bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Hyper- and Microgravity on Collagen Post-Translational Controls of MC3T3-E1 Osteoblasts
Authors: Saito Mitsuru , Soshi Shigeru , Fujii Katsuyuki 
Published: April 2006

Abstract
We attempted to study the effects of microgravity (by clinostat) and hypergravity (using centrifugation) on collagen metabolism using murine MC3T3-E1 osteoblasts, especially focusing on collagen cross-link formation. We found that altered gravitational load affected the post-translational modification of collagen, particularly the collagen maturation pathway, through altered expression of enzymes involved in cross-link formation.
Introduction: Gravitational loading plays important roles in the stimulation of differentiated osteoblast function and in the maintenance of skeletal tissues, whereas microgravity seems to result in osteopenia caused by impaired osteoblast differentiation. The aim of our study was to clarify the effects of altered gravitational environments on collagen metabolism, particularly the relationship between post-translational collagen quality and enzymes involved in cross-link formation, using murine osteoblastic MC3T3-E1 cells.
Materials and Methods: Cells were cultured under vector-averaged microgravity (1 × 10−3g) using a clinostat or under conventional centrifugation techniques to generate hypergravity (20g and 40g) for 72 h. We then examined the expression patterns of lysyl oxidase and the two lysyl hydroxylase isoforms telopeptidyl lysyl hydroxylase (TLH; procollagen-lysine, 2-oxyglutarate, 5-dioxigenase 2 [PLOD2]) and helical lysyl hydroxylase (HLH; [PLOD1]) by quantitative real time polymerase chain reaction (PCR) analysis. Quantitative analysis of reducible immature (dihydroxylysinonorleucine, hydroxylysinonorleucine, and lysinonorleucine) and nonreducible mature (pyridinoline and deoxypyridinoline) cross-links, and maturation rate analysis of immature to mature cross-links by conventional metabolic labeling using tritium lysine were also performed.
Results: Hypergravity upregulated both TLH mRNA expression and enzyme activity compared with stationary cultures, whereas microgravity stimulated both HLH mRNA expression and enzyme activity. These results were consistent with increased relative occupancy rates of telopeptidyl hydroxylysine-derived cross-links and helical hydroxylysine-derived forms observed under hypergravity and microgravity, respectively. Hypergravity stimulated not only lysyl oxidase mRNA expression but also increased enzyme activity and the sum of immature and mature cross-links. Furthermore, the conversion rate of immature cross-links to mature compounds was markedly increased under hypergravity but decreased under microgravity.
Conclusion: Altered gravitational loading may affect the post-translational modification of collagen through altered expression of enzymes involved in cross-link formation. These observations may be important in elucidating the mechanisms of osteopenia during space flight.
Cis-Acting Intronic Elements That Regulate Cartilage-Specific Alternative Splicing of the Type II Collagen (Col2) Pre-mRNA Lie at or Near Splice Site Junction Sequences Flanking Exon 2 of the Gene
Authors: Nishiyama Takayuki , Hatano Hiroshi , Kurosaka Masahiro , Bolander Mark E , Sarkar Gobinda 
Published: April 2006

Abstract
Knowledge of the cis-acting elements is required for identifying trans-acting splicing factors underlying cartilage-specific alternative splicing of Col2 pre-mRNA. By performing desired deletions in the mouse Col2 pre-mRNA, location of the intronic cis-acting elements was narrowed down to be at or near splice-junction sequences flanking exon 2 of the gene.
Introduction: Type II collagen (Col2) pre-mRNA undergoes cartilage-specific alternative splicing involving exon 2 during chondrocyte differentiation. Thus, the trans-acting protein factors that regulate the splicing are associated with the differentiation of chondrocytes. Knowledge of the cognate cis-acting elements is necessary to eventually identify the trans-acting factors.
Materials and Methods: To localize the cis-acting sequences, we created several deletions within a minigene containing exon 1 to exon 4 of mouse Col 2 gene and evaluated alternative splicing of the resulting pre-mRNAs in ATDC5 cells, a model of insulin-stimulated chondrocyte differentiation. The first deletion reduced intron 1 from 3799 to 259 bp, the second reduced intron 2 from 1108 to 94 bp, the third combined the above two deletions, and the fourth was derived from the third by removing intron 3 and exon 4. ATDC5 cells harboring these constructs were cultured for up to 21 days with or without insulin. Alternative splicing was evaluated by determining the ratio of Col2B (lacks exon 2) to Col2A (has exon 2) RNAs by reverse transcription-polymerase chain reaction.
Results: The deletion in intron 1 had no effect on the alternative splicing while other deletions affected splicing (demonstrated by the presence of splicing intermediates) in cells cultured without insulin or with insulin for 1 week. The splicing intermediates were not seen from any construct when cells were cultured longer (14–21 days) with insulin.
Conclusion: These results show that the 259-bp intron 1, the 94-bp intron 2, and exon 2 sequences retained in the fourth construct provide cis-acting signal sufficient for insulin-induced cartilage-specific alternative splicing of Col2 pre-mRNA.
The Nitrogen-Containing Bisphosphonate, Zoledronic Acid, Influences RANKL Expression in Human Osteoblast-Like Cells by Activating TNF-α Converting Enzyme (TACE)
Authors: Pan Beiqing , Farrugia Amanda N , To Luen Bik , Findlay David M , Green Jonathan , Lynch Kevin , Zannettino Andrew CW 
Published: April 2006

Abstract
Bisphosphonates are used to prevent osteoclast-mediated bone loss. Zoledronic acid inhibits osteoclast maturation indirectly by increasing OPG protein secretion and decreasing transmembrane RANKL expression in human osteoblasts. The decreased transmembrane RANKL expression seems to be related to the upregulation of the RANKL sheddase, TACE.
Introduction: Bisphosphonates (BPs) exhibit high affinity for hydroxyapatite mineral in bone and are used extensively to treat malignancy-associated bone disease and postmenopausal bone loss by inhibiting osteoclast (OC)-mediated bone resorption.
Materials and Methods: We examined the effect of the most potent nitrogen-containing BP available, zoledronic acid (ZOL), on the expression of RANKL and osteoprotegerin (OPG), critical factors in the regulation of OC formation and activation, in primary osteoblast (OB)-like cells derived from human bone, using flow cytometry, ELISA, semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), in situ immunofluorescence staining, and Western blotting.
Results: Our studies show that ZOL, while not significantly affecting RANKL or OPG gene expression, markedly increased OPG protein secretion and reduced transmembrane RANKL protein expression in OB-like cells. The reduction in transmembrane RANKL expression was preceded by a marked increase in the expression of the metalloprotease-disintegrin, TNF-α converting enzyme (TACE). In addition, the decreased transmembrane expression of RANKL could be partially reversed by a TACE inhibitor, TAPI-2.
Conclusions: Our studies indicate that ZOL, in addition to its direct effects on mature OCs, may inhibit the recruitment and differentiation of OCs by cleavage of transmembrane RANKL in OB-like cells by upregulating the sheddase, TACE.
Identification of Promoter Regions Involved in Cell- and Developmental Stage-Specific Osteopontin Expression in Bone, Kidney, Placenta, and Mammary Gland: An Analysis of Transgenic Mice
Authors: Higashibata Yuji , Sakuma Takahiko , Kawahata Hirohisa , Fujihara Shinji , Moriyama Keiji , Okada Atsushi , Yasui Takahiro , Kohri Kenjiro , Kitamura Yukihiko , Nomura Shintaro 
Published: April 2006

Abstract
Cell-specific expression of GFP under the control of different lengths of the osteopontin promoter in transgenic mice identified the positive and negative regulatory regions for respective cell types. The results provide new insights for physiological and pathological expression of the osteopontin gene.
Introduction: Osteopontin (OPN) is a major non-collagenous bone matrix protein that is involved in normal and pathological calcification and is expressed in a tissue-specific manner. To investigate how such tissue-specific OPN gene expression is regulated in vivo, transgenic mice expressing the green fluorescent protein (GFP) reporter gene controlled by different lengths of the OPN promoter were generated.
Materials and Methods: Cell- and developmental stage-specific osteopontin expression in transgenic mice was examined by Northern blotting, immunoblotting, fluorescence examination, and in situ hybridization and compared with those of OPN.
Results and Conclusions: The line bearing the −5505 to +14 region of the OPN promoter was shown by Northern blotting and immunoblotting to express GFP in the same cells that express endogenous OPN (osteoblasts, hypertrophic chondrocytes, renal and mammary gland epithelial cells, and granulated metrial gland [GMG] placental cells) at the same stage in development. Thus, the 5.5-kb −5505 to +14 promoter region is sufficient for proper tissue-specific OPN expression. The lines carrying shorter segments of the OPN promoter showed different expression patterns. These patterns revealed a putative cis-acting element in the −5269 to −5263 region that restricts OPN expression to hypertrophic chondrocytes and a mammary gland-specific expressing element and a GMG cell-specific enhancing element in the −5505 to −3156 region. Furthermore, the −3155 to −1576 region seems to contain positive renal epithelial cell- and GMG cell-specific expression motif(s) as well as a negative regulatory element that prevents OPN expression in fibroblasts. Moreover, the −1576 to −910 region seems to contain a positive osteoblast-specific-expressing element. Thus, the 5.5-kb OPN promoter contains multiple cis-acting elements encoding positive and negative cell-specific regulatory systems.
Optimization of BMD Measurements to Identify High Risk Groups for Treatment—A Test Analysis
Authors: Johansson Helena , Oden Anders , Johnell Olof , Jonsson Bengt , de Laet Chris , Oglesby Alan , McCloskey Eugene V , Kayan Karthik , Jalava Tarja , Kanis John A 
Published: April 2006

Abstract
The aim of this study was to optimize the use of BMD measurements in case finding strategies. The use of clinical risk factors with and without BMD was explored in a random sample of the Sheffield female population ≥75 years of age. The use of clinical risk factors alone could identify women well above or well below a threshold of fracture risk. BMD assessment can be confined to a minority of women (∼20%) in whom the measurement aids in prognostication of fracture.
Introduction: The aim of this study was to develop a methodology to optimize the role of BMD measurements in a case finding strategy. We studied 2113 women ≥75 years of age randomly selected from Sheffield, UK, and adjacent regions. Baseline assessment included hip BMD and clinical risk factors. Outcomes included death and fracture in women followed for 6723 person-years.
Materials and Methods: Poisson models were used to identify significant risk factors for all fractures and for death with and without BMD and the hazard functions were used to compute fracture probabilities. Women were categorized by fracture probability with and without a BMD assessment. A 10-year fracture probability threshold of 35% was taken as an intervention threshold. Discordance in categorization of risk (i.e., above or below the threshold probability) between assessment with and without BMD was examined by logistic regression as probabilities of re-classification. Age, prior fracture, use of corticosteroids, and low body mass index were identified as significant clinical risk factors.
Results: A total of 16.8% of women were classified as high risk based on these clinical risk factors. The average BMD in these patients was ∼1 SD lower than in low-risk women; 21.5% of women were designated to be at high risk with the addition of BMD. Fifteen percent of all women were reclassified after adding BMD to clinical risk factors, most of whom lay near the intervention threshold. When a high probability of reclassification was accepted (without a BMD test) for high risk to low risk (p1 ≤ 0.8) and a low probability accepted for low to high risk (p2 ≤ 0.2), BMD tests would be required in only 21% of the population.
Conclusion: We conclude that the use of clinical risk factors can identify elderly women at high fracture risk and that such patients have a low average BMD. BMD testing is required, however, in a minority of women—a fraction that depends on the probabilities accepted for classification and the thresholds of risk chosen. These findings need to be validated in other cohorts at different ages and from different regions of the world.
How Many Women Have Osteoporosis?
Authors: Melton L. Joseph , Chrischilles Elizabeth A. , Cooper Cyrus , Lane Ann W. , Riggs B. Lawrence 
Published: April 2006

Abstract
Osteoporosis is widely viewed as a major public health concern, but the exact magnitude of the problem is uncertain and likely to depend on how the condition is defined. Noninvasive bone mineral measurements can be used to define a state of heightened fracture risk (osteopenia), or the ultimate clinical manifestation of fracture can be assessed (established osteoporosis). If bone mineral measurements more than 2 standard deviations below the mean of young normal women represent osteopenia, then 45% of white women aged 50 years and over have the condition at one or more sites in the hip, spine, or forearm on the basis of population-based data from Rochester, Minnesota. A smaller proportion is affected at each specific skeletal site: 32% have bone mineral values this low in the lumbar spine, 29% in either of two regions in the proximal femur, and 26% in the midradius. Although this overall estimate is substantial, some other serious chronic diseases are almost as common. More importantly, low bone mass is associated with adverse health outcomes, especially fractures. The lifetime risk of any fracture of the hip, spine, or distal forearm is almost 40% in white women and 13% in white men from age 50 years onward. If the enormous costs associated with these fractures are to be reduced, increased attention must be given to the design and implementation of control programs directed at this major health problem.
Desmoid Tumor With Ossification in Chest Wall: Possible Involvement of BAMBI Promoter Hypermethylation in Metaplastic Bone Formation
Authors: Kitazawa Sohei , Kitazawa Riko , Obayashi Chiho , Yamamoto Tetsuji 
Published: April 2006

Abstract
A rare case of desmoid-type fibromatosis with focal metaplastic bone in the chest wall suggested that enhanced responsiveness to BMP signaling by decreasing BAMBI expression through promoter hypermethylation plays a crucial role in the formation of metaplastic bone.
Introduction: Desmoid-type fibromatosis, originating from mesenchymal cells with myofibroblastic features, is a locally aggressive and frequently recurring infiltrative lesion. One such sporadic case with metaplastic ossification in the chest wall is presented.
Materials and Methods: A 43-year-old man was referred to the hospital with a gradually enlarging hard mass in the left anterolateral chest wall. A thoracotomy was carried out, and histopathological specimens were used for immunohistochemical, genetic, and methylation studies.
Results: Accumulation of altered β-catenin associated with a somatic heterozygous activating mutation in codon 41 was detected in the typical desmoid-type fibromatosis and at the ossifying focus. Among factors related to bone formation and the classical wnt-β-catenin signaling pathway, BMP and activin membrane-bound inhibitor (BAMBI) expression was specifically downregulated at the ossifying focus. Hypermethylation of the BAMBI promoter was observed in microdissected tissue from the ossifying focus but not in that from the typical desmoid-type fibromatosis.
Conclusions: Because both BMP and classical Wnt/β-catenin/LEF1 signaling cooperatively and mutually induce differentiation of mesenchymal cells into osteoblastic cells and promote bone formation, the epigenetic event leading to the enhanced responsiveness to BMP signaling may play a crucial role in the formation of metaplastic bone.
The theory of newsworthiness applied to Mexico's press. How the news factors influence foreign news coverage in a transitional country
Authors: Schwarz Andreas 
Published: April 2006

Abstract
Empirical studies which examine the theory of newsworthiness and the predictability of news coverage in transnational or developing countries still remain on the agenda of journalism research. Therefore, this study examines the influence of news factors on the foreign news coverage of three Mexican newspapers. Two main questions guide the research. First, is the theory of newsworthiness a valid approach for predicting news selection in a cultural context that is significantly different from western industrialized countries? Secondly, which are the relevant news factors that predict foreign news coverage in the Mexican press and thus shape the image of foreign nations? The results of a quantitative content analysis confirm the hypotheses of selection, additivity, and replication as they were originally postulated by Galtung and Ruge and thus prove the external validity of the theory of newsworthiness beyond western journalism.
Design eines Mobiltelefons für Senioren (Design of a Mobile Phone for Senior Citizens)
Authors: Baumann Konrad 
Published: April 2006

Zusammenfassung
Zu Beginn des Jahres 2005 können wir auf zehn Jahre Mobiltelefonie als Massenphänomen zurückblicken. Gleichzeitig gibt es immer noch zu wenige Mobiltelefone, die den Bedürfnissen der in der westlichen Welt anwachsenden Zielgruppe der Senioren entgegenkommen. Ein neuartiges Konzept von hoher Einfachheit führte zur Entwicklung eines Mobiltelefons bestehend aus Hardware, Software und Serviceangebot. Im Zuge des Designprojekts wurde eine Befragung der Zielgruppe mit interessanten Ergebnissen durchgeführt.
Opposite associations of age-dependent insulin-like growth factor-I standard deviation scores with nutritional state in normal weight and obese subjects
Authors: Schneider Harald Jörn , Saller Bernhard , Klotsche Jens , März Winfried , Erwa Wolfgang , Wittchen Hans-Ullrich , Stalla Günter Karl 
Published: April 2006

Objective: Insulin-like growth factor-I (IGF-I) has been suggested to be a prognostic marker for the development of cancer and, more recently, cardiovascular disease. These diseases are closely linked to obesity, but reports of the association of IGF-I with measures of obesity are divergent. In this study, we assessed the association of age-dependent IGF-I standard deviation scores with body mass index (BMI) and intra-abdominal fat accumulation in a large population.
Design: A cross-sectional, epidemiological study.
Methods: IGF-I levels were measured with an automated chemiluminescence assay system in 6282 patients from the DETECT study. Weight, height, and waist and hip circumference were measured according to the written instructions. Standard deviation scores (SDS), correcting IGF-I levels for age, were calculated and were used for further analyses.
Results: An inverse U-shaped association of IGF-I SDS with BMI, waist circumference, and the ratio of waist circumference to height was found. BMI was positively associated with IGF-I SDS in normal weight subjects, and negatively associated in obese subjects. The highest mean IGF-I SDS were seen at a BMI of 22.5–25 kg/m2 in men (+0.08), and at a BMI of 27.5–30 kg/m2 in women (+0.21). Multiple linear regression models, controlling for different diseases, medications and risk conditions, revealed a significant negative association of BMI with IGF-I SDS. BMI contributed most to the additional explained variance to the other health conditions.
Conclusions: IGF-I standard deviation scores are decreased in obesity and underweight subjects. These interactions should be taken into account when analyzing the association of IGF-I with diseases and risk conditions.
DAX1 and X-linked adrenal hypoplasia congenita: clinical and molecular analysis in five patients
Authors: Mantovani Giovanna , De Menis Ernesto , Borretta Giorgio , Radetti Giorgio , Bondioni Sara , Spada Anna , Persani Luca , Beck-Peccoz Paolo 
Published: April 2006

Objective: Mutations in the gene coding for the orphan nuclear receptor DAX1 cause X-linked adrenal hypoplasia congenita (AHC). Affected boys usually present with primary adrenal failure in early infancy or childhood. Impaired sexual development due to hypogonadotropic hypogonadism becomes manifest at the time of puberty. Moreover, evidence from Dax1 knockout mice and a limited number of patients with AHC, suggests that mutations in DAX1 may directly cause abnormalities in spermatogenesis. The aim of this study was to characterize clinically and genetically five patients with AHC.
Design: DNA sequencing analysis, endocrine testing, testicular ultrasound and semen analysis with 1-year follow-up after gonadotropin treatment.
Methods: We report on five men with classic AHC manifestations. Genomic DNA was extracted from patients’ peripheral blood leukocytes and the coding region, splice sites, and promoter (−240 bp) region of DAX1 were directly sequenced.
Results: Three known and two novel mutations were detected in the DAX1 coding sequence in these patients. Semen analysis was performed in four of the five patients and showed azoospermia. Twelvemonth treatment with gonadotropins did not restore fertility in these patients. All patients showed a normal testicular Doppler ultrasound, in contrast with that observed in Dax1-deficient mice, which display abnormalities in the rete testis.
Conclusions: These cases further expand the number of DAX1 mutations reported in the literature, as well as our clinical knowledge of this rare disease.
Mutations and sequence variants in GDF9 and BMP15 in patients with premature ovarian failure
Authors: Laissue Paul , Christin-Maitre Sophie , Touraine Philippe , Kuttenn Frederique , Ritvos Olli , Aittomaki Kristiina , Bourcigaux Nathalie , Jacquesson Laetitia , Bouchard Philippe , Frydman Rene , Dewailly Didier , Reyss Anne-Céline , Jeffery Luke , Bachelot Anne , Massin Nathalie , Fellous Marc , Veitia Reiner A 
Published: April 2006

Background and objective: Mutations in bone morphogenic protein 15 (BMP15) and growth/differentiation factor 9 (GDF9) lead to altered fertility in animal models. In the human, a heterozygous point mutation of BMP15 has been associated with premature ovarian failure (POF).
Subject and methods: We have directly sequenced both genes in a cohort of 203 POF patients presenting with primary or secondary amenorrhea and high FSH levels and in a control population including 54 women with regular menstrual cycles who had at least one child.
Results: We have identified several heterozygous variants. One alteration in GDF9 (S186Y) and one in BMP15 (L148P) may have pathogenic effects as both positions are conserved in vertebrate species, ranging from the chicken to mammals. These variants were absent in the control samples. We also found synonymous and neutral substitutions.
Conclusions: We propose that although mutations in BMP15 and GDF9 are not a major cause of ovarian insufficiency, they may be involved in POF.