bluuebunny/crossref_metadata_2025 huggingface dataset:
Ulrastructure of cytoskeletal element of endothelial and stromal cells of rat marrow
Authors: Campbell Ferrell R.
Published: February 2005

This study reports the distribution of microfilaments, microtubules, and intermediate filaments in endothelial cells, reticular cells, and macrophages of bone marrow of rats following fixation with glutaraldehyde, tannic acid, and saponin. In endothelial cells bundles of microfilaments are seen along the basal surface, where these cells adhere to underlying extracellular materials. The reticular cells, especially those that are closely associated with the endothelium of sinusoids, contain many intermediate filaments and microtubules as well as microfilaments. The reticular cell processes that partially cover the endothelium and extend among the blood cells have numerous microtubules and intermediate filaments arranged longitudinally within them; these cytoskeletal elements appear to provide mechanical support for the processes. Macrophages also have many microtubules and intermediate filaments but these organelles do not extend into the thin processes of these cells as is the case with reticular cells. Bundles of microfilaments are observed in the cytoplasm of adventitial and endothelial cells at sites where migrating blood cells are attached to these cells producing local regions of stress.
Staging equine seminiferous tubules by Nomarski optics in unstained histologic sections and in tubules mounted in toto to reveal the spermatogenic wave
Authors: Johnson Larry , Hardy Vince B. , Martin Michael T.
Published: February 2005

Nomarksi optics were used to identify stages of the spermatogenic cycle of seminiferous tubules in sectioned tissue or in whole dispered tubules and to characterize the equine spermatogenic wave. Embedded tissues were sectioned at 20 μm. Whole dispersed tubules were obtained by enzymatic digestion of thin slices of fresh testis. Dispersed tubules were fixed, dehydrated in graded levels of alcohol, infiltrated with Epon, and mounted in toto on glass slides. Stages of the spermatogenic cycle could be idetified under Nomarski optics in both histologic sections and tubules mounted in toto. Stage dependent nuclear chromatic and cytoplasmic changes in spermatogonica, spermatocytes, and spermatids were evident. Spermatid development included chromatin condensation, nuclear elongation, acrosomal development from the Golgi and proacrosomic granules, migration of the annulus and mitochondrial alignment, and the transient appearance of the chromatoid body and manchette. Both nuclear and cytoplasmic details of Sertoli cells were revealed. In tubules mounted in toto, the spermatogenic wave along the length of the tubules occurred as a consecutive set of stages occupying small regions to that of humans than that of rats. The combination of enzymatic isolation of seminiferous tubules and identification of spermatogenic stages by Nomarski optics facilitates examination of the spermatogenic wave in species whose tubules are tightly bound and not easily teased apart.
Ultrastructure of oocyte migration through the mouse ovarian surface epithelium during neonatal development
Authors: Wordinger Robert , Sutton Jacklene , Brun‐Zinkernagel Anne‐Marie
Published: February 2005

Previous studies using light microscopy have described the presence of oocytes within the ovarian surface epithelium (OSE) of the neonate ovary and their subsequent release into the periovarian space. The ultrastructural examination and quantitative estimate of oocyte migration through the OSE is described in this study. The surface of the mouse ovary is covered by a simple squamous to simple cuboidal epithelium resting on a distinct basal lamina. Healthy, non‐atretic primordial follicles located in the periphery of the ovarian cortex interact with the OSE. Oocytes within the primordial follicles are large (50–70 μm), spherical cells surrounded by a single layer of squamour granulosa cells. Migratory oocytes initially display a ruffled border and extended pseudopodia like cellular extensions towards the OSE. These processes subsequently compromise the basal lamina of the OSE and extend between the epithelial cells. Granulosa cells retract as junctional complexes between them and the oocyte are no longer observed. The oocyte migrates between the OSE cells and passes into the periovarian space without the loss of either OSE or granulosa cells. The rate of oocyte migration reaches a peak during the first week of neonatal development and then gradually diminishes until by day 28 of development no oocyte migration was observed.
Identification of glyoxylate cycle enzymes in chick liver—the effect of vitamin D3: Cytochemistry and biochemistry
Authors: Davis Walter L. , Jones Ruth G. , Farmer Gene R. , Dickerson Todd , Cortinas Elma , Cooper O. J. , Crawford Linda , Goodman David B. P.
Published: February 2005

Information regarding the presence of the glyoxylate cycle in chick liver was sought. This metabolic pathway has long been thought to be absent from vertebrate tissues. Previous studies in other tissues have shown that, when present, this pathway is sensitive to vitamin‐D. Thus, the effect of long‐term vitamin‐D deficiency and subsequent vitamin‐D replacement on liver structure was studied by light microscopy. In addition, specific biochemical assays for the presence of glyoxylate cycle enzymes were performed. Light microscopy of lipid extracted tissues, light microscopic histochemistry, and quantitative histochemistry showed that the hepatocytes from vitamin‐D‐deficient animals contained primarily lipid. Hepatocytes from normal and vitamin‐D‐replete livers contained primarily carbohydrate as judged by their staining with periodic acid‐Schiff (PAS). Also, malate synthase positive peroxisomes were seen in hepatocytes from normal and vitamin‐D‐treated chicks. Structures positive for this glyoxylate cycle enzyme were rarely seen in the hepatocytes from vitamin‐D‐deficient animals. Biochemical analyses showed the presence of the two unique glyoxylate cycle enzymes, isocitrate lyase and malate synthase, in chick hepatocytes. The activity of these enzymes was markedly increased in the vitamin‐D‐replete livers. In addition, chick hepatocytes demonstrated the capacity to oxidize fatty acid in the presence of cyanide. This activity, which is characteristic of peroxisomal B‐oxidation rather than mitochondrial, was stimulated by vitamin‐D treatment. Lastly, incubation of chick liver in the presence of a fatty acid substrate (palmitate) led to higher tissue glycogen content. The latter was further increased in liver from vitamin‐D‐replete animals. These data show the presence of glyoxylate cycle enzymes in a higher vertebrate and indicate that this tissue is endowed with the capacity to convert lipid to carbohydrate.
Immunocytochemical localization of follicle stimulating hormone in normal human stomach
Authors: Mandrekar Pranoti S. , Sheth Anil R. , Doctor Vatsala M. , Zaveri Jayesh P. , Sheth Nandini A.
Published: February 2005

Immunoreactive follicle‐stimulating hormone (IR‐FSH) is detected in sections of formalin‐fixed and paraffin‐embedded gastric mucosal tissue of normal men, using the immunoperoxidase staining technique and specific antisera to hFSH (NIDDK, NIH). Positive staining for IR‐FSH was detected in the parietal cells lining the gastric glands of the intermediate zone. The staining was intracytoplasmic and distributed throughout the cytoplasm. IR‐FSH was also found to be present in the basal part of the foveolar epithelium. Stromal tissue and nuclei were devod of the stain. The zymogen cells in the deeper region of the mucosa did not show any detectable staining for IR‐FSH. The presence of IR‐FSH in gastric mucosa was also detected by radioimmunoassay.

Gel chromatography of the gastric tissue extract showed a single peak of FSH immunoreactivity that coeluted with the 125I‐labled highly purified FSH preparation (NIDDK, NIH). Furthermore, the FSH in the pituitary tissue extract had a chromatographic profile similar to that of IR‐FSH from gastric tissue, and 125I‐FSH labeled highly purified FSH, indicating a close resemblance in their molecular sizes. These results demonstrate that IR‐FSH is present in the normal human gastric mucosa. The role of this regulatory petpide in gastric tissue, if any, needs to be investigated.
In vivo staining of mouse preimplantation embryos with hoechst 33342
Authors: Sawicki W. , Mystkowska E. T.
Published: February 2005

Female mice bearing secondary oocytes or preimplantation embryos of various stages were injected with Hoechst 33342 (H 33342), either intravenously or intraperitoneally and sacrificed at various intervals afterward. The dye penetrated through the wall of oviduct and stained the nuclei of its cells as well as mitotic chromosomes of secondary oocytes, the pronuclei of one‐cell embryos, and nuclei of blastomeres and polar bodies. The nuclear fluorescene was observed in living cells flushed out of the oviduct as well as in those fixed in oviduct, embedded in paraffin, and sectioned. H 33342 injected in a dose of 10 μg/g of body weight failed to interfere with preimplantation development of stained embryos as indicated by the number of blastocysts per mouse and number of cells per blastocyst.
Comparison between two finlte‐element modelling methods for measuring change in craniofacial form
Authors: Lozanoff Scott
Published: February 2005

Finite‐element modelling of form change is a useful morphometric technique for measuring differences between anatomical patterns. Two different finite‐element algorithms currently are used. One method requires normalized coordinates as input data, while the second method uses globalized coordinates as input data. This study determines whether the two finite‐element methods provide equivalent measures of three‐dimensional form change when applied to the nasal septa of embryonic mice. Computer models of the nasal septa from mice of 15 and 17 days gestation were generated. Homologous landmarks were identified so that each nasal septum was represented by a tetrahedral finite‐element. These elements were subjected to both finite‐element modelling methods. Results show that the two algorithms use different interpolation functions and yield dissimilar intermediate results, but generate identical strain matrices as well as equivalent principal extensions, directions of form change, variables of form change, and graphical displays. Therefore, results are directly comparable from studies using either finite‐element modelling method.
Immunohistochemical studies on the development of cells containing progastricsin (minor pepsinogen) in comparison to prochymosin and pepsinogen in bovine abomasal mucosa
Authors: Cybulski Wojciech , Andrén Anders
Published: February 2005

The localization of progastricsin was studied in cells of abomasal mucosa from cattle of different ages and feeding regimes and compared to the localization of prochymosin and pepsinogen in the same material by use of an immunofluorescence technique with specific rabbit antibodies.

Immunoreactivity for progastricsin was first found in calves at the age of about 45 days in surface mucous cells in the pit of the fundic gland. In older calves and adults, mucous neck cells also produced progastricsin. In the pyloric mucosa, on the other hand, traces of progastricsin immunoreactivity were found in the lower base of the pyloric gland even in newborn calves. When the calves grew older, progastricsin‐immunoreactive cells also developed in the pit and later in the neck of the pyloric gland; and the number of these cells in this region increased with age. The development of progastricsin‐producing cells seemed to be influenced only by age and not by the feeding of milk to the calves.

The ontogeny of progastricsin, prochymosin, and pepsinogen exhibited an interesting pattern in cattle, as they started to be produced at three different ages and gave three different patterns of development in the cells of abomasal mucosa. The number of cells producing prochymosin was closely correlated with milk‐feeding, while the development of progastricsin was most related to the age of the calf. The most stable factor during the development of the cells in the abomasum was the number of cells producing pepsinogen.
Localization in the rat spleen of carbon‐laden macrophages introduced into the splenic artery: A subpopulation of macrophages entering the white pulp
Authors: Miyakawa Kazuhisa , Matsuno Kenjiro , Ohmori Jun , Kotani Masahiko
Published: February 2005

Heavily carbon‐laden (HC) macrophages, largely derived from the red pulp of the donor spleen, were injected into the splenic artery of recipient rats. Immediately after injection, HC macrophages were found only in the marginal sinus and in the splenic cords. With time after injection, they appeared successively at the periphery of the white pulp, in the deeper white pulp, and finally in and near the germinal centers, suggesting migration of HC macrophages from the marginal sinus towards the germinal centers. The number of HC macrophages in and near the germinal centers reached a peak at 12 h. Most of the HC macrophages in the white pulp were spherical or ovoid in shape with a diameter of 7–11 μm in sections, having an eccentric round or oval nucleus often with a distinct nucleolus and a cap‐like or horseshoe‐like cytoplasm filled with carbon. When immunostained with monoclonal antibodies against rat macrophage subpopulations, more than 90% of HC macrophages in the white pulp were found to be ED1+2−3−. A population of the same type of macrophages, both in morphology and phenotype, were found in the red pulp of the donor spleen. They were different from the major residents, red pulp scavenger macrophages, which were ED1+2−3− and larger in size and irregular in shape. These results suggest the presence of a distinct subpopulation of macrophages which actively migrate into the splenic white pulp including the germinal centers. A discharge of transferred macrophages from the red pulp to the general circulation is also suggested.
Comparison of the distribution patterns of tenascin and alkaline phosphatase in developing teeth, cartilage, and bone of rats and mice
Authors: Väkevä Liisa , Mackie Eleanor , Kantomaa Tuomo , Thesleff Irma
Published: February 2005

Tenascin is a glycoprotein of the extracellular matrix, which has been associated with differentiation of hard tissue forming cells. Alkaline phosphatase (AP) is involved in calcification, and it has also been suggested to function in cell differentiation. We have compared the distributions of tenascin and AP in the developing skull and teeth of embryonic and growing rats and mice. Tenascin was localized by immuno‐Peroxidase and AP by enzyme histochemical staining of tissue sections. Both tenascin and AP were largely restricted to bone, cartilage, and teeth. In cartilage, tenascin was expressed in the perichondrium, whereas AP activity was detected only in the hypertrophic cartilage. In growing intramembranous bone, tenascin and AP were expressed in the periosteum and endosteum. AP activity was restricted to the inner layer of the periosteum, whereas tenascin expression extended to the more superficial layers. In bud‐staged teeth tenascin but no AP activity was localized in the condensing mesenchymal cells around the epithelial bud. At the bell stage both tenascin and AP activity were localized in the cuspal mesenchyme, and the intensity of staining decreased towards the cervical region.

In summary, tenascin was present at all sites of AP activity except in the epithelial cells of the enamel organ and the hypertrophic cartilage of the mandibular condyle. In mesenchymal tissues tenascin was more widely distributed than AP. It can be suggested that tenascin has functions at earlier stages of hard tissue formation than AP.
Tenotomy‐induced motor endplate alterations in rat soleus muscle
Authors: Pachter Bruce R. , Spielholz Neil I.
Published: February 2005

The effects of tenotomy on the ultrastructure of rat soleus muscle motor endplates were examined both qualitatively and quantitatively. Rat soleus muscle was studied 2 weeks following tenotomy and compared with normal littermates. The motor endplates from the tenotomized muscles were found to exhibit both degenerative and regenerative changes. Degeneration consisted of postjunctional fold breakdown, exposed junctional folds, myelin‐like bodies within the subjunctional sarcoplasm, and dense bodies within the Schwann cell cytoplasm. The regenerative changes consisted of several small nerve terminals occurring within the same primary synaptic cleft and several axons wrapped by the same Schwann cell. The results demonstrate that tenotomy induces denervation‐like changes at endplates that lead to terminal sprouting within the neuromuscular junctional area and remodelling.
Redistribution of membranes and cytoskeletal proteins in chicken oxyntic cells during the HCl secretory cycle: Ultrastructural and immunofluorescence study
Authors: Koenig Cecilia S. , Dabiké Monica
Published: February 2005

Changes in ultrastructure and cytoskeletal organization by avian oxyntic cells, at the onset of HCl secretion, were analysed. Cells in resting state, induced by fasting and cimetidine, were compared with histamine stimulated secreting cells. Ultrastructural studies were done by transmission electron microscopy; the distribution of prekeratin, myosin, and filamin‐like protein, by immunofluorescence; and that of F‐actin using FITC‐phalloidin.

Resting cells show short pericellular clefts. These are increasingly deepened in secreting cells by a reorganization of the lateral cell borders involving displacement of the junctional complexes toward the cell base and incorporation of the tubular system to the luminal plasma membrane. In secreting cells, the processes of the secretory surface are concentrated in a pericellular groove. Histamine stimulation induces a drastic redistribution of cytoskeletal proteins. In chicken oxyntic cells, in addition to the F‐actin cytoskeleton associated with the membranes of the secretory surface, there is a cytoskeletal ring containing F‐actin, myosin, and a filamin‐like protein, located at the level of the junctional complexes. In resting cells, filaments and masses of cytoskeletal matrix are associated with the zonula adherens. In secreting cells, the junctional complexes maintain their association with the filamentous ring, while the amorphous matrix is replaced by microfilaments that support the processes of the luminal surface. Intermediate filaments form a peripheral ring probably associated with the zonula adherens, and project from the ring toward the cell cytoplasm. Thus, with the onset of HCl secretion, the apical cytoskeletal ring of resting cells displaces toward the cell base. A role for this cytoskeletal ring in the changes in shape parallel to HCl secretion is discussed.
Histochemical, ultrastructural, and electron microprobe analytical studies on the localization of calcium in rat incisor ameloblasts at early stage amelogenesis
Authors: Takano Yoshiro , Yamamoto Tsuneyuki , Domon Takanori , Wakita Minoru
Published: February 2005

The enamel organs of rat incisors were separated from the enamel surface and processed for rapid freezing and freeze‐substitution. A histochemical stain for calcium (GBHA) of thick Epon sections revealed intense calcium reactions in the secretory ameloblasts, exclusively in the tubulovesicular structures extending throughout their distal cytoplasm. Electron microscopy revealed a thin layer of amorphous material with clusters of electron‐dense granules along the distal surface of secretory ameloblasts. In young secretory ameloblasts without typical Tomes' processes, a considerable number of mitochondria were located in the distal cytoplasm and contained numerous electron‐dense granules. Similar dense granules as well as fine ribbon‐like electron‐dense figures, all containing significant amounts of calcium, were observed in some of the tubulovesicular structures at the distal end of these cells. A putative exocytotic figure of such dense granules was also observed. The electron‐dense granules were rare in more differentiated ameloblasts with elongated Tomes' processes, which occasionally displayed ribbon‐like figures in some of the tubulovesicular structures in the process region. No significant calcium peak was detected in the extracellular amorphous material, secretory granules, or along the lateral plasma membranes. These observations may imply high calcium concentrations in mitochondria and tubulovesicular structures in the distal cytoplasm of secretory ameloblasts relative to that of the cytosol and support the possible contribution of these organelles in secretory ameloblasts to cellular calcium regulation at least in the early stage of amelogenesis.
Evidence that apatite crystals of rat incisor enamel have hexagonal cross sections
Authors: Kallenbach Ernst
Published: February 2005

Images of nearly cross sectioned enamel crystals obtained with the transmission electron microscope were examined in detail and correlated with various possible cross‐sectional shapes of the crystals. The following images were seen: 1) elongated hexagons with sharp outlines, maximal density, and minimal size (type A profile); 2) elongated hexagons with one pair of long sides of high contrast, two pairs of short sides of low contrast, high density in the center of the image, and low density towards the low contrast sides (type B profile); 3) slanted hexagons with one pair of high contrast sides, two pairs of low contrast sides (one pair of long, one pair of short sides), and the density decreasing from the center towards the low contrast sides (type C profile); this profile was seen more frequently than the type B profile; and 4) octagons with low contrast edges all around, the density decreasing from the center towards the edges (type D profile). Types B, C, and D profiles were larger than type A profiles. Similar crystal images have been described in the literature. When tilting a specimen in increments of 6°, the transformation of type A to type C and type C to type D profiles was observed. Many crystal images did not change their shape greatly when tilting the section through 6°. No rectangular or rhomboidal profiles were seen. It is argued that types A, B, C, and D profiles cannot be generated by apatite crystals with a parallelepiped cross section. They are easily explained, however, on the basis of crystals with hexagonal cross section.
A scanning electron microscopy morphometric study of the rabbit peritoneal surface
Authors: Gaudio Eugenio , Casale Nicoletta , Pannarale Luigi , Priori Alberto , Marinozzi Giulio
Published: February 2005

Rabbit peritoneum was studied by SEM to obtain information and statistically meaningful morphometric data of different sites of visceral and parietal peritoneum and to verify the existence of “stomata.”

Samples were fixed by intraperitoneal infusion of glutaraldehyde, and were photographed by SEM under standard conditions. Morphometric data were obtained by Kontron MOP Videoplan. Variable cell surface patterns were present even within limited areas; however, “stomata” were not observed. The heterogeneity of data obtained can be related to the dynamism of mesothelial cell activity and to the different motilities of the underlying organs.
Impaired development of the thymic primordium after neural crest ablation
Authors: Kuratani Shigeru , Bockman Dale E.
Published: February 2005

Impaired thymic development as a result of ablation of neural crest has been observed in embryos late in development. The present study was initiated to determine what changes are effected early in thymic development by neural crest ablation. The epithelial primordia of the thymus were studied in chick embryos on the sixth day of incubation. Embryos with neural crest ablations were compared with sham‐operated and untreated controls. Neural crest ablation inhibited formation of epithelial thymic primordia. Primordia in experimental embryos were fewer in number and were smaller than in shams and untreated controls. When primordia from shams and controls were transplanted to the chorioallantoic membrane of chick hosts, they were able to develop into organs with the typical features of embryonic thymus. Similar transplantation from neural crest‐ablated animals, on the other hand, led to small, predominantly epithelial structures with meager lymphoid development. These findings are consistent with the hypothesis that mesenchyme derived from cranial neural crest is critical in initiating and sustaining the development from pharyngeal pouches of epithelial structures competent to attract and support the proliferation and differentiation of lymphoid stem cells.
Myotome and early neurogenesis in chick embryos
Authors: King Earl D. , Munger Bryce L.
Published: February 2005

The present study was undertaken in order to verify the identification of profiles of presumptive growth cones in vivo. The developing spinal nerves of chick embryos were studied by light and electron microscopy. We traced the onset of efferent and afferent innervation of the myotome in 2‐ to 4‐day‐old chick embryos in order to be sure that we were examining the growing tips of axons. In the process of studying these growing axons, we were able to observe some unique relationships of neural tube, myotome, and differentiating spinal nerves. The neural tube tightly abuts the myotome in Hamburger and Hamilton's (HH) stage 14 chick embryos and cytoplasmic projections from the myotome directly abut the neural tube. The first ventral roots could be identified in HH stage 15 embryos and dorsal roots in HH stage 16 embryos, both under 2½ days of age. The advancing spinal nerve courses toward the anterior or cranial half of the myotome, and growth cones directly contact the medial wall of the myotome. The spinal nerves continue to abut tightly the myotome during the succeeding day of embryonic life, and growth cones enter the substance of the myotome by 3 days, or HH stage 19 embryos. These dorsolaterally directed axons will form the dorsal ramus of the spinal nerves and the ventral ramus continues to be contiguous with the myotome. Invasion of the myotome by axons (putative innervation), and thus innervation of myotomal cells in the 3‐day chick embryos, was a totally unexpected finding. The myotome and its potential derivatives thus have extensive neural contact by 3 days of embryonic life in the chick. These findings document a parallel differentiation of afferent and efferent elements of the nervous system and confirm previous accounts identifying growth cones in an intact organism. These findings suggest that afferent as well as efferent nerves may have critical roles in the differentiation of the mesodermal as well as ectodermal derivatives.
Stage‐dependent spontaneous frog dorsal root ganglion neuritogenesis on polylysine in vitro
Authors: Pollack Emanuel D. , Liebig Veronica
Published: February 2005

Dorsal root ganglia of larval frog extended elaborate neuritic arrays in vitro under minimal culture conditions in the absence of medium‐supplemented stimulatory factors. The highly adhesive attachment substratum polylysine provided the necessary condition for exuberant outgrowth, the extent of which was dependent on the developmental stage of the animal from which the neural tissue was derived, as was the capability for long‐term survival. It appears that an appropriate substratum can substitute for added growth factors in eliciting robust and long‐lived sensory neurites in vitro.
Myosin isozyme expression in response to stretch‐induced hypertrophy in the Japanese quail
Authors: Matthews William , Jenkins Robert R. , Gonyea William J.
Published: February 2005

When skeletal muscle is subjected to stretch it undergoes a rapid increase in muscle mass. However, the effect of stretch on the native myosin isozyme content of muscle has received attention only recently. Using the Japanese quail to investigate stretch‐induced hypertrophy, we demonstrated an increase in the expression of fast myosin in the predominantly slow anterior latissimus dorsi muscle (ALD). The fast myosin content of the control quail ALD is not sufficient to be quantified on native myosin pyrophosphate gels. After 33 days of stretch, the fast myosin content (N = 10) averaged 16 ± 11% in the stretched muscles and reached a maximum of 40%. Mean hypertrophy in the stretched muscle, as indicated by muscle weight, was 247 ± 91%; (range, 168–378%). Fast myosin was consistently expressed in muscles with hypertrophy greater than 250%. Muscle fiber size from the stretched muscles contained a greater number of fibers with small cross‐sectional areas than was observed in controls. These results indicate that substantial remodeling occurs in the stretched ALD muscle of the Japanese quail.
Effects of temperature and buffer composition on calcium sequestration by sarcoplasmic reticulum and plasma membrane of rabbit renal artery
Authors: McGuffee Linda J. , Little Sally A. , Mercure Juanita V. , Skipper Betty J. , Wheeler‐clark Ellyn S.
Published: February 2005

45Ca electronicroscopic autoradiography was used to examine the effects of buffer composition and temperature on the distribution of calcium in rabbit renal artery smooth muscle cells. The results show that the relative distribution of calcium is dependent on both the buffer used (Tris or Krebs) and the temperature of the bathing solution (25°C or 34°C). Krebs buffer at 34°C gave the highest relative activity in the plasma membrane, sarcoplasmic reticulum, and mitochondria. Buffer and temperature had little effect on the relative activity of the nucleus or cytoplasm. Next, we identified the cellular sites of calcium accumulation after 5, 15, 30, or 60 min exposure to 45Ca in Krebs buffer at 34°C. The results show that sarcoplasmic reticulum and plasma membrane are the primary sites of calcium accumulation during influx into these cells. Although the amount of 45Ca in the cell continues to increase with longer exposure, the relative distribution of calcium is essentially the same after 5 or 60 min. The data also indicate that the relative activity of plasma membrane + sarcoplasmic reticulum (a combination site that includes sarcoplasmic reticulum within a mean distance of 275 nm of the plasma membrane) is similar to the membrane alone and is lower than the sarcoplasmic reticulum alone.
Functional, physical, and ultrastructural localization of CD15 antigens to the human polymorphonuclear leukocyte secondary granule
Authors: Buescher E. S. , Livesey S. A. , Linner J. G. , Skubitz K. M. , McIlheran S. M.
Published: February 2005

A murine monoclonal IgM antibody, M3, which interferes with both polymorphonuclear leukocyte (PMN) phagocytosis and bactericidal activity, was used to examine the subcellular location of antigens bearing 3‐fucosyllactosamine (CD15 antigens) within this cell type. Percoll gradient‐separated secondary granule fractions were rich in CD15 antigens, with at least seven antigens recognizable in SDS‐PAGE/electroblot studies. Sonication/sedimentation experiments using secondary granule fractions showed that both soluble and sediment‐able CD15 antigens were present. Exposure of purified PMN to the secondary granule secretagogue phorbol myristate acetate caused extracellular release of two or three CD15 antigens, which could be purified by immunoprecipitation using antibody M3. Triton X‐114 phase‐partition experiments showed that secondary granule fraction CD15 antigens could be partitioned into hydrophilic (aqueous phase) and hydrophobic (detergent phase) antigens, suggesting that several of these antigens were integral secondary granule membrane components. Ultra‐structurally, PMN intracellular granules showed two patterns of CD15 expression, localization over both granule matrix/granule membrane and localization to only granule membrane. Colocalization studies showed that lactoferrin and CD15 antigens were both present in a subset of intracellular granules, confirming a secondary granule location for these antigens.
Blisters in the area pellucida, area opaca, and segmental plate of avian embryos
Authors: Lash James W.
Published: February 2005

This is a special communication in an area of special interest to all researchers using avian material. Avian embryos in the Northeast, representing four species (chicken, quail, duck, guinea hen), have been found to be drastically deficient in presomitic tissue (segmental plate tissue) between 45 and 60 h of incubation. These deficiencies first appear in the embryo as blisters, then, through tissue repair, they disappear and the embryos continue seemingly normal development. Similar blisters and excrescences appear in the area pellucida and area opaca between 20 and 30 h of incubation. Associated with these blisters and excrescences in very young embryos and blisters in segmental plates, but not necessarily the result of them, is a high incidence of congenital malformation during later development. These anomalies may be affecting the results obtained in avian research.
Elastin in human, baboon, and mouse liver: An immunohistochemical and immunoelectron microscopic study
Authors: Porto Luis CristóVão , Chevallier Michèle , Peyrol Simone , Guerret Sylviane , Grimaud Jean‐Alexis
Published: February 2005

Light microscope histochemistry and immunohistochemistry, and routine electron microscopy techniques were performed to analyse elastin distribution and structure in the human liver compared with that in baboon and mouse. In man and baboon, elastic fibers stained by iron hematoxylin or orcinolnew fuchsin seemed to be solitary and were few in number; in the mouse they were thinner but abundant, both in the portal tract and in hepatic veins. Orcein or resorcin‐fuchsin stains, employed after oxidation of tissue sections, revealed a network comprising elastic, elaunin, and oxytalan fibers, which was also demonstrated by immunofluorescence with anti‐elastin antibody in man and baboon. At the ultrastructural level, the elastic fibers of the human portal tract corresponded to discontinuous patches of amorphous material intermingled with few microfibrils. These contrasted with the thinner elastic fibers of baboon and mouse liver which had a core of amorphous material. In man and baboon, these fibers meshed into slender bundles of microfibrils often exhibiting small spots of amorphous material (elaunin fibers) and terminated as isolated microfibrils (oxytalan fibers). Immunoelectron microscopy of elastin carried out on baboon liver tissue labelled the amorphous material and also its microfibrillar component. Immunoperoxidase deposits were also associated with isolated bundles of microfibrils in the baboon portal stroma. Immunolabelling and elastic stains disclosed an important elastin portal network located around vascular, biliary structures and interspaced with collagen bundles. The structural polymorphism of elastin, assembling different relative amounts of amorphous material and microfibrils, might have a relationship with the required elasticity in a given species.
Immunohistochemical localization of calbindins (28K and 9K) in the tissues of the baboon Papio ursinus
Authors: Opperman Lynne A. , Pettifor John M. , Ross F. Patrick
Published: February 2005

An indirect immunoperoxidase procedure was used to detect the presence of calbindin‐D28K and calbindin‐D9K in the cerebellum, kidney, and duodenum of the baboon Papio ursinus. Antibodies to chick calbinding‐D28K and to both rat and mouse calbindin‐D9K were used. The cerebellum and kidney were shown to contain calbindin‐D28K; the doudenum contained calbindin‐D9K. In the cerebellum, positive staining was found in the Purkinje cells only; in the kidney, positive staining was found in the distal convoluted tubules, connecting tubules, and collecting tubules, extending deep into the medullary regions of the kidney. Staining in the duodenum was confined to the enterocytes of the villi, with no stain present in the crypt regions or goblet cells. Thus the baboon, a primate, contains the larger of the calbindins in both the cerebellum and kidney as does the human and monkey, but its distribution in the kidney is more generalized than that found in humans. The molecular weight of calbindin‐D9K was found to be similar to that found in other animals. However, the calbindin‐D28K from the baboon tissues appears to be slightly smaller than the protein found in other animals and may therefore be of similar size to the human calbindin‐D28K (Mr 26,000).
Hamster airway at parturition: Ultrastructure of the full‐term fetal trachea and effects of parturition
Authors: Cooney Rodger A. , Chopra Dharam P.
Published: February 2005

Limited studies have described the ultrastructure of trachea of late fetal and neonatal hamsters but the effects of parturition and the onset of breathing on structure have not been discussed. This study describes morphological features of ante‐ and post‐partum tracheal mucosa and submucosa and contrasts these features in fetal and neonatal hamster siblings. Significant differences between these siblings are noted in tracheal cells interfacing the lumen. Such cells of the fetal animals usually possessed cytoplasm of medium electron density with cisternal rough endoplasmic reticulum (RER). Surface membranes of these cells possessed numerous microvilli. In contrast, corresponding cells of post‐natal animals often had lucent cytoplasm with mostly tubular or vesicular RER. Surface membranes of these cells possessed microplicae (microridges).

This study also considers characteristics of fetal and neonatal tracheal development including: lomasome‐like structures in secretory cells; dichotomous forms of oligocilia in mucosal and submucosal cells; intramembranous particles of hemidesmosomes; particles and mitochondria associated with desmosomes; and affiliations of ciliary basal bodies with the cytoskeleton, cell membrane, and with endoplasmic reticulum.
Sympathetic innervation of the hindlimb arterial system in the giraffe (Giraffa camelopardalis)
Authors: Kimani James Kirumbi , Mbuva Regina N. , Kinyamu Richard M.
Published: February 2005

We report the distribution of sympathetic nerves in the hindlimb arterial system of the giraffe based on the histochemical demonstration of monoamines by the sucrose‐potassium phosphate‐glyoxylic acid method. It is noted that the hindlimb arterial system shows regional variations in its sympathetic innervation with regard to the density and the penetration of the nerves into the tunica media not hitherto described. The femoral and popliteal arteries showed a paucity of sympathetic innervation. Distally the dorsal pedal and great metatarsal arteries showed sparse sympathetic innervation characterized by a tendency toward exclusion of the nerves toward the outer layers of the tunica media. In contrast, the anterior (cranial) tibial artery in the leg revealed a relatively rich pattern of sympathetic innervation and a greater penetration of the nerves into the tunica media. The latter part of the arterial system showed a marked thickening of the tunica media and luminal narrowing, thus suggesting a “sphincteric” function. It is conceivable that this sphincter subserves a dual function, namely, to modulate blood flow to the distal parts of the limbs, and secondly to channel blood to the thigh and crural musculature. Pertinent to this is the fact that the presumptive sphincter occurs immediately after the crural muscular branches are given off.
Transplantation of labeled fetal spinal cord fragments into juvenile myelin‐deficient rat spinal cord
Authors: Hasegawa Mitsuhiro , Rosenbluth Jack
Published: February 2005

Minced and triturated fragments from the spinal cord of normal rat fetuses (15–18 days gestation) labeled with the fluorescent dye fast blue (FB) were successfully transplanted into juvenile myelin‐deficient rat spinal cord under direct observation. Clusters of myelinated fibers were found subsequently in the recipient spinal cord, and, by fluorescence microscopy, clusters of FB‐labeled cells were found at corresponding sites. The results indicate that the surgical approach used is suitable for transplantation of tissue fragments into a defined region of juvenile rat spinal cord, that FB can be used to locate the transplanted cells subsequently, and that FB does not interfere with maturation of the donor glia or with myelin formation.
Immunohistochemical demonstration of amelogenin penetration toward the dental pulp in the early stages of ameloblast development in rat molar tooth germs
Authors: Inai Tetsuichiro , Kukita Toshio , Ohsaki Yasuyoshi , Nagata Kengo , Kukita Akiko , Kurisu Kojiro
Published: February 2005

In order to examine the synthesis and secretion of enamel protein by ameloblasts in their early stages of development, immunohistochemical localization was carried out at light and electron microscopic levels using a monoclonal antibody produced in a preliminary experiment. Materials used were tooth germs of mandibular first molars of rats at 0–5 days after birth.

Immunoblot analysis after two‐dimensional electrophoresis revealed that antigen molecules recognized by the monoclonal antibody were amelogenins of 26–28 kDa (pI, 6.6–7.0).

An immunohistochemical examination using this monoclonal antibody demonstrated that the presecretory ameloblasts in their early stages of differentiation both synthesized amelogenin and secreted through a classical merocrine secretory pathway. In some presecretory ameloblasts as well as ameloblasts we observed the distended cisternae of rough endoplasmic reticulum (rER) which demonstrated heterogenous immunolabelling. The immunolabellings were also detected in the predentin as well as the intercellular spaces of odontoblasts and dental pulp cells which indicated penetration of amelogenin from the presecretory ameloblast layer to the dental pulp. The presence of coated pits at the plasma membrane of odontoblasts in close proximity to enamel protein along with the immunolabelling of lysosomes of the odontoblasts suggests the phagocytosis of the enamel protein into the odontoblasts. These observations suggest the possibility that the penetration of enamel protein toward the dental pulp and odontoblasts plays a role in the interaction between ameloblasts and odontoblasts.
Cellular distribution of inhibin in marmoset testes during development
Authors: Garde Seema V. , Sheth Anil R. , Kulkarni Sujata A.
Published: February 2005

Using polyclonal antibodies against a 13 KD human testicular inhibin, immunocytochemical localization studies were carried out in marmoset monkey testes. The pattern as well as the intensity of immunocytochemical staining for inhibin vary substantially during development. In early development (day 1 to 2 months) Leydig cells are the predominant cell types showing intense staining which reaches its nadir at 3 months. Subsequently both Sertoli cells as well as Leydig cells show equal intensity of inhibin staining. Testicular inhibin is likely to play a vital role in cell to cell communication.
Features of polyingression and primitive streak ingression through the basal lamina in the chicken blastoderm
Authors: Harrisson Fernand , Callebaut Marc , Vakaet Lucien
Published: February 2005

The de‐epithelialization of cells of the upper layer during the phenomena of polyingression and primitive streak ingression was studied by analyzing, from the time of laying to the end of gastrulation, the ultrastructure of the basal lamina underlying the upper layer. The electron density of the basal lamina and associated extracellular materials was enhanced by addition of tannic acid to the fixative. Special attention was also paid to the spatial and temporal distribution of blebs at the basal surface of the upper layer, and to the contribution of the de‐epithelialized cells to the formation of the deep layer. The results indicate that a nascent basal lamina is already present at the time of laying, especially beneath regions of the area pellucida where polyingression is not apparent. From the onset of incubation, the basal lamina rapidly develops, and it is interrupted by a large number of blebs. However, during the first 6–8 h of incubation, i.e., stages 1–2 of Vakaet (Arch. Biol. (Liège) 81:387–426, 1970), a downward movement of deepithelialized cells that insert into the deep layer and form the endophyll persists cranially. This phenomenon of polyingression, which starts during the intrauterine period, probably extends from caudal to cranial and comes to an end by stage 3. During these first three stages, the number of blebs progressively decreases, especially in the cranial part of the area pellucida, and a thicker, continuous basal lamina associated with numerous interstitial bodies is laid down. The caudal part of the upper layer is still actively blebbing at that time. Due to the convergence of this area toward the axis of the blastoderm, which leads to ingression at and elongation of the primitive streak up to and including stage 6, the number of blebs at the basal surface of the upper layer progressively decreases. From stage 7 on, blebs are virtually absent; shortening of the primitive streak and formation of the head process begin. At the level of the head process, primitive streak ingression has ceased and a novel basal lamina is progressively deposited beneath the upper layer. By stage 9, a thick, smooth basal lamina physically separates the upper layer from the head mesenchyme. Summarizing, at the time of gastrulation, the presence of blebs that perforate the basal lamina is correlated with the de‐epithelialization of cells. Before incubation, however, de‐epithelialization of upper‐layer cells occurs before the assembly of the basal lamina. Up to stage 3, the de‐epithelializing cells, randomly distributed in an area in front of the limit of primitive streak ingression, insert into the deep layer and form endophyll. Behind this limit, the de‐epithelialization occurs at the level of the primitive streak only and leads to the formation of mesoblast and, from stage 4 on, of definitive endoblast.
Norepinephrine‐induced cardiac hypertrophy of the cat heart
Authors: Marino Thomas A. , Cassidy Michael , Marino Deborah R. , Carson Nancy L. , Houser Steven
Published: February 2005

Norepinephrine administration causes progressive hypertrophy of the mammalian heart as measured by myocardial mass. The purpose of this study was to determine the growth response of the myocardial tissue components as well as the myocardial cell itself to norepinephrine. Young, adult cats were given low doses of norepinephrine in dextrose or dextrose alone twice daily for 15 days. On day 16, there were no changes in the animals body weight, right ventricular systolic pressure, right ventricular end‐diastolic pressure, heart rate, cardiac index, or blood pressure. However, the right ventricle/body weight, the left ventricle/body weight and the total heart weight/body weight were increased significantly in the norepinephrine treated animals. The increase was on the order of 40%. The cardiac muscle cell was also significantly increased in size and both the right and left ventricular cardiac muscle cells exhibited a dramatic increase in size as measured by cross sectional area. Upon stereological examination it was found that the amount of hypertrophy as seen in the cardiac muscle cells was paralleled by the hypertrophy seen in the other tissue components of the myocardium. The volume density of the muscle cells, the interstitial components, as well as the blood vessel compartment were identical in the control and in the norepinephrine‐treated groups. In conclusion, this study demonstrates that the response of the myocardium to norepinephrine is similar to that seen in response to a volume overload rather than that seen in response to pressure overload.