bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification and responsiveness of prolactin‐containing secretory granules in clonal rat mammotrophs
Authors: McGill John R. 
Published: February 2005

AbstractClonal pituitary cells (2B8) derived from embryonic Rathke's pouch epithelium of Wister‐Imamichi rats established by Ishikawa et al. (1977) were used in this study. Late‐passage 2B8 cells were found to contain small secretory granules which contained immunoreactive prolactin as demonstrated by electron microscopic immunocytochemistry. When 2B8 cells were incubated in the presence of various agents that are known to stimulate or inhibit prolactin secretion, the volume density of the secretory granules in the cytoplasm was shown to be altered.
Development of the frontal bone and cranial meninges in the embryonic chick: An experimental study of tissue interactions
Authors: Tyler Mary Stott 
Published: February 2005

AbstractThe frontal region of the embryonic chick was studied to determine whether epithelial influences are necessary for frontal bone development. The frontal bone is a membrane bone, of neural crest and head mesodermal origin, which develops within mesenchyme sandwiched between two epithelia, neural ectoderm and epidermis. Rudiments were treated enzymatically to separate epithelial and mesenchymal tissues. Frontal mesenchyme then was grown as chorioallantoic membrane grafts either in the presence or absence of neural ectoderm and/or epidermis. The results indicate that neural ectoderm, though required during early stages of development to induce frontal bone development (Schowing, 1968), is not required during later stages (HH 22–30, the stages tested in this study) for osteogenesis. Epidermis, however, was shown to be required for frontal bone development during the stages tested. Frontal mesenchyme formed bone when epidermis was present on the outer aspect of the mesenchyme, and did not form bone when the epidermis had been removed prior to grafting, whether or not neural ectoderm was present. This dependence upon epidermis continues beyond the onset of meningeal differentiation. Once the outer ectomeninx‐dermis is distinguishable from the inner endomeninx, osteogenic capabilities are confined to the ectomeninx‐dermis layer. Furthermore, the ectomeninx‐dermis layer attached to epidermis is able to form membrane bone in the absence of the endomeninx and neural ectoderm. The endomeninx, though normally nonchondrogenic, was shown to be capable of forming cartilage when the neural ectoderm is removed. Neural ectoderm, therefore, may have an inhibitory effect on chondrogenesis in the endomeninx.
Boar spermatozoa observed by rapid‐freeze and deep‐etch method
Authors: Toyama Yoshiro , Nagano Toshio 
Published: February 2005

AbstractBoar spermatozoa were observed by a rapid‐freeze, deep‐etch, and rotary shadowing technique. Domains of particles were found on the ES face of the plasma membrane in the proximal part of the postacrosomal region. Particles are 17 nm in diameter, have a central pit, and appear to contain either five or six subunits. The diameter of the subunits is about 7 nm. The particles are arranged hexagonally within the domain. Straight parallel ridges, 15 nm wide, were found on the entire PF face of the plasma membrane in the postacrosomal region. The ridges run almost parallel to the long axis of the spermatozoon. Part of the postacrosomal sheath could be seen through artificial openings in the PF face of the plasma membrane. The postacrosomal sheath seems to be a sheet of closely packed particles 7 nm in diameter and has striations with a periodicity of 15 nm. The ridges on the PF face of the cell membrane appear to be reflected by the striations of the postacrosomal sheath. In the neck and tail regions of the spermatozoa, orderly arranged particles were observed on the ES and PF faces of the plasma membrane.
Giant bistratified bipolar cells in monkey retina
Authors: Mariani Andrew P. 
Published: February 2005

AbstractA bipolar cell type with a dendritic span in the outer plexiform layer (OPL) larger than any other type of monkey retinal bipolar cell and an axon which terminates in two separate strata (Polyak's 7a and 7d) of the inner plexiform layer (IPL) are described from Golgi‐impregnations of the rhesus monkey retina. These giant bistratified bipolar cells connect with many cones in the OPL, and although the axon has terminals in both the outer and inner parts of the IPL, Golgi‐electron microscopy (EM) demonstrates that the nature of this cell type's dendritic contacts with cones is as wide‐cleft basal junctions.
Ovarian, oviductal, and adrenal vascular connections in female lizards (genus Anolis)
Authors: Jones Richard E. , Summers Cliff H. , Austin Harriet B. , Smith Hobart M. , Gleeson Todd T. 
Published: February 2005

AbstractThe urinogenital blood vessels of Anolis equestris and A. carolinensis were studied using dissection, injection of silicone rubber, and histology. A new blood‐vascular connection between small veins in the pampiniform plexus at the base of the ovary and an ostial extension of the secondary oviductal vein is described. Chemical messengers could thus be carried in the blood from the ovarian venous drainage to the oviduct. Furthermore, close apposition of the secondary oviductal vein and artery provides an anatomical basis for countercurrent exchange of these messengers. A circular venous arcade, involving the supracardinal vein and branches of the oviductal veins, also is described; this arcade could serve to deliver adrenal hormones to each oviduct.
Hypotelorism in trisomy 1‐producing mice
Authors: v. Domarus Helmut 
Published: February 2005

AbstractTrisomy 1 embryos in mice are smaller in all dimensions, showing a developmental retardation as compared with euploid mice. Very rarely the trisomic embryos develop a typical hypotelorism with holoprosencephalon and missing olfactory nerves. Corneal distances, angles between the optic nerves and further microscopic examination showed no intermediate forms between the trisomy 1 embryos and the rare trisomy 1 embryo with hypotelorism. There seems to be a threshold, beyond which the major developmental derangement occurred. This is an experimental model showing parallels to the occasional varying phenotypes in human trisomies.
Effects of age and strain differences on the red nucleus of the mouse mutant Dystonia musculorum
Authors: Stanley Edith , Messer Anne , Strominger Norman L. 
Published: February 2005

AbstractThe mouse mutant Dystonia musculorum exhibits pathological changes in the magnocellular neurons of the red nucleus. The present study shows that allelic differences occur in the age of onset and severity of this pathology. The magnocellular neurons of the Jackson allele (dtJ) almost completely disappear prior to 4 weeks of age while some of these cells are retained in the adult of the Albany strain (dtAlb). However, acetylcholinesterase histochemistry suggests that the remaining rubral neurons in dtAlb are nonfunctional. This pathology may contribute to the severe locomotor disturbances seen in these animals.
Blood vessels of the Peyer's patch in the mouse: I. Topographic studies
Authors: Yamaguchi K. , Schoefl G. I. 
Published: February 2005

AbstractThe topographic distribution of blood vessels in Peyer's patches of mice was studied by light and scanning electron microscopy with whole mounts of flattened gut segments and vascular corrosion casts. Peyer's patches are imbedded in the intestinal wall and share its blood supply. Two to four mural trunks may contribute to the area of the patch. In and around the lymphoid nodules the microcirculation is highly specialized. The nodule is permeated by a meshwork of fine capillaries that is supplied by arterioles entering on the serosal and lateral surfaces. Blood flow to the lymphoid nodule appears tobe monitored by arterial sphincters; the dense lymphatic tissue can also beby passed by arteriovenous communications. An extensive venous network encircles the nodule. Most of these venules are lined by high endothelium which is penetrated by lymphocytes. The geometry of these vessels suggests a slow and turbulent flow in these vascular segments that may aid margination of lymphocytes. A planar capillary plexus lies subjacent to the mucosal epithelium in the dome area.
A morphometric analysis of rat ventral prostate in organ culture
Authors: Martikainen Paula , Suominen Jyrki 
Published: February 2005

AbstractA stereologic, morphometric method was used for determining the quantitative and qualitative changes in the rat ventral prostate during organ culture. The volume density of epithelium (VVEP), lumina (VVLU), and interstitium (VVIT) as well as the proportion of epithelium of the tissue, (VVEP) (VVEP+VVIT), the length density of tubular structures (Lv), mean diameter of the lumina (DLU), height of the epitheluium (h), and mean width of the interacinar tissue (λAP) were evaluated. In the perfusion‐fixed prostate these parameters gave the closest approximation for the in vivo situation: VVEP was 0.19 mm3/mm3; h 19.5 μm; VVEP/(VVEP+VVIT) 0.63 mm3 VVLU 0.70 mm3/mm3; DLU 230 μm; VVIT 0.11 mm3/mm3; λap 84.1 μm; and Lv 17.5 mm/mm3. Dissection of the prostate for culture caused leakage of prostatic secretions and a consequent diminution of VVLU (0.41 mm3/mm3) and DLU (151 μm), as well as folding of the epithelium and distortion of the interacinar tissue (VVIT 0.25 mm3/mm3). During 10 days culture in a defined medium, the prostate under‐went involutive changes including loss of total weight, a decrease of VVEP, and an increase of VVIT. During the first day a stimulatory effect on the epithelium occured, which might have been caused by a loss of androgenic control or by substances in leaking secretions. Testosterone postponed many of these changes and maintained the secretory function better. Thus, on day 4 the morphology of the prostate resembled better the situation in vivo than at the beginning of involutionary culture. However, later during culture changes, similar to those found without testosterone but weaker, were noted.Statistical analysis of data showed that it is more advisable to use many pieces from one prostate lobe rather than to use many animals. Analysis of one slice is also sufficient to give relevant data on that piece.
Transverse periosteal sectioning and femur growth in the rat
Authors: McLain James B. , Vig Peter S. 
Published: February 2005

AbstractCircumferential cuts through the periosteal covering of long bones have been demonstrated to transiently increase epiphyseal growth. This effect appears to be independent of vascular changes accompanying surgery and has been hypothesized to relate to releasing tension in the periosteal envelope. This study was designed to address problems of previous investigations by controlling for the effects of the surgical procedure and by using regression analyses to analyze intra‐ and interanimal variations in the length and proportionality of the femur in experimental, sham, and control Sprague‐Dawley male rat littermates. Experimental animals received circumferential periosteal sectioning of the right femur and no operation to the left limb. A sham operation without periosteal sectioning was performed on the right femur in the sham group. Right to left differences were analyzed using two multiple regression models; one involved three absolute length measurements as the dependent variables, while the other used the three ratios of these length measurements as the dependent variables. The ratio measures were utilized to reflect changes in bone proportionality.Circumferential periosteal section was followed by an alteration in the shape of rat femurs at 2 weeks postsurgery with a slight retardation of the length dimension from medial epicondyle to head of the femur and an overgrowth of the length dimension from the lateral epicondyle to the greater trochanter. The sham procedure produced a proportional decrease in all length measurements. The experimental procedure was also associated with surface bone apposition at the site of section. At 3 weeks postsurgery, normalization of bony contours between sham, experimental, and control groups had occurred; however, there were still some statistically significant decreases of length dimensions in the sham and experimental groups. In the experimental group the length measurement involving the weight‐bearing head of the femur remained reduced at 3 weeks postsurgery.It is hypothesized that the functional demands of the long bone play an important role in the effect of periosteal regulation on growth. In situations where a normal tensive force is exerted on the bone, the periosteal envelope will act to restrain epiphyseal growth. When the bone is under a normal compressive force the release of periosteal tension is not a quantitatively significant stimulus to epiphyseal growth and the effects of surgical intervention and muscle trauma will play a more important role in the growth response of the epiphyses.
Ultrastructure of the bone marrow in three murine strains with non‐malignant lymphoproliferative syndromes NZBxW, BXSB, and MRL/1pr
Authors: Brookoff Daniel , Weiss Leon 
Published: February 2005

AbstractThree mouse strains, NZBxW, BXSB, and MRL/1pr have well documented congenital lymphoproliferative syndromes and lupus‐like disease. We studied the ultrastructures of the marrows of these mice searching for a model for intramedullary lymphopoiesis. In MRL/1pr, the strain with the most severe disease, the marrow was largely populated by large lymphocytes associated with dark branching stromal cells. These stromal cells are apparently of a recently recognized cell type which has been associated with extremely accelerated eosinophilopoiesis and erythropoiesis. They did not appear in the lymph nodes and spleens of the MRL/1pr mice or in the marrows of the other strains. BXSB marrows showed some non‐proliferant lymphocytic infiltrates and heightened erythropoiesis while NZBxW marrows resembled controls. We suggest that the dark stromal cells in the MRL/1pr marrows were important in supporting the production or differentiation of lymphoid precursor cells.
Electron microscopic study of intramembranous changes in protein‐extracted peripheral nervous system myelin
Authors: Cullen Michael J. , Peterson Richard G. , deF. Webster Henry 
Published: February 2005

AbstractSciatic nerves from young mice were incubated for 2–8 hours in 0.5% Triton X‐100 in 0.5 M ammonium acetate, a solution which solubilizes the large and small basic proteins of the myelin sheath. As previously noted (Peterson and Gruener, 1978), myelin sheaths from treated nerves extensively split and unravelled along major dense lines. Small focal areas of compact myelin remained. In freeze‐fracture replicas, areas of myelin with lamellar splitting contained few intramembranous particles, while membrane areas with greater than normal densities of particles were associated with the patches of compact myelin membrane. Fixation for as short a time as 15 minutes stabilized the myelin membrane enough to prevent the Triton X‐100 effects, even when incubations were extended to 20 hours. Controls, both untreated and 0.5 M ammonium acetate‐treated nerves, had predominantly compact myelin sheaths; their leaflets were covered with numerous intramembranous particles. The data suggest that Triton X‐100 alters the compact structure of peripheral nervous system myelin. In areas where lamellae are split and separated, there is a loss of intramembranous particles. It appears that the loss of intramembranous particles is related to the removal of the basic proteins which are located in major dense line regions of compact myelin sheaths.
Intercellular contacts of lymphocytes during migration across high‐endothelial venules of lymph nodes. An electron microscopic study
Authors: Campbell Ferrell R. 
Published: February 2005

AbstractThe migration of lymphocytes across the wall of high‐endothelial venules was studied by electron microscopic examination of murine lymph nodes fixed with glutaraldehyde and tannic acid. Regions of close membrane apposition, referred to in the present study as “intercellular contacts,” were observed between migrating lymphocytes and endothelial cells of the vessel wall. At high magnification the intercellular contacts resolve into pentalaminar structures resembling gap junctions. However, the location of these contacts suggests that they are regions of membrane adherence utilized for locomotion of the lymphocytes across the endothelium. At present, it is unclear whether these intercellular contacts are communicating junctions or sites of membrane adherence.
Distribution and size of Boettcher cells in the little brown bat, rabbit, and other species
Authors: Ramprashad Fred , Money Kenneth E. , Landolt Jack P. , Correia Manning J. , Laufer Jerry 
Published: February 2005

AbstractThe distribution and size of Boettcher cells were determined from serial sections of the temporal bones of four little brown bats and six rabbits. In addition, one harp seal and one two‐toed sloth were examined. In the little brown bat, the heights of the Boettcher cells measured 4–8 μm and they were found throughout much of the length of the cochlea. There were four rows in most of the lower basal coil, five rows in the upper basal coil, and four rows in the middle coil. In the rabbit there were nine rows in the basal coil and 12 rows in the middle coil. The heights of the Boettcher cells were approximately 14 μm in the rabbit. In the two‐toed sloth, Boettcher cells were sparsely distributed along the basal coil; similarly, in the harp seal, Boettcher cells were confined solely to the basal coil, where there were only three rows, which measured approximately 18 μm in height. The distribution and size of Boettcher cells in the rabbit and the little brown bat were compared to those in other mammalian species.
Relationship between the quality of fixation and the presence of stippled material in newly formed enamel of the rat incisor
Authors: Nanci A. , Warshawsky H. 
Published: February 2005

AbstractExtracellular accumulation of a granular material that is presumed to be an organic “precursor” to mineralized enamel has been reported. This material, generally referred to as “stippled material,” was observed mainly after immersion fixation with osmium tetroxide. In studies with perfusion fixation, the presence of stippled material was inconsistent. Therefore, it appeared that the occurrence of stippled material was dependent on the method of fixation. To test this assumption, tissues were fixed by immersion in either osmium tetroxide or glutaraldehyde and by perfusion with either glutaraldehyde or a mixture of acrolein, glutaradehyde, and formaldehyde. It was found that as the quality of cellular preservation improved, the occurrence of stippled material decreased. Since no stippled material could be found in material judged to be well fixed, it was concluded that stippled material is not an extracellular precursor to mineralized enamel, but is a breakdown product resulting from poor fixation.
Formation of multinucleated fibroblasts in the periodontal ligaments of old mice
Authors: Cho Moon‐Il , Garant Philias R. 
Published: February 2005

AbstractMultinucleated cells were observed to account for more than 17% of all cells in the periodontal ligament (PDL) of 20‐month‐old mice. The number of nuclei contained in sections of these cells ranged from 2 to 17, with over 50% of the multinucleated cells containing four or more nuclei within the plane of section. The multinucleated cells contained several cytoplasmic features resembling those previously described by the authors as characteristic of PDL fibroblasts. The multinucleated cells did not resemble osteoclasts or foreign body giant cells. It is suggested that fibroblasts develop a tendency to fuse and form multinucleated cells in the aged PDL. Similar cells were not observed in the PDL of young (5‐week‐old) mice or in the tail tendon at any age.
Meckel's diverticulum. I. Extramedullary myelopoiesis in the yolk sac of hatched chickens (Gallus domesticus)
Authors: Oláh Imre , Glick Bruce 
Published: February 2005

AbstractWe have described an extramedullary myelopoietic tissue located in the wall of the yolk sac. This myelopoietic site is absent at hatch and it produces only granulocytic and monocytic cells during the regression of the yolk sac from 2 to 7 weeks of age. The granulocytic and monocytic cells are located in two distinct zones. The monocytic cells migrate close to the lumen of the yolk sac where they may fuse and form giant cells. There are no mature granulocytes present. Cell migration has not been observed. Therefore, the fate and function of the young granulocytic cells are unknown. In this extramedullary myelopoietic tissue, the absence of erythrocyte and thrombocyte formation may indirectly suggest that these cells develop together in sinuses that are lacking in the wall of the yolk sac.
Phenoxyethanol as a nontoxic substitute for formaldehyde in long‐term preservation of human anatomical specimens for dissection and demonstration purposes
Authors: Frølich Karin W. , Andersen Ling Merete , Knutsen Arne , Flood Per R. 
Published: February 2005

AbstractFormaldehyde has recently been declared a potential carcinogen. Occupational health authorities throughout the world are therefore likely to put stricter regulations to its use also within anatomical disciplines.We have been able to reduce the atmospheric concentration of formaldehyde in our dissection rooms to below the detection limit of a conventional Dräger tube multigas analyzer (i.e., below 0.5 ppm or 0.6 mg formaldehyde/m3 air), by extracting previously formaldehyde‐fixed material for more than 3 months in 1% phenoxyethanol in tap water.In this fluid our material has remained soft and flexible with a consistency and color retention suitable for dissection and demonstration purposes for up to 10 years. Fungal attacks are rare and we have been unable to raise bacteria from such specimens. Even the microscopical structure of most tissues remains satisfactory after 5 years in 1% phenoxyethanol.The unpleasant and irritating smell traditionally felt in dissection rooms is almost absent in out facilities, but some of our students still mention slight odor, headache, drowsiness, and mild eye, nose, and throat irritation during their dissection practice periods.