bluuebunny/crossref_metadata_2025_split huggingface dataset:
The fate of thecal smooth muscle cells in postovulatory hamster follicles
Authors: Martin Gary G. , van Steenwyk Gretchen , Miller‐Walker Cindy 
Published: February 2005

AbstractSmooth muscles cells (SMC) have been identified in the theca externa of preovulatory follicles in several mammals. The function of these cells is not clear. It has been suggested that they are involved in ovulation and may play a role in the collapse of ruptured follicles and their transformation into corpora lutea (CL). In this study we used transmission electron microscopy (TEM) to examine the ultrastructure of SMC at the base of hamster follicles during the formation and regression of CL. For the first three days following ovulation, the CL are surrounded by a distinct theca externa composed of 1–3 layers of spindle‐shaped cells. The cells were identified as SMC by the masses of filaments in the cytoplasm, dense attachment plaques and caveolae along the plasma membrane and an external lamina surrounding each cell. On the fourth day after ovulation, the theca externa is fragmented and TEM observations suggest the following three fates for theca externa cells: (1) many cells degenerate, (2) some cells persist as SMC, (3) some cells possess few or no filaments and appear similar to fibroblasts. The significance of these results is discussed in regard to ovarian contractions, the fate of CL, and the recycling of ovarian tissues.
A cytochemical study of nuclear changes in fertilized hamster eggs
Authors: Da‐Yuan Chen , Longo Frank J. 
Published: February 2005

AbstractNucleoprotein changes during male and female pronuclear development have been examined in fertilized hamster eggs utilizing the ammoniacal silver reaction (ASR) at the light and ultrastructural levels of observation. Prior to its incorporation, the paternally derived chromatin was heavily laden with ASR product. Immediately upon gamete fusion the sperm nucleus underwent a dramatic increase in staining, suggesting an augmentation in the availability of reactive sites already present in the sperm nucleus or an accumulation of “new” reactive sites from the egg cytoplasm. With subsequent transformations of the sperm nucleus into a male pronucleus, there was a progressive reduction in ASR product associated with the paternal chromatin. Concomitantly, the condensed maternal chromosomes remaining in the zygote after the conclusion of meiosis dispersed and developed into a female pronucleus; these changes were accompanied by a progressive decrease in ASR staining. At the conclusion of pronuclear development, the morphologically similar male and female pronuclei were diffusely stained with the ASR. The increase in ASR staining of the sperm nucleus immediately following gamete fusion demonstrates a major effect of the egg cytoplasm on the paternal chromatin that, heretofore, has not been recognized. This augmentation and the following decrease in ASR staining may reflect changes in nucleoproteins during pronuclear development. Differences in nuclear staining are discussed in light of previous studies of nucleoprotein transitions at fertilization.
Ultrastructural evidence of continued reorganization at the aging (11–26 months) rat soleus neuromuscular junction
Authors: Cardasis Constance Ann 
Published: February 2005

AbstractUltrastructural remodeling, with evidence of focal deafferentation and reinnervation, occurs within normal young adult rat soleus neuromuscular junctions (Cardasis and Padykula, 1981). This may be related to normal variations in function. Recognition of this plasticity provides a basis for analysis of aging changes in junctional ultrastructure.Thirty soleus junctions were studied between 11 and 26 months of life. In these junctions, compared to younger ones (3–5 months) synaptic sites with the conventional ultrastructure become increasingly sparse. There is an increase in extent and frequency of exposed junctional folds, of intervention of Schwann cell cytoplasm between axon and junctional folds, and of numbers of lysosomes in all cytoplasmic profiles. Often primary clefts are shallow or missing, and secondary folds are widened and contain collagen. Features limited largely to these older junctions include highly pleomorphic myonuclei, deeply invaginated by myofibrils, and an increase in cellular profiles between basal lamina and sarcolemma. The identity of these profiles is unknown.At other locations within many of the same endplates, small intact terminals are associated with larger expanses of junctional folds, and several small terminals occur within the same primary cleft. Such terminals frequently contain dense‐cored vesicles. These observations suggest continuation of some terminal axonal regeneration. Thus, the ultrastructure of these aging neuromuscular junctions reveals the same degenerative and regenerative events suggested by the ultrastructure of younger junctions, but suggests a shift in the balance between them.
Structural domains of the muscle‐tendon junction. 1. The internal lamina and the connecting domain
Authors: Trotter John A. , Eberhard Susan , Samora Ann 
Published: February 2005

AbstractThe force generated within skeletal muscle fibers of vertebrates is transmitted to the tendon at the muscle‐tendon junction. Ultrastructural analysis of the murine muscle‐tendon junction following a variety of experimental manipulations has produced evidence that the muscle‐tendon junction can be described in terms of four principal domains (Trotter and Eberhard, 1983), two of which are discussed in the present report. Each domain is defined by the shape and orientation of its principal components, and by its position with respect to the plasma membrane. The internal lamina is composed of actin filaments, with a center to center spacing of approximately 12 nm, oriented mainly parallel to the principal vector of contractile force, and to the plasma membrane. These filaments are cross‐linked into a structural unit, perhaps by the electron‐dense structures which are associated with them. The internal lamina is morphologically connected to the external lamina (lamina densa) by a population of fine filaments oriented approximately perpendicular to the principal vector of contractile force. These filaments which constitute the connecting domain, are approximately 2–8 nm in diameter and are at least 50 nm long. They pass through three separate regions: the sarcoplasm between the internal lamina and the plasma membrane; the plasma membrane proper; and the extracellular space between the plasma membrane and the lamina densa. This third region is often referred to as the lamina lucida. These filaments are composed of at least three separate components in series, linked together by noncovalent interactions. The existence of these discrete structural domains implies that each has a different molecular composition and different mechanical properties.
The effects of beta adrenoceptor blockade with atenolol on myocardial cellular and subcellular hypertrophy in spontaneously hypertensive rats
Authors: Lauva Ines K. , Tomanek Robert J. 
Published: February 2005

AbstractIn this study we investigated the effects of chronic β adrenoreceptor blockade with atenolol on cellular and subcellular hypertrophy in spontaneously hypertensive rats (SHR). Atenolol was injected subcutaneously (20 mg/kg) twice daily commencing in four‐week‐old rats. The treated animals (SHR‐A) were compared to their nontreated controls and normotensive, Wistar‐Kyoto (WKY) controls at the age of 16 weeks. A group of atenolol‐treated WKY was also studied. Chronic drug treatment was effective in attenuating the rise in systolic blood pressure characteristic of SHR, but did not normalize the values to those of WKY. Cardiac hypertrophy, characteristic of SHR, was modified by drug treatment as evidenced by left ventricular weights as well as myocardial cell size. The cells from the subendocardium underwent selective hypertrophy in SHR which was attentuated by about 50% after atenolol treatment. Stereological analysis of electron micrographs showed that while relative mitochondrial volume was not affected by treatment, relative myofibrillar volume (%) decreased in both subepicardium (SHR = 63.28 ± 1.25; SHR‐A = 56.72 ± 1.37) and subendocardium (SHR = 66.53 ± 1.27; SHR‐A = 58.30 ± 1.51). This change raised the mitochondrial/myofibrillar volume ratio, which is characteristically low in SHR compared to WKY. Sarcoplasm, which included all cell constituents except mitochondria, increased with atenolol treatment, but water concentration remained unchanged. The data suggest that attenuation of hypertrophy in SHR after β blockade is associated with selective effects on the myocardial cell involving primarily the myofibrillar cell compartment.
The sensory innervation of the ovary: A horseradish peroxidase study in the rat
Authors: Burden Hubert W. , Leonard Marilyn , Smith Carlton P. , Lawrence I. E. 
Published: February 2005

AbstractInjections of horseradish peroxidase (HRP) into the right or left ovary of the rat produced labeling of perikarya in both nodose ganglia and ipsilateral dorsal root ganglia (DRGs) from T10 to L2. The greatest concentration of labeled cells was in T13 and L1, DRGs. It is suggested that visceral afferent fibers from the ovary may mediate visceral reflexes that modulate ovarian function.
Ethanol inhibition of compensatory ovarian hypertrophy in unilaterally ovariectomized rats
Authors: Rudeen P. Kevin , Bo Walter J. , Krueger W. A. 
Published: February 2005

AbstractThe purpose of this study was to determine the effect of ethanol consumption on compensatory ovarian hypertrophy (COH) which occurs follwoing unilateral ovariectomy. Holtzman rats, 40 days old, were either unilaterally ovariectomized or sham‐ovariectomized. The rats were then placed into subgroups which would receive either an ad libitum chow and water diet, a liquid diet, or a liquid diet containing 5% ethanol. The animals were maintained on their respective diets for 11 days. The rats were killed at 51 days of age, and the ovaries and uteri were removed, weighed, and prepared for histological investigation. The results showed that uteri from ethanol‐fed animals failed to develop epithelial glands and exhibited a condensed stroma in comparison to uteri from animals fed ad libitum or pair‐fed to ethanol‐fed rats. Also, rats that were fed ad libitum had a COH of 82 ± 16% and rats that were pair‐fed a liquid diet had 114 ± 28% COH; rats that were fed the liquid diet containing ethanol did not experience compensatory ovarian hypertrophy (−3 ± 10%). Histologically, the ovaries of rats fed ad libitum showed large numbers of corpora lutea and only a few mature ova. The histology of ovaries from pair‐fed animals was similar to those from animals fed ad libitum. In contrast, the ovaries from the animals fed the ethanol diet had nearly twice as many mature ova but only one‐fourth as many corpora lutea as the number seen in ovaries from the other groups. The data show that ethanol consumption inhibits COH by suppressing ovulation and the subsequent luteal formation.
A radiographic study of variations of the human fetal spine
Authors: Bagnall K. M. , Harris P. F. , Jones P. R. M. 
Published: February 2005

AbstractVariations of the vertebral column were considered to be those deviations from the norm which were still compatible with normal life and not pathological. The incidence of these variations is described as seen radiographically in a group of normal human fetuses.Ossification centers for the costal processes of cervical vertebra 7 were found to be common (19%), being present in approximately one‐fifth of the total number of fetuses studied. They were mostly present as bilateral centers (15%), but because of the cross‐sectional nature of the study, it could not be determined whether these centers would have developed into actual cervical ribs. Far less common were the presence of lumbar ribs (1%). Ossification of the vertebral centra was found to be confusing with no clearly defined pattern being evident. In particular, there was a suggestion that some of the vertebral centra might well develop at least initially from bilateral centers. There was also evidence that the vertebral body was the product of four centers and this was supported by other literature. No variations were found which suggested that the vertebra develops from two somite levels, and this appears to be in conflict with the commonly accepted resegmentation theory.
Mesometrial smooth muscle in the mouse: Its control of uterine blood flows
Authors: Liebgott Bernard 
Published: February 2005

AbstractThe form and function of the mesometrial smooth muscle and the interposed mesometrial branches and tributaries of the uterine vessels were studied in the nonpregnant and pregnant mouse to see whether contractions of mesometrial muscle alter uterine blood flows. Histological sections of mouse uterine horn demonstrated that the outer longitudinal layer of myometrium extends onto the mesometrium and sandwiches the mesometrium and its vessles as a bilaminar myometrial extension (BME). The BME ends midway across the mesometrium as a free edge. Cleared specimens, perfused with silicone rubber, revealed that the mesometrial branches and tributaries of the uterine vesels formed longitudinally communicating looping arcades between adjacent mesometrial vessels. Comparisons with human dissections and uterine histological sections revealed similar patterns of mesometrial smooth muscle and mesometrial blood vessele. BME activity and its control of mesometrial blood flow were studied by transillumination of the surgically exposed mesometria of anesthetized day 12 pregnant mice. Observed contractions of the BME coincided precisely with uterine contractions measured at the cervix and the BME contractions diminished or stopped venous outflow particularly in the midhhorn regions. Arterial flows seemed to be unaffected and were diminished or halted only during infrequent forceful and sustained contractions. Trapped venous outflow passed up or down the venous arcades to escape through less restricted mesometrial veins. Uterine and BME contractions normally take place throughout gestation. It is possible that abnormally long and forceful contractions may compormise the embryo or fetus.
The structure of the parietal pleura and its relationship to pleural liquid dynamics in sheep
Authors: Albertine Kurt H. , Wiener‐Kronish Jeanine P. , Staub Norman C. 
Published: February 2005

AbstractWe studied the parietal pleura of six sheep to obtain information on pleura structure, blood supply, and lymphatic drainage. In the strict sense, the parietal pleura is composed of a single layer of mesothelial cells and a uniform layer of loose, irregular connective tissue (about 23 μm in width) subjacent to the mesothelial cells. The parietal pleural blood vessels are 10–15 μm from the pleural space. Tracer substances put in the pleural space are removed at specific locations. Colloidal carbon and chick red blood cells are cleared by teh parietal pleural lymphatics located over the intercostal spaces at the caudal end of the thoracic wall and over the lateral sides of the pericardial sac. In these areas the mesothelial cells have specialized openings, the stomata, that directly communicate with the underlying lymphatic lacunae. Cells and particulate matter in the pleural space are cleared only by the parietal pleural lymphatics. Compared to the visceral pleura, we believe the thinness of the parietal pleura, the closeness of its blood vessels to the pleural space, and its specialized lymphatic clearance pathways, together indicate that the parietal pleura plays a major role in pleural liquid and protein dynamics in sheep.
The postovulatory cat oviduct and uterus: Correlation of morphological features with progesterone receptor levels
Authors: Verhage Harold G. , Murray Mary K. , Boomsma Robert A. , Rehfeldt Patricia A. , Jaffe Randal C. 
Published: February 2005

AbstractOviducts and uteri were obtained from cats at estrus and up to 14 days after coitus. Progesterone binding sites were estimated by Scatchard analysis, serum levels of progesterone were determined by radioimmunoassay, and key morphological parameters of the lining of the epithelium of the oviduct and the deep uterine glands were quantitated.Progesterone cytosol binding was hightest at estrus, significantly depleted by day 4, and continued a gradual decline out to day 14 in both tissues. Nuclear binding was markedly elevated at day 4; with time the binding decreased until by day 14 it was equal to or lower than detected at estrus. The initial depletion of cytosol binding and rise in nuclear binding coincided with the initial rise in serum progesterone levels.Within the oviduct, the increase in nuclear binding coincided with the onsdet of regressive changes within the epithelium. These changes included atrophy, deciliation, and apotosis.Within the uterine glands, the increase in nuclear binding coincided with the onset of the progestational response. This response included cell hypertrophy, glycogen synthesis and deposition, and with longer exposure to elevated levels of progesterone, the disappearance of these glycogen deposits.These results clearly illustrate the immediate effect of low levels of progesterone on the subcellular compartmentalization of the progesterone receptor system, and the down regulation of the total receptor system when target tissues are exposed to a continuous elevation of serum progesterone. These result also illustrate that similar changes in receptor compartmentalization induce different morphological responses within target tissues from the same animal.
Histochemical survey of the distribution of the epidermal melanoblasts and melanocytes in the mouse during fetal and postnatal periods
Authors: Hirobe Tomohisa 
Published: February 2005

AbstractIn order to clarify the time of onset of the differentiation of epidermal melanoblasts and melanocytes in C57BL/10J mice, pieces of skin were excised on various days after gestation and subjected to the dopa reaction and to the combined dopa‐premelanin reaction. Cells positive to the combined dopa‐premelanin reaction (melanoblast‐melanocyte population) were first identified on prenatal day 14 in the dorsal and ventral skin, and increased in number until day 17. The population remained constant (about 140 cells/0.1 mm2 for the dorsal skin and about 65 cells/0.1 mm2 for the ventral skin) until postnatal day 4, and then decreased. However, cells positive to the dopa reaction (melanocyte population) were first indentified on prenatal day 16 in the dorsal and ventral skin, and increased until postnatal day 4 (about 95 cells/0.1 mm2 for the dorsal skin and about 25 cell/0.1 mm2 for the ventral skin), then gradually decreased and disappeared by day 30. These results indicate that mouse epidermal melanoblasts begin to differentiate on prenatal day 14, and 2 days later tyrosinase activity is induced within the cells.
Compensatory follicular hypertrophy during the ovarian cycle of the house gecko, Hemidactylus frenatus
Authors: Jones Richard E. , Summers Cliff H. 
Published: February 2005

AbstractThe house gecko (Hemidactylus frenatus) exhibits an ovarian cycle that can be divided into early follicular, vitellogenic, and luteal phases. Serial sections through the right ovary of animals in the three phases allowed us to quantify follicular size, condition, and number, as well as germinal bed activity. There are six to eight healthy, growing follicles in each ovary, arranged in a stepwise size hierarchy. This number does not vary among the three phases, even though one follicle becomes atretic and one ovulates during each cycle. Therefore, compensatory follicular hypertrophy occurs, leading to replacement of lost follicles and maintenance of the follicular size hierarchy.
On the maturation rate of the neutrophil
Authors: Zajicek G. , Shohat M. , Polliack A. 
Published: February 2005

AbstractFifty‐three maturing bone marrow cells of the granulocyte cell series stained with Giemsa stain and magnified 1,000 times were scanned by a “computerized microscope” consisting of a LSI‐11/23 microprocessor and a black‐and‐white video camera attached to a “frame grabber.” Each sampled cell was digitized into 70 × 70 pixels, each pixel representing 0.04 μm of the real image. The pixel gray values ranged between 0 and 255. Zero stood for white, 255 represented black, while the numbers in between stood for the various shades of gray. The cells represented six different stages of granulocytic maturation: myeloblast, promyelocyte, myelocyte, metamyelocyte, band form, and polymorphonuclear granulocyte.A discriminant analysis program selected 19 features best distinguishing between the six different cell types and computed five canonical discriminant functions defining a Space in which maturation was studied. In the Space, distance between two cells serves as a measure of similarity. The closer two cells are, the more similar they are and vice versa. This measure was applied here to express the degree of similarity between the neutrophil maturation classes, and since they represent states in the neutrophil life history, it is applicable also as a yardstick for the quantitation of differentiation. In the Space, the life history of a cell is represented by a trajectory originating in the myeloblast and terminating in the granulocyte state. Displacement along the trajectory represents cell maturation that is expressed relatively to the least differentiated state of the myeloblast. The further a cell from this state the more mature it is. The same yardstick also serves for differentiation rate estimates represented in the Space by displacement velocities that are derived from the known “transit times” of a cell in each state. The methodology is also applied for cell production estimates.Unlike other “computerized microscopes” serving for cell classification, the instrument described in this study is primarily a cell‐comparator providing a precise measure of similarity between any two cells.
Acetylcholinesterase and choline acetyltransferase staining of neurons in the opossum esophagus
Authors: Seelig L. L. , Doody P. , Brainard L. , Gidda J. S. , Goyal R. K. 
Published: February 2005

AbstractThe purpose of the present investigation was to identify and compare cholinergic intramural neurons in the lower esophageal sphincter and esophageal body by histochemical staining for acetylcholinesterase and the enzyme that synthesizes acetylcholine, choline acetyltransferase. Opossums were anesthetized and their abdominal cavity was opened by a midline incision to expose the esophagogastric junction. The lower esophageal sphincter was identified manometerically and localized in situ with markers. Tissues were removed, rapidly frozen in freon cooled with liquid nitrogen and serial cryostat sections were obtained from the lower esophageal sphincter and esophageal body. Sections were stained with one of the above histochemical procedures and adjacent sections were stained with Solachrome cyanin, which differentially stains nerve elements from muscle fibers. The muscle of the lower esophageal sphincter and esophageal body was stained with nonspecific cholinesterase with some selectivity of intensity of reaction in the various smooth muscle layers. All identifiable plexus neurons in the esophagus stained for nonspecific cholinesterase and acetylcholinesterase. Nerve fiber tracts were also stained for acetylcholinesterase within the longitudinal and circular layers of the tunica muscularis. Reaction for choline acetyltransferase showed no staining in the muscle layers or nerve fiber tracts of either part of the esophagus studied; however, selected neurons within the myenteric plexus of both regions (approximately 38%) were reactive. There was no significant difference in the number of positive choline acetyltransferase neurons in the lower esophageal sphincter or esophageal body.