bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light and electron microscopic studies on cellular alterations in the normal bovine placentome
Authors: Björkman Nils H. 
Published: February 2005

AbstractPlacentomes from 12 cows ranging from about 45 days of gestation to full term were studied with light and electron microscopy. The cryptal epithelium and the trophoblast both comprised uninucleate, binucleate and multinucleate cells. The uninucleate cryptal cells were provided with small mitochondria and essentially rough‐surfaced endoplasmic reticulum of varying appearance. The uninucleate trophoblastic cells were characterized by an abundance of mitochondria and by morphological evidence of absorption (pinocytosis and phagocytosis). Mitotic figures and sites with cellular degeneration were frequent on the cryptal side but less so on the trophoblastic side. It is concluded that cell turnover is rapid, being confined mainly to the cryptal cells. This is a process in the continuous growth and remodelling of the placentome. There is morphological evidence that the degenerated cells are absorbed by the trophoblast.
Ultrastructure of uterine smooth muscle following progesterone or progesterone–estrogen treatment
Authors: Bo Walter J. , Odor D. Louise , Rothrock Martha L. 
Published: February 2005

AbstractThe ultrastructural effect of progesterone, alone and in combination with estrogen, on smooth muscle cells of the rat uterus was studied. Adult, bilaterally ovariectomized rats were untreated (controls) or treated with either progesterone (1 mg), estrogen (1 μg) or both on three consecutive days.Uterine muscle cells appeared larger and myofilaments more abundant in the progesterone‐treated rats than in the other groups of animals. Many micropinocytotic vesicles and several dense bodies were present in muscle cells of control, progesterone and estrogen‐progesterone‐treated rats. In the progestrone‐treated group, smooth muscle cells contained little granular endoplasmic reticulum and few ribosomes and glycogen particles, similar to the controls. Mitochondria were more numerous than in the control animals but similar to those seen in the estrogen or estrogen‐progesterone‐treated rats. Although an accumulation of granular endoplasmic reticulum, free ribosomes, glycogen particles and extensive Golgi complexes occurred in both estrogen and estrogen‐progesterone‐treated rats, they were more extensive in the former group.The observations indicate that progesterone alters the ultrastructure of the smooth muscle cells but not to the degree observed following estrogen stimulation. It does not markedly inhibit the effect of estrogen on the fine structure of the uterine smooth muscle cells. These observations support previous biochemical studies on glycogen concentration, RNA and protein synthesis in the rat uterus.
Luteotropic complex of the mouse
Authors: Choudary Jasti B. , Greenwald Gilbert S. 
Published: February 2005

AbstractPregnant mice were hypophysectomized on day 6 and injected subcutaneously with various hormones from days 6 to 9 to establish the minimal requirements for the maintenance of functional corpora lutea. Luteal activity was assessed by the maintenance of pregnancy, weight of embryonic swellings, mean diameter and morphology of corpora lutea, and vaginal histology.Treatment with 2 mg progesterone maintained pregnancy but not corpora lutea in three of five animals. However, the embryonic swellings were significantly (P < 0.0005) smaller than those of pregnant control animals. Pregnancy was maintained in all animals when progesterone was combined with 1 μg of estrone. The weights of embryonic swellings and the degree of vaginal mucification in the combined steroid group were similar to those of intact control animals.Treatment with either ovine prolactin, bovine LH, ovine FSH or estrone failed to maintain corpora lutea or pregnancy. Combined injection of prolactin with LH or estrone did not maintain pregnancy or corpora lutea. On the other hand, treatment with 500 μg of prolactin and 200 μg of FSH maintained pregnancy in 12 of 14 animals. All of the aforementioned parameters of luteal activity were comparable to values in intact, control animals.The data indicate that luteal function in the mouse during the early post‐implantation period requires a luteotropic complex rather than a single hormone. Prolactin and FSH constitute the minimal luteotropic complex in the pregnant mouse. The luteotropic activity of FSH was not due to its contamination with LH and the effect of FSH was apparently not mediated through estrogen secretion, since pregnancy was not maintained by prolactin and estrone.
Inhibition of limb regeneration in the axolotl after treatment of the skin with actinomycin D
Authors: Carlson Bruce M. 
Published: February 2005

AbstractIn this experiment actinomycin D was used to explore the action of the wound epidermis on underlying tissues during limb regeneration. In axolotl forelimbs the skin was removed from the elbow to the shoulder. Skin from the right limbs was soaked for three hours in actinomycin D (5.0 or 10.0 μg/ml 0.6% NaCl). For controls, skin from left limbs was soaked in 0.6% NaCl for the same period of time. Each piece of skin was orthotopically replanted, and both limbs were amputated through the treated skin, proximal to the elbow. After an initial healing period, the control limbs regenerated normally. Except for a slightly paler color, limbs bearing actinomycin‐treated skin were indistinguishable from the controls, both grossly and histologically, during the first week following amputation. While the control limbs formed early blastemas, no grossly visible evidence of regeneration was apparent in the experimental limbs, but histologically some dedifferentiation was occurring. Normally three to four digits were seen in the control regenerates before blastemas appeared on the experimental limbs. By 35–40 days blastemas had appeared on most experimental limbs. These developed very rapidly, and within a short time many of them had attained levels of development close to the controls. Actinomycin D temporarily suppresses formation of the apical epidermal cap and the subsequent aggregation of dedifferentiated cells into a blastema. When the effect wears off, an apical cap forms and the dedifferentiated cells quickly organize into a blastema and begin to differentiate.
Inclusion bodies of type II alveolar cells: Species differences and morphogenesis
Authors: Kikkawa Yutaka , Spitzer Richard 
Published: February 2005

AbstractIn order to evaluate pathological alterations of the inclusion bodies of Type II cells in the mammalian lung, normal morphology of inclusions has been studied in rabbit, sheep, rat, mouse, dog, hamster and guinea pig. In rabbit, and sheep the fetal development of the inclusions has also been investigated.After a standard method of fixation, three different types of inclusions have been found in the species studied. The first type of inclusion is seen in the fetal rabbit, fetal sheep, dog, rat and mouse. In these species the inclusions contain heavily osmiophilic, coarsely lamellar material. In all of these species, the inclusions seem to form from an interaction between tubulo‐vesicular bodies, located near the Golgi apparatus, and multivesicular bodies. These are certain variations in the appearance of the inclusions among these species.The second type of inclusion is seen in the hamster and guinea pig, in which lightly osmiophilic material accumulates during the maturation of the inclusions. In these species, a granular dense body seems to occupy an important role in the formation of the inclusion bodies.In the third group, the postnatal rabbit and sheep, the inclusions appear vacuolated.It is postulated that the seemingly inconsistent results of the acid phosphatase activity of inclusions in several species may indeed be a reflection of species differences in the mode of formation of inclusion bodies.
The influence of pituitary hormones and norepinephrine on the size of adipose cells in organ culture
Authors: Slavin Bernard G. , Elias Joel J. 
Published: February 2005

AbstractThe technique of organ culture was used to test the effects of various pituitary hormones and norepinephrine on the size of brown and white adipose cells of mice. The hormonal effects were measured by means of histologic analysis and cell width measurements. A concentration of 10 μg/ml of somatotropin (STH), adrenocorticotropin (ACTH) or lipotropin (LPH) was sufficient to reduce the size and content of intracellular lipid in white fat cells while a concentration of 100 μg/ml was required for similar effects on brown fat cells. Norepinephrine, at concentrations of 0.1 μg/ml or 1.0 μg/ml, was sufficient to reduce markedly the size and lipid content of both types of adipose cells. On a molar basis, these hormones acted in a similar range of concentration. The reduction in size and amount of intracellular lipid in brown and white adipose cells by STH, ACTH, and LPH were prevented when combined with 10 μg/ml of insulin. Insulin prevented the lipid depletion effect of norepinephrine in brown but not white adipose cells.
Cytoplasmic fine structure during hormonally controlled differentiation in vaginal epithelium
Authors: Eddy Edward M. , Walker Bruce E. 
Published: February 2005

AbstractCells of the vaginal epithelium of ovariectomized mice undergo differentiation in response to estrogen or progesterone injection. Estrogen causes an increase in number of cytoplasmic filaments in the basal and newly formed spinous layer and mucification of surface cells already present. The cells derived from the basal layer under estrogen influence later form a keratinized epithelium. Progesterone causes heightening and mucification of surface cells and invasion of leucocytes into the epithelium without mucification or keratinization of other cells. When estrogen is followed two days later by progesterone, spinous and more superficial cells are lost and replaced my mucous cells derived from the basal layer. Although the fine structure of basal and spinous cell cytoplasm looks identical, the spinous cells do not form mucous cells under progesterone influence. The reverse sequence of progesterone followed by estrogen produces a low epithelium which is then replaced by a keratinized epithelium. The surface mucous cells present during progesterone influence do not keratinize, however. Thus, fine structural features of basal cells typical for the influence of a given hormone do not limit or characterize the potential of daughter cells derived from that layer. Conversely, when hormones are used in sequence, cells which leave the basal layer under the influence of one hormone do not acquire the fine structural features characteristically produced by the second hormone used, even though basal cells are readily altered.
Nerve endings in skin of the australian black snake
Authors: Proske Uwe 
Published: February 2005

AbstractHistological preparations from skin of the Australian black snake, Pseudechis Porthyriacus have revealed myelinated nerve fibers terminating in several structures. The commonest of these, the simple “End Button,” was seen in the epidermis from all regions of the body. An end organ, the “touch corpuscle” occurred in the epidermis of the upper and lower lip, while in the dermis of the upper and lower jaw an encapsulated structure, the “club corpuscle” was frequently encountered. These more complex structures could not be revealed in skin of the trunk where only “end buttons” were seen.
Light and electron microscopy of the adrenal medulla of macaca mulata monkey
Authors: Al‐Lami Fadhil 
Published: February 2005

AbstractThe fine structure of the adrenal medulla of Macaca mulata monkey was studied after double fixation with paraformaldehyde and OsO4; other fixations were employed for comparison. Only one cell type was seen. The cytoplasm contained an uneven distribution of chromaffin vesicles which were either spherical or elongated and 0.1–0.3 μ in diameter. There were two principle vesicle categories: dark and compact forms which comprised the majority (about 80%) and lighter, mostly larger, vesicles with a finely granulated appearance. The Golgi apparatus was often seen in relatively clear areas where few other organelles were present. Vesicles, 0.1–0.2 μ in diameter, which stained heterogeneously were also observed. They were few in number and always associated with the Golgi apparatus. The chromaffin cells lay in close proximity, but in no specific relationship, to thin‐walled blood vessels. Nerve endings which were partially embraced by Schwann cells were in synaptic relation to the chromaffin cells.These findings are compared with previous observations in other mammals and the nature of the dark and light vesicles is discussed.
Spermatogenesis in the rabbit following ligation of the epididymidis at different levels
Authors: Paufler S. K. , Foote R. H. 
Published: February 2005

AbstractLigatures were placed unilaterally on the ductus deferens (experiment 1), on the ductus deferens and the middle of the corpus epididymidis (experiment 2) and on the ductus deferens, corpus epididymidis and ductuli efferentes (experiment 3) in 39 rabbits. The untreated contralateral side served as a control. Vasectomy alone appeared to have no effect upon the testes, or upon spermatozoa accumulated during a period of 12 weeks proximal to the ligature. In experiment 2 severe disruption of spermatogenesis occurred. Diameter of the seminiferous tubules decreased, testes atrophied, and the stages of the seminiferous epithelium were abnormal and often not classifiable. Some regeneration was observed after 12 weeks.In experiment 3 there was only a moderate and more transient disturbance of spermatogenesis. This occurred in spite of an accumulation of fluid in the testis due to the ligature on the ductuli efferentes, which prevented testicular effluent from reaching the caput epididymidis. These results suggest that when testicular effluent is allowed to reach the caput, but nonresorbed residues are prevented from further transport (experiment 2), a feedback to the testis occurs which is more harmful than that produced by preventing tubular contents from leaving the testes.
The ultrastructure of granulosa cells in the newborn rabbit ovary
Authors: Gondos Bernard 
Published: February 2005

AbstractIn the first two weeks of life the pregranulosa cells located in the sex cords of the rabbit ovary become increasingly flattened and elongated to isolate and encircle individual oocytes. During this period there is a marked increase in the amount of intracytoplasmic lipid in the pregranulosa cells. The lipid is associated in clusters with adjacent mitochondria. The accumulation of lipid deposits within the pregranulosa cells suggests that the newborn rabbit ovary may be capable of steroid synthesis.
A quantitative study of the nucleus of the mesencephalic tract of the trigeminal nerve of the cat
Authors: Dault Stephen H. , Dale Smith R. 
Published: February 2005

AbstractThe number of cells in the mesencephalic nuclei of 38 cats averaged 2015 and ranged from 1237 to 2946. The individual right and left nuclei averaged 980 cells and ranged from 581 to 1489. About 3% of the cells were chromatolytic in the control animals.Various nerves were sectioned and the animals were sacrificed 14 days later. After unilateral section of the nerve to the masseter muscle 18% of the cells in the ipsi‐ and 9.7% of the cells in the contralateral nuclei were chromatolytic. After simultaneous unilateral section of the nerves to both the masseter and temporalis muscles 3% of the ipsi‐ and 23% of the cells of the contralateral nuclei were chromatolytic. After unilateral section of the inferior alveolar nerves 13% of the cells of the ipsi‐ and 9% of the cells of the contralateral nuclei were chromatolytic. After unilateral section of the lingual nerves 9% of the cells of the ipsi‐ and 7% of the cells of the contralateral nuclei were chromatolytic. After unilateral section of the hypoglossal nerves 12% of the ipsi‐ and 10% of the cells of the contralateral nuclei were chromatolytic.These results provide anatomical evidence that the axons of the cells of the mesencephalic nuclei are distributed to both the ipsi‐ and contralateral peripheral nerves. These findings also confirm the presence of such axons in the lingual and inferior alveolar nerves and demonstrate their heretofore unsuspected presence in the hypoglossal nerve.
H3‐leucine incorporation in antigenically stimulated rat popliteal lymph node cells
Authors: Slonecker Charles E. 
Published: February 2005

AbstractThe effect of antigenic stimulation with pertussis and sheep red blood cell antigens was studied in the rat popliteal lymph nodes. H3‐leucine was used to assess protein metabolism in the various cell types of the reactive lymph nodes following both primary and secondary stimulation with these antigens. Radioautographs of tissue smears were used to make quantitative and qualitative assessments of the extent of intracellular protein synthesis. In addition, changes in the cellular populations of various lymphoid cell lines were determined utilizing differential cell counts and total cells present in the reacting nodes. These data were used principally to assess the role of the lymphocytic cells in the ontogeny of the immune response.Large and medium lymphocytes responded to antigenic stimuli by increasing intracellular protein synthesis. This newly synthesized protein most likely reflected the requirements of large and medium lymphocytes for growth, division and the production of immunoglobulins. The small lymphocytes, as a group, showed only minimal changes in intracellular protein synthesis following antigenic stimulation.The responses by large and medium lymphocytes and plasma cells were qualitatively similar following primary and secondary stimuli. The differences in these responses appeared to be reflected by the number of cells involved and by the temporal sequence in which the cells appeared.
The placenta of the four‐eyed opossum (philander opossum)Philander opossum)
Authors: Enders Allen C. , Enders Robert K. 
Published: February 2005

AbstractThe placental membranes of the four‐eyed opossum were studied by light and electron microscopy. The individual fetuses in each uterus were surrounded by amnion, had allantoic sacs of approximately the same size as each fetus, and were situated in a common yolk sac cavity. The extent of the choriovitelline placenta was marked by a prominent sinus terminalis, and at this margin there was a region where the trophoblast cells penetrated folds of the endometrium. Elsewhere the choriovitelline placenta was closely applied to the uterine epithelium along most of its surface, but the microvilli of the two epithelia did not interdigitate. Numerous inclusion bodies were seen in the trophoblast of both the choriovitelline and bilaminar omphalopleure portions of the placenta, but the aggregates were larger in the latter. The endoderm cells of the choriovitelline placenta had extensive endoplasmic reticulum and numerous mitochondria, but did not have conspicuous absorption canaliculi.Placentation in the four‐eyed opossum appears to represent a progressive advance over that of the Virginia opossum both in confluence of the yolk sacs of the fetuses and in having a region of penetration of the maternal endometrium by trophoblast.
Studies on the innervation of the medial meniscus in the human knee joint
Authors: Wilson A. S. , Legg P. G. , McNeur J. C. 
Published: February 2005

AbstractHistological and ultrastructural studies on the medial meniscus in the human knee joint show that nerve fibres, both myelinated and unmyelinated, extend from the periarticular plexus into the meniscus as far as the intermediate third. These neural elements are not exclusively paravascular in position and it is reasonable to postulate a function other than vasomotor or vasosensory for them.
Alterations in fine structure of the opossum adrenal cortex following sodium deprivation
Authors: Long John A. , Jones Albert L. 
Published: February 2005

AbstractThe fine structure of adrenal cortices of opossums maintained on a sodium deficient diet for 21 days has been examined. After this treatment, the thickness of the zona glomerulosa is increased due to hypertrophy and hyperplasia of the parenchymal cells. After 21 days on the low sodium diet, the glomerulosa cells are characterized by large accumulations of smooth surfaced endoplasmic reticulum. This appearance is in marked contrast to the sparse representation of smooth surfaced reticulum in control animals. The rough surfaced endoplasmic reticulum becomes organized into long flattened cisternal profiles in parallel array and appears to be increased in quantity. The Golgi complex is also hypertrophied but marked changes in other organelles were not observed. Cells of the zona fasciculata appear to be unaffected by sodium depletion. Large lipid droplets accumulate in the zona reticularis of experimental animals but this zone is otherwise comparable to control animals. The bearing of these results on hypotheses of physiological control of secretion of the zona glomerulosa are discussed.
Evidence for a structural relationship between sarcoplasmic reticulum and Z lines in dog papillary muscle
Authors: Edge Maxine B. , Walker Sheppard M. 
Published: February 2005

AbstractElectron micrographs of dog papillary muscle fibers show the sarco‐plasmic reticulum (SR) as an extensive three‐dimensional network of diverging and converging tubules that is continuous throughout each sarcomere and in successive sarcomeres. The network surrounds each myofibril and is continuous across the fiber. Tubules of the SR network are oriented transversely and longitudinally. Interconnections of transversely and longitudinally oriented SR tubules form circular pathways in the network. A structural relationship appears to exist between the Z line and longitudinally and transversely oriented tubules of the SR network at their points of apposition with the Z line. A rather constant space approximately 100 Å wide is seen between SR tubules apposed at the Z line in cross‐sections and in favorable longitudinal sections of fibrils. This space is traversed by electron‐opaque strands which appear to be connections between SR tubules and the Z line. Other lines of evidence support the view that Z lines and SR tubules are connected. One of these is the change of position of Z line SR tubules in relation to the change of position of Z lines in adjacent fibrils. Another line of evidence is the continuity of SR apposed at the Z line and SR connected to the sarcolemma.
Ultrastructure of cortical synapses after failure of presynaptic activity in ischemia,
Authors: Williams Vick , Grossman Robert G. 
Published: February 2005

AbstractThe fine structure of cerebral cortical synapses was investigated during failure of synaptic transmission produced by ischemia. Presynaptic and postsynaptic potentials evoked in the anterior sigmoid gyrus of the cat by stimulation of the nucleus ventralis lateralis and the DC potential between cortical layer IV and the white matter were recorded with micropipettes during cerebral ischemia produced by arterial hemorrhage in paralyzed, artificially ventilated animals. After failure of the spontaneous electrocorticogram and postsynaptic responses, the presynaptic volley failed with development of depolarization of intracortical fiber terminals and loss of axon terminal excitability. The gyrus was then biopsied and fixed in collidine‐buffered OsO4. An altered pattern of distribution of synaptic vesicles was observed after presynaptic afferent fiber terminal activity was abolished by 3.5 to 4.0 minutes of cerebral ischemia. Clumping of vesicles in a region away from the cynaptic cleft was seen in about 10% of synaptic endings, and there was more than a two‐fold increase in the number of presynaptic profiles devoid of vesicles in ischemic cortex.