bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of thyrotropin‐releasing hormone on development of the pituitary–thyroid system in fetal rats in organ culture
Authors: Takizawa Tatsuya , Yamamoto Masako , Arishima Kazuyoshi , Eguchi Yasunobu 
Published: February 2005

AbstractSix groups of thyroid glands from 18‐day fetal rats were explanted to organ culture for 2 days. In one group, thyroid was cultured alone and in the remaining five groups thyroid was cocultured with pituitaries from fetuses ranging in age from 17 to 21 days. In each of the groups, half of the cultures had thyrotropin‐releasing hormone (TRH) added to the medium. Histometric parameters of the thyroid follicle such as diameter and cell height were used as indicators of development of the thyroid gland. When 18‐day thyroid was cultured alone, addition of TRH did not accelerate development. When either one 18‐day or two 17‐day pituitaries were cocultured with thyroid, a significant increase in diameter and cell height was seen. Addition of TRH to the medium induced little or no further change. When the thyroid was cultured with 19‐ to 21‐day pituitaries, a marked increase in thyroid development was observed; and the addition of TRH caused further acceleration in thyroid development. These results suggest that, in organ culture, 17‐ to 18‐day pituitary glands can release some thyrotropin (TSH) with or without additional TRH. Older pituitaries (19‐ to 21‐day) apparently can release an amount of TSH in the presence of TRH that is greater than their own spontaneous TSH secretion.
Vasoactive intestinal peptide‐immunoreactive nerves in the rat kidney
Authors: Knight David S. , Beal John A. , Yuan Zhi Ping , Fournet Timothy S. 
Published: February 2005

AbstractAn indirect immunohistochemical method in which an avidin‐biotinylated horseradish peroxidase complex is bound to the secondary antibody was used to visualize vasoactive intestinal peptide‐immunoreactive (VIPI) nerves in the rat kidney. Rats were perfused with 4% paraformaldehyde or 2% paraformaldehyde + 0.15% picric acid in 0.1 M phosphate buffer, then transferred to the buffer. After 24–48 hours, the kidneys were sectioned with a Vibratome at 200 or 300 μm and incubated in the primary antiserum for 18 hours at room temperature. A sparse plexus of VIPI nerves innervates the rat renal calyx. Some VIPI nerves innervate interlobar arteries and each succeeding segment of the arterial tree including afferent arterioles, but most innervate arcuate and interlobular arteries. VIPI axons do not innervate each arcuate artery or each interlobular branch of an arcuate artery with equal density. Although some axons follow each interlobular branch, most form a dense plexus on only one or two branches. Therefore, most VIPI nerves in the rat kidney innervate a restricted segment of the renal arterial tree. These nerves may be efferent and may selectively dilate arcuate and smaller arteries, or they may be afferent and may sense local changes in mechanical or chemical parameters.
Relationship between genital ridge formation and settlement site of primordial germ cells in chick embryos
Authors: Ukeshima Atsumi , Kudo Masayuki , Fujimoto Toyoaki 
Published: February 2005

AbstractChick embyros from stage 15 to stage 18, which is the most frequent extravasation period, were investigated by means of serial sections and light microscopy in order to learn the detailed relationship between the settlement sites of the primordial germ cells (PGCs) and the forming genital ridge. PGCs circulating in the vascular system came out of the small vessels in the splanchnopleure posterior to the vitelline artery. This PGC extravasation was limited to an area about 1.2 mm caudal to the vitelline artery. After the extravasation, the PGCs entered the neighboring thickened coelomic epithelium of the splanchnopleure. This thickened epithelium, which had incorporated the PGCs, changed the location toward the future gonadal site with the advance of development. At stage 16, the thickened portion of the epithelium was located in the splanchnopleure; then it moved toward the somatopleure via the coelomic angle; finally, at stage 18, this epithelium occupied the region between coelomic angle and the mesonephros which corresponded to the future genital ridge. This means that the thickened epithelium of the splanchnopleure which initially incorporated the PGCs becomes the superficial epithelium of the genital ridge in more advanced stages. The thickened portion of the epithelium of the splanchnopleure at stage 16 is thought to be the definitive gonadal anlage.
Hemopoietic cells in the liver and spleen of the embryonic and early postnatal mouse: A karyometrical observation
Authors: Sasaki Kazunobu , Matsumura George 
Published: February 2005

AbstractHemopoietic cells in the liver and spleen of embryonal and early neonatal mice were karyometrically examined by light microscopy. Hepatic hemopoiesis started at 11 days gestation, and proerythroblasts and less differentiated cells with nuclei larger than 7 μm in diameter, appeared in the primitive hepatic cords. After 12 days, the liver contained a number of mature erythroblasts. The immature large hemopoietic cells disappeared from the liver at 16 days gestation. Splenic hemopoiesis began at 16 days gestation. Hemopoietic cells with nuclei measuring larger in diameter than 8 μm appeared in the splenic cords, and the immature cells could be seen even at 2 days after birth.Development of embryonic hemopoiesis from the liver to the spleen is discussed in relation to yolk sac and bone marrow hemopoiesis.
Electron microscopic cytochemical localization of a basolateral calcium adenosine triphosphatase in vitamin D replete chick enterocytes
Authors: Davis Walter L. , Jones Ruth Gwendolyn , Farmer Gene R. , Matthews James L. , Martin James H. , Bridges George 
Published: February 2005

AbstractA cytochemical technique for the electron microscopic localization of calcium adenosine triphosphatase (Ca‐ATPase) was utilized to localize this enzyme in the enterocytes of rachitic and vitamin D‐replete chicks. In animals treated with cholecalciferol (CC, vitamin D3), an electron‐dense reaction product was located along the basolateral membranes of the absorptive cells within 72 hr after injection. Similarly, a reaction product was identified in association with the basolateral membranes within 24 hr after injection of 1,25‐dihydroxycholecalciferol, the active metabolite of vitamin D. A microvillar reaction product was not seen in either of these two groups. Electron‐dense reaction products were also seen in association with mitochondria and scattered throughout the cytoplasm of these enterocytes. The Ca‐ATPase reaction product was dependent upon the presence of medium calcium and substrate (ATP), was inhibited by vanadate, and was heat labile. In the rachitic animals, a reaction product indicative of Ca‐ATPase activity was not seen in association with either the basolateral membranes or the mitochondria. These data appear to indicate that an energy‐requiring calcium‐activated membrane pump plays a role in the flux of calcium across the enterocytes of the small intestine.
Role of muscle neurotization in the reinnervation of murine muscle grafts
Authors: Klueber Kathleen M. 
Published: February 2005

AbstractAlthough the reinnervation of muscle grafts has been demonstrated, the question remains as to the source of neurons reinnervating the graft. A muscle graft could be reinnervated by its original neurons (neural neurotization) or by sprouting of axons which supply the intact myofibers of surrounding muscles (muscle neurotization). The objective of this study was to evaluate the role of muscle neurotization in the reinnervation process using both horseradish peroxidase and fluorescent tracers. Observations from 20 muscle grafts indicate that the neurons reinnervating the grafts are from the original motor neuron pool. Thus muscle neurotization may not occur during the reinnervation process.
Phorbol ester stimulates macrophage invasion of fibrin matrices
Authors: Castellucci Mario , Montesano Roberto 
Published: February 2005

AbstractMacrophages migrate through a fibrin‐rich extracellular matrix in chronic inflammation, wound healing, and other pathophysiological processes. To investigate the factors that might influence the ability of mononuclear phagocytes to invade fibrin matrices, we cultured macrophage‐like P388D1 cells as well as resident and thioglycollate‐elicited mouse peritoneal macrophages on three‐dimensional fibrin gels, and we examined the effect of agents known to stimulate a variety of macrophage functions, including the production of fibrinolytic enzymes. Cells grown on fibrin gels under control conditions, as well as cells treated with either bacterial lipopolysaccharide or concanavalin A, remained confined to the gel surface. In contrast, the tumor promoter 4β‐phorbol 12‐myristate 13‐acetate (PMA) induced both P388D1 cells and peritoneal macrophages to invade the underlying fibrin matrix. The invasive behavior of PMA‐treated P388D1 cells was not affected by protease inhibitors of various specificities. These results demonstrate that certain exogenous signals can profoundly modify the ability of macrophages to migrate through fibrin matrices.
Structural changes in nuclear chromatin in rat pituitary after chronic stress of low intensity
Authors: Komitowski Dymitr , Muto Shuhei , Weiss Jürgen , Schmitt Bertold , Taylor George T. 
Published: February 2005

AbstractAcute, intense sources of “psychogenic” stress clearly modify the structure and function of the hypophysis, and there are concomitant changes in many peripheral physiological systems. Less dramatic sources of stress yield more equivocal results. An experiment is reported in which nuclear morphology of adenohypophyseal cells from 49 male rats exposed to a chronic, low‐intensity stressor was examined both by conventional histological and computer‐assisted‐image‐processing methods. The hypothesis tested was that an unequivocal pattern of morphological changes in the nucleus and nuclear chromatin would be revealed by image processing. Rats were killed after living for a year in a relatively low‐stress environment, “crowded” in groups of five animals per cage. The control condition was a minimal stress environment of two rats per cage. Results suggested few signs of pathology from peripheral measures of hypophyseal activity, and direct light microscopic examination of the gland revealed no differences between the two groups. Analysis of computer‐enhanced images of the pars distalis nuclei from the adenohypophysis, on the other hand, generated findings that were statistically and biologically significant. Nuclear size increased in the stress condition, the number of chromatin and area occupied by the particles increased, and the position of chromatin shifted toward the periphery of the nucleus. Perhaps more important, optical density analysis indicated that chromatin was less tightly packed in the experimental animals. Implications are that chronic, low‐intensity stress modulates nuclear structural changes from a dormant to an active state that portend changes in the peripheral systems influenced by the hypophysis.
Pericardium of rodents: Pores connect the pericardial and pleural cavities
Authors: Nakatani Toshio , Shinohara Harumichi , Fukuo Yoshifumi , Morisawa Satoshi , Matsuda Takeshi 
Published: February 2005

AbstractNumerous circular fenestrations or pores were present in the pericardium of the rat, golden hamster, and mouse. The pericardial pores were most numerous in the mouse. They were usually less than 50μm in diameter and situated in a meshwork formed by thick, wavy bundles of collagen fibers and thin, straight, elastic fibers. These pores directly connected the pericardial and pleural cavities and indirectly connected the right and left pleural cavities; i.e., the pericardial cavity in the rodents is not independent from but intercommunicates with the adjacent pleural cavities.There were many aggregates of free cells or milky spots in the pericardium. They principally consisted of lymphocytes, macrophages, and mast cells and were directly exposed to the pericardial cavity.
Expression of cellular glycoconjugates in transfilter‐induced metanephric mesenchyme
Authors: Laitinen Liisa , Virtanen Ismo , Saxén Lauri , Lehtonen Eero 
Published: February 2005

AbstractExpression of glycoconjugates during transfilter‐induced differentiation of metanephric mesenchyme was studied by using fluorochrome‐ and peroxidase‐coupled lectins. All cells in the uninduced metanephric mesenchyme expressed mannose, β‐D‐galactose (β‐Gal), N‐acetylglucosamine (GlucNAc), and terminal sialic acids. Additionally, solitary cells showed terminal α‐D‐galactose (α‐Gal) typical of mouse endothelial cells. During culture, undifferentiated mesenchymal cells seemed to disappear from induced explants, and many of the stromal cells between the evolving tubules presented terminal α‐Gal residues. Similar positivity could be revealed in monolayer cultures of induced mesenchymes. A number of tubules in induced explants displayed α‐L‐fucosyl (Fuc) residues, characteristic of mature proximal tubules. Some terminal Ga1NAc residues, recognized only by Dolichos biflorus agglutinin, emerged in a few tubular cells after prolonged culture. The early tubules and glomerular bodies displayed a basement membrane presenting both terminal Gal‐(β1‐‐3)‐Ga1NAc and Ga1NAc residues. These positivities disappeared later from many tubular structures and glomerular bodies but persisted in tubules expressing proximal tubular differentiation. The glomerular bodies displayed only one cell type, reminiscent of maturing podocytes, presenting terminal Ga1‐(β1‐‐3)‐Ga1NAc and Ga1NAc residues. Later these saccaride residues became covered by sialylation, as they could then be revealed only after treatment with neuraminidase.The results indicate that the segment‐specific expression of saccharide residues during differentiation of nephron in vitro resembles the sequence seen in vivo. This study also suggests that the basement membranes surrounding the nephron show a stepwise, segment‐specific maturation. Despite the presence of endothelial cells in the metanephric explants, only avascular glomeruli evolved in this differentiation model.
Innervation of muscle receptors in the cross‐reinnervated soleus muscle of the cat
Authors: Ip M. C. , Luff A. R. , Proske U. 
Published: February 2005

AbstractIt has recently been reported (Gregory et al., J. Physiol., 331:367–383, 1982) that cutting a muscle nerve and letting it grow back into the muscle or cross‐uniting the muscle with a foreign nerve results in major disruption of the normal response patterns of muscle spindles and tendon organs. Here we report observations on the structure of muscle receptors in cross‐reinnervated and self‐reinnervated soleus muscles in an attempt to detect abnormalities that might account for their disturbed function. Eight soleus muscles were reinnervated with the extensor digitorum longus nerve for periods up to 449 days and two were self‐reinnervated. Following the physiological investigation, the muscle was fixed and stained according to the method of Barker and Ip (J. Physiol., 69:73P‐74P, 1963). Spindles and tendon organs were teased from the muscle and photographed. In one cross‐reinnervated muscle an attempt was made to isolate all receptors. About two‐thirds of the normal number of spindles and tendon organs were found. Three categories of receptor were identified: normal, abnormal, and those having no visible nerve endings. There appeared to be little difference in degree of abnormality of receptors in self‐ and cross‐reinnervated muscles. Of the 180 spindles, 3% were normal, 43% had no visible endings, and 54% had abnormal endings. Of 80 tendon organs, 38% were normally innervated, 33% were without visible innervation, and 29% had abnormal endings. We conclude that following long‐term cross‐reinnervation and self‐reinnervation of soleus there is extensive disruption of the normal innervation pattern of both spindles and tendon organs which could account for their functional abnormalities.
Ultrastructure of the main excretory duct epithelia of the rat parotid and submandibular glands with a review of the literature
Authors: Sato Atsuko , Miyoshi Sakuichiro 
Published: February 2005

AbstractThe fine structure of the main excretory duct (MED) epithelia of the rat parotid and submandibular glands was investigated by scanning and transmission electron microscopy. The structure of these two MED epithelia was compared. Five principal cell types were observed in the MED epithelium of the parotid gland‐cuboidal, basal, light (types I and II), dark, and tuftThis cell has been given different names such as “peculial cell” (Järvi and Keyrilainen, 1955), “brush cell” (Rhodin and Dalhamn, 1956), “tuft cell” (Järvi, 1962), “multivesicular cell” (Silva, 1966), “undifferentiated cell” (Johnson and Young, 1968), “s‐cell” (Ferguson, 1969), “agranular light cell” (Riches, 1972), “caveolated cell” (Nabeyama and Leblond, 1974), and “fibrillo vesicular cell” (Wattel and Geuze, 1978). The term “tuft cell” has been used throughout the present study.
cells. The cuboidal cells, which were stratified in two or three layers, were the most numerous. Basal cells were situated adjacent to the basal lamina of the epithelium. The type I light cells had well‐developed basal plasma membrane infoldings. The type II light cells had poorly developed basal plasma membrane infoldings. The dark and tuft cells resembled those of the MED epithelium of the rat submandibular gland.Four principal cell types were observed in the MED epithelium of the submandibular gland—light cells (types I and 11), dark, tuft, and basal cells. The two types of light cells were the most numerous. Dark cells with regular and dense microvilli were relatively narrow in shape and had complicated basal plasma membrane infoldings. There were numerous vesicles or channel—like vesicles in their apical cytoplasm. Tuft cells were characterized by prominent microvilli, many vesicles of various sizes in the apical cytoplasm, and no basal infoldings.Peroxisomes were present in the MED epithelia of the rat parotid and submandib‐
ular glands, especially in light and cuboidal cells.
Nuclear shaping in spermatids of the Thai leaf frog Megophrys montana
Authors: Asa Cheryl S. , Phillips David M. 
Published: February 2005

AbstractTransmission electron microscopy of Thai leaf frog testis revealed a unique pattern of spermatid nuclear morphogenesis. Chromatin condenses into a continuous cylindrical coil within a roughly spherical nucleus. Later the nuclear membrane conforms to the contours of the uncoiling nuclear contents. In the mature sperm, the long, tapering nuclesus is helically shaped. This developmental sequence occurs in the absence of a microtubular manchette, raising questions about the role of this structure in nuclear shaping in spermatozoa of other species.
Periapical innervation of the ferret canine and the local retrograde neural changes after pulpectomy
Authors: Holland G. R. 
Published: February 2005

AbstractThe amputation of the dental pulp severs a population of axons that are predominantly in the Aδ and C fiber size range and are principally involved in nociception. Local periapical neuromas, if they are formed after pulpectomy, may be the sites of spontaneous nervous activity that may, in some circumstances, be involved in the genesis of chronic pain. The periapical tissues from the mandibular canines of four ferrets were examined 3 months after pulpectomies. Silver‐stained paraffin sections were examined in three dimensions at the light microscope level. Ultrathin sections were examined at the electron microscope level. Compared with contralateral and independent controls, the principal changes were the loss of the periodontal plexus around the root apex, the extension of damage well below the apical foramen, and the persistance of inflammation 12 weeks postoperatively. While a somewhat disorderly mass of nerve fibers develops subapically, the arrangement has only some of the features usually associated with neuromas.
Regional differentiation in the stomach of the green anole
Authors: Lehman Sharon , Smith Allen A. 
Published: February 2005

AbstractThe stomach of Anolis carolinensis (Reptilia: Iguanidae) has four histologically and histochemically distinct regions. The gastroesophageal junction has an acidic surface mucin and no glands. The cardia has an acidic surface mucin and mucous glands. This acidic mucin appears to contain neither sulfates nor sialic acid. The fundus has a neutral surface mucin and mucoserous glands. The pylorus has a neutral surface mucin and mucous glands.
Ultrastructural cytochemistry of trout arterial fibrils as elastic components
Authors: Isokawa Keitaro , Takagi Minoru , Toda Yoshihisa 
Published: February 2005

AbstractThe trout arterial wall contains numerous extracellular fibrils that are presumed to be elastic. However, the cytochemical properties of the arterial fibrils have not been studied. Thus, we have ultrastructurally and cytochemically examined these fibrils, utilizing routine uranyl acetate and lead (UA‐Pb) double staining, the tannic acid (pH 7.0)‐uranyl acetate (TA‐UA) method as an electrondense staining for elastin, and Thiéry's periodic acid‐thiocarbohydrazide‐silver proteinate (PA‐TCH‐SP) method to localize vicinal glycol‐containing complex carbohydrates. The arterial fibrils, about 23 nm in thickness, were interwoven at random but frequently showed the circular alignment to the long axis of the aorta. Occasionally they appeared to coalesce side by side, and the coalesced portion tended to lose its affinity for UA‐Pb stains. The TA‐UA method stained the fibrils moderately to intensely and stained the coalesced parts of the fibrils more intensely. All of those TA‐UA positive fibrils were completely removed after elastase en bloc digestion. The PA‐TCH‐SP method did not stain the arterial fibrils but stained another kind of much thinner interfibrillar filamentous structure. These results suggest that the fibrils in the wall of trout ventral aorta are elastin in nature and do not contain vicinal glycols, although the fibrils usually exist in a fibrillar form, which is unlike mammalian amorphous elastin.
Ultrastructural and immunocytochemical studies of prolactin‐secreting cells (PRL cells) in the anterior pituitary gland of the female musk shrew (Suncus murinus L.)
Authors: Ishibashi Toshiko , Shiino Masataka 
Published: February 2005

AbstractProlactin‐secreting cells (PRL cells) in the anterior pituitary gland of the female musk shrew were identified by the protein A—gold procedure combined with electron microscopy. Their secretory granules were spherical, and showed variuos sizes ranging in diameter from 100 nm to 800 nm according to the difference in physiological conditions of the animals.In pregnant and lactating animals, the PRL cells exhibited morphologically active features, i.e., a large prominent Golgi apparatus and a well‐developed rough endoplasmic reticulum (RER) consisting of densely packed parallel lamellae. In pregnant and estrogen‐treated animals, the secretory granules of PRL cells significantly increased in size as compared with those of virgin animals.The most remarkable ultrastructural change observed in PRL cells of pregnant, lactating, and estrogen‐treated female musk shrews was the occurrence of “intracisternal” granules. They were small and spherical, and were located without limiting membranes inside the dilated cisternae of the RER. Intracisternal granules, as well as ordinary secretory granules, were found to be immunoreactive for PRL by the protein A—gold procedure. These results suggest that PRL cells of the female musk shrew may possibly utilize a “bypass” route to form hormone‐containing granules under highly activated cellular conditions.