bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assemblies of linear arrays of particles in the apical plasma membrane of mitochondria‐rich cells in the gill epithelium of the atlantic hagfish (Myxine glutinosa)
Authors: Bartels Helmut 
Published: February 2005

AbstractIn the gill epithelium of the Atlantic hagfish Myxine glutinosa a mitochondria‐rich cell type is described which ultrastructurally resembles the chloride cells in other fish species. Freeze‐fracture replicas reveal different supramolecular structures in the luminal plasma membrane and in the intracellular amplification (tubular system) of the basolateral plasma membrane of these mitochondria‐rich cells. In the luminal plasma membrane ordered assemblies of particles and fibril‐like elements are regularly found. On the P face, the assemblies are composed of up to 20 linear arrays of particles which are preferentially located in the microvillar membrane on which they show a helicoidal orientation. The arrays are formed by globular (diameter 8–9 nm) and rod‐shaped (length 16–20 nm) particles, which occasionally are so tightly end‐to‐end attached that they generate fibril‐like structures. The distances between adjacent arrays within an assembly measure 10–15 nm. On the E face complementary patterns of linear grooves are present. These assemblies have not previously been demonstrated in the freeze‐fractured plasma membrane of branchial chloride cells. In the membrane of the tubular system, emerging from the basolateral plasma membrane of the mitochondria‐rich cells, infrequently repeating rows of 7–8 nm particles are present in addition to randomly distributed globular particles (diameter 7–8 nm). Complementary patterns of grooves are present on the E face. These intramembranous structures resemble the repetitive elements which have been previously described in the tubular system of branchial chloride cells in euryhaline teleosts and the subunits of which are considered to be the sites of ion pumps.
Network and lamellar structures in the tail muscle fibers of the metamorphosing anuran tadpole
Authors: Sasaki Fumie , Horiguchi Tsuyoshi , Takahama Hideki , Watanabe Kyozo 
Published: February 2005

AbstractNetworks of regularly arranged tubular units and lamellar structures were observed in the degenerating tail muscle fibers of spontaneously metamorphosing anuran tadpoles. These networks appeared to be similar to those previously found in the skeletal muscle of other animals under abnormal conditions. They stained clearly with ruthenium red (RR) and a continuity with the transverse tubular system (T tubules) of triads was clearly observed. The diameter of the tubular unit, 20–25 nm, was almost equal to that of the T tubules of the intact tail muscle fibers, indicating the network structures were probably formed by T tubules connecting together. In the early stages of metamorphosis, networks in the tetragonal configuration were observed within the end region of the muscle fibers. At the climax of metamorphosis, well‐developed networks in which the tubular units were arranged in a hexagonal pattern were seen in various regions of the fibers. Other observed lamellar structures may originate from lateral elements of the triads. The formation of the network structure is discussed.
Fine structure of the forelimb regenerate of the african clawed toad, xenopus laevis
Authors: Furlong Stephen T. , Heidemann Merle K. , Bromley Stephen C. 
Published: February 2005

AbstractForelimb regenerates from postmetamorphic Xenopus froglets were examined at various stages postamputation by light microscopy and scanning and transmission electron microscopy. The outside surface of the wound epithelium was found to exhibit progressive changes following amputation with a distinct difference in appearance between stump epidermis and wound epithelium at all stages examined. The internal structure of the wound epithelium is characterized by loosely arranged cells with numerous cell junctions and abundant intracellular filaments. The wound epithelium is separated at an early stage from the underlying cells by a thick band of extracellular matrix. Cells accumulating beneath the wound epithelium were morphologically similar to blastemal cells from completely regenerating limbs in other species but no evidence of myogenesis or abortive myogenesis was seen. Blastemal cells from the central portion of the regenerate were observed at varius stages of chrondrogenesis with those immediately beneath the wound epithelium least advanced in this respect. Those located more laterally appear not to be directly involved in chondrogenesis. Although the usual explanation for lack of complete regeneration in this species is inadequate innervation of the regenerate, the fine structure of the regenerating spikes noted here is markedly different than that of denervated, amputated newt limbs.
Immunohistochemical localization of neurotensin in hamster adrenal medulla
Authors: Pelto‐Huikko Markku , Salminen Tapio , Partanen Matti , Toivanen Matti , Hervonen Antti 
Published: February 2005

AbstractNeurotensin‐like immunoreactivity was localized in nerve fibers and terminals of hamster adrenal medulla at light and electron microscopy using the peroxidase‐antiperoxidase method. Numerous varicose neurotensin‐immunoreactive nerves and terminals were found among nonlabeled cell groups situated peripherally in the adrenal medulla. Combined formaldehyde‐glutaraldehyde (Faglu) fluorescence and immunohistochemistry of the same vibratome section showed that only norepinephrine cells were innervated by neurotensin‐immunoreactive nerves. All norepinephrine cells seemed to be innervated by neurotensin‐immunoreactive nerves. Neurotensin‐immunoreactive nerves disappeared after extrinsic denervation of the adrenal gland. By electron microscopy numerous neurotensin‐immunoreactive terminals were seen to make synaptic contacts with norepinephrine cells and with autonomic ganglion cells present in small numbers among norepinephrine cells. In the terminals neurotensin‐like immunoreactivity was localized mainly in large dense‐cored vesicles, but some precipitates were also associated with small vesicles, diffusely scattered in the axoplasm. The present findings suggest that in the hamster adrenal medulla part of the nerve terminals arising from splanchnic nerves contain neurotensin‐like peptide. The functional significance of these nerves in the hamster adrenal medulla remains to be elucidated.
Morphological studies on the distribution of enamel matrix proteins using routine electron microscopy and freeze‐fracture replicas in the rat incisor
Authors: Bai P. , Warshawsky H. 
Published: February 2005

AbstractEnamel contains two categories of biochemically characterized proteins. Amelogenins are dissociated from enamel without physical disruption of the tissue whereas enamelins are obtained only when the crystallites are dissolved. Ultrastructural visualization of these proteins was attempted using routine electron microscopy and freeze‐fracture replicas. Fresh, fixed, and 4.0 M guanidine‐HCl‐extracted samples of enamel from the secretory (young) and maturation (maturing) stages were compared. Decalcified and stained thin sections of fixed enamel revealed intercrystallite particulate material and “crystallite ghosts” which were identical to the crystallites themselves in young enamel and which corresponded to the periphery of the crystallites in maturing enamel. In contrast, 4.0 M guanidineextracted enamel contained no intercrystallite particulate material but only “crystallite ghosts.” Globular particles observed in freeze‐fracture replicas of fresh and fixed enamel samples were also removed by 4.0 M guanidine extraction. Incubation of guanidine‐extracted enamel with albumin and ovalbumin solutions restored the globular particles. It was concluded that amelogenins are the nonstructural, heterodispersed particulate material in the intercrystallite space. Enamelins constitute the integral template protein which initially provides for elongation of enamel crystallites. They then regulate the continuous growth in width and thickness during maturation and are progressively displaced to the periphery. The illusion that these “protein ghosts” are contained within the crystallite profile can be explained by the parallelepiped shape of the crystallite segment in thin sections.
Structure of the avian kidney
Authors: Morild I. , Bohle A. , Christensen J. A. 
Published: February 2005

AbstractThe kidneys from 6 domestic fowl were fixed in situ by perfusion from the left ventricle. In the bird there are two types of nephrons. One reptiliantype without Henle's loop and medullary tissue, and one mammalian‐type with Henle's loop lying in medullary tissue. Serial sections from kidney tissue embedded in plexiglass or in paraffin were used to study the architecture of eight reconstructed reptilian‐type nephrons from different cortical levels. All reconstructed nephrons had four major bends, but particularly in the subcapsular nephrons additional bends parallel to the kidney surface were found. There was no loop of Henle, but before entering the collecting duct the distal tubule usually had a very thin‐walled segment. No proximal convoluted part was found in the reptilian‐type nephrons. The length of the tubules varied between 3,000 μm and 6,000 μm. In the distal tubule a macula densa segment was found in all nephrons of the reptilian and mammalian type. The capillary network between the inter‐ and intralobular veins was composed of increasingly larger capillaries towards the intralobular vein. Segments of the distal tubule were indented into these capillaries and completely surrounded by them. In the nephrons of the mammalian type the proximal tubule was found to be convoluted as is usual for mammalian species.
Distribution and characterization of anionic sites in trophoblast and capillary basal laminas of human placental villi
Authors: King Barry F. 
Published: February 2005

AbstractThe distribution of anionic sites was studied in the trophoblastic and fetal capillary basal laminas of developing human placental villi with the cationic stain ruthenium red. At 7–12 weeks of gestation the trophoblastic basal lamina (TBL) contained ruthenium red‐positive granules in a quasi‐regular array throughout the lamina densa or sometimes concentrated at the interstitial surface of the lamina densa. The capillary basal lamina (CBL) (and anionic sites) were not present at this age. Anionic sites were also associated with collagen or reticular fibrils. At term, the TBL was largely devoid of anionic sites except for some distributed along its interstitial surface. The CBL was present in later gestation and sometimes had arrays of anionic sites. In order to characterize the anionic sites, minced pieces of villi were incubated in the presence or absence of either chondroitinase ABC, heparitinase, neuraminidase, or Streptomyces hyaluronidase in appropriate buffer systems. Incubation of early villi with heparitinase resulted in the disappearance of the TBL‐associated sites. Chondroitinase ABC appeared to reduce staining of collagen‐associated sites. In term villi, heparitinase removed those few sites still associated with the TBL but did not affect sites associated with the CBL or collagen. Chondroitinase ABC resulted in the disappearance of all anionic sites. In later gestation, a number of developmentally important macromolecules are transported across the trophoblast and enter the fetal capillaries. We conclude that the absence of an array of polyanionic sites from the term placenta TBL and the reduction in the amount of extracellular matrix intervening between the trophoblast and capillaries are adaptations to enhance the exchange of macromolecules across the placenta.
A possible mechanism of partial twinning in a calf
Authors: Easton Thomas W. 
Published: February 2005

AbstractA two‐headed calf had doubled heads and necks, externally normal forelimbs and thorax, incompletely doubled hearts and lungs, and a persistent sinus venosus, with abnormal pulmonary and systemic circulation. Study of the specimen indicated that partial twinning involved the development of the notochord as an anteriorly branched structure, with retention of the single condition posteriorly. It is proposed that anteroposterior compression of the embryonic disk could have induced the formation of double notochords. The way in which compression was produced is suggested.
Age does not affect numbers of taste buds and papillae in adult rhesus monkeys
Authors: Bradley Robert M. , Stedman Hazel M. , Mistretta Charlotte M. 
Published: February 2005

AbstractTaste buds and papillae in tongues of rhesus monkeys were examined and counted to determine if there are age‐related differences in general morphology or numbers of receptor organs. Tongues from 15 monkeys in five groups aged 4–31 years were studied with light microscopy. Fungiform, circumvallate, and foliate papillae were examined and taste buds in each papilla type were counted. Numbers of papillae did not differ with age through 31 years; however, at 24 years and older, fungiform papillae were reduced in number in some animals that had lost tongue tips due to trauma. There were no age‐related differences in numbers of taste buds in any of the three gustatory papilla types, nor did taste bud diameter alter with age. From data on each papilla type, estimates were made of total numbers of lingual taste buds. Totals ranged from about 8,000 to 10,000 and there were no agerelated differences. These results support other recent reports that taste buds are not decreased in number in old rats or humans. Since taste bud numbers and general morphology are maintained even in old age, any age‐related differences in taste behavior cannot be attributed to gross degenerative changes in lingual taste buds.
Changes in the nuclear uptake and retention of 3H‐estrogen in gonadotrophs and lactotrophs as a function of age
Authors: Nogami H. , Yoshimura F. , Herbert D. C. , Aufdemorte T. B. , Gates G. A. , Holt G. R. , Sheridan P. J. 
Published: February 2005

AbstractA quantitative autoradiographic immunocytochemical study was performed in which the nuclear uptake and retention of 3H‐estradiol (3H‐E2) by luteinizing hormone (LH) and prolactin (PRL) cells was examined in 19–21‐year‐old baboons. 3H‐E2 concentrating cells were found in all of the three lobes of the pituitary in varying percentages (38.7%, pars distalis; 17.1%, pars intermedia; 6.3%, pars nervosa). Approximately 80% of PRL cells and nearly 100% of LH cells were labeled. A count of the number of silver grains over nuclei revealed a marked variation of the accumulation of 3H‐E2 by LH cells and to a lesser extent in PRL cells. These results suggest functional heterogeneity among LH and PRL cells. The present results are discussed in relation to the physiological state of old animals.
An ultrastructural morphometric analysis of the adenohypophysis of lactating rats
Authors: Cinti Saverio , Sbarbati Andrea , Marelli Mariella , Osculati Francesco 
Published: February 2005

AbstractA morphometric analysis of the adenohypophysis (pars distalis) of lactating rats was carried out by a semi‐automated method at the ultrastructural level. The cellular elements were identified by their ultrastructural morphology. The following values were considered for the morphometric study: numerical density of cells/mm3 of tissue and the percentage of parenchymal volume occupied by every cell type. Mammotropes (PRL cells) numbered 624 × 103/mm3 and occupied 59.9% of the parenchymal volume (p.v.). Somatotropes (GH cells) numbered 206 × 103/mm3 and occupied 15.0% of the p.v. Folliculo‐stellate cells (FS cells) numbered 128 × 103/ mm3 and occupied 8.1% of the p.v. Gonadotropes (GN cells) numbered 47 × 103/mm3 and occupied 6.0% of the p.v. Adrenocorticotropes (ACTH cells) numbered 45 × 103/Vmm3 and occupied 3.8% of the p.v. Thyrotropes (TSH cells) numbered 36 × 103mm3 and occupied 3.4% of the p.v. PRL cells were characterized by aspects compatible with intense hormone production. GH cells did not show differences with those of nonlactating animals. Folliculo‐stellate elements appeared hypertrophic with abundant cytoplasm, enlarged Golgi complex, and dilation of the follicular lumina. GN cells had abundant cytoplasm with a well‐developed and dilated ergastoplasm, particularly in type II GN cells. ACTH cells did not show differences with those of nonlactating animals. TSH cells showed moderate nucleocytoplasmic activation. These fine structural morphometric findings are discussed in relation to other studies regarding nonlactating adenohypophysis and hormone changes during lactation.
A three‐dimensional reconstruction of high endothelial venules in the mouse lymph node:An enzyme‐histochemical study
Authors: Müller Edith , Stempfel Sonia 
Published: February 2005

AbstractA three‐dimensional reconstruction of high endothelial venules (HE‐venules) of an entire mouse lymph node is presented. The reconstruction has been made by means of the histochemical technique for α‐naphthylacetate esterase. The course of the HE‐venules is shown in coherence with lymphocytic aggregates (follicles and unit), which were concomitantly reconstructed.Carbonic anhydrase, glutamate‐, and α‐glycerophosphate dehydrogenase were found in the high endothelia, while calcium‐stimulated NA+ K+ ATP‐ase and the acetylcholinesterase were localized to the endothelia and/or to the perivascular sheath of the HE‐venules and submarginal capillaries.
Whether blood is contained in the arteries of the living animal by Galen of Pergamon: A translation
Authors: Goss Charles Mayo , Chodkowski Elizabeth Goss 
Published: February 2005

AbstractDr. Charles Mayo Goss was professor and chairman of the Department of Anatomy at the University of Alabama (1938–1947) and at Louisiana State University Medical School (1947–1965) and continued to teach after he retired at George Washington (1966–1975) and South Alabama (1975–1981). He edited the 25th, 26th, 27th, 28th, and 29th American editions of Gray's Anatomy. He also was editor of The Amatomical Record for 20 years (1948–1968). His research was on the heart in very early mammalian embryos.He became very interested in the works of Galen and translated five of them. The sixth was published after his death and co‐authored by his daughter Elizabeth Goss Chodkowski. He was anxious to show that many “errors” attributed to Galen are mistakes of translation, interpretation, or understanding.
Multicellular tumor spheroid interactions with bone cells and bone
Authors: Wezeman Frederick H. , Guzzino Katheryn M. , Waxler Beverly 
Published: February 2005

AbstractIn vitro coculture techniques were used to study HSDM1C1 murine fibrosarcoma multicellular tumor spheroid (HSDM1C1‐MTS) interactions with mouse calvarial bone cells having osteoblastic characteristics and mouse bone explants. HSDM1C1‐MTS attached to confluent bone cell monolayers and their attachment rate was quantified. HSDM1C1‐MTS interaction with bone cells was further demonstrated by the release of 3H‐deoxyuridine from prelabeled bone cells during coculture with multicellular tumor spheroids. HSDM1C1‐MTS‐induced cytotoxicity was mimicked by the addition of 10−5 M prostaglandin E2 (PGE2) to 3H‐deoxyuridine‐labeled bone cells. The effects of low (10−9 M) and high (10−5 M) concentrations of PGE2 on bone cell proliferation were also studied. Higher concentrations of PGE2 inhibited bone cell proliferation. HSDM1C1‐MTS resorbed living explants in the presence of indomethacin, suggesting that other tumor cell products may also participate in bone resorption. HSDM1C1‐MTS caused direct bone resorption as measured by the significantly elevated release of 45Ca from prelabeled, devitalized calvaria. However, the growth of a confluent bone cell layer on devitalized, 45Ca‐prelabeled calvaria resulted in a significant reduction in the amount of 45Ca released subsequent to the seeding of HSDM1C1‐MTS onto the explants. Bone cells at the bone surface may act as a barrier against invasion and tumor cell‐mediated bone resorption. Violation of this cellular barrier is achieved, in part, by tumor cell products.
Scanning electron microscopy of basolateral surfaces of rat renal tubules isolated by sequential digestion
Authors: Jones David B. 
Published: February 2005

AbstractRenal tubular cells and segments isolated by a trypsin, pepsin, pronase E digestion procedure were studied with scanning electron microscopy. The basal and lateral surfaces of S1, S2, S3 proximal tubular (PT) segments, descending and ascending thin limbs of Henle (TL), distal ascending thick limb of Henle, or distal straight tubule (DST) and distal convoluted tubule (DCT) segments, connecting tubules (CNT), and collecting ducts (CD) were identified and characterized. The basal processes of the S1 and S2 PT cells were fan shaped, were oriented in a circumferential direction, and terminated in microvilli at the basement membrane. S3 PT cells had microvillous basal processes mainly on the lateral edges of the cells. The basal processes of DST and DCT were similar to PT in orientation but terminated on the basement membrane with flattened, thin attachments. The long‐loop descending TL and the ascending TL exhibited distinctive interdigitating cell processes. TL segments with simple contours were present in smaller numbers and were characteristic of short‐loop descending limbs. CNT showed some cells with basal surfaces resembling DCT cells and others resembling CD cells. Both cortical and medullary CD segments exhibited intercalated cells with round basal contours and a sparse pattern of basal infolding clefts. The cortical CD principal cells revealed a much more elaborate mosaic of plicae, clefts, and microvilli than those of the medullary CD. These observations extend the previous knowledge gained from transmission electron microscopy and assist in the interpretation of that knowledge.
Topographical studies of lymphocyte localization using an intracellular fluorochrome
Authors: Brenan M. , Parish C. R. , Schoefl G. I. 
Published: February 2005

AbstractA procedure for analysing the topographical localization in tissue sections or whole‐organ mounts of lymphocytes labelled with an intracellular DNA‐binding fluorochrome, Hoechst dye No. 33342, is described. The localization, of intravenously injected lymphocytes in spleen, popliteal lymph nodes, and Peyer's patches was followed up to 7 days. In the case of spleen, both B and T lymphocytes initially localised in the marginal zone. Subsequently, B cells appeared to exit via the red pulp, while T cells aggregated around vessels in the white pulp. In Peyer's patches, B and T lymphocytes localized to different lymphoid areas. The advantages and potential applications of this technique are discussed.
Renal microvasculature of the rainbow trout, Salmo gairdneri: Scanning electron microscopy of corrosion casts of glomeruli
Authors: Brown J. Anne 
Published: February 2005

AbstractScanning electron microscopy of corrosion casts of blood vessels permits detailed and accurate study of the microcirculation. The present study examined the renal microvasculature of the rainbow trout, Salmo gairdneri. The conventional picture of a glomerulus with one afferent arteriole was common, but glomeruli were often supplied by two afferent arterioles. In the majority of these, the intrarenal artery gave rise to a single afferent arteriole that branched to form two smaller vessels before reaching the glomerulus. Glomeruli with two afferent arterioles that arose independently from the intrarenal artery also occurred. The majority of glomeruli had a single efferent arteriole, but a proportion of glomeruli had two efferent arterioles. Efferent arterioles were smaller in diameter than the afferent arterioles. The glomerular capillaries were arranged in lobules, with few anastomoses between lobules, so that, for glomeruli with two afferent or two efferent arterioles, vascular perfusion and thus filtration within discrete lobules is probable.