bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maturation and water composition of murine cerebrum, cerebellum, brain stem and spinal cord
Authors: Blinderman Elliott , Brown W. Jann 
Published: February 2005

AbstractPercentage change in water content and total solids was determined for the developing murine brain for both males and females from birth to 120 days.The central nervous system was divided into four components: (1) cerebrum (2) cerebellum (3) brain stem (4) spinal cord. The percentage of water was determined by dessication for groups of five animals at each day from birth to 20 days and then at five‐day increments to day 60 and at day 90 and day 120.Plots of the per cent solids (water content) against body weight showed a linear relationship for all parts except the cerebellum. No sex differences were noted. The cerebellum showed an early rapid water loss with a changing rate to a linear curve as the animal matured.Growth data were submitted to asymptotic regression using a computer to fit a curve y = α+βρx when y is the per cent solid at time × (in days) and α, β, ρ the constants to be determined. All of the central nervous system components gave constants of the same order of magnitude.
An enzymatic procedure for dechorionating the fish embryo, Oryzias latipes
Authors: Smithberg Morris 
Published: February 2005

AbstractThe tough, fibrous resilient, acellular capsule (chorion) of fish embryos has been characterized as protein‐keratin‐like in composition. It has resisted digestion by common proteinases, such as trypsin, chymotrypsin, pepsin, and papain. We have been able to remove the chorion with pronase, a commercially available (Calbiochem) proteolytic enzyme of bacterial origin with broad substrate specificity.The enzyme at concentrations of between 0.5 and 0.00625% was tested at room temperatures in several Ca++ and Mg++‐free solutions including a weak salt solution (0.1% NaCl), Yamamoto solution (0.7% NaCl), and distilled water with either phosphate or Tris buffer at pH 6.0–11.5. The embryos were in their first day of development at the start of the treatment.It was found that the enzyme was most effective in Tris‐buffered water, less so in weak salt solution and least effective in Yamamoto solution. Phosphate buffer caused some precipitation of the enzyme. The chorion was thinned over a wide range of pH (7.0–11.0) and in concentrations of enzyme between 0.5–0.0125% within 21–36 hours. Although the embryos frequently escaped from the thinned chorion by rhythmical movements, many of the embryos could be removed easily with the aid of common forceps. Once removed from the chorion the embryos were placed in phosphate buffered weak salt solution (Rugh), where, with few exceptions, they developed normally.Considering least mortality and highest yield of embryos with maximally thinned chorions, Tris‐buffered distilled water at pH 9.5 or 10.0 in an enzyme concentration of 0.025% was found to be optimal. Under these conditions 78% of the total number of embryos treated had completely thinned chorions within 24 hours.
The distribution of vitamin C in the human fetus. Histochemical observations
Authors: Hörnblad Yngve , Swinyard Chester A. 
Published: February 2005

AbstractThe distribution of ascorbic acid in 17 tissues and organs of 20 human fetuses (10–23 weeks of age), was studied histochemically by means of the silver nitrate technic. The metallic silver precipitates which were formed by silver nitrate reduction by ascorbic acid could only be uniformly seen in tissues where quantitative biochemical studies indicated the concentration to be greater than 10 mg/100 gm of tissue. The human fetus derives its supply of ascorbic acid from maternal sources and there were no significant differences between the youngest (10 weeks) and oldest fetuses (23 weeks) studied. The concentration and uniformity of distribution of ascorbic acid throughout the organ was most conspicuous in the adrenal and thyroid gland, liver and the proximal convoluted tubules of the kidneys. In the pancreas no ascorbic acid was found in Islet cells but occasional alveolar cells were filled with precipitates. Fine granulation was observed in germ cells of the gonads and heavier accumulation in the follicular supporting cells and interstitial cells of Leydig. Muscle fibers did not reveal granulation but perivascular connective tissue cells in muscle and glands were occasionally heavily granulated.
Observations on the yolk sac and reichert's membrane of ectopic mouse embryos
Authors: Porter David G. 
Published: February 2005

AbstractEmbryos developing from mouse blastocysts transplanted to the kidneys and testes of recipient mice were studied by light and electron microscopy. The yolk sac and Reichert's membrane of ectopic embryos were morphologically normal and had normal staining and histochemical properties. In electron micrographs Reichert's membrane was of low electron density and had a fine fibrillar structure. The cells of the parietal material within their ergastoplasm that closely resembled the membrane both in texture and electron density. The probability that the parietal yolk sac cells are responsible for the elaboration of Reichert's membrane in the mouse is discussed in relation to other work on the subject.The occurrence of discrete eosinophilic bodies in transplants in which the development of the inner cell mass was abortive is reported. The light microscopic appearance and fine structure of these bodies revealed close similarities to the parietal yolk sac and to Reichert's membrane. It is concluded that they represent yolk sac cells embedded in an abnormal Reichert's membrane.
A fluorescence and electron microscopic study on central monoamine nerve cells
Authors: Fuxe Kjell , Hökfelt Tomas , Nilsson Ove , Reinius Staffan 
Published: February 2005

AbstractBy combining the histochemical fluorescence method for catecholamines (CA) and 5‐hydroxytryptamine (5‐HT) with electron microscopy it has been possible to study the ultrastructure of the central CA and 5‐HT nerve cells of the locus coeruleus and the nuc. raphe dorsalis. The CA and the 5‐HT nerve cells have the same ultrastructural characteristics: a well‐developed granular reticulum and a peri‐nuclearly situated, prominent Golgi apparatus which almost completely surrounds the nucleus. Agranular vesicles (300–500 Å in diameter) are found mainly in a perinuclear area in association with the Golgi apparatus. They are similar to the small agranular vesicles present in large numbers in the presynaptic bags. A few complex vesicles and granular vesicles (600–1200 Å in diameter) are noticed throughout the cytoplasm. No certain changes are observed in the different types of vesicles after treatment with reserpine or MAO inhibitors.It is suggested that the agranular vesicles contain CA, since these vesicles are most numerous in a perinuclear area where the concentration of the amines are highest. In spite of the low number of agranular vesicles present as compared to the high number found in nerve terminals they might store at least a considerable part of the amines, since the amine concentrations are much lower (100–1000 X) in the nerve cells than in the terminals.
Regulation of pigment cell colonization of PET mouse leg muscles
Authors: Reams Willie M. 
Published: February 2005

AbstractThe results of autoplastic and homoplastic transplants of PET mouse tissues indicate that the state of differentiation of the developing muscles limits the extent of invasion by pigment cells of the muscles of the leg in PET mice. Additionally, intracoelomic grafts into host chick embryos of PET mouse leg tissues has given evidence which suggests that the pigment cell behavior is affected also by a restriction of pigment cell proliferation and concurrent migration by the initiation of pigment cell morphogenesis. Thus it appears that the colonization of the leg muscles by pigment cells in the PET mouse is governed both by the structural limitations and morphogenetic influence imposed upon the melanoblasts by the tissue substrate.
Ultrastructure of the thymic reticulum in guinea pig cytological aspects of the problem of the thymic secretion
Authors: Izard Jacques 
Published: February 2005

AbstractThymic reticular cells of the guinea pig were studied at different stages of its development and involution: the fetus of the last third of pregnancy, the newborn, the puberal adult and the adult implanted with estradiol.Most of the reticular cells were epithelial with desmosomes and tonofilaments originating from the endodermic primordium. In the medulla, some of these epithelial cells appeared to be transformed into elements of Hassall's corpuscles with an increase of tonofilaments in close association with keratohyalin granules.Moreover, phagocytic reticular cells were occasionally seen. Their origin remains unknown (epithelial or menschymal ?).The problem of the thymic secretion is discussed. There was no convincing evidence of a secretion of protein or polypeptid inside these reticular cells whatever the age of the animal. However, it is not possible to exclude the presence of another form of endocrin secretion, especially a colloid or a steroid secretion, at least in the fetus and newborn thymus.
The effect of a muscle relaxant on the growth and differentiation of skeletal muscles in the chick embryo
Authors: Ahmed Yehia Y. 
Published: February 2005

AbstractThe present work is concerned with the extreme controversy of views over the problem of the dependency of embryonic muscular development on neural factors.A chemopharmacological method was adopted to selectively block the motor nerve endings. One hundred and seventy‐seven chick embryos, 6–7 days old, were injected in ovo with marginal doses of oily tubocurarine. The control embryos were injected with arachis oil. Eleven days after injection, the majority of the embryos injected with curare were macroscopically stunted, especially the limbs. Specimens from experimental and control embryos were fixed simultaneously in isotonic 10% formalin made in Howard's solution. Sections were stained with hematoxylin and eosin, Mallory's phosphotungstic acid hematoxylin and Van Gieson. Dawson's technique was used to demonstrate the whole of the embryo skeletons. Microscopic examination of the limb musculature revealed inhibition of development and differentiation. The muscle fibers were reduced in size and number, poorly striated and contained many centrally situated nuclei.In the chick, it is suggested that at a critical time of development the final differentiation and maturation of skeletal muscles begin to become dependent on the anatomical and physiological intactness of the motor nerves. This time is found to be approximately between the sixth and seventh days of incubation. The significance of these observations is discussed.
The effect of pregnancy on the submandibular glands of mice
Authors: Travill Anthony 
Published: February 2005

AbstractStructural changes occurring in the submandibular glands of mice during pregnancy were studied. The submandibular glands of 12 mice were examined immediately post‐partum, and those of a further 12 six weeks post‐partum. They were compared with glands of virgin female and young adult male mice. The mean weight of the glands immediately after pregnancy was 75% greater than that of the glands of virgin female mice of the same age.In both hematoxylin and eosin, and Mallory‐Heidenhain stained sections there was evidence of masculinization of the submandibular glands during pregnancy. The percentage of convoluted granular tubules in the glands increased; as did also the diameter of the tubules. The characteristic appearance of the constituent cells of the tubules in the gland of the virgin female, with basal striations and centrally located nuclei was converted to that seen typically in the young adult male, where the cells have basally located nuclei, and an abundance of apical granules but no basal striations.Regression in both the weight and microscopical appearance of the glands to the non‐pregnant condition occurred within the six weeks following pregnancy.The apparent masculinization of the submandibular glands during pregnancy is thought to be an expression of the complementary endocrine factors acting at that time.
Fine structure of the seminiferous tubule of the swiss mouse. The spermatid
Authors: Gardner Paul J. 
Published: February 2005

AbstractElectron micrographs from this study demonstrate several stages in the formation of the nuclear cap and acrosome by the Golgi system. Formation of small vesicles from Golgi membranes, coalescence of these vesicles into the nuclear cap with concomitant fusion of contained granules to form the acrosome, is confirmed. Mitchondria, which at low magnifications appear to be “empty,” are shown by high magnification to contain dilated intracristal spaces. In many cases cristae are arranged parallel to the mitochondrial surface.In later spermiogenesis, appearance of the caudal sheath or manchette, proximal centriole, and terminal annulus (“ring centriole”) precede formation of the middlepiece and flagellum. The presence of a series of parallel “annulated” membranes has been described. The exact nature of these membranes, which appear to connect with the cisternae of the endoplasmic reticulum, remains to be investigated.
The gross morphology of the coronary arteries of the common squirrel monkey
Authors: Colborn Gene L. 
Published: February 2005

AbstractThe coronary arteries of 16 squirrel monkeys were pre‐perfused with acetone and subsequently filled with vinyl acetate. Thirteen of the hearts were then bleached, dehydrated and cleared in cedar oil; three were subjected to corrosion in concentrated hydrochloric acid.The right coronary artery arises from the right coronary sinus of Valsalva. In 50% of specimens, the “artery of the conus” arises independently from the same sinus by a separate ostium; in the other 50% being a branch of the proximal portion of the right coronary artery. The right coronary distributes vessels supplying the lateral three‐fourths of the anterior right ventricle, all of the posterior right ventricle, the posterior one‐third of the interventricular septum, the right atrium, the posterior papillary muscles of the right ventricle, the atrioventricular node, the sinus node (in 9 specimens), and the medial one‐third of the posterior left ventricle. The left coronary artery, supplying the remainder of the heart, arises in all cases from the left coronary sinus and bifurcates to form the ventrally terminating anterior interventricular coronary artery and the left coronary circumflex. In one specimen, the left coronary artery supplied the atrioventricular node.
A new cytoplasmic component in the trophoblast cells of the rat and mouse
Authors: Toro Imre , Rohlich Paul 
Published: February 2005

AbstractTissue blocks removed from placentas of rats and mice at different gestational age were fixed in either OsO4 or glutaraldehyde or both, embedded into Araldite, and thin sections were examined with the electron microscope. A hitherto undescribed cytoplasmic component consisting of convoluted thread‐like elements embedded in a clear ground substance has been regularly found in the trophoblast II cells of rats and mice. The ovoid‐shaped cytoplasmic component, termed by us glomerular body, is about 1 to 1.5 μ in its greatest diameter and is composed of electrondense 400 to 500 Å thick threads which appear to have a fine filamentous and granular structure. The threads were often observed in close topographical relationship with free ribosomes. The thread‐like elements of the glomerular body were occasionally found dispersed or lined up under the cell membrane of the foetal side of the trophoblast II cell. In some instances similar structures were observed in the nucleus. The nature and significance of the glomerular body is unknown.
Growth of hair in the ventral glands of castrate gerbils following testosterone administration
Authors: Mitchell Ormond G. , Butcher Earl O. 
Published: February 2005

AbstractA study was made of the growth of hair in the ventral gland of the adult male gerbil, Meriones unguiculatus. The gland is composed of pilosebaceous complexes in which the hair follicles exhibit a very long anagen and a short telogen. Castration causes an almost immediate cessation of growth of the gland follicles. Daily treatment with 320 μg testosterone proprionate results in re‐establishment of hair growth within 72 hours. Growth continues and at three weeks the ventral gland resembles that of normal animals. No influence was observed of the physiological hair cycle of the general skin on the follicles of the ventral gland or of testosterone on the hair cycle of the general skin. The pilosebaceous complexes of the mid‐ventral skin of the male gerbil are androgen sensitive and differ both morphologically and physiologically from those of the general skin.
Blood and lymph vessels in the jejunal villi of the white rat
Authors: Mohiuddin A. 
Published: February 2005

AbstractThe typical jejunal villus is tongue‐ or chisel‐shaped, in which the lacteal is axial, the artery paraxial and the vein lies near one of the lateral borders. The artery forms a T‐junction with the specially wide marginal capillary at the tip which distributes blood to the greater part of the subepithelial capillary plexus. This plexus is so dense that no epithelial cell is more than 30 μ away from the blood stream. The higher density of the plexus in the tip reflects the higher functional capacity of the epithelium there and the plexus in the base of the villus is less dense in keeping with the lower functional capacity of the basal epithelium. The veinbegins in a manner which does not suggest the presence of an arterio‐venous anastomosis.
The fine structure of parasympathetic nerve cells in the otic ganglia of the rabbit
Authors: Dixon John S. 
Published: February 2005

AbstractThe ultrastructure of parasympathetic neurons in the otic ganglia of the rabbit is described with the object of providing a basis for comparisons of parasympathetic with sympathetic nerve cells. The neuronal cytoplasm contains Nissl substance, mitochondria, dense bodies, agranular Golgi membranes, neurofilaments (60 to 100 Å in diameter) and microtubules having diameters about 200 Å and filled with irregularly dense material. Granulated vesicles (about 900 Å in diameter) consisting of a limiting membrane and enclosing a dense spherical droplet of about 500 Å diameter are also present in the cytoplasm and processes of these neurons and in presynaptic terminals, thus disproving the hypothesis put forward by some authors that the presence of granulated vesicles indicates a sympathetic nervous pathway. Long, tubular bodies with a dense central core are described which are possibly peculiar to parasympathetic neurons. The nuclear membrane is double, porous and sometimes exhibits localized, deep invaginations of its surface.Junctional complexes are described between apposing membranes of neurons and satellite cells which are morphologically similar to zonulae adhaerentes.Small gaps exist in the cytoplasmic sheath surrounding the neurons. Over these areas only a basement membrane separates the nerve cell from the connective tissue space and the significance of this finding is discussed.
The influence of thyroid and testicular hormones on the epithelium of crypts of Lieberkühn in the rat's intestine
Authors: Carriere Rita M. 
Published: February 2005

AbstractThe growth of duodenal crypts of Lieberkühn was investigated in male Sherman rats subjected to thyroidectomy, and/or castration. Histological sections were studied, counting interphase nuclei and mitoses in 25 longitudinally sectioned crypts per animal. At 49 gm body weight, initial control animals had an average of 65.8 ± 2.4 cells per crypt section, and 80 days later, sham‐operated controls weighed 269 gm and had 91.4 ± 5.1 cells per crypt section. There were only 75.0 ± 3.7 cells per crypt section 80 days after thyroidectomy, while castrates had 97.0 ± 2.6 cells per crypt section. Thyroidectomy combined with castration produced results similar to thyroidectomy alone, 74.0 ± 2.5 cells per crypt section. Treatment of such doubly operated rats with testosterone during the last 42 days of the experiment significantly increased the cell number, to 82.7 ± 2.8 per crypt section, while thyroxine increased it to 100.8 ± 4.3. Thus, in the rat, the number of cells per crypt increases between juvenile and adult stages, and this growth is subject to endocrine regulation, particularly by the thyroid.The mitotic index of crypt cells increases with age, from 3.9 ± 0.1% at 49 gm body weight, to 5.2 ± 0.3% at 269 gm body weight. Castration did not interfere with this increment, but it was reduced in the absence of thyroid hormone, and was restored by the injection of thyroxine to thyroidectomized castrates.Finally, from related observations in previously reported and unpublished experiments, it is suggested (1) that the influence of thyroid hormone on crypt cell number may be mediated, at least in part, through an action on growth hormone release from the anterior pituitary and (2) that the rate of change in cell number with age may be determined in some measure by a change in the rate of cell displacement toward the villus tip, in addition to a change in mitotic index.
Hormonal determinants of the development of masculine and feminine behavior in male and female rats
Authors: Whalen Richard E. , Edwards David A. 
Published: February 2005

AbstractTo investigate the role of gonadal hormones during the postnatal period on the development of masculine and feminine behavior 129 male and female rats were hormonally manipulated at birth. Within 24 hours of birth male and female rats were: (a) sham operated, (b) gonadectomized, (c) gonadectomized and given testosterone, or (d) gonadectomized and given estrogen. When adult all animals were given testosterone and tested for the display of male behavior, and then given estrogen and progesterone and tested for female behavior. Male behavior: Males exhibited mounting responses more frequently than females regardless of hormone manipulation at birth. Androgen and estrogen at birth did not facilitate mounting behavior in either sex. Males exhibited more frequent intromission responses than females. Animals treated with androgen at birth showed more frequent intromission behavior than non‐treated animals. Androgen facilitated intromission relatively more in males than in females. Estrogen at birth did not facilitate intromission behavior. Female behavior: Males castrated at birth, normal females, and females ovariectomized at birth showed high levels of receptivity. No other animal exhibited frequent lordosis. The data indicated that behavioral sexual differentiation induced by hormones in in‐fancy is best characterized by an inhibition of the potential to display feminine behavior.
Subcommissural organ, lateral hypothalamus, and dorsal longitudinal fasciculus in water and salt metabolism
Authors: Crow Lowell T. 
Published: February 2005

AbstractTwenty‐two albino rats were divided into three groups for chronic brain electrode implantation. The effects of subsequent stimulation and ablation of the subcommissural organ (SCO), the bilateral lateral hypothalamic nuclei (LH), and the dorsal longitudinal fasciculus (FLD) on volume of water intake, and on concentration of urinary excretion were observed over twenty‐two hour periods of free access to water both before and after treatments.It was observed that neither stimulation nor lesion of the SCO resulted in disruption of water intake or of urinary volume and concentration. Similar stimulation of LH potentiated drinking, while similar lesions produced a hypodipsia that necessitated tube feeding. Lesions of LH produced, in addition, marked elevation of urine volume, but no change in urine concentration. Sectioning of the FLD was followed by effects similar to those following lesions of the LH nuclei.