bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of the in vivo incorporation of S35 methionine by two‐celled mouse eggs and blastocysts
Authors: Weitlauf Harry M. , Greenwald Gilbert S. 
Published: February 2005

AbstractFive‐day‐old mouse blastocysts were transferred into the oviducts of recipients on the second day of pregnancy. S35 methionine was then injected into the recipients and the blastocysts and native 2‐celled eggs were recovered six hours later. Radioautographs reveal that the blastocysts incorporate S35 methionine while exposed to the tubal environment to the same degree that they would in the uterus. However, the 2‐celled eggs in the same oviducal environment incorporate little or no methionine. It is therefore concluded that the difference in the incorporation of S35 methionine is due to maturational changes in the blastocyst rather than to a deficiency of the labelled amino acid in the tubal lumen.
The microscopy of “brown degeneration” in the adrenal gland of the mouse
Authors: Schardein J. L. , Patton G. R. , Lucas J. A. 
Published: February 2005

Abstract“Brown degeneration,” a pigmentary process of the adrenal gland of the mouse, was consistently induced by administration of ethinyl estradiol. Mice similarly treated with diethylstilbestrol or peanut oil (control) developed only small amounts of pigment. Histochemically, the pigment was ceroid and had its origin in the inner cells of the cortex in both females and males, with the fully developed pigmentation distributed in the cortex in animals of both sexes, and also in the medulla in males. Ultrastructurally, ceroid formation progressed from small pigment granules morphologically similar to lysosomes, to large composite, pleomorphic pigment bodies composed of unique granular configurations and membranous components. The ceroid deposits were interpreted to represent lipid products resulting from altered fat metabolism.
An electron microscopic study of the innervation of papillary muscles in the rat
Authors: Novi Anna M. 
Published: February 2005

AbstractThe left ventricular papillary muscles of rats were studied under the electron microscope. The tissue was fixed in glutaraldehyde 6.25%, postfixed in osmium tetroxide 2% and embedded in Epon 812. Sections were stained with lead according to Karnovsky.The terminal distribution of nerve fibers and their relationship with target cells represented by cardiac and vascular smooth muscles were investigated. Nerve bundles followed the course of vessels to the perivascular spaces around the smallest arterioles. At this level the bundles became progressively thinner and individual axons were observed leaving the bundles and penetrating between myocardial cells. In the micrographs, the unmedullated axons contained in the bundles were of three different types. Axons of type 1, chiefly containing neurofilaments, were considered the most proximal portion of the nerve fibers involved in the conduction of impulses. Axons of type 2 were characterized by the appearance of agranular and granular vesicles. Axons of type 3, or nerve endings, represented the anatomical endpoint of individual axons. True myoneural junctions (nerve‐muscle close contact) have been detected. More frequently, axons of type 3 end in the intercellular space (loose contact). Only a loose contact relationship was observed between the axons and vessels walls.
Dissociability of developmental processes in the morphogenesis of the ear in Ambystoma, as revealed by X‐ray damage
Authors: Piatt Jean 
Published: February 2005

AbstractEggs of Ambystoma maculatum from the same clutch were separated at Harrison's stage eight into three groups and maintained at 8°, 14° and 20°C, respectively, until stage 28. At these three temperatures the respective number of hours between stages eight and 28 were 291, 171, 99. Half of each group was then x‐irradiated with 600 r and the right ear vesicle substituted for that of the non‐irradiated complement. Subsequent development of the irradiated grafts, all reared at 20°C, was compared among the groups.Within the range of temperatures employed, hypothermia alone has no effect upon final ear development; every left ear in all groups developed normally. Development of irradiated grafts in the 8° group is decidedly more abnormal than in either 14° or 20° groups. With the exception of the VIIIth ganglion, development of the grafts in 14° and 20° groups is approximately the same. On the basis of 8° = 1, average developmental ratings for the three groups are approximately as follows: size — 1:2:2. differentiation — 1:2:2. ganglion — 1:2:5.The data demonstrate that the chronologically older ear is more radiosensitive than the younger, despite morphological parity among groups at time of irradiation. This suggests that prolonged hypothermia may dissociate in time the invisible or biochemical processes of development from the purely morphological; the pace of the former is less retarded than the latter.
The Tylotrich (Hair) follicle of the american opossum
Authors: Mann Stanley J. 
Published: February 2005

AbstractTylotrich follicles are present in the skin of the marsupial, the American opossum (Didelphis virginiana). Their morphology, ancillary structures, time of development, size and distribution of epidermal pads, are similar to tylotrich follicles found in eutherian mammals. The presence of tylotrich follicles in the marsupial suggests that they arose early in the evolution of mammalian skin.
Anatomical changes with age in the heart and ductus arteriosus in the dog after birth
Authors: House Edwin W. , Ederstrom H. E. 
Published: February 2005

AbstractThe heart‐weight to body‐weight ratios were calculated for 242 dogs in 11 groups ranging from one day to adult. The base‐apex diameters, internal transverse diameters, external transverse diameters, and the anterior, posterior, lateral, and interventricular septal wall thicknesses were measured in left ventricles of hearts taken from 45 animals of nine different age groups. The ductus arteriosus was examined for patency in all puppies.The heart‐weight to body‐weight ratios were found to be highly variable and failed to show significant changes with age. The average ratios increased during postnatal development from 7.17 gm/kg in the newborn to 8.87 in adults.The left ventricular diameters and wall thicknesses increased progressively with age and were four times larger in adults than in the newborn. Diameter to wall‐thickness ratios were calculated and did not change with age. Since the heart weight increased 10–16 times faster than the wall thickness, wall‐thickness to heart‐weight ratios were found to decrease with age indicating a faster lengthening than thickening of the myocardial fibers. The ductus arteriosus was functionally open in all puppies less than four days of age and did not close anatomically until 7–8 days of age.
Observations on the development of the electrocardiogram
Authors: Paff George Hugo , Boucek Robert Joseph , Harrell Timothy Charles 
Published: February 2005

AbstractThis experiment was designed to reveal the developing pattern of the ECG occurring in chick embryos during the period between 11 and 22 somites and to relate these findings to the appearance of blood circulation and the ability of the heart to exhibit atrioventricular block under the influence of digitalis. Using a unipolar electrode placed directly upon hearts of a graded series, the first recorded ECG was a simple V wave at 11 somites (sometimes 10) which increased in amplitude and rate through the 16 somite stage. In 16 or 17 somite embryos two deflections appeared on the descending limb of the V wave. In the light of subsequent changes these were recognized as the first indications of the P wave and QRS complex. Within an hour of development (17 to 18 somites) three events coincided, i.e., appearance of the primitive P wave and QRS complex; the beginning of blood circulation as evidenced by flow through extraembryonic capillaries; and the ability of the hearts to show a block at the AV junction. This last occurs despite the fact that an obvious PR interval is not present at 18 somites. However, from the 18 to the 21 to 22 somite stage rapid changes in the pattern of the ECG were recorded. The PR interval emerges; the P wave and QRS complex become incisive and are followed by an obvious T wave.The developmental pattern is the exact duplicate of the changes which can be recorded in reverse, by treating a single 60 hour embryonic heart with eserine (Paff, Boucek and Glander, '66) or apparently any acetylcholinesterase inhibitor (work in progress).
The comparative anatomy and phylogeny of the tentorium cerebelli
Authors: Klintworth Gordon K. 
Published: February 2005

AbstractThe morphology of the tentorium cerebelli was investigated in representatives of the chordata. A tentorium cerebelli characterized birds and mammals but was regularly absent in fishes, amphibians, and reptiles. The data suggest that the tentorium cerebelli emerged relatively late in phylogeny as bilateral folds of dura mater on either side of the brainstem in the cerebro‐cerebellar fissure. Subsequent evolution was characterized by the union of these septa behind the brainstem and by a progressive lengthening of the straight sinus. Tentorial ossification distinguished a further evolutionary step in some mammalian lines. The inferred evolutionary pattern of the tentorium cerebelli resembles the successive stages which the human tentorium undergoes during ontogeny.
Fine structure and staining of mucosubstances on “intercalated cells” from the rat distal convoluted tubule and collecting duct
Authors: Griffith Lyle D. , Bulger Ruth Ellen , Trump Benjamin F. 
Published: February 2005

AbstractA second and previously unrecognized cell type which is identical to the intercalated cells of the collecting duct exists in the rat distal convoluted tubule. These cells are distinctly different from the principal cells which have long been recognized with light and electron microscopy.The intercalated cells have numerous irregular apical microvilli, a high concentration of nearly round mitochondria located in the apical cytoplasm, and a basal nucleus.A variety of coated and uncoated vesicles in the apical cytoplasm were identified by electron microscopy. The cytoplasmic surface of the apical plasmalemma also was studded with club‐shaped densities.Light and electron microscopic histochemical techniques for acid mucosubstances were carried out on tissue prepared by rapid freezing techniques or intravascular perfusion fixation. The luminal surfaces of the cells from both the distal convoluted tubule and collecting duct stained for acid mucosubstances. In some cases, the intercalated cells stained more intensely with this technique than the adjacent principal cells. The apical cytoplasm of the intercalated cells was also more PAS positive than that of the principal cells.
Electron microscopy of the mouse retina prepared by freeze‐substitution
Authors: Van Harreveld A. , Khattab F. I. 
Published: February 2005

AbstractThe isolated retina of albino mice was fixed by freeze substitution. This method allows the electron microscopic examination of the surface layer of the tissue only. On the scleral side of the retina a considerable space was found between the outer and inner rod segments. In the spaces between the latter, microvilli of the Mueller cells seemed to float freely in the inter‐rod material. On the vitreal side extracellular space was observed in bundles of nonmyelinated fibers which are destined to form the optic nerve, and often in the inner plexiform layer. Treating the retina with 5 mM glutamate caused ballooning of elements in the plexiform layer (probably dendrites) and sometimes of the inner and outer rod segments. No obvious swelling was observed of the Mueller cells, the ganglion cells and of the nonmyelinated nerve fibers.
Migration of embryos in the anastomosed uterine horns of the pig
Authors: Miller O. C. , Dziuk P. J. 
Published: February 2005

AbstractOne ovary was removed from 28 gilts and the uterus was transected, closed and anastomosed in one of four patterns. In three of the patterns the uterine horns were jointed near the uterotubal junction and in the fourth pattern the uterus formed one continuous tube from one oviduct to the cervix. Gilts were mated, then killed at 15 to 60 days of gestation when fetuses were located. The proportion of gilts pregnant was lower (P < 0.05) in the two groups requiring passage of sperm through an anastomosis than in the two groups where fertilization did not require that sperm traverse an anastomosis. Ten gilts were pregnant when killed and embryos were distributed in both horns in each gilt. Embryos can pass through an anastomosis and migrate and are spaced quite evenly even after disturbance of the normal anatomical relationships between uterine horns.
Localization of phosphate in bone cells of fresh calvaria by means of a dilute silver acetate solution
Authors: Kashiwa Herbert K. 
Published: February 2005

AbstractThe silver‐substitution procedure originally recommended by von Kossa was modified to localize soluble phosphate in bone cells. Calvaria from newborn to five‐day‐old Wistar rats were stained fresh in 0.03% Ag acetate prepared in 5% mannitol solution. The substituted silver was reduced to its metallic state with 1% pyrogallol. The tissues were then dehydrated, cleared, and mounted whole. The cytoplasm of osteoblasts, osteocytes and osteoclasts contained black granules which were thought to be sites of phosphates or carbonates. The intracellular black granules were shown not to be due to either chloride precipitation or to silver reduction by ascorbic acid. Both of these compounds were localized outside the cells. Tests to determine the state of the localized phosphate or carbonate in the cells showed that the anions were not in the ionic or diffusible state nor organically bound, but complexed to calcium. This was shown by elution of phosphates from the cells when calcium was chelated by Na2 EDTA in 5% mannitol solution at pH 7. The intracellular black granules were thought not to be sites of insoluble calcium phosphate or carbonate but sites of readily stainable, calcium phosphate which is rendered nondiffusible by being bound to protein or mucoprotein.
Antler growth and osteoporosis I. Morphological and morphometric changes in the costal compacta during the antler growth cycle
Authors: Banks William J. , Epling Glenwood P. , Kainer Robert A. , Davis Robert W. 
Published: February 2005

AbstractThree three‐year‐old Rocky Mountain mule deer were studied for a year to determine the role of skeletal mineral in antler growth. Costal biopsy material, which was obtained at four‐week intervals, was analyzed histologically and histometrically. There was a cyclic mobilization of costal cortical bone during antler growth despite the dietary access to high quantities of elements essential for bone development. Following antler growth the ribs returned to a stable configuration with few resorption spaces. Corresponding to the period of possible weakening from the internal remodeling, there also appeared to be a thickening of the cortical bone by circumferential lamellar addition. A cyclic physiological osteoporosis was produced.
Investigations on the innervation of the diaphragm in cats and rodents
Authors: Wilson Andrew S. 
Published: February 2005

AbstractIn cats, rats and mice the diaphragm possesses an intrinsic plexus of nerve fibres which are concentrated in a narrow band situated approximately halfway between the edge of the central tendon and the peripheral attachment of the musculature. Contributions to the plexus originate in both phrenic and lower six intercostal nerves and both possess three categories of fibres. The first is composed of unmyelinated fibres which ramify on the walls of companion vessels. The second comprises myelinated fibres ranging from 6–10 μ in diameter and these have been classified as afferent components. The third category, forming the major part of the phrenic outflow but only a minor part of intercostal contributions, comprises inyelinated fibres which range from 10–16 μ in diameter and possess preterminal expansions. Phrenic fibres of the third category have been identified as efferent components because they terminate in motor end plates but the function of corresponding intercostal components cannot be defined conclusively.Quantitative studies at three distinct levels within each of ten phrenic nerves in cats, show an increase in the number of myelinated fibres of diameter 12–20 μ in the peripheral third of the nerve. This suggests that the phrenic nerve receives an accession of fibres in its peripheral third.
Studies on the fine structure of muscle fibers and associated satellite cells in hypertrophic human deltoid muscle
Authors: Reger James F. , Craig Ann S. 
Published: February 2005

AbstractElectron microscopy of hypertrophic left deltoid muscle of a nineyear‐old female diagnosed with neuro‐ectodermal dysplasia and concomitant muscle hypertrophy was made. Satellite cells, similar in morphology to myoblasts, are found situated apposed to and beneath the basement lamina of muscle fibers. Satellite cells contain mitochondria, granular ER free ribosomes, polysomes and 50–100 Å thick, randomly oriented filaments. Plasmalemmae of apposed satellite and muscle cells show varying numbers of caveolae and degrees of interdigitation similar to plasmalemmae between fusing myoblasts of embryonic muscle. Discontinuities in the muscle fiber plasmalemma and confluence, or overlie, of satellite cell and muscle fiber plasmalemmae are sometimes seen.One possible interpretation of the above evidence suggests that, in this example of muscle hypertrophy, satellite cells may assume myoblast‐like properties and serve as focal points for muscle fiber enlargement during muscle hypertrophy.
Determination of the red blood cell count and haemoglobin content of urodele blood
Authors: Friedmann G. B. , Algard F. T. , McCurdy H. M. 
Published: February 2005

AbstractRed blood cell count and haemoglobin content for blood of normal adult salamanders, Taricha granulosa, are presented. The RBC count is some 4 × 104/mm3 blood and the haemoglobin level some 4.5 gm/100 ml blood. Some evidence suggesting transient changes in these levels for a brief period immediately following hibernation is discussed.
Normal development of the lateral motor column in the brachial cord in Rana pipiens
Authors: Pollack Emanuel D. 
Published: February 2005

AbstractCounts of differentiating motor cells over the length of the brachial lateral motor column (LMC) indicate that a large decrease in cell number takes place during the larval period. During the same period an increase in nuclear size of the motor cells occurs with a maximum size attained just following forelimb emergence. Comparison between development of the LMC at the brachial and lumbo‐sacral levels indicates a slight lag in brachial LMC development. Cell number remains greater in the brachial LMC than in the lumbo‐sacral LMC, but nuclear size is consistently less in the brachial column. Probably no significant change in cell number occurs after metamorphosis, though there is an increase in cell size.
Effects of X‐irradiation of immature hamsters on growth and development of gonads
Authors: Turbyfill C. L. , Chang M. C. 
Published: February 2005

AbstractHamsters were x‐irradiated at 300 R on 1, 7, 14, 21 or 30 days after birth and sacrificed at the age of 33 days.The body weight, testicular weight and the development of seminiferous tubules were severely affected by irradiation on day 1. The ovarian weight and the number of oocytes were more affected by irradiation on day 7 or 14. Effects of irradiation of immature hamsters on their growth and development of gonads appears to be permanent as irradiation of males on day 1 destroyed all their germ cells by day 33 and irradiation of females on day 7 caused their permanent sterility up to four months of age.
Reconstitution of the external granular layer of the cerebellar cortex in infant rats after low‐level X‐irradiation
Authors: Altman Joseph , Anderson William J. , Wright Kenneth A. 
Published: February 2005

AbstractThe heads of three‐day old rats were irradiated with a single dose of 200 r x‐ray and the animals were killed afterwards at intervals ranging from ten minutes to five days. Necrosis in the external granular layer of the cerebellum was evident by the fourth hour and the pyknotic cells increased in number up to 12 hours after irradiation. Between 24 to 48 hours all the pyknotic cells disappeared and the width of the layer was drastically reduced. By the third day after irradiation the external granular layer began to increase in width, and by the fourth day it was indistinguishable from normal. In adults of this group the cerebellum appeared structurally normal. In another experiment the cerebellum of rats was exposed from birth onward to 200 r on five successive days. In the animals killed immediately or one day after the last radiation session the external granular layer was totally or subtotally eradicated. In the animals surviving for four days the external granular layer reappeared over many regions of the cerebellum, and by the sixth day after irradiation it was present over its entire surface. In the latter group in animals that survived to 30 and 90 days of age the cerebellum contained a large, though subnormal, population of granule cells, indicating that the reconstituted cells were able to differentiate. These results suggested that the proliferative matrix of the postnatally developing cerebellum may be endowed with regenerative capacity.
The ultrastructure of the placental labyrinth in the kangaroo rat, Dipodomys
Authors: King Barry F. , Tibbitts F. Donald 
Published: February 2005

AbstractRepresentative pieces of labyrinth of near‐term chorioallantoic placentas from three species of Dipodomys and one species of Microdipodops were fixed in glutaraldehyde and osmium tetroxide and examined with the electron microscope. The barrier separating the fetal and maternal blood streams in the labyrinth was found to consist of (1) the fetal endothelium and its associated basal lamina (basement membrane), (2) a single layer of trophoblast which is cellular rather than syncytial, and (3) the maternal endothelium and its associated basal lamina. Thus the chorioallantoic placenta appears to be of the endotheliochorial type in these rodents rather than hemochorial or hemoendothelial as previously suggested.
The testicular interstitial cells of a lion and a three‐toed sloth
Authors: Sinha Akhouri A. , Seal Ulysses S. 
Published: February 2005

AbstractThe fine structure of testicular interstitial cells of lion and three‐toed sloth showed an abundance of agranular endoplasmic reticulum, mitochondria and lipid droplets. Mitochondria were usually small and rod to rounded in shape, but large bizarre forms, such as triangular, oval and rounded with tubular and lamellar cristae were also observed. Mitochondria with lamellar cristae occurred in lion, but not in three‐toed sloth. These cristae were highly developed and appeared unique for the testicular interstitial cells. Both small and large mitochondria closely adhered to lipid droplets which were found singly or in clusters. The stored lipid droplets probably serve as a major source of substrate in androgen biosynthesis. The possible role of agranular endoplasmic reticulum in androgen biosynthesis is suggested.