bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microappendages on the ventral surface of the primitive streak chick embryo
Authors: Harri James E. , Low Frank N. 
Published: February 2005

AbstractFresh pullet eggs (White Leghorn Strain) were incubated to obtain the primitive streak stage of development. Blastoderms were fixed in situ with isotonic aldehyde fixatives and prepared for scanning electron microscopy by means of postosmication, critical point drying and gold‐palladium coating.The ventral surface of the chick blastoderm exhibits extreme pleomorphism. There is variation among microappendages (microvilli, blebs, ruffles) which tend to define cellular outlines. In recessed areas adjacent to the ventrolateral aspect of the primitive streak microappendages are present in great profusion. Here clusters of them possess intricate physical relationships. Microvilli may arise from either blebs or ruffles. Other microvilli may terminate in blebs. Extensive connecting structures are present. The primitive streak chick embryo is discussed as a model for the study of microappendages of the plasmalemma.
Intrapulmonary airway morphology in three species of monkeys: A correlated scanning and transmission electron microscopic study
Authors: Castleman W. L. , Dungworth D. L. , Tyler W. S. 
Published: February 2005

AbstractIntrapulmonary airways were studied in rhesus (Macaca mulatta), stumptail (Macaca arctoides), and bonnet (Macaca radiata) monkeys by correlated scanning and transmission electron microscopy. Lobar, segmental, and subsegmental bronchi in all three macaques were lined by pseudostratified columnar epithelium composed primarily of ciliated cells, mucous cells, and basal cells. Neuronal processes and cells containing dense‐core vesicles were also observed. Terminal bronchioles in rhesus and stumptail monkeys were short and only developed to a single generation. Terminal bronchioles were moderately longer in bonnet monkeys and were occasionally developed to two generations. Terminal bronchioles in bonnet and stumptail monkeys were lined by ciliated pseudostratified columnar epithelium which included nonciliated bronchiolar epithelial (Clara) cells. The arrangement of epithelium in terminal bronchioles differed slightly in rhesus monkeys. All three species had long respiratory bronchioles. They were lined by simple, nonciliated cuboidal and squamous epithelium which usually did not contain secretory droplets. Capillaries were often observed immediately below the luminal epithelium. Cuboidal cells containing dense‐core vesicles were a rare component of the epithelium of respiratory bronchioles in stumptail monkeys. Alveolar ducts were lined by an epithelium composed of type I and type II cells. The results of this study indicate that there is general similarity in the mucosal structure of bronchi and respiratory bronchioles between macaques and man but that there are differences in the number of generations and epithelial lining of terminal bronchioles.
Simultaneous autoradiographic and immunohistochemical localization of estrogen and gonadotropin in the rat pituitary
Authors: Keefer Donald A. , Stumpf Walter E. , Petrusz Peter , Sar Madhabananda 
Published: February 2005

AbstractA combined autoradiographic and immunohistochemical technique is introduced which is suitable to simultaneously localize hypophyseal sites of nuclear (3H)‐estradiol uptake and anti‐hCG‐characterized “gonadotropes”. Most, but not all, “gonadotropes” show significant nuclear concentration of radioactivity. A large percentage of non‐“gonadotropes” also show nuclear uptake of label.
Scanning electron microscopy of cardiac endothelium of the dog
Authors: Peine Craig J. , Low Frank N. 
Published: February 2005

AbstractTissue obtained from young dogs was fixed in buffered aldehydes by vascular perfusion or direct immersion. Selected hearts were maintained in modified mammalian Ringer's solution for three to five minutes prior to fixation. The chambers of the heart and related valves were exposed by dissection and prepared by routine techniques for observation by scanning electron microscopy (SEM). Subsequent to SEM studies, selected specimens were embedded in Epon 812 and sectioned for transmission electron microscopy (TEM).The cardiac endothelium, when fixed immediately in buffered aldehydes, presents an essentially invariable surface throughout the interior of the heart. The predominant nuclear bulges and attenuated peripheral plasmalemma are consistently smooth, with occasional marginal ruffles, scattered microvilli and small blebs. Apart from the higher population of nuclear bulges on valvular surfaces, local variations in SEM of endocardium occur in response to the various stages of systole and diastole encountered. These physiological changes do not produce microappendages.Immersion for three to five minutes in (Chenoweth's) Ringer's solution, prior to fixation, produces a substantial population of microappendages. The cellular surface acquires a swirled appearance erupting in microvilli, blebs and ruffles. These exhibit considerable pleomorphism.There is great lability of the endocardial surface in response to a classic “holding solution” widely used in preparatory techniques. In preparing soft tissues for SEM caution must be used if physiological “holding solutions” are used prior to fixation.
Ultrastructural immunocytochemical localization of neurophysin in freeze‐substituted neurohypophysis
Authors: Silverman A. J. , Knigge K. M. , Zimmerman E. A. 
Published: February 2005

AbstractUsing an immunohistochemical technique at the electron microscopic level, we have observed that within the axon terminals of the guinea pig neurohypophysis neurophysin is present in the large neurosecretory granules, as well as in the axoplasm. A description of a freeze‐substitution technique for neural lobe is also present.
Developmental morphology of the subarachnoid space and contiguous structures in the mouse
Authors: McLone David G. , Bondareff William 
Published: February 2005

AbstractDevelopment of pia‐arachnoidal membranes in the mouse occurs in four stages: the first (prenatal days 10–13) follows closure of the neural tube and is a period of initial vascularization of the developing telencephalon; the second (prenatal days 14–16) is a period of delineation during which the limits of the subarachnoid space are defined; the third (prenatal day 17 to birth) is a period of ensheathment of pia‐arachnoidal blood vessels, and the fourth (birth to postnatal day 21) includes addition of smooth muscle to larger vessels, the appearance of macrophages in the subarachnoid space, and a general increase in extracellular collagenous and elastic fibers.The mesenchyme over the telencephalic surface in the 10‐day fetus has a typically large extracellular space. By the 13th fetal day cerebrospinal fluid begins to seep into and replace it. The mesenchymal extracellular compartment is reduced peripherally, resulting in a compacted pia‐arachnoidal tissue which limits the peripheral extent of the subarachnoid space. By the 21st postnatal day a subarachnoid space typical of the adult animal has been established.
Localization of growth hormone‐release‐inhibiting hormone (somatostatin) in the rat brain
Authors: Pelletier Georges , Leclerc Rachel , Dube Donald , Labrie Fernand , Puviani Romano , Arimura Akira , Schally Andrew V. 
Published: February 2005

AbstractUtilizing an immunoperoxidase technique at the light microscope level, growth hormone‐release‐inhibiting hormone (somatostatin) was localized in the external zone of the median eminence, the subcommissural organ, the organum vasculosum of the lamina terminal is and the pineal gland. No positive reaction was detected in any other brain area.
Radioimmunological evidence for early functional activity in chick embryonic alpha cells
Authors: Benzo Camillo A. , Stearns Susan B. 
Published: February 2005

AbstractA radioimmunoassay for glucagon was utilized to investigate early developmental aspects of glucagon synthesis and release in the chick embryo. Immunoreactive glucagon was detected in both the pancreas and blood plasma from the fifth embryonic day onwards. The present data show that the chick embryonic alpha cell has the potential for secretory activity very early in development, and suggest a developmental role for glucagon in hepatic glycogen metabolism.
Localization of tropomyosin in mouse embryo fibroblasts
Authors: Jorgensen A. O. , Subrahmanyan L. , Kalnins V. I. 
Published: February 2005

AbstractAntiserum to chick skeletal muscle tropomyosin was used to localize tropomyosin in mouse embryo fibroblasts by the indirect fluorescein labeled antibody technique. Specific staining was observed in cytoplasmic fibers, which extended out into the cell processes. The staining pattern in these cells is similar to that previously described by others for actin. This observation suggests that in fibroblasts tropomyosin, like actin, is localized in fibers in the cytoplasm.
Effects of fetal decapitation on the structure and function of leydig cells in rhesus monkeys (Macaca mulatta)
Authors: Tseng Michael T. , Alexander Nancy J. , Kittinger George W. 
Published: February 2005

AbstractFetal decapitation in utero has enabled us to study the role of fetal pituitary hormones in the development of the fetal testis. Testes from males decapitated near 80 days of gestational life and later delivered at 150 days were smaller than normal and about one‐tenth the normal weight. The size of the seminiferous tubules was similar in both groups; however, the number of Leydig cells seemed reduced. In addition, the Leydig cells of the experimental group contained smaller mitochondria with reduced tubular cristae, fewer lipid droplets, and reduced agranular endoplasmic reticulum. Androgen production was inhibited. Measured by radioimmunoassay, the testosterone level in the umbilical vein was 329 ± 82 pg/ml in six decapitated fetuses, 412 ± 62 pg/ml in ten normal fetuses. The level in the umbilical artery was 328 ± 56 pg/ml in five decapitated fetuses, 658 ± 140 pg/ml in normal fetuses. These studies suggest that chronic deprivation of fetal pituitary hormones inhibits the growth and development of the testis in general and of the Leydig cells in particular.
The dual origin of vaginal epithelium
Authors: Cunha Gerald R. 
Published: February 2005

AbstractThe absence of the cranial three‐fifths of the vaginae of male mice carrying the gene, Testicular Feminization, provides strong support for the view that vaginal epithelium is of dual origin, the cranial three‐fifths being of Mullerian in origin and the caudal two‐fifths being derived from the urogenital sinus.
Fine structure of hepatocytes from fasted and fed rats
Authors: Babcock Muriel B. , Cardell Robert R. 
Published: February 2005

AbstractThe fine structure of hepatocytes from rats maintained on a controlled feeding schedule are described. Liver samples were processed for electron microscopy, histochemistry and chemical determinations of glycogen at precise time‐intervals following a 30‐hour fast and a 2‐hour meal. Hepatocytes from 30‐hour‐fasted rats with extremely low hepatic glycogen levels were devoid of glycogen particles. Centrilobular cells showed areas of the cytoplasm rich in vesicles of smooth endoplasmic reticulum (SER) while periportal hepatocytes contained less extensive regions of SER. Soon after feeding the fasted rats, glycogen particles appeared in regions of the cell rich in SER. Centrilobular hepatocytes contained numerous glycogen areas which were infiltrated with tubules of SER, while periportal cells showed dense glycogen deposits with SER restricted to the periphery of the masses of glycogen. Throughout glycogen deposition each glycogen particle was closely associated with membranes of SER until maximum glycogen deposition was achieved 12 hours after initiation of feeding. At this point SER was reduced to the lowest amounts of the time‐periods studied. During stages of glycogen depletion SER proliferated and reached the highest concentration measured in this study. Tubules of SER were present throughout the glycogen masses of centrilobular hepatocytes, whereas in periportal cells the organelle was restricted to the periphery of the glycogen masses. It is concluded that SER is associated with glycogen particles in rat hepatocytes during both deposition and depletion of glycogen.
Renewal of the epithelium in the descending colon of the mouse. IV. Cell population kinetics of vacuolated‐columnar and mucous cells
Authors: Chang W. W. L. , Nadler N. J. 
Published: February 2005

AbstractProliferation and migration of cells in the vacuolated‐columnar and mucous cell lines were studied in the descending colon of adult female mice given a single injection or a continuous infusion of 3H‐thymidine and killed at various intervals from one hour to 12 days. This investigation was carried out using one μm‐thick Epon sections which were radioautographed after staining with the periodic acid‐Schiff technique and iron‐hematoxylin.In the normalized crypts with ten equal segments, labeled vacuolated cells at one hour after injection of 3H‐thymidine were encountered in the lower four segments and in decreasing numbers in segments 5 through 7. From the percent labeled cells in segments of the crypt, the birth rate and fluxes of cells were computed. Moreover, it was found that a cell in the vacuolated‐columnar cell line would undergo three mitotic cycles on the average from its birth at the cryptal base to its extrusion from the surface; of these three cycles, the last one which took place from segment 3 to segment 7 appeared to be a changeover from dividing cells to non‐dividing cells, in accordance with the “slow cut‐off” model of Cairnie et al. ('65b).Mucous cells located in segments 1 through 6 of the crypt were capable of incorporating 3H‐thymidine and thus capable of undergoing mitosis. However, the rate of turnover of mucous cells based on proliferative rate was found to be much lower than the rate of turnover of mucous cells based on the transit time in the non‐dividing segments of the crypt. Since there was a concomitant overproduction of cells in the vacuolated‐columnar cell line and some morphological similarity between vacuolated cells and newly formed mucous cells in the lower portion of the crypt, it was concluded that some vacuolated cells would give rise to mucous cells. This putative transformation occurred in the lower four segments of the crypt.Mucous cells which were formed by transformation would migrate upward along the cryptal wall and accumulate more mucus in the theca; in doing so, they would undergo two divisions, on the average, before they became non‐dividing mucous cells.In ascending the cryptal walls, both vacuolated‐columnar cells and mucous cells appeared to migrate at a similar speed; they moved much slower at the base of the crypt and accelerated toward the upper portion of the crypt, but they migrated at a constant speed in the non‐dividing segments of the crypt.
The two to four‐cell embryos as source tissue of the tetrapeptide preventing ovulations in the hamster
Authors: Kent Harry A. 
Published: February 2005

AbstractA tetrapeptide compound, derived from oviductal contents at 40 hours post‐coitus, prevents ovulation when injected subcutaneously into cyclic hamsters (Kent, '73). The present experiments were designed to determine whether the source of the tetrapeptide is from the ova, embryos, oviducts or semen. Oviducts were either untouched or ligated at the ovarian or uterine end to limit contents to embryos, semen or ova and the contents then recovered at 40 hours pc and injected into cyclic hamsters. The results indicate that the source of the tetrapeptide is the embryos.
Anti‐horseradish peroxidase associated with tubular structures in the endoplasmic reticulum of plasma cells in stimulated lymph nodes of mice
Authors: Tomonaga Susumu , Schoefl Gutta I. 
Published: February 2005

AbstractTubular structures are described in dilated cisternae of the endoplasmic reticulum in plasma cells of lymph nodes stimulated with horseradish peroxidase (HRP). A positive reaction for anti‐HRP antibody suggests that they are formed of immunoglobulins or are at least closely associated with them.
Ultrastructural observation of anterior pituitary gonadotrophs following hypophysial portal vessel infusion of luteinizing hormone‐releasing hormone
Authors: Luborsky‐Moore J. L. , Poliakoff Steven J. , Worthington W. Curtis 
Published: February 2005

AbstractLuteinizing hormone‐releasing hormone (LHRH) (50 ng) was infused with a microcannula into hypothalamo‐hypophysial stalk portal vessels of adult male rats. Anterior pituitaries were prepared for electron microscopy at 1, 5, 10, 15, 30 and 60 minutes after infusion. Granule release (exocytosis) from gonadotrophs was stimulated within one minute. Evidence of increased protein synthesis began at 5–10 minutes but was not maximal until 15 minutes. The majority of new granules appeared in the Golgi apparatus at 15 and 30 minutes. This study provides morphological evidence for LHRH‐induced hormone and synthesis release under physiological conditions.
Microvascular structure of the human epididymis
Authors: Kormano Martti , Reijonen Kalevi 
Published: February 2005

AbstractThe microvascular anatomy of the human epididymal duct system from rete testis to vas deferens was studied using microangiography and histology. Various segments of the duct system show significant differences in the density and arrangement of the small blood vessels. The rete testis is poorly vascularized while the first lobulated segment of the epididymis, which is formed by the efferent ducts is provided with a dense subepithelial capillary bed. The more distal segments of the epididymis have less dense capillarization surrounding the epididymal duct. In the vas deferens the blood vessels form a double capillary network. The outer capillary network surrounds the smooth muscle layers and the inner is located immediately beneath the duct epithelium. The organization of blood capillaries in the human epididymis and the differences seen in different portions of the excurrent duct system follow basically the general pattern seen in some experimental animals.
The andrenocortical homolog in the lake sturgeon, Acipenser fulvescens rafinesque
Authors: Youson J. H. , Butler D. G. 
Published: February 2005

AbstractThe adrenocortical homolog in the chondrostean fish, Acipenser fulvescens, is confined within yellow corpuscles located at the dorsal junction of the two kidneys near the cardinal veins. The concentration and distribution of this tissue in chondrosteans appear to be a condition intermediate between that of cyclostomes and teleosts. The homology of this tissue to adrenocortical tissue of higher vertebrates is demonstrated in its Δ5‐3β‐hydroxysteroid dehydrogenase activity and the ultrastructure of the cells.The cells contain large lipid droplets and an abundance of smooth endoplasmic reticulum and mitochondria. The abundance of smooth endoplasmic reticulum, a large Golgi apparatus and an extensive elaboration of the plasma membrane suggest the high degree of steroidogenic activity of these cells. Apposed plasma membranes make contacts through the unique cell contacts described in the adrenocortical cells of mammals (Friend and Gilula, '72). The Golgi apparatus is described as a most conspicuous component of the cytoplasm and is presented as further evidence for the important involvement of this organelle in corticosteroidogenesis in vertebrates.These morphological observations are discussed in relation to the known secretory products of this tissue in the sturgeon, and it is suggested that there is a need for further examination of the corticosteroids produced by lower vertebrates.
Morphological changes in the trophoblast, uterus and corpus luteum during delayed implantation and implantation in the western spotted skunk
Authors: Sinha Akhouri A. , Mead Rodney A. 
Published: February 2005

AbstractMorphological interactions of trophoblast and uterus from stages of preimplantation and implantation were studied in 14 western spotted skunks. In addition, the granulosa lutein cells and plasma progesterone levels were studied. In animals several days from implantation the height of epithelial cells decreased, but began to increase in animals approaching implantation. During the preimplantation period a few leucocytes infiltrated the epithelium, but in animals just prior to implantation many leucocytes infiltrated the epithelium. However, in the implanted animals leucocyte infiltration was not observed. The increased infiltration of epithelium was possibly in response to the proximity of trophoblast or due to some antigenic material from the trophoblast. The unimplanted blastocyst had a layer of trophoblast and the embryonic disc. As implantation approached, the trophoblast formed trophoblastic knobs which apposed the luminal epithelium. Subsequently microvilli of trophoblastic and epithelial cells interdigitated. Junctional complexes were observed between many adhering microvilli and/or cell processes. The first attachment of trophoblast and epithelium occurred in the abembryonic region. Later the trophoblastic cell processes and/or individual cells penetrated the epithelium and reached the basal lamina. In addition to the penetration of the trophoblast, sometimes individual trophoblastic and epithelial cells fused. In the fused cells, remnants of junctional complexes and plasma membranes were observed. The fused cells did not penetrate the basal lamina and were not observed in the stroma.During the delay period the corpus luteum contained predominantly small granulosa cells and some large granulosa lutein cells, but only large lutein cells were observed in the implanted animals. The plasma progesterone levels fluctuated during the time of implantation and should not be regarded as a basis to predict nidation in the skunk.
A quantitative analysis of muscle cell changes in compensatory hypertrophy and work‐induced hypertrophy
Authors: Seiden David 
Published: February 2005

AbstractThe cytological characteristics of two modes of muscle hypertrophy were studied in the extensor digitorum longus muscle of the rat. Compensatory hypertrophy (CH) was produced by tenotomy of the tibialis anterior muscle and work‐induced hypertrophy (WIH) was produced by forced swimming of the animal. While both methods produced an increase in muscle weight and cell size, these two parameters did not correlate. Morphometric analyses of the hypertrophied muscle cells demonstrated that in CH‐muscle there was an increase in mitochondrial volume density, a decrease in myofibrillar volume density and no change in sarcotubular or nuclear volume density. WIH‐muscle demonstrated an increase in sarcotubular volume density but no change in mitochondrial, myofibrillar or nuclear volume density. It is concluded that in CH‐muscle, the cell volume increase is attributable to mitochondrial volume increase and that there is no increase in the contractile myofibrillar component of the cell. WIH‐muscle, on the other hand, has a cell volume increase which is attributable to a proportional increase in these organelles.