bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal modulation of androgen synthesis in the mink (Mustela vison) is associated with qualitative changes in testicular steroidogenesis in vitro
Authors: Tähkä Klaus M. , Teräväinen Tommi , Sundqvist Christer 
Published: June 2005

AbstractAnnual changes in testicular weight and microsomal androgen synthesis were studied in the mink (Mustela vison). Testicular samples were taken at different phases of the annual reproductive cycle. Steroidogenesis was assessed by investigating seasonal differences in the testicular conversion of [4‐14C]pregnenolone (P) and [4‐14C]dehydroepiandrosterone (DHA) to metabolites in vitro. The steroid metabolites were identified by thin‐layer chromatography. Seasonal changes in the capacity of the testis to produce testosterone from DHA and P correlated positively with the annual reproductive cycle of the species as well as with our earlier findings on plasma testosterone levels. Although the percentage conversion to testosterone (T) from both substrates decreased (39.8% to 19%, DHA; 33% to 15.5%, P) during testicular regression, the in vitro production of androstenedione (A) was increased. The A/T ratio changed from 0.32 (DHA) and 0.42 (P) during testicular activation in November to 1.9 (DHA) and 2.52 (P) during regression in September. Both substrates were utilized efficiently throughout the reproductive cycle. During testicular regression the decreased conversion to T was associated with a marked qualitative and quantitative increase (per unit weight) in the production of unidentified metabolites. The conversion to 5α‐reduced androgens appears to be insignificant, since none of the main 5α‐reduced testicular androgens were identified at any phase of the reproductive cycle.Our data suggest that the observed differences in testosterone production in vitro are in part due to changes in the activity of 17β‐hydroxysteroid dehydrogenase and possibly also in the enzymes catalyzing the conversion of C21 steroids to androgens. It would also appear that seasonal modulation of androgen synthesis in this species is associated with a prominent qualitative shift in testicular steroidogenesis rather than with a marked reduction in the microsomal capacity to use the substrates.
Stimulation of prostaglandin synthesis in fish follicles by a phorbol ester and calcium ionophore
Authors: Goetz Frederick William , Hsu Sheau‐Yu , Selover Amy 
Published: June 2005

AbstractThe effects of the phorbol ester, phorbol 12‐myristate‐13‐acetate (PMA), and the calcium ionophore, A23187, on prostaglandin E (PGE) and F (PGF) levels were investigated using incubates of brook trout (Salvelinus fontinalis) and yellow perch (Perca flavescens) ovarian tissue. The combination of PMA (0.1 μg/ml) and A23187 (0.1 μg/ml) synergistically stimulated an increase in PGE and PGF levels in incubates of brook trout follicles obtained from females prior to germinal vesicle breakdown, prior to ovulation and postovulation. The highest levels were observed in incubates of follicles taken just prior to ovulation. By itself, PMA also stimulated PGE and PGF accumulation while A23187 was much less effective. A23187, but not PMA, stimulated in vitro ovulation of brook trout follicles. Both cycloheximide and actinomycin inhibited PGE and PGF accumulation in incubates of preovulatory brook trout follicles stimulated with PMA but these inhibitors did not block ovulation induced by A23187 or PMA/A23187.The effect of PMA and A23187 were tested on the following 3 yellow perch tissue preparations: 1) isolated follicles [free of extrafollicular tissue (EF)], 2) EF tissue, and 3) intact tissue (containing undissected follicles attached to EF tissue). Incubates with all tissue types were performed in the presence or absence of 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20β‐PG, 0.1 μg/ml). PMA (0.1 μg/ml) in combination with A23187 (0.01 μg/ml) stimulated PGE and PGF accumulation in all tissue types though the greatest increase was generally observed in intact preparations. There was a lower accumulation of PGE in intact and EF tissue incubates stimulated with 17,20β‐PG and PMA. In addition, in incubates of ovarian tissue from several perch there was a higher accumulation of PGF in intact preparations stimulated by PMA or PMA/A23187 in the presence of 17,20β‐PG.The results for both species indicate that phorbol esters (PEs) can stimulate prostaglandin synthesis in follicles and, given that PEs have been shown to stimulate protein kinase C, it is possible that this enzyme is naturally involved in the control of ovarian PG synthesis in fish. It also appears that the stimulation is related to maturational stage in brook trout and steroid stimulation in yellow perch.
Ambystoma maculatum gastrulae have an oriented, fibronectin‐containing extracellular matrix
Authors: Johnson Kurt E. , Darribère Thierry , Boucaut Jean‐Claude 
Published: June 2005

AbstractDuring early development of the urodele Ambystoma maculatum, the appearance and distribution of fibronectin‐containing fibrillar extracellular materials were studied by immunocytochemistry. Fibronectin (FN) first appears in the early blastula (stage 7) as thin punctate fibrils on the cell surface concentrated in the marginal zone. In late blastulae (stage 9), thin fibrils are found throughout the blastocoel roof. Early gastrulae (stage 10) have numerous fibrils and multifibrillar strands concentrated in the dorsal lip region and oriented preferentially along a line parallel to the dorsal lip‐animal pole axis. There is a striking increase in the amount of FN fibrils during the rest of gastrulation. This FN‐containing network can be transferred to plastic substrata with preservation of the preferential orientation observed in vivo. Dorsal marginal zone explants placed on such conditioned substrata show polarized outgrowth toward the animal pole region of conditioned areas when placed on the dorsal lip side or the ventral marginal zone side of conditioned substrata. This outgrowth occurs symmetrically on bovine plasma FN‐coated substrata, is prevented by Fab' fragments of antibodies to FN but fails to occur on laminin coated substrata. When migrating mesodermal cells from early gastrulae are cultured on substrata conditioned by deposition of the fibrillar matrix, these cells exhibit striking contact inhibition of locomotion, a phenomenon that may explain dispersal of migrating mesodermal cells across the blastocoel roof. When leading edges of mesodermal cells collide, cells abruptly change direction. When leading edges collide with trailing edges, the trailing edges detach from the substratum and cells move apart in the direction of the leading edge. © 1992 Wiley‐Liss, Inc.
A high molecular weight proteoglycan is differentially expressed during development of the mollusc Concholepas concholepas (Mollusca; Gastropoda; Muricidae)
Authors: Brandan Enrique , González Mauricio , Inestrosa Nibaldo C. , Tremblay Colette , Urrea Rodrigo 
Published: June 2005

AbstractIncorporation of radioactive sulfate to hatched veliger larvae of the gastropod muricid Concholepas concholepas indicated that over 87% of the sulfated macromolecules were found in the detergent insoluble fraction, rich in extracellular matrix (ECM) components. The sulfated material was solubilized with guanidine salt followed by urea dialysis and fractionated by DEAE‐Sephacel chromatography. Three sulfated compounds eluting at 0.7, 1.1, and 3.0 M NaCl, called peaks I, II, and III, respectively, were obtained. The sulfated compound present in peak I was degraded by pronase or sodium alkaline treatment to a small sulfated resistant material, suggesting the presence of a proteoglycan (PG). Filtration analysis on Sephacryl S‐500 and SDS‐PAGE of the intact PG indicates that it has a high molecular weight (360,000 to over 1 × 106). Monoclonal antibodies (mAb) against this PG were produced. The specificity of one mAb, the 6H2, was demonstrated by size chromatography and ELISA analysis. The epitope recognized by this mAb seems to be present in the core protein of the PG. Both the extent of sulfation and the presence of different sulfated species of PGs were evaluated during the development of this mollusc. A twelvefold increase in the incorporation of sulfate to PGs per milligram of protein was found in veliger larvae compared to blastula‐glastula stages. This change correlated well with the differential expression of the sulfated PG present in peak I. Biochemical and immunological analysis indicate that high levels of this PG are found in veliger and trocophore larvae in comparison with blastula‐gastrula and early juveniles. These results indicate that a high molecular weight PG probably of the ECM is differentially expressed during the development of the gastropod Concholepas concholepas. © 1992 Wiley‐Liss, Inc.
Mechanism of tongue protraction during prey capture in the spadefoot toad Spea multiplicata (Anura: Pelobatidae)
Authors: O'Reilly Susan R. , Nishikawa Kiisa C. 
Published: June 2005

AbstractRecent studies have used muscle denervation experiments to examine the function of muscles during feeding in frogs. By comparing the results of denervation experiments among taxa, it is possible to identify evolutionary changes in muscle function. The purpose of this study was to examine the function of jaw and tongue muscles during prey capture in Spea multiplicata, a representative of the superorder Mesobatrachia. All members of this group possess a disjunct hyoid apparatus. We predicted that Spea would possess a novel mechanism of tongue protraction on the basis of its hyoid morphology. High‐speed video motion analysis and muscle denervation were used to study the feeding behavior and mechanism of tongue protraction in Spea. Although Spea possesses a relatively long tongue, its feeding behavior is similar to that of short‐tongued frogs of similar body size. Denervation of the m. submentalis had no effect on feeding behavior. When the m. geniohyoideus was denervated, the tongue pad was raised and moved forward slightly, but did not leave the mouth. When the m. genioglossus was denervated, the tongue pad was raised slightly, but no forward movement of the tongue occurred. A similar result was obtained after the mm. genioglossus and geniohyoideus were denerva ed simultaneously. Thus, both the mm. genioglossus and geniohyoideus are necessary for normal tongue protraction in Spea. In contrast, only the m. genioglossus is necessary for normal tongue protraction in archaeobatrachians and neobatrachians. We hypothesize that the disjunct hyoid is responsible for the greater role of hyoid movement during feeding in mesobatrachians. © 1995 Wiley‐Liss, Inc.
Menger's theorem for infinite graphs with ends
Authors: Bruhn Henning , Diestel Reinhard , Stein Maya 
Published: June 2005

AbstractA well‐known conjecture of Erdős states that given an infinite graph G and sets A, ⊆ V(G), there exists a family of disjoint A − B paths 𝓅 together with an A − B separator X consisting of a choice of one vertex from each path in 𝓅. There is a natural extension of this conjecture in which A, B, and X may contain ends as well as vertices. We prove this extension by reducing it to the vertex version, which was recently proved by Aharoni and Berger. © 2005 Wiley Periodicals, Inc. J Graph Theory 50: 199–211, 2005
Studies on the ketone‐catalyzed decomposition of caroate in aqueous alkaline medium
Authors: Selvararani S. , Medona B. , Ramachandran M. S. 
Published: June 2005

AbstractThe kinetics of ketone‐catalyzed decomposition of caroate (peroxomonosulfate) was studied in aqueous alkaline medium at 25°C. The rate follows simple second‐order kinetics, first order in each [Ketone] and [PMS]. The rate constant values are independent of hydroxide ion concentrations over the range from 0.05 M to 0.15 M. The experimental results suggest that the nucleophilic addition of SO ion at the carbonyl carbon leads to the formation of oxirane intermediate in the rate‐determining step. Oxirane reacts rapidly with another SO to give the parent ketone, oxygen, and SO. The observed substituent effect on the activation energy EA and Arrhenius (A) factor suggests that the electron‐donating substituents stabilize the activated state and make the entropy of activation more negative. This can be explained by the fact that the mechanism of oxirane formation shifts from concentric to nonconcentric process as we go from acetone to 3‐hexanone. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 483–488, 2005
Synthesis of polyetherols with purine ring. Kinetics and mechanisms of reactions, part 2: Reactions in the presence of triethylamine
Authors: Cisek‐Cicirko Irmina , Lubczak Jacek 
Published: June 2005

AbstractThe kinetics and mechanism of reaction between hydroxymethyl derivatives of uric acid and oxiranes in the presence of triethylamine as catalyst was studied. The formation of polyetherols was inhibited in initial steps of the reaction. Two different mechanisms were established for the reactions in which intermediates contained O‐hydroxymethyl and O‐(2‐hydroxyethyl) groups. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 472–482, 2005
Stages 1–2 non–rapid eye movement sleep behavior disorder associated with dementia: A new parasomnia?
Authors: Arnulf Isabelle , Mabrouk Tarek , Mohamed Khalil , Konofal Eric , Derenne Jean‐Philippe , Couratier Philippe 
Published: June 2005

AbstractA 55‐year‐old woman with a progressive dementia and frontal syndrome was hospitalized because she was agitated every night after falling asleep (spoke, laughed, cried, tapped, kicked, walked, and fell down). She slept 5.5 hours during video polysomnography, but the theta rhythm electroencephalograph recording typical of sleep stages 1 to 2 and the spindles and K‐complexes typical of sleep stage 2 contrasted with continuous muscular twitching, prominent rapid eye movements, vocalizations, and continuous, complex, purposeful movements typical of rapid eye movement (REM) sleep behavior disorder. This newly described stages 1–2 non‐REM sleep behavior disorder suggests that central motor pattern generators were disinhibited during non‐REM sleep. © 2005 Movement Disorder Society
Micronodular thymoma: an epithelial tumour with abnormal chemokine expression setting the stage for lymphoma development
Authors: Ströbel Philipp , Marino Mirella , Feuchtenberger Martin , Rouzière Anne‐Sophie , Tony Hans Peter , Wulbrand Ulrich , Förster Reinhold , Zettl Andreas , Lee Harris Nancy , Kreipe Hans , Laeng R Hubert , Müller‐Hermelink Hans Konrad , Marx Alexander 
Published: June 2005

AbstractThe aetiology of primary B‐cell lymphomas of the thymus is enigmatic. Although thymic follicular lymphoid hyperplasia (TFH) is commonly associated with myasthenia gravis (MG), lymphoma is not a complication of this condition. The present paper reports a high frequency of monoclonal B‐cell populations (6 of 18 cases; 33%) in micronodular thymoma (MNT), a peculiar thymic epithelial neoplasm with a B‐cell‐rich stroma, while B cells were consistently polyclonal in TFH (25 cases) and other types of thymomas (15 cases) (p < 0.001). An intratumoural lymphoma could be identified in three of the six monoclonal MNTs. Sequencing of the monoclonal IgH chain revealed partially overlapping VDJ gene usage in MNT and thymic mucosa‐associated lymphoid tissue (MALT) lymphomas. The neoplastic epithelium of MNTs, but not of TFH and other types of thymoma, expressed high levels of dendritic cell, T‐cell, and B‐cell chemoattractants, such as CCL18, CCR6, and CCL20. It is concluded that abnormal chemokine expression in an epithelial tumour, MNT, can promote the recruitment of MALT, the emergence of monoclonal B cells, and, eventually, the subsequent development of mediastinal lymphomas. More generally, the concept that expression of a ‘high‐risk’ spectrum of chemokines due to local or genetic factors may interfere with B‐cell homeostasis and may contribute to MALT lymphoma development in chronic inflammatory states is proposed. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Reactivity of Si‐H and Si‐vinyl end functionalized siloxanes toward PBT: A model system study
Authors: Fustin C.A. , Sclavons M. , Pantoustier N. , Bebelman S. , Truffier‐Blanc D. , Bailly C. , Merlin P. 
Published: June 2005

AbstractBased on a previous model compound study, we investigated the melt reactivity of Si‐H and Si‐vinyl end‐functionalized siloxane oligomers towards polybutylene terephthalate (PBT) in the presence of platinum(0)‐catalyst. We clearly observed grafting of the Si‐H functional oligomer onto PBT and have also indications for grafting of the Si‐vinyl oligomer. The grafting efficiencies and kinetics of both siloxane model compounds are compared and roughly quantified by infrared spectroscopy. This result indicates that the same reactive groups that are used to vulcanize silicone gums at high temperature can also be used to favor compatibility with a polyester matrix, opening perspectives toward polyester‐siloxane thermoplastic elastomers. POLYM. ENG. SCI. 45:1067–1072, 2005. © 2005 Society of Plastics Engineers
Survey of professionals' expectations of developmental task achievement of cystic fibrosis self‐care in children
Authors: Patton Susana R. , Graham Julie L. , Holsclaw Douglas , Varlotta Laurie 
Published: June 2005

AbstractWe surveyed 174 professionals with at least 6 months of experience working with children and adolescents with cystic fibrosis (CF), to obtain estimates of ages at which 50% of children with CF may be able to perform each of 44 self‐care behaviors related to the treatment of CF. Respondents were 63 physicians, 36 nurses, 24 dietitians, 18 respiratory therapists, 17 nurse practitioners, 10 social workers, and 4 psychologists, who had a mean of 11.4 years (SD = 7.5) of experience working with pediatric patients with CF. Mean age estimates for self‐care behaviors ranged from 5.5–13.9 years. For each item, responses varied among respondents, as reflected by a mean standard deviation of 2.75 years for all behaviors. Analyses of concordance suggested a high level of agreement among respondents for the order of mastery of specific skills related to diet and enzymes use only. To date, there are no empirically defined age estimates for when children with CF may be able to perform specific self‐care behaviors involved in the management of CF. This survey is the first step in generating age estimates for self‐care independence in CF. Future research should conduct an objective assessment of children's CF knowledge and skill in performing these behaviors, and compare these findings to the age estimates offered in this study. Pediatr Pulmonol. 2005; 40:135–140. © 2005 Wiley‐Liss, Inc.
Effect of nebulized albuterol on blood glucose in patients with diabetes mellitus with and without cystic fibrosis
Authors: König P. , Goldstein D. , Poehlmann M. , Rife D. , Ge B. , Hewett J. 
Published: June 2005

AbstractOver 90% of cystic fibrosis (CF) patients are treated with bronchodilators, and 6% have diabetes. Some with asthma also have diabetes, and most are treated with bronchodilators. Systemic administration of adrenergic agents can cause increases in blood glucose, but the effect of inhaled agents is unclear. A double‐blind study was performed on 10 patients with type 1 diabetes mellitus (DM) without CF (3 male, 7 female, mean age 25.5 years) and 9 patients with insulin‐dependent CF‐related diabetes (CFRD) (8 male, 1 female, mean age 21.9 years). On 2 separate days before 9 AM fasting and the morning dose of insulin, 2.5 mg of albuterol or nebulized placebo were given. Blood glucose was measured by finger stick with a glucose reflectance meter before and 15, 30, 45, and 60 min after treatment. No significant changes from baseline or differences between placebo and albuterol occurred in either group. The mean maximum increase from baseline in DM was 20 mg/dl on placebo, and 38 mg/dl on albuterol; in the CFRD, the respective changes were 7 and 7 mg/dl. Two DM patients had a > 50 mg/dl increase on albuterol vs. placebo; no CFRD patients had differences of such magnitude. DM patients had greater increases from baseline than CFRD patients on placebo and albuterol. Differences reached statistical significance at 30 and 45 min on placebo, and 45 min on albuterol. Albuterol 2.5 mg by nebulizer causes no clinically significant increases in blood glucose in DM or CFRD patients. Diabetes patients without CF have a significantly greater increase of glucose with time (placebo or albuterol) than CFRD patients. Pediatr Pulmonol. 2005; 40:105–108. © 2005 Wiley‐Liss, Inc.
Glucocorticoid induction of cleft palate in mice; no correlation with inhibition of mucopolysaccharide synthesis
Authors: Andrew Floyd D. , Zimmerman Ernest F. 
Published: June 2005

AbstractGlucocorticoids were administered once intramuscularly on day 11.5 of gestation to pregnant C3H/An mice. Triamcinolone acetonide (10 mg/ kg) produced 80% fetal cleft palates and reduced 35S‐sulfate incorporation into palate mucopolysaccharides to 74% of control values. Cortisol acetate (320 mg/ kg) administration under the same conditions resulted in 70% cleft palate and 35% of control incorporation. A nonteratogenic dose of cortisol (64 mg/kg) in‐hibited mucopolysaccharide synthesis to 68% of control values, i.e., this effect was similar to that obtained with the teratogenic dose of triamcinolone. Maximal palatal mucopolysaccharide synthesis occurs during day 14.5 of gestation, the time at which fetal palate shelves normally move horizontally and grow toward each other prior to fusion. Marked inhibition of mucopolysaccharide synthesis by glucocorticoids at this time has been considered to be the basis of their induction of cleft palates, analogous to their antiinflammatory effects on other connective tissue. However, our results suggest that the induction of cleft palate by gluco‐corticoids is not related to inhibition of mucopolysaccharide synthesis by them but rather to growth inhibition.
Inhibition of palatal fusion in vitro by β‐2‐thienylalanine
Authors: Baird G. , Verrusio A. C. 
Published: June 2005

AbstractThe effect of β‐2‐thienylalanine on palatal fusion was studied in vitro. Palatal shelves were dissected from 13‐ and 14‐day C57BL/6J mouse embryos and placed on agar‐solidified Eagle's medium containing equimolar concentrations of β‐2‐thienylalanine and phenylalanine. Closure of the palate proceeded normally in these explants—the marginal edges of the shelves fused to form an epithelial band, which then broke down and permitted mesenchymal continuity of the palatal processes. However, fusion was delayed, or completely inhibited, in all explants grown on medium supplemented with 2 mM β‐2‐thienyla‐lanine alone. The degree of inhibition depended on the stage of development of the embryo from which the palatal shelves were obtained—explants from early 13‐day embryos showed no adherence of the midpalatal epithelium, but 14‐day explants formed an epithelial band along the full length of the palate. Numerous mitotic figures, as well as areas of active cartilage and bone proliferation, demonstrated that the cultures were viable in the presence of the analogue.
Teratologic effects of LSD in explanted early chick embryos
Authors: Lee Hsin‐Yi , Hart Nathan H. , Kalmus Gerhard W. 
Published: June 2005

AbstractChick embryos were explanted at stages 4–7 and cultured for 20 h with or without LSD. At any stage 10 μg/ml LSD or higher caused abnormalities in axial structures, particularly somites, in over 50% of the embryos. LSD had no apparent effect on morphogenesis of the heart, but significantly lowered the pulse rate. Cellular degeneration occurred in severely affected structures, but LSD at embryotoxic doses caused alterations in neither cell morphology nor mitotic activity. The effects of LSD were not permanent, i.e., the embryos retained the ability to undergo normal morphogenesis when, after 4–5 h of treatment with 10 μg/ml LSD, they were subcultured on plain nutrient medium.