bluuebunny/crossref_metadata_2025_split huggingface dataset:
DNA replication and cell division in the hamster uterus
Authors: Krueger Wayne A. , Maibenco Helen Craig 
Published: February 2005

AbstractCell renewal in specific uterine tissues was studied by autoradiography in thymidine treated and thymidine, colchicine treated hamsters. All cell types were found to replicate DNA and to divide during the estrous cycle. However, tissue types differed in the extent of cell renewal and in the time during the cycle when maximal turnover occurred. Peak DNA replication by uterine epithelium, the most active tissue, occurred during the afternoon of the second day of diestrus. Connective tissue was the second most active cell type in DNA renewal; while connective tissue cells of the myometrium incorporated thymidine at a rather constant level throughout the cycle, those of the endometrium (stroma) fluctuated during the estrous cycle with peak labeling activity being found during the morning of the second day of diestrus. A few smooth muscle cells replicated DNA during proestrus but no labeled muscle cells were observed during the other stages of the cycle.The extent of renewal of the different cell types in the hamster uterus during the estrous cycle is greater than that which has been reported in the rat. This difference may be due to timing of necropsy rather than to a species variation.
Causes of the zonal distribution of glycogen in the liver acinus after a fat‐rich diet. I. Glycogen deposition in the acini of rat livers during ‘normal’ ‘reversed’ perfusion
Authors: Otter W. Den , Tuit G. 
Published: February 2005

AbstractDifferent acinar glycogen patterns are observed in rat liver after different diets. Experiments were carried out to determine if these patterns depend on the concentration of blood glucose in the various zones of the acinus or on the direction of the blood flow. It is possible to investigate this problem by reversal of blood flow in a perfusion apparatus. Livers were perfused with Krebs‐Henseleit solution, the same volume of bovine erythrocytes, and 379 mg% glucose, 2.5% albumin and different quantities of heparin. Perfusion in the normal direction is possible through the vena porta and in the reversed direction by perfusing through the vena cava. The reported results show that glycogen localization depends on the acinar enzyme pattern for glycogen synthesis rather than the direction of blood flow.
Crystal growth in rat incisor enamel
Authors: Selvag Knut A. , Halse Agnar 
Published: February 2005

AbstractThe width and thickness of hydroxyapatite crystals and the crystal density at various stages of rat incisor amelogenesis were studied using electron microscopy. The cross‐sectional profile of the crystals increased from 259 × 12.7 Å at the surface of the ameloblast to 454 × 249 Å in the completely mineralized enamel. In agreement with previous observations, many crystals had a regular, flattened hexagonal profile during the matrix formation stage. During enamel maturation, the crystals assumed more irregular surface contours, the crystals tending to adapt themselves to the available space. In completely mineralized enamel, the crystals were as irregular in shape as the crystals in human enamel, and they occupied around 85% of the volume. While the crystals at the onset of mineralization were separated by a distance of 120–150 Å, the crystals eventually became relatively closely packed, separated by a fine space only 10–25 Å in width. A lower number of crystals per unit cross‐sectional area of the enamel prisms was observed in fully mineralized enamel as compared with the early stages of amelogenesis. Since evidence of fusion of crystals is lacking, the decrease in crystal density appears to result from swelling of the enamel prisms.
Localization of cholesterol in peripheral nerve: USE of [3H] digitonin for electron microscopic autoradiography
Authors: Napolitano Leonard M. , Saland L. , Lopez J. , Sterzing P. V. , Kelley R. O. 
Published: February 2005

AbstractTritiated digitonin of high specific activity has been incorporated into fixation of adult rat sciatic nerve. Electron microscope autoradiograms developed four to thirteen days after coating indicate highest concentration of label over or near myelin sheaths. Label is observed over areas of reasonable myelin preservation as well as in areas of artifact and membrane disruption. The technique is suggested for use as a means of fairly specific localization of free cholesterol in tissues. In addition, the activity of the isotope used permits visualization of autoradiograms after short exposure times.
Surface patterns in the reproductive tracts of the rabbit observed by scanning electron microscopy
Authors: Kanagawa H. , Hafez E. S. E. , Pitchford W. C. , Baechler C. A. , Barnhart Marion I. 
Published: February 2005

AbstractThe ultrastructure of cell surface and tissue organization of reproductive tracts of female rabbits were observed by scanning electron microscopy. In the vagina, straight and shallow longitudinal folds were observed. Complex, very deep, narrow folds with small crypts were observed in the cervix uteri. Two types of cells were recognized: ciliated cells and secretory non‐ciliated cells. The internal os area contained more ciliated cells than the external os area. In the uterus, two different patterns of fold formations were observed: shallow fold formation in a random direction or mosaic pattern in the lower part of the uterus, and wave‐like folds in the middle or upper part of the uterus. The lower part of the uterus contained more ciliated cells than the mid and upper part of the uterus. At the uterotubal junction, four large folds and four small folds from the isthmus are projected into the uterine lumen forming a rosette‐like structure. In the oviduct, longitudinal fold formations were observed through the isthmus to ampullae. The number of ciliated cells gradually increased from the isthmus to the ampullae. The fimbriae, made of several mucosal folds arranged like flower petals, were composed of a high percentage of ciliated cells.
The persistence of a circadian rhythm in histamine response in guinea pigs maintained under continuous illumination
Authors: Scheving Lawrence E. , Sohal G. S. , Enna Carl D. , Pauly John E. 
Published: February 2005

AbstractAdult guinea pigs were carefully standardized for at least seven days prior to each experiment; this included an artificial light‐dark cycle with light extending from 0600 to 1800. On three experimental days, eight animals were injected subcutaneously with 300 μg of histamine at six‐hour intervals over a 24‐hour period; each animal received four injections during one day. The size of the erythema produced each time was measured. In all three experiments a prominent group rhythm was demonstrated with maximum response occurring during the dark phase; minimum response always occurred during the latter part of the light phase. Such results indicate a strong synchronization among the animals of the group.Two additional, similar studies were performed on animals standardized in one case for 21 days and in the second for 35 days under continuous illumination. The group rhythms of histamine response under these conditions, when compared to the light‐dark adapted group rhythm, were greatly modified in phasing and profile. The circadian rhythm in response to histamine persisted in each individual animal. The change in the phasing and profile of the group rhythm was due to a partial desynchronization among the individual animals subjected to continuous illumination.
Immunohistochemical and histochemical studies of pituitary β‐lipotrophs
Authors: Moon Henry D. , Li Choh Hao , Jennings Barbara M. 
Published: February 2005

AbstractThe presence of β‐lipotrophin or an immunologically similar substance was demonstrated in the intermediate lobe cells and some basophils of the anterior lobe by both fluorescent and peroxidase‐conjugated antibody methods. These basophils were found to be corticotrophs, i.e., reactive with anti‐ACTH. ACTH, when added to anti‐β‐LPH, decreased the fluorescence and peroxidase reactions of intermediate lobe cells and the anterior lobe corticotrophs. The addition of MSH to anti‐β‐LPH produced a slight decrease in the reaction between the intermediate lobe cells and anti‐β‐LPH. The intermediate lobe cells also reacted with anti‐ACTH. Both Somatotrophs and lactotrophs reacted with anti‐β‐LPH to give positive fluorescence or peroxidase reactions. However, the addition of STH to anti‐β‐LPH abolished the reaction between anti‐β‐LPH and somatotrophs. Similarly, LTH, when added to anti‐β‐LPH, abolished the positive reaction of lactotrophs to anti‐β‐LPH. When STH, LTH and ACTH were added to anti‐β‐LPH, the fluorescence of the somatotrophs and lactotrophs was abolished, whereas the corticotrophs maintained their fluorescence at a reduced intensity. These results indicate that the somatotrophs and lactotrophs do not contain β‐LPH and that corticotrophs contain β‐LPH.
An electron microscopic analysis of the nerve of the pterygoid canal in the mouse
Authors: Shimozawa Atsumi 
Published: February 2005

AbstractElectron microscopic analyses of the greater petrosal nerve, the deep petrosal nerve and the nerve of the pterygoid canal near the point of their union in the mouse were made to clarify the courses of their fibers. Most of the nerve fibers of the greater and deep petrosal nerves passed through into the pterygoid canal nerve, but in some specimens a few nerve fibers (less than 100) coursed from the deep petrosal nerve to the greater petrosal nerve or conversely. Therefore, except for these, the source of the unmyelinated fibers of the greater petrosal nerve from the deep petrosal nerve may be eliminated; these fibers may be derived from the facial nerve proximal to the greater petrosal nerve.
Embryology of the sheep. III. The respiratory system, mesenteries and celom in the fourteen to thirty‐four day embryo
Authors: Bryden M. M. , Evans Howard , Binns Wayne 
Published: February 2005

AbstractThe day‐by‐day developmental changes which occur in the respiratory system, mesenteries and celom of the sheep embryo from 14 to 34 days coital age are documented chronologically and described. This work provides standards of normal development which can be used as a basis for future work on abnormal development of these structures.The respiratory diverticulum which first appears on the seventeenth day is seen as a primitive lung bud on the nineteenth day and becomes bilobed on day 20. By the twenty‐first day a laryngotracheal tube is present and the larynx develops in the next ten days.The dorsal mesogastrium forms on the eighteenth day and the omental bursa is seen as an invagination by the twenty‐first day. A splenic primordium associated with the omentum is present by the twenty‐seventh day.The dorsal mesentery appears on the eighteenth day and undergoes torsion, herniation and coiling on the twentieth, twenty‐second and twenty‐seventh days. The ventral mesentery is present on the seventeenth day but disappears centrally between the eighteenth and twenty‐first days.An extraembryonic celom is seen on the fourteenth day and the formation of the intraembryonic celom occurs on day 15. Development of the pleuroperitoneal membranes commences on the twenty‐first day. Complete separation of pericardial and pleural cavities is completed by the twenty‐eighth day.
Accumulation of lipid. Droplets in ventricular cardiac muscle of the bat following administration of parachlorophenylalanine: The influence of hibernation
Authors: Hagopian Martin , Gershon Michael D. , Nunez Eladio A. 
Published: February 2005

AbstractThe effect of the administration of p‐chlorophenylalanine on the fine structure of the ventricular cardiac muscle of active and hibernating bats was studied. The concentration of norepinephrine in the bat heart was also measured. In the active animal, p‐chlorophenylalanine induced a striking increase in the size and number of lipid droplets. Moreover, the lipid droplets exhibited an intimate association with mitochondria. The mitochondria in such associations showed extreme variations in form but exhibited normal arrangement of cristae. p‐Chlorophenylalanine also induced a slight increase in the number of glycogen granules but no other effects were apparent. During hibernation, the administration of p‐chlorophenylalanine failed to produce a change in either the size or number of lipid droplets. The concentration of norepinephrine in the heart of active and hibernating bats was not altered by the injection of the drug. The present findings indicate that lipid accumulation in ventricular myocardium following injection of drugs is not necessarily the result of depletion of cardiac stores of norepinephrine.
Electron microscopic and histochemical studies on the synaptic vesicles in mouse vas deferens and atrium after 5‐hydroxydopamine administration
Authors: Chiba Tanemichi 
Published: February 2005

AbstractAfter administration of 5‐hydroxydopamine, one of the “false” adrenergic transmitters, core materials within both large and small vesicles of the adrenergic nerves increase in density, while clear vesicles in the cholinergic nerves do not change. In the vas deferens of the mouse, initial sign of the uptake is seen as early as one minute after intravenous administration. Eighty to ninety percent of vesicles in the adrenergic nerve varicosities are filled with dense cores by more than 100 mg/kg of 5‐OH‐DA administration. 5‐OH‐DA stored in the vesicles remains for seven to ten days and gradually disappears thereafter. After administration of 5‐OH‐DA, acetylcholinesterase (AChE) activity is examined in the nerve varicosities in the atrium. AChE activity in the adrenergic nerve fibers is discussed in the light of these findings.
Thyroxine and the development of the tibia in the embryonic chick
Authors: Hall B. K. 
Published: February 2005

AbstractEmbryonic chicks were treated with exogenous L‐thyroxine or with thiourea at eight days of incubation and the subsequent development of the tibia studied.The weight of the tibia was 62% lower than that from normal embryos, and the length of the tibia 24% below normal in the embryos treated with thiourea. This reduced rate of growth was shown to be due to a reduction in the rate of maturation of chondroblasts into chondrocytes, reduced chondrocyte hypertrophy and defective deposition of acid mucopolysaccharide into the cartilage matrix. Osteogenesis per se was unaffected. It was concluded that thyroxine plays a role in the control of chondrocyte maturation and in cartilage matrix production during normal development.The epiphyses of the tibiae from the embryos treated with thiourea were extensively eroded, invaded by marrow and more fragile than those from untreated embryos, indicating that thyroxine is essential for the maintenance of the integrity of the articular cartilage. An abnormal core of bone developed within the proximal epiphysis of these embryos.Exogenous thyroxine at concentrations as low as 100 pg/embryo also reduced the growth of the tibia below that seen in untreated embryos. Evidently the cells of the skeleton are sensitive to both lowered and increased levels of circulating thyroxine.
Topology of the lateral nasal cartilages: The anatomical relationship of the lateral nasal to the greater alar cartilage, lateral crus
Authors: Drumheller Glenn W. 
Published: February 2005

AbstractThis investigation was undertaken to help fulfill the practical need of the rhinologic surgeon for a more accurate anatomical knowledge of the cartilages of the nasal tip.Four adult caucasian noses aged 62–88 years were embedded en bloc and serially sectioned. The nasal cartilages of one were reconstructed in wax. Anatomical relationships of the lateral nasal cartilage to the lateral crus of the greater alar cartilage were compared. The findings were compared with descriptions found in the literature.The lateral nasal cartilage curls to varying degrees laterally and upward on its inferior margin where it underrides the lateral crus of the greater alar cartilage. The curl is greater anteriorly and diminishes postero‐laterally to the point where the cartilage lies flat. The lateral crus of the greater alar cartilage also may curl medially and downwards on its superior margin where it overrides the lateral nasal cartilage. Sesamoid cartilages are present in all specimens.These findings, although known to many rhinologic surgeons, are not clearly established in the literature.
Anatomical relationships of the cerebral and dural venous systems in the parasagittal area
Authors: Browder Jefferson , Browder Ann , Kaplan Harry A. 
Published: February 2005

AbstractThe cerebral and dural venous systems are derived from separate layers of the vascular plexus that cover the brain in early embryonic life. The cerebral veins arise from the inner layer of the plexus which invests the neural tube and join the dural systems in the superior midline concomitant with the development of the sinuses. The dural veins, the lateral lacunae and the dural sinuses arise from the outer embryonic plexus. In the fully developed human these two systems are separate except for an occasional communication between a lateral lacuna and a superior cerebral vein just before the vein joins the superior sagittal sinus. The lateral lacunae are a distinct anatomical entity and their venous meshwork is to be regarded as a part of the dural venous system.
Radiation induced abnormalities in early in vitro mouse embryos
Authors: Kirkpatrick Jay F. 
Published: February 2005

AbstractFemale mice were superovulated and mated, and the two‐cell embryos were collected and cultured in vitro. The embryos were exposed to x‐irradiation (0–491 rads) during the two‐cell stage, before the appearance of the next cleavage plate, placed in new unirradiated culture medium and observed during subsequent development. Morphological abnormalities which occurred as a result of irradiation included fragmentation, disintegration, granulation, incomplete cleavage, cleavage cessation, nuclear degeneration and pycnosis and cytoplasmic vacuolization. There was no damage to the zona pellucida.The types of abnormalities indicated an agreement with the results of previous in vivo studies. A distinct correlation existed between morphological abnormalities and embryo death. The greatest number of abnormalities resulted within five hours following irradiation, but increased through 20 hours post‐exposure. At doses above 300 rads, the magnitude of damage was greater in the in vitro embryos than that shown in previous in vivo studies.
The organization of the contractile apparatus of vertebrate smooth muscle
Authors: Bois Richard M. 
Published: February 2005

AbstractSmooth muscle of the small intestine of the rat was fixed by vascular perfusion employing aldehydes in a balanced salt solution, followed by immersion fixation in aldehydes and post‐osmication. In such tissue preparations thick filaments approximating 140 Å in diameter are observed in virtually all the smooth muscle cells. The thick filaments are rather uniformly distributed among the more numerous thin filaments. The nearest neighbor distances between the thick filaments range from 400 to 700 Å. The thick to thin filaments ratio is found to apporximate 1:12. Only thin filaments are observed in the most distal segment of terminal processes of muscle cells and the tips of these processes appear to be lined by attachment plaques. A clear segregation of the thick filaments from both dense bodies and attachment plaques is seen. Distally along the tapering extremities of muscle cells progressively more of the plasma membrane is found lined by attachment plaques. These observations are interpreted as strong evidence that the contractile apparatus of the vertebrate smooth muscle cell consists of interdigitating arrays of thick and thin filaments collated into contractile units by the anchoring of the thin filaments in dense bodies and attachment plaques.
Localization and correlation of catecholamine‐containing cells with adenyl cyclase and phosphodiesterase activities in the human fetal heart
Authors: Dail William G. , Palmer Gene C. 
Published: February 2005

AbstractThe present investigation attempts to correlate the appearance of catecholamines to receptor‐induced metabolic events (adenyl cyclase‐phospho‐diesterase) in the developing human heart. Adrenergic innervation, examined with the Falck‐Hillarp fluorescence technique as well as by electron microscopy, reveals the presence of catecholamine‐containing cells in or near the fetal heart at all ages studied (8–18 weeks). In most instances these cells occur either in association with extrinsic nerves along the aorta and pulmonary trunk or in the interatrial septum. Ultrastructural features of these cells include dense core vesicles. Acetylcholinesterase positive cardiac nerves and ganglion cells are observed. Highest basal activities of adenyl cyclase are found at the sixth fetal week. The enzyme is activated by fluoride ion from the eighth through the seventeenth fetal week, but not by catecholamines. Glucagon stimulates this enzyme at the seventeenth fetal week. Phosphodiesterase activity is progressively increased from the eighth to the seventeenth weeks and is inhibited by aminophylline from the tenth through the fifteenth week. Although catecholamine cells are present in the fetal heart, adrenergic fibers are absent at all ages studied. Failure to observe adrenergic fibers may correlate with the lack of hormonal activation of receptor mechanisms.
The sympathetic innervation of the cervical lymphatic duct of the dog
Authors: Todd Gordon L. , Bernard George R. 
Published: February 2005

AbstractThe sympathetic innervation of these ducts was studied by means of the Falck fluorescence histochemical technique and electron microscopy. A loose network of sympathetic fibers was observed on the surface of the lymphatic duct, yet there were large areas of the duct wall void of any fibers. The majority of the fibers branched from the plexuses of sympathetic fibers surrounding the vasa vasorum of the ducts. Sympathectomy experiments demonstrated the fibers do not travel up the vagosympathetic trunk or the carotid artery to reach the ducts, but apparently are carried along the plexuses of sympathetic fibers surrounding the smaller blood vessels outside the carotid sheath. The individual branches not accompanying any blood vessels would travel along the duct for distances up to several hundred microns, with occasional branches, to terminate without any specializations. The nerve fibers were encased in a Schwann cell sheath which in some cases only partially surrounded the fibers. Several of the axon profiles contained synaptic vesicles including small granular (or dense‐cored) and agranular vesicles and a few large synaptic vesicles. In all cases observed, the axons and their Schwann cell sheath were located in the adventitia outside the smooth muscle cells.
The development of the tibia in hypophysectomized chick embryos
Authors: Hall B. K. , Girouard R. J. 
Published: February 2005

AbstractChick embryos were hypophysectomized by partial decapitation at 33 hours of incubation and the subsequent morphogenesis and growth of the whole embryo and the growth, histology and histochemistry of the tibia studied.Twenty‐five percent of the increase in body weight which normally occurs between 12 and 18 days of incubation and 60% of the normal growth of the tibia over the same period failed to occur in the hypophysectomized embryos. Histological studies indicated that the diminished skeletal growth resulted from reduced proliferation of chondroblasts within the epiphyseal growth zone and from reduced deposition of acid mucopolysaccharides into the cartilaginous matrix. The differentiation and hypertrophy of the chondrocytes produced in the hypophysectomized embryos was not affected. Therefore, the pituitary gland exerts considerable control over the development of the cartilaginous skeleton in the embryonic chick.Osteogenesis was reduced as a consequence of the reduced chondrogenesis in the long bones from the hypophysectomized embryos.