bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression patterns of the murine LIM class homeobox gene lim1 in the developing brain and excretory system
Authors: Fujii Tetsuya , Pichel Jose G. , Taira Masanori , Toyama Reiko , Dawid Igor B. , Westphal Heiner 
Published: February 2005

AbstractWe report the cloning, sequence analysis, and developmental expression pattern of lim1, a member of the LIM class homeobox gene family in the mouse. lim1 cDNA encodes a predicted 406 amino acid protein that is 93% identical with the product of the Xenopus LIM class homeobox gene Xlim1. We have characterized lim1 expression from day 8.5 post coitum onward. Northern blot analysis of RNA transcripts indicates that lim1 is expressed both during embryogenesis and in the adult brain. Analysis by whole‐mount and section in situ hybridization shows lim1 expression in the central nervous system from the telencephalon through the spinal cord and in the developing excretory system including pronephric region, mesonephros, nephric duct, and metanephros. In the metanephros, lim1 is strongly expressed in renal vesicles and S‐shaped bodies, and transcripts are also detected in the ureteric branches. © 1994 Wiley‐Liss, Inc.
Alternative splice form of type II procollagen mRNA (IIA) is predominant in skeletal precursors and non‐cartilaginous tissues during early mouse development
Authors: Sandell Linda J. , Nalin Andrew M. , Reife Robert A. 
Published: February 2005

AbstractType II collagen, generally considered to be characteristic of cartilage, has been localized in specific non‐cartilaginous structures during embryogenesis and development of the skeleton. Type II procollagen is synthesized in two different forms generated by alternative splicing of exon 2 in the precursor mRNA transcript. One form (type IIA procollagen) contains a large cysteine‐rich domain in the NH2‐terminal propeptide, while the second form (type IIB procollagen) does not. These two forms are spatially expressed during development and chondrogenesis with the type IIB procollagen mRNA primarily expressed by chondrocytes while the IIA form is expressed in chondroprogenitor cells (Sandell et al. [1991] J. Cell Biol. 114:1307–1319). The present study demonstrates that the early non‐cartilage expression, by somites, mesenchymal and epithelial cells, is predominately the alternate splice form, type IIA procollagen mRNA. Later in development, the type IIB mRNA splice form is expressed by chondrocytes. During the development of intramembranous bones, such as the mandible, type IIA procollagen mRNA is also expressed. In this tissue, the splice form does not switch to type IIB mRNA and no cartilage is formed. These results show that expression of type IIA mRNA, whether by epithelial or mesenchymal cells, precedes formation of overt skeletal structures. © 1994 Wiley‐Liss, Inc.
Expression patterns of mRNAs for the gap junction proteins connexin43 and connexin42 suggest their involvement in chick limb morphogenesis and specification of the arterial vasculature
Authors: Dealy Caroline N. , Beyer Eric C. , Kosher Robert A. 
Published: February 2005

AbstractGap junctions which comprise a family of proteins called connexins have been implicated in the morphogenesis of the chick limb bud. We have examined the expression patterns of two members of the connexin family, connexin43 (Cx43) and connexin42 (Cx42), during the early development of the chick limb bud and embryo by in situ hybridization. Cx43 mRNA is expressed in high amounts in the apical ectodermal ridge (AER), which promotes the outgrowth of the mesodermal cells of the limb bud, and in the ectopic AER of the limb buds of polydactylous diplopodia‐5 mutant embryos. In contrast, little Cx43 expression is detectable in nonridge limb ectoderm at early stages of limb development. These results suggest that Cx43 gap junctions may integrate the activity of the cells comprising the AER and compartmentalize them into a functionally distinct entity capable of directing limb outgrowth. In addition, Cx43 exhibits high expression in the posterior subridge mesoderm of the early limb bud that is growing out in response to the AER, but little expression in the anterior mesoderm. This graded distribution of Cx43 transcripts correlates with a functional gradient of gap junctional communication along the anteroposterior (AP) axis, and suggests that Cx43 gap junctions may be involved in pattern formation across the AP axis. At later stages of development, Cx43 is transiently expressed in high amounts in the precartilage condensations of the carpals and metacarpals, at a time when critical cell‐cell interactions are occurring that trigger cartilage differentiation. In contrast, in the developing limb, Cx42 is expressed exclusively by the central artery. In the remainder of the chick embryo, Cx42 is expressed in high amounts by the vessels comprising the arterial vasculature, but is not expressed by the venous vasculature. Thus, Cx42 gap junctions may be involved in specification of the arterial vasculature of the limb and embryo. Cx42, but not Cx43, is expressed in the ventricle of the heart, and by cells along the intrasclerotomal fissure that separates the rostral and caudal halves of the sclerotome of somites into distinct communication compartments. © 1994 Wiley‐Liss, Inc.
Regulation of amelogenin gene expression during tooth development
Authors: Chen Enhong , Piddington Ronald , Decker Sylvia , Park Jonathan , Yuan Zhi‐An , Abrams William R. , Rosenbloom Joel , Feldman George , Gibson Carolyn W. 
Published: February 2005

AbstractThe amelogenins are the predominant matrix proteins in developing enamel and are crucial for proper enamel mineralization. Transgenic mice were constructed in order to identify the segment of the amelogenin gene required for specific expression in enamel organ cells. A 3.5 kb fragment of the bovine X‐chromosomal amelogenin gene that includes a TATA box, the transcription initiation site, and 32 bp of exon 1 was linked to the βgalactosidase gene and injected into fertilized mouse eggs. Newborn transgene positive mice expressed βgalactosidase activity in developing teeth treated with the chromogenic substrate Xgal. Foci of ameloblasts were positive in newborn mice; stain intensity and number of positive ameloblasts increased in 1‐day and 2‐day postnatal mice. Some of the adjacent stratum intermedium cells also were positive in the later stages. Targeting of the transgene to the enamel organ was specific; the only other cells observed to be positive were macrophages, which have endogenous βgalactosidase activity. © 1994 Wiley‐Liss, Inc.
Heteroaggregate von Aryl‐ und Alkyllithiumreagentien: Faszinierende Strukturen mit grundlegender Bedeutung
Authors: Gossage Robert A. , Jastrzebski Johann T. B. H. , van Koten Gerard 
Published: February 2005

AbstractOrganolithiumverbindungen werden oft als einkernige Spezies dargestellt. Tatsächlich lagern sich diese Verbindungen aber zusammen, wobei Heteroaggregate mit verschiedenen organischen Gruppen, auch solchen mit Heteroatomen, entstehen können. Bei Reaktionen mit Organolithiumreagentien wird oft nicht beachtet, dass sich das “reine” lithiumorganische Homoaggregat in ein Heteroaggregat mit abweichender Struktur und Reaktivität umwandeln kann. Wenn das Organolithiumreagens oder das Substrat chirale Zentren enthält, kann auch diastereoselektive Selbstorganisation auftreten (die bevorzugte Bildung eines bestimmten Aggregat‐Diastereomers). Die Auswirkungen dieses Verhaltens auf Struktur und Reaktivitätsmuster von Organolithiumreagentien ist das Thema diese Kurzaufsatzes.
Cardiovascular lesions in Swiss mice fed a high fat — Low protein diet with and without betaine supplementation
Authors: Ball Carroll R. , Williams W. Lane , Collum Julius M. 
Published: February 2005

AbstractYoung adult mice of an albino stock (Taconic Swiss) were fed a hypolipotropic diet with a fat content (lard) of 28% and 8% protein (casien). The same diet containing betaine hydrochloride (2%) as a lipotropic supplement was fed to one‐half the mice.After seven weeks of restriction to these diets (with and without betaine supplementation) pronounced lesions had developed in the hearts. These lesions consisted of myocardial necrosis and thrombi within atrial lumina. The thrombi increased progressively in size, reaching critical and lethal dimensions for 75% of the animals by 13 weeks. Atrial dilatation, as a compensating mechanism, was a typical response. Small foci of myocardial necrosis with calcification and fibrosis were common in the ventricles. All mice surviving for longer than 13 weeks showed the myocardial changes ventricles. All mice surviving for longer than 13 weeks showed the myocardial changes and the thrombosis described above. Mural necrosis was observed in the intramyocardial branches of coronary arteries but thrombosis was infreqent within these vessels. There was extreme weight loss which paralleled the onset and increasing severity of the cardiac lesions. Betaine, as a dietary lipotrope, did not prevent or alter the cardiovascular lesions.
Incidence of the ponticulus posticus of the first cervical vertebra between ages six to seventeen
Authors: Kendrick George S. , Biggs Norman L. 
Published: February 2005

AbstractLateral cephalometric radiographs of 353 young caucasoid orthodontic patients from 6 years to 17 years were examined for the presence of ponticulus posticus of the first cervical vertebra. Visualization of the posterior fossa was not obstructed and in each case the squamous occipital and posterior arch of the atlas could be clearly defined. Of the 353 subjects, 56 (15.8%) showed some degree of a ponticulus posticus. Of these, 24 (14.6%) of 164 were males and 32 (16.9%) of 189 were females, with no apparent sex differences in the occurrence of this anomaly. Those showing a ponticulus were divided on the basis of bilateral complete or incomplete and unilateral complete or incomplete. There were numerous variations in the size and location of the ossification centers in the atlanto‐occipital membrane. The youngest female with a ponticulus was six years seven months and the oldest 16 years 11 months, while the youngest male was six years four months and the oldest 16 years five months. Two females with a unilateral partial ponticulus were observed over a one to two year period. During this time a complete unilateral radiopaque ponticulus had developed.
Autoradiographic investigation of cell proliferation in the brains of rats and cats
Authors: Altman Joseph 
Published: February 2005

AbstractCell proliferation in the brains of rats and cats was investigated autoradiographically. Two young adult rats were injected intraperitoneally with 2 mc of thymidine‐H3 and killed after a two weeks' exchange period. Two adult cats were injected intraventricularly with 0.5 mc of thymidine‐H3 and killed one week later. Labeling of cell nuclei in the brain, presumed to reflect DNA turnover and cellular proliferation, was investigated. In the rats, some neuroglia cells were found labeled in all parts of the brain, suggesting a low rate of glial proliferation. In addition, circumscribed small regions with numerous labeled neuroglia and microglia cells were seen in several brain regions, suggesting the occurrence of local glial proliferative reactions in these presumably normal brains. A few apparently labeled neurons were seen in the neocortex, and a proliferative region of granule cells was identified in the dentate gyrus of the hippocampus. In the cats labeling of glia cells was highest in the midline region, near the point of injection of the radiochemical, with a gradient of decreasing number of labeled cells both laterally and in the anteroposterior direction of the neuraxis. Neurons with apparently labeled nuclei were observed in the midline cortex bilaterally in both animals. These results indicate that glia cells can multiply in the brains of young adult rats and adult cats and they support the possibility that new neurons may be formed in forebrain structures, both in rodents and carnivores.
Light and electron microscopy of the islets of langerhans of the saimiri monkey pancreas
Authors: Winborn William B. 
Published: February 2005

AbstractThe distribution of alpha, beta, and other islet cells in the tail of the pancreas of the Central American monkey (Saimiri sciurea) revealed by the light and electron microscopes, is similar to that occurring in man. Differentiation of acinar, islet and duct cells is based on the presence or absence of specific granules and the special morphology of the cytoplasm and its membrane systems. Conspicuous lipid droplets appear in the islets, largely confined to beta and delta cells. An “intergrade” cell is present, possessing features of both alpha and beta cells, as well as a nongranular variety of delta cells.Nerve processes which display synaptic vesicles and clusters of mitochondria are present within the islets. Islet and acinar cells are sometime separated by connective tissue or a reticulum, as observed in light microscopy, but there may be simple apposition of their respective plasma membranes. The fine structure of this reticulum presents several levels of organization. Duct cells possess lipid masses similar to those in islet cells. These duct cells, unlike islet cells, are agranular and possess microvilli and cytoplasmic blebs, both of which show internal structures.
Fine structure of the rectal (salt‐secreting) gland of the spiny dogfish, Squalus acanthias
Authors: Bulger Ruth E. 
Published: February 2005

AbstractThe rectal gland of the spiny dogfish, Squalus acanthias has been described by light and electron microscopy. The cell outline shows remarkable complexity in electron micrographs. The basal plasma membrane has numerous complex infoldings and interdigitations separated by groups of mitochondria. The lateral plasma membrane also shows extensive interdigitation. The apical region demonstrates profiles of interleafing cell processes with much membrane interdigitation occurring between them but containing few mitochondria. The apical surface has microvilli which extend into the tubular lumen and are covered with nap‐like filaments. Glands of some fish were catheterized and attempts were made to correlate the fine structure of these glands with the known secretory rates. The cellular morphology of the secretory cells of the rectal gland correlates well with that seen in other ion‐transporting tissues, although some unique specializations were noted.
Fine structure of the guinea pig adrenal cortex
Authors: Sheridan M. N. , Belt W. D. 
Published: February 2005

AbstractThe adrenal cortex of the male guinea pig has been examined with the electron microscope. Many of the cells of the zone glomerulosa possessed bizarreshaped nuclei with frequent cytoplasmic invaginations. The internal structure of the mitochondria was entirely cristaform, the cristae being spaced at reasonably regular intervals. A rough‐surfaced endoplasmic reticulum was present in this zone only. The outer fasciculata showed an abundance of lipid in droplet from. The mitochondrial internal structure of this zone was predominantly cristaform, but the cristae were aggregated in clumps instead of being evenly spaced. Smooth‐surfaced cytoplasmic vacuoles were frequent. The inner fasciculate and the reticularis were generally similar. They differed from the above zones in that little lipid was present in droplet form and by the presence of a profusion of smooth‐surfaced cytoplasmic vacuoles which were interpreted as being homologous with the agranular endoplasmic reticulum. Mitochondria of the inner fasciculata were irregular in shape, while those of the reticularis were larger and more regular. In all zones of the cortex, the vascular channels were lined with an endothelium separated from the parenchymal cell by a space which was frequently seen to contain fibrils as well as fibroblast‐like cells.
Histology of the anterior hypophysis, thyroid and gonads of two types of dwarf mice
Authors: Bartke Andrzej 
Published: February 2005

AbstractThe histology of the anterior hypophysis, thyroid and gonads of dwarf (dw) and Ames dwarf (df) mutants of Mus musculus was compared. Orange G, aldehyde fuchsin and PAS stains were used to differentiate cells of the hypophysis. In both types of dwarf the anterior hypophysis was small, acidophils were lacking and the number of thyrotropic hormone producing cells was reduced. The thyroids were reduced in size, the follicles were small and some tissue was not organized into follicles. Testes were nearly normal. Ovaries were small and large follicles and corpora lutea were lacking.Growth hormone (STH) and thyrotropic hormone (TSH) were administered to both types of dwarfs. The treatment had no effect on the anterior hypophysis but number and size of follicles in the thyroid was increased The response was greater in df dwarfs; STH and TSH had more effect than STH alone. Testes of treated mice were only slightly changed but most of the df and some dw males became fertile. The ovaries became large and functional. Thyroids of dwarfs treated with thyroxine were not changed.It is concluded that the primary hormone deficiencies in both types of dwarf are the same, but that there are physiological differences as revealed by responses to STH and TSH treatment.
Topography of the nasal glands in rats and some other mammals
Authors: Bojsen‐Møller Finn 
Published: February 2005

AbstractThe topography of nasal glands in rats, guinea‐pigs, rabbits, cats, and monkeys was studied in osmium tetroxide and PAS‐stained whole mounts and ordinary sections. In rats Bowman's glands in the olfactory region were arranged in rows between the branches of the olfactory nerve. Mucous acini were only found on the rat septum in connection with Jacobson's organ, and serous acini were found on the septum posteriorly in the respiratory region, and on the lateral wall of the nasal cavity around the maxillary sinus ostium. No mixed glands were present. All the serous glands discharged their secretion through long excretory ducts into the ostium internum of the vestibule of the nose. In this area rats had 15–20 duct openings on each side. On the basis of considerations regarding airstream and pressure in the vestibule, the hypothesis is advanced that the openings act as small nozzles humidifying the inspired air by their atomized secretion. Since no serous or mucous glands in the rat open on the surface in the nasal cavity proper, it is concluded that the surface mucous sheet is derived exclusively from the goblet cells and Bowman's glands. In the other mammals the opening of the serous glands showed a similar pattern.
Mucosal reduplications associated with the ampullary portion of the major duodenal papilla in humans
Authors: Brown James Oliver , Echenberg Robert Jay 
Published: February 2005

AbstractMucosal reduplications of the ampullary mucosa in the major duodenal papilla have been found to be of two types: (1) columnar‐shaped projections apparently related to the wall of the terminal bile duct in adults only, are structures acquired postnatally; (2) leaf‐like flaps that are generally transversely oriented along the caudal wall of the ampullary space both in adults and in fetuses are congenital structures concerned in guarding the orifice of the main pancreatic duct against the incursion of back‐flowing fluids.
Body and organ weights and linear measurements of the adult Mongolian gerbil
Authors: Kramer A. W. 
Published: February 2005

AbstractData were collected from a colony of 49 male and 55 female two‐year‐old Mongolian gerbils, Meriones unguiculatus (Milne‐Edwards, 1867). This report gives tables which present data regarding linear measurements of body and organs and absolute and relative organ‐weight data. The means, standard deviations, ranges, and coefficients of variation were summarized in the tables. Grossly observed pathological organs were omitted from the study. The tables give information about this species which could be helpful in future laboratory investigations where the body‐and organ‐weight ranges, variability and linear measurements of this species may be of practical value.
Marginal bands in nucleated erythrocytes
Authors: Maser Morton D. , Philpott Charles W. 
Published: February 2005

AbstractMarginal bands from erythrocytes of several non‐mammalian vertebrates were studied by light and electron microscopy. Cells were observed in thin sections after various fixing procedures and in wholemount preparations. Isolated marginal bands were prepared by air drying and freeze drying. The marginal bands are composed of tubular elements which vary in diameter from 200 Å to 500 Å, depending on the preparation method. It is suggested that these tubules are part of a general class of microtubules, and that the real diameters of microtubules are approximately twice those observed in fixed and sectioned material.
The culture and karyotype of rat lymphocytes stimulated with phytohemagglutinin
Authors: Rieke William O. , Schwarz M. Roy 
Published: February 2005

AbstractA simple method leading to growth and mitosis in over 95% of shortterm cultures of lymphocytes from the blood, lymph or thymus of the rat is described. The method which is modified from Moorhead's original technique (′60) employs standard tissue culture medium (Eagles MEM or TC no. 199), 20% fresh rat serum, washed lymphocytes, penicillin, and phytohemagglutinin‐P (0.01 cm3/cm3 of culture of a 1:5 dilution of stock solution). Details of culture technique and factors contributing to growth failures are discussed.The chromosomes of male and female Lewis rats were studied in metaphase spreads of cultured cells. The karyotypes of these rats are presented and found to be in agreement with those recently reported by Hungerford and Nowell (′63).
Hemodynamic factors in the development of the chick embryo heart
Authors: Jaffee Oscar Charles 
Published: February 2005

AbstractBlood flow patterns have been outlined in the chick embryo heart. The initial flow pattern adapts to the heart form but soon vascular forces affect cardiogenesis. Spiralling of the blood streams in the sinus venosus appears to lead to an expansion of this chamber. The atrial septum forms between parallel streams and evidence is presented that blood flow contributes to septation. Interatrial flow develops with a fusion of the inflow streams bringing the entire systemic venous return into the right atrium when the left atrium receives a small pulmonary return; the difference in pressures is believed to lead to perforation of the septal wall.The ventricular septum also forms between parallel bloodstreams. Inhibition of the left ventricular outflow, brought about by the application of trypan blue to the embryos, was associated with the production of ventricular septal defects. Higher pressures in the left ventricles, brought about by increased vascular resistance to these chambers, led to the defects as evidenced by left to right flow through the defects. An interpretation of the origin of this common congenital anomaly is thus offered.