bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of some endocrine glands, hormones and blinding on the histology and porphyrins of the Harderian glands of golden hamsters
Authors: Hoffman Roger A. 
Published: February 2005

AbstractHarderian glands of female or castrated male hamsters contained scattered luminal pigment deposits and a single cell type. Two cell types were found in the glands from intact males. Glands from both male and female animals showed abundant cytoplasmic lipids. Pigment formation appeared to be endogenous and in some cases occurred by extrusion of cells from alveolar walls and their subsequent transformation. Holocrine secretion was demonstrable. Porphyrin concentrations in the glands from females were increased three weeks after bilateral blinding and decreased following hypophysectomy, ablation of one Harderian gland, unilateral blinding, treatment with thiourea or exposure to an environmental temperature of 8°C. Ovariectomy or ovariectomy plus treatment with 17‐α‐estradiol for three weeks had no effect on the Harderian glands nor did pinealectomy. Porphyrin concentrations in the glands from male hamsters were extremely low. Castration increased these concentrations over 100‐fold and modified the morphology toward that of the female while testosterone proprionate treatment prevented these changes. Administration of H3‐thymidine and subsequent radioautography revealed a peak in mitotic activity between 9:30 PM and 12:30 AM at the end of the light period or the beginning of the dark period. Longterm blinded or blinded, castrated males had Harderian glands which were microscopically “lacelike” due to intense steatogenesis.
Collagen distribution in the rat demonstrated by a specific anti‐collagen antiserum
Authors: Engel M. B. , Catchpole H. R. 
Published: February 2005

AbstractA specific anti‐collagen antiserum was prepared in rabbits using as antigen a rat tail collagen preparation free of serum protein reactants. This antiserum reacted with several forms of isolated collagen and with rat urine, but not with rat serum. It was coupled to fluorescein and used to label sites of collagen in frozen and dried cryostat sections of rat tissues. The indirect method, with uncoupled serum, was also used routinely.Tubular and glomerular basement membranes, Bowman's capsule, basement membrane of skin and lung, reticular fibers of spleen and the connective tissue framework of muscle were strongly stained, as was also new bone on trabecular borders and around osteocytes.The supporting fibers of normal hyaline cartilage, calcified bone, most tendons and the deeper fibers of skin were less stained or unstained under identical conditions and are presumably masked or blocked in situ.Cytoplasm or cytoplasmic processes in some fibroblasts of skin and tendon, cytoplasm of osteocytes and some cartilage cells in elastic cartilage were stained.Reaction and masking in fibers are presumably related to the modes of collagen linkage both within the fiber and externally with the ground substance matrix. Activity could be elicited in tendon by a brief heating at 60°C sufficiently to abolish the collagen birefringence. These collagen linkages are believed to be of importance in determining its behavior in overall processes of tissue disaggregation.
The fine structure of progressive stages of myocardial mitosis in chick embryos
Authors: Hay Don A. , Low Frank N. 
Published: February 2005

AbstractThe fine structure of mitosis in myocardial cells possessing myofibrils from embryonic chick hearts (4.5–6 days incubation age) is described. In these cells during prophase, chromosomes appear, but the nuclear membrane, Golgi complexes, and Z bands mostly disappear. In metaphase, lipid droplets and large quantities of membranous cisternae localize around the centrioles, while sarcomeric lengths of myofibrils (largely without Z bands) are found disoriented in the periphery, mainly in the polar zones. In anaphase the cisternae collect near the chromosomes, as reconstruction of the nuclear membrane commences. An intact nuclear envelope and well‐formed Golgi complexes characterize telophase, but Z bands still are not present. During all of the mitotic stages, junctional complexes between dividing cells and adjacent resting cells persist.
The permeability of the guinea pig parietal yolk sac placenta to peroxidase and ferritin
Authors: King Barry F. 
Published: February 2005

AbstractThe permeability of the guinea pig parietal yolk sac placenta late in gestation was investigated by means of electron microscopy using the tracer proteins ferritin and peroxidase. The parietal yolk sac consists of a layer of trophoblast, a thick extracellular lamina (Reichert's membrane) and a layer of endoderm. After injection into the maternal vascular system, the proteins crossed the trophoblast by means of small pinocytotic vesicles. Both proteins readily permeated Reichert's membrane and then moved by an intercellular pathway between endoderm cells to reach the uterine lumen. After injection of ferritin into the uterine lumen, the protein was observed between endoderm cells and throughout Reichert's membrane. Presumably the marked permeability of the endodermal epithelium to the tracer molecules is due to the absence of zonulae occludentes around the endoderm cells. Parietal endoderm cells exhibited limited pinocytotic activity regardless of the site of injection. The results indicate that the parietal yolk sac placenta of the guinea pig is permeable to relatively large molecules and therefore it may be an important pathway in overall maternal‐fetal exchange in this species.
Cellular growth in hypophysectomized or diabetic adult rats during protein repletion
Authors: Leathem James H. , Koishi Hideo 
Published: February 2005

AbstractThe influence of hypophysectomy or alloxan diabetes on the capacity of the adult male rat to replete organ protein composition was studied. Adult male rats that were fed a protein‐free diet for 30 days exhibited a loss of protein in the liver, kidney, gastrocnemius muscle and heart and of RNA. Total DNA and cell size (P/DNA) changes varied with the organ studied. Hypophysectomy followed by protein refeeding moderated the increase in liver protein and cell size and prevented the increase in RNA observed in normal rats. Diabetes had no effect on liver repletion. Hypophysectomy completely prevented the normal increase in kidney mass, total protein and cell size associated with refeeding, whereas diabetes moderated only the cell size increase. Diabetes effectively blocked the anticipated increase in protein synthesis in the gastrocnemius muscle associated with refeeding, whereas hypophysectomy was followed by an increase in total muscle protein. Repletion of the heart was prevented by hypophy‐sectomy but not by diabetes in which an increase in total protein and in cell size occurred. Neither endocrine deficiency prevented a gain in body weight nor in nitrogen retained but distribution of the retained amino acids was markedly modified. Thus organ responses to endocrine deficiencies are influenced by body protein reserves.
Morphological variations of pigment granules in eyes of the rhesus monkey
Authors: Hu Funan , Endo Hidehiko , Alexander N. J. 
Published: February 2005

AbstractMelanin granules of rhesus monkey eyes develop in four stages. Early in stage I, they are small, spherical or elongated, membrane‐limited vesicles containing parallel arrays of membranes oriented along the long axis and having regular periodicity. Melanization of these membranes, which is indicated by increased thickness and electron opacity, leads to the formation of stages II and III granules. In stage IV, their internal structure is completely obliterated by electron‐dense melanin. During this process of development, melanosomes are transformed from thin, long vesicles into large ovoid bodies.By 60 days of gestation, melanosomes have developed in the pigmented epithelium of the iris, ciliary body, and retina, those in the retina being more mature and fully pigmented than the others.Stromal pigment cells of the uveal tract develop later than those of the pigmented epithelium. Pigment first appears in the iris at 140 days, then in the ciliary body, and lastly (150 days) in the choroid, where only well‐developed melanosomes are found.Melanosomes of the stromal pigment cells as well as those of the pigmented epithelium may have their origin in the iris. Early melanosomes (stage II) are present almost exclusively in the iridial cells whereas mature forms are found in the ciliary and retinal cells.
Cinemicrography of mouse oocyte maturation utilizing nomarski differential‐interference microscopy
Authors: Sorensen Ralph A. 
Published: February 2005

AbstractThe analysis of in vitro mouse oocyte maturation using Nomarski differential‐interference optics and time‐lapse cinemicrography provides information on the morphological events of oocyte maturation and their duration with greater precision than previously available. Furthermore, some previously unreported morphological events are described. The breakdown of the germinal vesicle was preceded for 41 minutes by extreme activity of the germinal vesicle membrane. The perivitelline space formed precociously by expansion of the zona pellucida rather than by shrinkage of the oocyte. Condensation of the bivalents, centromeric repulsion, formation of the metaphase I plate, and growth of the spindle apparatus were observed. Metaphase I, defined as the period from formation of the metaphase plate to the beginning of anaphase, lasted four hours and twenty‐seven minutes. Anaphase chromosome separation began 11 hours and 15 minutes after disintegration of the nucleolus, and was complete within ten minutes. Polar body formation began before the completion of anaphase. The mid‐body formed between the separating anaphase dyads, and moved with the telophase spindle to the newly formed oocyte‐polar body boundary.
Canaliculi and tubulovesicles of rat parietal cells
Authors: Leeson Thomas S. 
Published: February 2005

AbstractMucosa of the rat stomach was (fast) frozen rapidly by immersion in liquid nitrogen or Freon 22 before chemical fixation in glutaraldehyde and/or osmium tetroxide. In parietal cells, continuity between membranes of the canalicular system and tubulovesicles was seen. This confirms the hypothesis that membrane flow between the two elements occurs in the secretory cycle. Such continuity is difficult to demonstrate in material fixed directly and presumably, therefore, the rapid freezing was effective in preventing changes in membranes and membrane flow during the period of fixation.
Localization of thiamine pyrophosphatase in synaptic vesicles
Authors: Griffith D. L. , Bondareff W. 
Published: February 2005

AbstractIn the perikarya of pontine reticular formation neurons thiamine pyrophosphatase activity was localized within the innermost lamellae of the Golgi complex and, to a lesser extent, within cisternae of the rough endoplasmic reticulum. In axons, thiamine pyrophosphatase activity was localized within tubular profiles, presumed to be endoplasmic reticulum, and in axonal terminals it was found within presynaptic vesicles. This selective localization of pyrophosphatase activity suggests the derivation of synaptic vesicles from membranes of the Golgi complex.
Intramural distribution of adrenergic and cholinergic nerve fibers innervating arterioles of the hamster cheek pouch
Authors: Ausprunk Dianna H. , Berman Herbert J. , McNary William F. 
Published: February 2005

AbstractElectron microscopic, autoradiographic and histochemical techniques were used to determine the distribution of adrenergic and cholinergic nerve fibers within the walls of arterioles having a width of 35 to 60 μ in the hamster cheek pouch. Nerves were confined to the adventitia and their varicose regions were distributed so that 86% were located within 1 μ of the media. Arterioles exposed to 3H‐norepinephrine and examined by light microscopic autoradiography exhibited several sites of silver grain accumulation, as a result of the uptake of 3H‐norepinephrine by adrenergic nerve fibers. In electron autoradiographs, approximately 70% of all adventitial nerve fibers exhibited silver grains and are therefore considered to be noradrenergic. The majority of all nerve‐associated silver grains were located near the adventitial‐medial junction. Smooth muscle cells sometimes possessed concentrations of silver grains above background levels, perhaps reflecting the capacity of these cells to take up norepinephrine. Acetylcholinesterase activity was demonstrated in 16 to 44% of the adventitial nerve fibers and they are presumed to be cholinergic. Acetylcholinesterase‐stained fibers were distributed throughout the adventitia with 43% being located closer than 1 μ to the media. The morphological identification of a dual adrenergic and cholinergic innervation of arterioles of the hamster cheek pouch indicates the probable presence of an active as opposed to a passive vasodilatory mechanism.
Palatal closure in the mouse as demonstrated in frozen sections
Authors: Greene R. M. , Kochhar D. M. 
Published: February 2005

AbstractDuring development of the secondary palate, mouth‐opening reflexes and swallowing movements have been observed previously. They have been assumed to be necessary in order to allow the descent of the tongue, thus enabling movement of the palatine shelves from a vertical position lateral to the tongue, to a horizontal position superior to the tongue. Interpretation of fixed, paraffin‐embedded sections, showing large spaces in the oral cavity, has added to the concept that the tongue descends into a space.Hexane‐quenched, cryostat‐cut, frozen sections of fetal mice heads show that no oral space exists at any time during elevation of the palatine shelves. Interpretation of static micrographs indicates that prior to shelf elevation the tongue is in contact with the nasal septum above and the vertical palatine shelves laterally. When the shelves elevate they seem to “flow” dorsally and interpose themselves between the tongue inferiorly and the nasal septum superiorly.
The independent functions of the two heads of the lateral pterygoid muscle
Authors: McNamara James A. 
Published: February 2005

AbstractInvestigations on the role of the lateral pterygoid muscle in mandibular movements have been limited due to difficulties in obtaining consistent neuromuscular recordings in human subjects. The rhesus monkey was used as a substitute experimental animal. Thirty‐three Macaca mulatta were monitored in 113 electromyographic recording sessions. Two distinct functional patterns were identified from the region of the lateral pterygoid muscle, depending upon the location of the electrodes within this muscle. Through anatomical dissection of areas of electrode placement in 12 animals, the two patterns of activity were related to the inferior and superior heads of the lateral pterygoid muscle. The inferior head acted synergistically with the suprahyoid muscle group in opening movements of the mandible. No activity was noted in closing movements, or in swallowing. In contrast, the superior head was not active during opening movements. Electromyographic activity of the superior head, antagonistic to the suprahyoid muscles, was observed during such closing movements as chewing and clenching of the teeth and during deglutition. The superior head presumably positioned or stabilized the condylar head and disc against the articular eminence during closing movements of the mandible, while the inferior head assisted in the translation of the condylar head downward, anteriorly, and contralaterally during opening movements. Thus, the two heads of the lateral pterygoid can be considered as two functionally distinct muscles.
Fine structure of olfactory epithelium in the mud puppy, Necturus maculosus
Authors: Farbman Albert I. , Gesteland Robert C. 
Published: February 2005

AbstractThe olfactory epithelium of Necturus is approximately 300 μ thick, or two to three times the thickness seen in most other vertebrates. The epithelium contains three cell types, olfactory receptor cells, supporting cells and basal cells. The receptor cell population is made up of both non‐ciliated and ciliated cells in a ratio varying from 1:1 to 2:1. The ciliated cell morphology is essentially similar to that of other vertebrates. The non‐ciliated cells contain groups of centrioles located at various levels in the supranuclear cytoplasm and a fibrogranular complex similar to that seen in cells engaged in ciliogenesis. This variable morphology suggests a continuous turnover of olfactory cell population, or, at least, a continuous turnover of the dendritic portion of the cell. Alternatively it may indicate that there are two different receptor cell populations with different functions. The supporting cells in the olfactory epithelium contain a variable number of secretory granules. In the anterior part of the nasal sac there are relatively more cells with many granules whereas in the posterior region the supporting cell cytoplasm contains mostly smooth endoplasmic reticulum. Olfactory receptor axons are ensheathed in groups by basal cell cytoplasm before they leave the epithelium.
The coronary vessels in the heart of a marsupial, Trichosurus vulpecula
Authors: Dowd David A. 
Published: February 2005

AbstractThe coronary arteries and veins are described in the phalanger (Trichosurus vulpecula), an Australian marsupial, after study of 16 hearts. Several hearts were prepared by injection of the vessels with either latex or vinyl plastic.The distributing branches of both coronary arteries are within the myocardium and are not visible on the surface of the heart. The right coronary artery arises in typical fashion and supplies the non‐septal wall of the right ventricle almost entirely, the dorsal half of the interventricular septum, the dorsal part of the non‐septal wall of the left ventricle and part of the right artium and its ventral auricle. The left coronary artery also arises typically and supplies the greater part of the non‐septal wall of the left ventricle, the ventral part of the interventricular septum, part of the infundibulum, the left atrium and part of the right atrium. At its origin it is larger than the right coronary artery. The ventral and dorsal septal arteries have an unusual course lying in the subendocardial tissue of the right ventricle. It is believed that arteries in this position have not been described previously.The great cardiac vein opens directly into the right atrium. A typical coronary sinus is present but formed only from veins draining the dorsal aspect of the heart.It is concluded that the coronary circulation in T. vulpecula closely resembles that of the avian heart and is unlike both the monotreme and placental mammalian patterns.
Prenatal size–age relationships and external morphology in the mongolian gerbil (Meriones unguiculatus)
Authors: Bagwell J. N. , Leavitt W. W. 
Published: February 2005

AbstractEmbryos from timed matings were studied at days 12–24 of gestation with respect to crown‐rump length and external appearance. A linear increase in length was observed from the twelfth (2.5 mm) to the twenty‐fourth (27.7 mm) day with the largest increases occurring between days 20 and 21 (3.8 mm) and days 22 and 23 (4.2 mm). The smallest daily increases were observed between days 15 and 16 (1.01 mm) and days 21 and 22 (1.03 mm), while the average daily increment for the remaining days was between 1.5 mm and 2.5 mm. Major changes in external appearance occurred on days 13, 14, 17 and 20 of gestation. Those features which could be observed externally were described for each of the days during the period studied. Late prenatal development in the gerbil resembles that of other myomorph rodents but proceeds at a slower rate than in other species such as the mouse or hamster. This slower rate of development may be of value when precise timing of drug administration and recovery of embryos is necessary.
Preliminary ultrastructural demonstration of hyaluronic acid‐proteoglycan interaction in cartilage matrix
Authors: Quintarelli G. , Vocaturo A. , Bellocci M. , Rodén L. , Ippolito E. , Baker J. R. 
Published: February 2005

AbstractRecent chemical studies have indicated that the chondroitin sulfate proteoglycan of cartilage interacts with hyaluronic acid to form high molecular weight aggregates. In the present study, morphological evidence has been obtained that this interaction represents a physiologically occurring phenomenon, as indicated by the finding that the proteoglycan particles disappear from tissue sections on digestion with a hyaluronidase from Streptomyces hyalurolyticus, which is specific for hyaluronic acid.
Electron microscopic immunohistochemical localization of growth hormone‐release inhibiting hormone (somatostatin) in the rat median eminence
Authors: Pelletier Georges , Labrie Fernand , Arimura Akira , Schally Andrew V. 
Published: February 2005

AbstractUsing an immunohistochemical technique at the electron microscopic level, we have observed that growth hormone‐release inhibiting hormone (somatostatin), the hormone which inhibits the release of growth hormone, is contained in the secretory granules of many nerve endings mainly located in the external zone of the median eminence.
Identification of two populations of lymphocytes in rats and mice by routine transmission electron microscopy
Authors: Pereira Gerard 
Published: February 2005

AbstractStaining en bloc in aqueous uranyl acetate following double fixation in glutaraldehyde and osmium tetroxide reveals two types of lymphocytes (dark and light) in most rat and mouse lymphatic tissues studied by transmission electron microscopy. While only dark lymphocytes populate the thymus, both dark and light lymphocytes congregate within the bone marrow and the thymus‐independent areas or the spleen and lymph nodes. Two similar types of plasma cells coexist in the spleen and lymph nodes.
Alterations in hepatocytes after manipulation of the diet: Copper, zinc and cadmium interactions
Authors: Miller M. L. , Murthy L. , Basom C. R. , Petering H. G. 
Published: February 2005

AbstractMorphometric analyses of liver parenchymal cells were performed on male albino rats fed a semipurified diet supplemented with two levels of copper and zinc. These metals were administered in demineralized drinking water to four groups of animals at two levels. (1) 0.25 μgm Cu/ml, 2.5 μgm Zn/ml, and (2) 1.0 μgm Cu/ml, 10 μgm Zn/ml. Cadmium, also administered in the drinking water daily to rats at 17.2 μgm cadmium/ml, was given to one group of animals on each of the two semipurified diets. Two groups of rats were given laboratory chow plus 17.2 μgm Cd/ml for 71 days and for 280 days.Volume densities of all organelles diminished significantly when levels of copper and zinc were lowest. Surface densities of rough and smooth endoplasmic reticulum were significantly decreased.Higher levels of copper and zinc produced morphologic and morphometric parameters which fell just below those obtained for rats fed chow. Glycogen accumulation was highest when the levels of metal were low. Lipid inclusions were more frequent with semipurified diets than with chow.Hepatocytes from rats fed the semipurified diet with low copper and zinc plus cadmium demonstrated a significant increase in smooth endoplasmic reticulum compared to animals fed the semipurified diet alone. The smooth endoplasmic reticulum changed little when cadmium was given to rats receiving adequate copper and zinc. Smooth endoplasmic reticulum increased when diets included chow and cadmium whereas rough endoplasmic reticulum decreased.Cup‐shaped and elongated mitochondria with longitudinal cristae appeared in hepatocytes from animals fed chow with cadmium. These were not seen with semipurified diets and cadmium.