bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of colcemid on the structure and secretory activity of ameloblasts in the rat incisor as shown by radioautography after injection of 3H‐proline
Authors: Karim A. , Warshawsky H. 
Published: February 2005

AbstractEnamel secretion by ameloblasts was investigated in the incisors of 100 gm normal and colcemid‐injected male rats. Morphological studies were done on rats given a single intraperitoneal injection of 0.1 mg (1.25 mM) of colcemid and sacrificed 1 to 4 hours after injection. Protein synthesis and secretion were investigated with radioautography in normal and colcemid‐treated rats injected with 3H‐proline and sacrificed at intervals between 0.5 and 3.5 hours after injection. Colcemid was injected 0.5 hours prior to 3H‐proline in each experimental rat. Electron microscopic examination revealed several morphological alterations between 1 and 4 hours after injection of colcemid. These changes included fragmentation of the normally elongated rough endoplasmic reticulum into shorter profiles; a disorganization of thenormally tubular configuration of the Golgi apparatus into a number of separate but intact stacks of Golgi saccules; the disappearance of secretion granules and profiles of smooth endoplasmic reticulum from Tomes' processes; and the accumulation of secretion granules at the mature face ofthe Golgi stacks, as well as in the infranuclear cytoplasm where they are normally not found. Radioautography revealed that protein synthesis by the rough endoplasmic reticulum had continued in colcemid‐altered ameloblasts. Labeled secretion granules were found at the mature surface of the Golgi stacks and in the infranuclear cytoplasm, however they did not migrate into Tomes' processes. Consequently, labeled enamel matrix did not appear extracellularly at the same time as in normal controls. Quantitative radioautography in the light microscope revealed that the effect of colcemid, although reversed within 4 hours, had temporarily inhibited normal migration and exocytosis of secretion granules.
Hormones and the lung II. Immunohistochemical localization of thyroid hormone binding in type II pulmonary epithelial cells clonally‐derived from adult rat lung
Authors: Wilson Marjorie , Hitchcock Karen R. , Douglas William H. J. , Delellis Ronald A. 
Published: February 2005

AbstractThe type II pulmonary epithelial cell is the recognized site of surfactant synthesis and storage. Results of recent studies indicate that the thyroid hormones, triiodothyronine (T3) and thyroxine (T4), may be important regulators of surfactant production and/or release. Direct and indirect immunofluorescence techniques were used in an attempt to demonstrate binding of T3 and T4 in monolayer cultures of isolated type II cells. These cultured epithelial cells are clonally‐derived from adult rat lung, retain a diploid karyotype through 35 population doublings in vitro, contain granular inclusions (lamellar bodies) in the perinuclear cytoplasm, and synthesize phosphatidylcholine via the CDP‐choline pathway.In isolated type II cells, either of two fluorescent patterns was observed: (a) nuclear fluorescence accompanied by a reticular perinuclear network; or (b) diffuse cytoplasmic accumulations with concentrations around perinuclear cytoplasmic inclusions. Ultrastructurally these inclusions had the typical appearance of lamellar bodies. Histochemical studies demonstratedthat these inclusions contained surfactant‐associated nonspecific esterases and stained with Nile blue hydrochloride. The positive reactions with these two recognized markers for pulmonary surfactant indicate that these inclusions are indeed lamellar bodies, the putative sites of surfactant synthesis and/or storage. These findings suggest that the type II pulmonary epithelial cell contains specific binding sites for thyroid hormones, and support the hypothesis that thyroid hormones are regulators of surfactant metabolism.
Distribution of wheat germ agglutinin binding sites on normal human and guinea pig bone marrow cells: An ultrastructural histochemical study
Authors: Ackerman G. Adolph 
Published: February 2005

AbstractThe wheat germ agglutinin‐gold labeled ovomucoid (WGA‐Ovo‐G) method has been employed in the ultrastructural localization of WGA surface receptor sites on gluteraldehyde‐fixed normal human and guinea pig bone marrow cells. The number of gold particles per micron of cell surface were counted and data subjected to statistical analysis. WGA labeling ofthe bone marrow cells was found to be quite heavy and evenly distributed along the cell surface. Only macrophages, in both species, and a number of lymphocytes in the guinea pig exhibited limited WGA labeling. Comparison of morphologically similar cell types in human and guinea pig marrow indicated that WGA receptor sites were more abundant on the guinea pig hemic cells. WGA surface labeling was found to be not only related to cell type and to animal species but, in some instances, varied with the stage of maturation of a given cell line; viz., neutrophilic cell series in both man and guinea pig and erythrocytic cell series in the guinea pig.
Surface morphology of macrophages in the regressing corpus luteum, as revealed by scanning electron microscopy
Authors: Paavola Laurie G. , Boyd Charles O. 
Published: February 2005

AbstractActivated macrophages phagocytize moribund luteal cells and thus play a central role in the postpartum regression of corpora lutea in guinea pigs (Paavola, '79). When viewed by transmission electron microscopy (TEM), these luteal macrophages exhibit many surface protrusions. To characterize more fully the nature and extent of these evaginations, as well as to gain further understanding of phagocytes in their natural surroundings, luteal macrophages were studied in situ by scanning electron microscopy of regressing corpora lutea. Correlated TEM was carried out to confirm the identity of the various cell types. Even in low power scanning electron micrographs, macrophages are conspicuous, and can be readily distinguished from luteal cells by their surface topography. Luteal cell surfaces bear low ridge‐like folds and sparse microvilli. In contrast, macrophages characteristically exhibit highly developed surface projections, the most common of which are knob‐like or clubbed processes of varying size and shape. Other distinctive surface modifications displayed by luteal macrophages include long, slender filopodia, and well developed pseudopodia. These processes generally have an uneven distribution over the cell; thus, luteal macrophages may appear polarized with regard to surface activity. Both filopodia and pseudopodia occur in close contact with luteal cell surfaces. In addition, occasional luteal macrophages have surfaces that are covered with large, crater‐like depressions. The phagocytosis ofcells and cellular debris by macrophages was also observed. In summary, the highly pleomorphic surface activity of luteal macrophages appears to be correlated with their role in the removal of senescent luteal cells.
Roentgen cephalometric studies on skull development in rats. III. Gigantism versus acromegaly: Age differences in response to prolonged growth hormone administration
Authors: Savostin‐Asling Irene , Nakaiye Roy , Asling C. Willet 
Published: February 2005

AbstractExperimental conditions simulating the induction of clinical pituitary gigantism and acromegaly were established by prolonged administration of growth hormone in high dosage to adult male rats starting at two different ages: 6 months (growth still active) and 14½ months (growth virtually arrested). Treatment continued for 14½ months, controls receiving saline injections. Each group numbered eight at onset. Standardized x‐rays of skull were made in ventro‐dorsal and lateral planes, at onset, mid‐period, and end of the study. Representative dimensions of cranial and facial segments were measured, including lengths, widths, palate dimensions, gnathic and interzygomatic angles, and incisor curvature. Some related indices were calculated. Means and standard errors were computed, usually on five to eight rats (oldest controls: three only). The response pattern of overall skull length was most illustrative. Younger adult controls grew actively until 14 months of age (5%) while injected rats grew still faster (8%); thereafter, controls grew negligibly (1%) and injected rats only slightly (2%). Older controls showed negligible skull elongation from 14½ to 29 months of age, and growth hormone stimulated no gain. In the younger group, skull length gains were almost entirely in the facial region; cranium gained no length and widened only slightly. Cranial index increased slightly with the hormone. Facial (bizygomatic) width increased in both injected groups—proportionately in younger rats (to gigantism) and disproportionately in older rats. Palatal and dental growth followed facial patterns in both groups. Cranial vault bones thickened and, in older rats, developed surface irregularities, giving them a more massive, acromegaloid structure.
Morphology of the guinea pig respiratory tract
Authors: Schreider Jay P. , Hutchens John O. 
Published: February 2005

AbstractA morphologic description of the airways of the guinea pig was developed from measurements of casts of the lungs and nasal cavity and from measurements of frozen sections of the lungs. The lengths, diameters, branching pattern, and numbers of elements of the respiratory tract formed the basis for a representative model of the system. The brainching pattern is irregular to the pulmonary region but regularly dichotomous thereafter. The nasopharyngeal‐tracheobronchial region contributes 2.64 cm3 of the total respiratory volume of 21.62 cm3. The alveoli contribute 16.31 cm3 of the 18.98 cm3 pulmonary region. The nasal region consist of convoluted and irregular airways with a functional volume of 0.48 cm3.
The occurrence of an unusual tubular organelle in surface epithelial cells of the mouse ascending colon after injection of diazo‐oxo‐norleucine
Authors: Michaels John E. 
Published: February 2005

AbstractTubular structures were observed in surface epithelial cells of mice that had been injected with high dosages of diazo‐oxo‐norleucine (DON), a glutamine antagonist. The tubules often occurred in bundles which contained a variable number of tubules, often as many as one hundred being present. Within the bundles, the tubules were oriented either randomly or parallel to one another. They measured 25 to 35 nm in diameter with angular or circular profiles and were as long as 1 to 2 μm. In the center of each tubule, a smaller tubule‐like component was evident that measured 5 to 7 nm in diameter. With the exception of endoplasmic reticulum, often with attached ribosomes, organelles were excluded from the bundles. Since the tubules and the endoplasmic reticulum occasionally were observed to be continuous, it is suggested that the tubules may originate from this organelle.
A new organic solvent for use in the clearing of tissues. I. Soft tissue histology
Authors: Wishe Harvey I. , Roy Martin , Piliero Sam J. 
Published: February 2005

AbstractHistosol is a non‐flammable solvent mixture of synthetic aromatic hydrocarbons with a flash point of 124°F (T.C.C.). It has a lower vapor pressure and evaporation rate than other organic solvents, such as xylene, routinely used as clearing and deparaffinizing agents. Although both xylene and Histosol clear and deparaffinize soft organ tissues effectively in the preparation of permanently mounted stained slides, Histosol appears, in many instances, to be the choice solvent: tissues are easier to section; cell bordrs and cell surface modifications are most distinct; cytoplasmic eosinophilia is more vivid; and nuclear detail is improved. Of prime importance, Histosol is a safer and more efficient solvent for use in histological and pathological laboratories.
Proliferation of epithelial cells in the adult primate choroid plexus
Authors: Kaplan Michael S. 
Published: February 2005

AbstractAn adult rhesus monkey was injected intraperitoneally with [H3] thymidine (2.3 μCi/gram body weight) and perfused 90 minutes later with a mixture of aldehydes. One and a half micrometer plastic sections were then cut and dipped into liquid emulsion for radioautography. Labeled cells were observed in the choroid plexus of the anterior lateral ventricle; cell identification was evaluated using electron micrographs taken from serial thin sections of reembedded. radioautographic 1.5‐μm sections. The ultrastructure and location of both mitotic figures and labeled cells confirmed the presence of undifferentiated basal choroid plexus epithelial cells in the adult primate central nervous system.
Ultrasonographic determination of lumbar spine angulation
Authors: Jones Norbert A. , Gonzalez Antonio C. 
Published: February 2005

AbstractAbdominal ultrasonograms of recumbent, supine adult subjects were used to measure the angle formed between the horizontal plane and a plane along the anterior border of upper lumbar vertebral bodies. The angle, referred to as Φ, for male and female subjects averaged 8.8°. When this angle was compared in subjects with the hips flexed and extended, there was no significant difference. There was a significant difference between subjects in a recumbent position and a standing position. The amount of angulation was compared to the age of the individual and found to have a low correlation coefficient. The angle Φ appears to be a good indicator of the amount of lordosis, it relates well to previous methods of measuring lordosis, and it is a benign procedure in a genetically sensitive region.
The ultrastructure of cultures from the swarm rat chondrosarcoma
Authors: Hascall Gretchen K. , Kimura James H. 
Published: February 2005

AbstractWhen chondrocytes from the Swarm rat chondrosarcoma are isolated by trypsin and collagenase digestion and cultured in Petri dishes, they form a new extracellular matrix within 24 hours, with proteoglycan matrix granules and collagen fibrils. This rapid synthesis of new matrix, together with the biochemical and morphological characterization of the proteoglycans as typical of cartilage, demonstrates the value of these cultures as a model system for studies of synthesis, secretion, and organization of extracellular matrix.
Mitosis in pituitary MSH/endorphin cells of adult male rat pars intermedia: Light and electron microscopic observations
Authors: Saland L. C. 
Published: February 2005

AbstractSmall numbers of dividing cells were observed in the pituitary intermediate lobe of normal and p‐chloroamphetamine‐treated adult male rats. Ultrastructural examination reveals that the mitotic elements are granulated MSH/endorphin cells. Nerve fibers providing direct innervation could be found on dividing cells. The observations illustrate a limited potential for proliferation in the adult MSH/endorphin cell population.
The development of enamel structure in rat incisors as compared to the teeth of monkey and man
Authors: Warshawsky H. , Josephsen K. , Thylstrup A. , Fejerskov O. 
Published: February 2005

AbstractThe rat incisor is an excellent model system in which to study amelogenesis. However, the information obtained has not been extrapolated to the human because of alleged structural differences between the teeth. The obvious differences include continuous eruption in rat incisors and an enamel rod pattern in rats which seemingly differs from the keyhole pattern of human enamel. A comprehensive analysis was made of those features of enamel structure considered fundamental to the understanding of its formation. This was done by applying the knowledge of amelogenesis obtained in rat incisors to the teeth of monkey and man. The following points of basic similarity were established between these species: (1) Interrod enamel is secreted first. It forms the side walls of cavities which are initially occupied by Tomes' processes. (2) The formation of interrod cavities is followed by deposition of enamel rods within these spaces. (3) The rods conform to the shape of the cavities and are secreted from one surface of Tomes' process. (4) At the initial site of rod deposition its enamel is continuous with the interrod enamel wall. (5) Growth of the rod compresses the process to one side of the cavity resulting in an arcade‐shaped “space” between the rod and the remaining interrod walls. This study demonstrates that it is no longer necessary to postulate a keyhole structure for primate enamel, and it has established that a fundamental similarity exists in the basic structure and in the mode of formation of enamel in all three species.
Further electrophysiologic and anatomic correlates in a canine model of chronic myocardial infarction susceptible to the initiation of sustained ventricular tachyarrhythmias
Authors: Michelson Eric L. , Spear Joseph F. , Moore E. Neil 
Published: February 2005

AbstractA canine model of chronic myocardial infarction has been studied in which animals are susceptible to the initiation of sustained ventricular tachyarrhythmias using routine methods of programmed stimulation. The pacinginduced arrhythmias in this model are similar to those observed in man in their mode of initiation and termination, as well as in their response to both pacing and pharmacologic interventions. Indirect evidence has suggested a localized protected reentrant mechanism for these arrhythmias. The susceptibility to arrhythmia initiation in this model has been related to both electrophysiologic and histopathologic findings. Consistently, animals have demonstrated a marked heterogeneity of local properties of excitability and refractoriness at sites within areas of infarction. Correspondingly, animals have shown a marked inhomogeneity of histopathologic findings within areas of infarction, with close interspersing of normal and abnormal myocardium. Remarkably, even animals with small mottled infarctions, often less than 1 cm × 2 cm and electrocardiographically silent, were highly susceptible to the initiation of ventricular tachyarrhythmias, and especially fibrillation. Thus, initial provocative studies in this model have suggested its potential importance both in studying arrhythmia mechanisms and in evaluating the efficiency of potential antiarryhthmic interventions. In addition, this should be an ideal model in which to correlate pathophysiologic and morphologic alterations in the setting of chronic myocardial infarction.
A congenital abnormality in the arrangement of muscle bundles in a segment of the distal ileum, producing obstruction: A variant of the so‐called “giant meckels's diverticulum”
Authors: Valdes‐Dapena Marie A. , Marchildon Michael B. , Poole Catherine A. 
Published: February 2005

AbstractThis 4‐year‐old male child was diagnosed at birth as having several minor congenital anamolies. X‐rays taken during the first year of his life showed a single, massively dilated loop of bowel in the upper abdomen, not appreciated at the time.In 1980 he was admitted to Jackson Memorial Hospital with the diagnosis of small bowel obstruction. An upper gastrointestinal series showed one tremendously dilated loop of distal ileum. At laparotomy, the patient was found to have extreme segmental dilatation of one loop of distal ileum which ended abruptly; there was no evident external cause for obstruction.The resected loop contained in excess of 200 cc of watery brown liquid. The mucosal folds and underlying smooth muscle bundles, in the dilated portion only, were not arranged circumferentially but rather in a distinctive finger‐print‐like pattern with trifurcations, whorls, and intricate interdigitations which had probably produced contractions of a circus type rather than normal peristalic waves.We have been able to find only three reports in the literature in which, as was the case here, the so‐called “giant Meckel's diverticulum” presented as a single tremendously dilated segment of ileum, sharply demarcated at its distal end. In none of them is there any description of the orientation of muscle bundles. We believe that the abnormal arrangement of smooth muscle in the muscular coat in this specimen, and perhaps in the others, probably represents the underlying cause for the extreme localized dilatation.
The origin of the hippocampal commissure in the rat
Authors: Voneida Theodore J. , Vardaris Richard M. , Fish Stephen E. , Reiheld Craig T. 
Published: February 2005

AbstractThe present study was designed to determine the origin of commissural axons in the hippocampus. One hippocampus of 94 rats was pressure injected with 40% horseradish peroxidase (Sigma VI), or with 2–4% wheat germ agglutinin HRP (E‐Y Labs). Injections (0.001 to 0.1 μ1) were made through glass micropipettes with fitted plungers. Pipettes were positioned stereotaxically, and by electrophysiological monitoring through the injection syringe. An ipsilateral stimulating electrode activated CA3 and CA1 cells via Schaffer collaterals. Population potentials were monitored as the recording pipette was advanced from the cortical surface into the hippocampus. Wave forms of monosynaptically elicited field potentials provided an accurate indicator of its position. Following survival periods of 24 hours, the brains were processed according to the Mesulam method. Forty‐micron sections were serially mounted and counterstained. Injection sites and filled cells were plotted manually on a standard set of coronal sections. Our results indicate that field CA1 receives input from contralateral subfields CA1a and c, as well as from all CA3 subfields. In addition, rostral CA1 injections resulted in labeling of cells in the contralateral subiculum and entorhinal cortex. Homotopic connections exist between subfields CA3a and b; it appears that a major input to CA3c is from the contralateral polymorph cells of the dentate hilus. Commissural input to the dentate granule cells appears to be the giant polymorph and CA3c cells of the contralateral dentate hilus. With respect to the question of homotopicity our results suggest that commissural connections are predominantly homotopic in the mediolateral plane, although CA1 and CA3 injections also resulted in contralateral labeling of hippocampal cells caudal to the levels of injection.