revealed by reconstruction of serial histologic sections. It was found that while the right and circumflex arteries consist of sequential segments of muscles arising and inserting into the adventitia, the anterior descending has a distinctly different muscle pattern. In the right coronary artery, six muscle bundles occur in short segments (0.6 mm in length), while only four arranged in longer segments (1.6 mm) characterize the circumflex artery. Two of the four muscle bundles in the anterior descending follow a spiral course down the entire length of the artery, while the other two execute a short spiral with a staggered origin from collagen septa 0.6 mm apart. Of the two types of branching from the major arteries one has no muscle connection, while the other has muscle continuity with the major artery. Innervation of the major arteries occurs at the muscle origin and insertion sites. Nerves penetrate to the intima of the right, circumflex and the structurally independent branches, suggesting interesting reflex control for vasomotion. Movements of the coronary arteries as followed by cineangiographic techniques are apparently determined by the gross movements of the heart, the neuromuscular features of the arteries, and the location of the branches.

ISSN:0003-276X    

DOI:10.1002/ar.1091470204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractOn grounds of electron microscopic appearance (Hama, '60), the side of abdominal photoreceptor organ in crayfish (Orconectes virilis [Hagen]) has been questioned. Illumination of any part of ventral nerve cord (exclusive of A6ganglion), e.g., A2, A3, A4, A5, and afferent roots of A6, shows no physiological response. A6alone shows phototransduction process pulses. Sectioning of cord restricts locus to A6. Spurious effects from cephalic eye response were seen.Physiological investigation has restricted the crayfish‐tail photoreceptor–organ to include photosensitive elements lying only within the sixth abdominal ganglion, and two to four B‐fibers carrying nerve impulse responses through the ventral nerve cord. It is therefore possible to exclude the “Hama‐structures,” associated with the giant fiber system, and located diffusely in the nerve cord, from any role in the phototransduction process. Attention of anatomists is called to this primitive and interesting photorec

ISSN:0003-276X    

DOI:10.1002/ar.1091470205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractThe fine structure of goldfish peripheral blood cells was studied by electron microscopy correlated with light microscopy. Various methods of specimen preparation are described. Optimal preservation for electron micoscopy was attained with fixation in 1% OsO4in acetate‐veronal buffer (pH 7.3) and embedding in Epon. Electron micrographs of erythrocytes reveal division of nucleoplasm into chromatin and interchromatin material, and continuity between the latter and cytoplasm via nuclear pores. Erythrocyte mitochondria contain longitudinally oriented tubular internal structures. Variations in lymphocyte morphology are noted and the close association between membranes of the nuclear envelope, Golgi apparatus and endoplasmic reticulum is shown. Compound granules, the azure granules of stained blood smears, are described. A distinguishing feature of the granulocytes is their specific granulation. Neutrophilic granules appear to be membrane‐enclosed and contain varying amounts of dense material, the amount depending upon maturation, physiological state or degree of preservation. Specific eosinophilic granules are characterized by a dense matrix enclosing one or more crystalloid bodies. The specific granules of the basophil are large, membrane‐enclosed bodies, demonstrating different degrees of electron density. Similarities between thrombocytes and lymphocytes are evident from light and electron microscope studies. A phylogenetic relationship between vertebrate blood cells in indi

ISSN:0003-276X    

DOI:10.1002/ar.1091470206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractErythrocytes in fixed organs ofTragulus javanicus, the mouse deer or chevrotain, were measured and found to average 1.5 m̈ in diameter. This confirms Gulliver's observations, made over a century ago, of the minuteness of these cells. It appears, from the literature, thatTraguluswas considered to be a musk deer by Gulliver and others in his day. This probably accounts for the listing by most text‐books, even recent ones, of the musk deer as having the smallest mammalian erythrocyte. How the musk ox got into the picture is somewhat of a mystery. It is the mouse deer (Tragulus) that has the smallest erythrocyte, not the musk deer (Moschus) and most certainly not the musk ox (Ovibo

ISSN:0003-276X    

DOI:10.1002/ar.1091470207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractThe morphology of the boundary tissue of the seminiferous tubule of the rat has been investigated in testes from animals aged from birth to four months. In the adult, the boundary tissue consists of four layers: (1) an inner non‐cellular layer comprising a network of collagen fibrils sandwiched between two basement membranes (2) an inner cellular layer of flattened cells showing many of the characteristics of smooth muscle, including intracytoplasmic filaments and micropinocytotic vesicles, (3) an outer non‐cellular layer containing scattered colagen fibrils and associated usually with a single basement membrane and (4) an outer cellular layer, component cells of which contain no fine filaments. At birth, the seminiferous tubule rests upon a basement membrane which separates it from a layer of low cuboidal cells. External to this, there is a narrow intercellular zone containing scattered fibrillar material and a region consisting of numerous processes of mesenchyme cells. By ten days postnatal, four definite layers are established due to the differentiation of an outer cellular layer of flattened cells from the mesenchyme, and intracytoplasmic filaments have made their appearance within the inner cellular layer. In subsequent stages there is progressive thinning and specialization of the cellular layers and increased fibril content within the non‐cellular layers. By 22 days postnatal the boundary tissue appears virtually adult in morph

ISSN:0003-276X    

DOI:10.1002/ar.1091470208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractAn electron microscopic study was made on specimens of rat myocardium taken at various intervals after death, in order to determine the extent and character of autolytic change occurring during the first ten hours. Specimens were taken immediately after death and at 15 minutes, one hour, three hours, five hours and ten hours after death, fixed in 1% phosphate‐buffered osmium tetroxide and examined with the electron microscope.The first noticeable change was a rapid depletion of glycogen. The specimens taken one hour or more after death show a longer sarcomere length indicating a more relaxed state. This is believed to reflect the inability of these fibers to contract upon stimulation by the initial contact with the fixative. Nuclei, when encountered, showed more chromatin clumping than in fresh tissue, but the nuclear membranes were intact.Very little change was noted in the mitochondria, sarcoplasmic reticulum, or other cellular component

ISSN:0003-276X    

DOI:10.1002/ar.1091470209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractThis report presents an electron microscope study of white adipose cells depleted of their lipid inclusion by prolonged low food intake. The tissue was fixed in phosphate‐buffered 1% osmium tetroxide, embedded in Vestopal W, and sections were stained with lead hydroxide. Such cells differ in shape and size from signet‐ring cells. They are ovoid, diminished in size, and the cell surface has become indented in all planes of the cell. The intercellular space is expanded with concentrations of collagen fibers in close association with the cell surface. These changes are presumed to be mechanical events associated with loss of lipid from the cell. Subcellular changes include the appearance of an extremely large number of pinocytotic vesicles and cytoplasmic vesicles similar in appearance, membrane‐bound dense bodies, five‐layered membranous structures, vesiculated bodies, and areas of flocculent material. Mitochondria and nuclei appear to be similar to their counterparts in signet‐ring cells. Observations are discussed with relation to ultrastructural changes reported in other studies in which adipose cells were depleted of fat by acute starvation or experimental deprivation of insulin. It is suggested that intracellular structural changes are probably associated with adaptive alterations in the metabolism of

ISSN:0003-276X    

DOI:10.1002/ar.1091470210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY

摘要:

AbstractThe chief purpose of this paper is to show that the human fetal ovary is a rich source of large actively dividing cells. The material consisted of the ovaries from five stillborn, morphologically normal human fetuses; 150 mm negro; two, 160 mm white; an 800 gram white; and a term white. The ovaries of the first three fetuses were removed within several hours after birth; those from the last two were removed at autopsy, wrapped in cellophane, placed in an insulated container and mailed to me. These were prepared for study about 36 hours after autopsy. Smears and squashes were made according to modern methods, but no colchicine was used. The nuclei of the ova were very tough and did not respond well to the usual hypotonic technics. Best results were obtained from fragments of the ovary suspended in blood, smeared, dried in the air and stained with Wright's blood stain. Qualitative studies were made of the chromosomes, their shapes during prophase and metaphase of meiosis; and quantitative studies were made by planimetry of the areas of the squashed chromosomes as they occurred in enlarged photographs. The planimeter measurements of areas of squashed haploid chromosomes showed remarkable agreement in percentages of the total chromosome area included within each of the accepted seven classes of chromosomes from nucleus to nucleus. Sample karyotypes were made from nuclei of the five fetuses, but no unequivocal absolute numbers could be counted, because of the twisted condition of the chromosomes and the difficulty in identifying the smallest ones.

ISSN:0003-276X    

DOI:10.1002/ar.1091470211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1963

数据来源: WILEY