bluuebunny/crossref_metadata_2025 huggingface dataset:
Prostasin attenuates inducible nitric oxide synthase expression in lipopolysaccharide-induced urinary bladder inflammation
Authors: Chen Li-Mei , Wang Cindy , Chen Mengqian , Marcello Matthew R. , Chao Julie , Chao Lee , Chai Karl X.
Published: April 2006

Prostasin is a glycosylphosphatidylinositol-anchored serine protease, with epithelial sodium channel activation and tumor invasion suppression activities. We identified the bladder as an expression site of prostasin. In the mouse, prostasin mRNA expression was detected by reverse transcription and real-time polymerase chain reaction in the bladder, and the prostasin protein was localized by immunohistochemistry in the urothelial cells. In mice injected intraperitoneally with bacterial lipopolysaccharide (LPS), bladder prostasin mRNA expression was downregulated, whereas the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interferon-γ (IFN-γ), TNF-α, IL-1β, and IL-6 was upregulated. Viral promoter-driven expression of the human prostasin homolog in the bladder of transgenic mice attenuated the LPS induction of iNOS but did not abolish the induction. LPS induction of COX-2, TNF-α, IL-1β, and IL-6 expression, however, was not reduced by prostasin transgene expression. Liposome-mediated delivery of prostasin-expressing plasmid into mouse bladder produced similar attenuation effects on LPS-induced iNOS expression, while not affecting COX-2 or cytokine induction. Mice receiving plasmid expressing a catalytic mutant prostasin did not manifest the iNOS induction attenuation phenotype. We propose a proteolytic mechanism for prostasin to intercept cytokine signaling during LPS-induced bladder inflammation.
Time–Space Characteristics of Diurnal Rainfall over Borneo and Surrounding Oceans as Observed by TRMM-PR
Authors: Ichikawa Hiroki , Yasunari Tetsuzo
Published: April 2006

Five years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data were used to investigate the time and space characteristics of the diurnal cycle of rainfall over and around Borneo, an island in the Maritime Continent. The diurnal cycle shows a systematic modulation that is associated with intraseasonal variability in the large-scale circulation pattern, with regimes associated with low-level easterlies or westerlies over the island. The lower-tropospheric westerly (easterly) components correspond to periods of active (inactive) convection over the island that are associated with the passage of intraseasonal atmospheric disturbances related to the Madden–Julian oscillation. A striking feature is that rainfall activity propagates to the leeward side of the island between midnight and morning. The inferred phase speed of the propagation is about 3 m s−1 in the easterly regime and 7 m s−1 in the westerly regime. Propagation occurs over the entire island, causing a leeward enhancement of rainfall. The vertical structure of the developed convection/rainfall system differs remarkably between the two regimes. In the easterly regime, stratiform rains are widespread over the island at midnight, whereas in the westerly regime, local convective rainfall dominates. Over offshore regions, convective rainfall initially dominates then gradually decreases in both regimes, while the storms develop into deeper convective systems in the easterly regime. Aside from leeward rainfall propagation, shallow storms develop over the South China Sea region during the westerly regime, resulting in heavy precipitation from midnight through morning.
The Sustainable Development of U.S. Air Transportation
Authors: Bartle John R.
Published: April 2006

Sustainable development is a concept that has had great influence on natural resource policy; however, to date, it has had limited influence on transportation. This article examines how well U.S. air transportation practice meets the goal of sustainability and finds current practice to be unsustainable. Forecasted trends suggest that this problem will get worse. Neither current pollution control policies nor technological progress are sufficient to solve the problem. One potential solution is reduced use of air travel, however, the goals of mobility and speed of travel would be inhibited. Taxes could reduce the external costs caused by air pollution, however, there are administrative and political barriers to this. Institutional reform seems to be the logical solution, and the process to achieve this reform is described.
Sustainable Development in Public Administration
Authors: Leuenberger Deniz
Published: April 2006

Sustainability and sustainable development are concepts that are increasingly used in the field of public administration. In considering long-run planning, intergenerational equity, reduction of risk, and conservation of resources in administrative planning, sustainability may have a significant contributory role. This article traces the link between the principles of sustainable development and the tenets of public administration. In the application of broad-based sustainable development, it finds the reflection of efficiency, effectiveness, and citizen participation. By asking, Are the goals of sustainable development a match with public administration practice?, it finds that sustainable development may be applied to much of the work of the public sector, including to the provision of transportation, public housing, human services, and environmental protection. Finally, it suggests the unique contribution of sustainability to the field of public administration.
A Self-Financing, Multimodal, Public–Private Partnership Approach to Restore Metropolitan Mobility
Authors: DeCorla-Souza Patrick
Published: April 2006

The operate-design-build-operate concept presented in this article involves introducing rush-hour tolls prior to infrastructure investment to manage demand, with surplus revenue dedicated for infrastructure expansion. Not only would the existing highway system operate more efficiently, but so would the improved system. This approach provides up-front toll revenue to help pay for expensive urban freeway expansion projects, making them more financially feasible. The approach can facilitate private involvement in the delivery of integrated roadway pricing and transit and high-occupancy-vehicle systems in metropolitan areas. New public-private partnership approaches are suggested that employ outcome-based contracting systems and financial incentives to maximize public mobility goals. An illustrative application at the regionwide level is discussed.
A novel scoring schema for peptide identification by searching protein sequence databases using tandem mass spectrometry data
Authors: Zhang Zhuo , Sun Shiwei , Zhu Xiaopeng , Chang Suhua , Liu Xiaofei , Yu Chungong , Bu Dongbo , Chen Runsheng
Published: April 2006

Background

Tandem mass spectrometry (MS/MS) is a powerful tool for protein identification. Although great efforts have been made in scoring the correlation between tandem mass spectra and an amino acid sequence database, improvements could be made in three aspects, including characterization ofpeaks in spectra, adoption of effective scoring functions and access to thereliability of matching between peptides and spectra.

Results

A novel scoring function is presented, along with criteria to estimate the performance confidence of the function. Through learning the typesof product ions and the probability of generating them, a hypothetic spectrum was generated for each candidate peptide. Then relative entropy was introduced to measure the similarity between the hypothetic and the observed spectra. Based on the extreme value distribution (EVD) theory, a threshold was chosen to distinguish a true peptide assignment from a random one. Tests on a public MS/MS dataset demonstrated that this method performs better than the well-known SEQUEST.

Conclusion

A reliable identification of proteins from the spectra promises a more efficient application of tandem mass spectrometry to proteomes with high complexity.
CGHScan: finding variable regions using high-density microarray comparative genomic hybridization data
Authors: Anderson Bradley D , Gilson Michael C , Scott Abigail A , Biehl Bryan S , Glasner Jeremy D , Rajashekara Gireesh , Splitter Gary A , Perna Nicole T
Published: April 2006

Background

Comparative genomic hybridization can rapidly identify chromosomal regions that vary between organisms and tissues. This technique has been applied to detecting differences between normal and cancerous tissues in eukaryotes as well as genomic variability in microbial strains and species. The density of oligonucleotide probes available on current microarray platforms is particularly well-suited for comparisons of organisms with smaller genomes like bacteria and yeast where an entire genome can be assayed on a single microarray with high resolution. Available methods for analyzing these experiments typically confine analyses to data from pre-defined annotated genome features, such as entire genes. Many of these methods are ill suited for datasets with the number of measurements typical of high-density microarrays.

Results

We present an algorithm for analyzing microarray hybridization data to aid identification of regions that vary between an unsequenced genome and a sequenced reference genome. The program, CGHScan, uses an iterative random walk approach integrating multi-layered significance testing to detect these regions from comparative genomic hybridization data. The algorithm tolerates a high level of noise in measurements of individual probe intensities and is relatively insensitive to the choice of method for normalizing probe intensity values and identifying probes that differ between samples. When applied to comparative genomic hybridization data from a published experiment, CGHScan identified eight of nine known deletions in a Brucella ovis strain as compared to Brucella melitensis. The same result was obtained using two different normalization methods and two different scores to classify data for individual probes as representing conserved or variable genomic regions. The undetected region is a small (58 base pair) deletion that is below the resolution of CGHScan given the array design employed in the study.

Conclusion

CGHScan is an effective tool for analyzing comparative genomic hybridization data from high-density microarrays. The algorithm is capable of accurately identifying known variable regions and is tolerant of high noise and varying methods of data preprocessing. Statistical analysis is used to define each variable region providing a robust and reliable method for rapid identification of genomic differences independent of annotated gene boundaries.
Spatial analysis of hemorrhagic fever with renal syndrome in China
Authors: Fang Liqun , Yan Lei , Liang Song , de Vlas Sake J , Feng Dan , Han Xiaona , Zhao Wenjuan , Xu Bing , Bian Ling , Yang Hong , Gong Peng , Richardus Jan Hendrik , Cao Wuchun
Published: April 2006

Background

Hemorrhagic fever with renal syndrome (HFRS) is endemic in many provinces with high incidence in mainland China, although integrated intervention measures including rodent control, environment management and vaccination have been implemented for over ten years. In this study, we conducted a geographic information system (GIS)-based spatial analysis on distribution of HFRS cases for the whole country with an objective to inform priority areas for public health planning and resource allocation.

Methods

Annualized average incidence at a county level was calculated using HFRS cases reported during 1994–1998 in mainland China. GIS-based spatial analyses were conducted to detect spatial autocorrelation and clusters of HFRS incidence at the county level throughout the country.

Results

Spatial distribution of HFRS cases in mainland China from 1994 to 1998 was mapped at county level in the aspects of crude incidence, excess hazard and spatial smoothed incidence. The spatial distribution of HFRS cases was nonrandom and clustered with a Moran's I = 0.5044 (p = 0.001). Spatial cluster analyses suggested that 26 and 39 areas were at increased risks of HFRS (p < 0.01) with maximum spatial cluster sizes of ≤ 20% and ≤ 10% of the total population, respectively.

Conclusion

The application of GIS, together with spatial statistical techniques, provide a means to quantify explicit HFRS risks and to further identify environmental factors responsible for the increasing disease risks. We demonstrate a new perspective of integrating such spatial analysis tools into the epidemiologic study and risk assessment of HFRS.
In vitrocomparison of antiviral drugs against feline herpesvirus 1
Authors: van der Meulen K , Garré B , Croubels S , Nauwynck H
Published: April 2006

Background

Feline herpesvirus 1 (FHV-1) is a common cause of respiratory and ocular disease in cats. Especially in young kittens that have not yet reached the age of vaccination, but already lost maternal immunity, severe disease may occur. Therefore, there is a need for an effective antiviral treatment. In the present study, the efficacy of six antiviral drugs, i.e. acyclovir, ganciclovir, cidofovir, foscarnet, adefovir and 9-(2-phosphonylmethoxyethyl)-2, 6-diaminopurine (PMEDAP), against FHV-1 was compared in Crandell-Rees feline kidney (CRFK) cells using reduction in plaque number and plaque size as parameters.

Results

The capacity to reduce the number of plaques was most pronounced for ganciclovir, PMEDAP and cidofovir. IC50 (NUMBER)values were 3.2 μg/ml (12.5 μM), 4.8 μg/ml (14.3 μM) and 6 μg/ml (21.5 μM), respectively. Adefovir and foscarnet were intermediately efficient with an IC50 (NUMBER)of 20 μg/ml (73.2 μM) and 27 μg/ml (140.6 μM), respectively. Acyclovir was least efficient (IC50 (NUMBER)of 56 μg/ml or 248.7 μM). All antiviral drugs were able to significantly reduce plaque size when compared with the untreated control. As observed for the reduction in plaque number, ganciclovir, PMEDAP and cidofovir were most potent in reducing plaque size. IC50 (SIZE)values were 0.4 μg/ml (1.7 μM), 0.9 μg/ml (2.7 μM) and 0.2 μg/ml (0.7 μM), respectively. Adefovir and foscarnet were intermediately potent, with an IC50 (SIZE)of 4 μg/ml (14.6 μM) and 7 μg/ml (36.4 μM), respectively. Acyclovir was least potent (IC50 (SIZE)of 15 μg/ml or 66.6 μM). The results demonstrate that the IC50 (SIZE)values were notably lower than the IC50 (NUMBER)values. The most remarkable effect was observed for cidofovir and ganciclovir. None of the products were toxic for CRFK cells at antiviral concentrations.

Conclusion

In conclusion, measuring reduction in plaque number and plaque size are two valuable and complementary means of assessing the efficacy of an antiviral drug. By using these parameters for six selected antiviral drugs, we found that ganciclovir, PMEDAP, and cidofovir are the most potent inhibitors of FHV-1 replication in CRFK cells. Therefore, they may be valuable candidates for the treatment of FHV-1 infection in cats.
Hyperkalemia of the blood-primed ECLS circuit does not result in post-initiation hyperkalemia in infants < 10 kg
Authors: Fleming Geoffrey M , Remenapp Robert T , Bartlett Robert H , Annich Gail M
Published: April 2006

Objective: To assess the risk of hyperkalemia with blood-primed extracorporeal life support (ECLS) circuits in infants < 10 kg.

Design: Retrospective cohort study of all neonatal and pediatric patients <10 kg placed on ECLS from May 1998 to April 2001.

Measurements and main results: Data collection including patient weight, patient potassium levels pre- and post-initiation of ECLS, potassium level of the primed ECLS circuit, age of the packed red blood cell (PRBC) unit, type of preservative, and preservative reduction status. Seventy-six circuits were available for the analysis. The age of the PRBC unit and preservative reduction status significantly affected the potassium level of the primed ECLS circuit. Multivariate linear regression analysis showed no significant effect on the post-ECLS initiation patient potassium level with respect to the PRBC age, the preservative reduction status, the patient potassium level prior to ECLS initiation, and the potassium level of the primed ECLS circuit.

Conclusions: Initiation of ECLS in infants <10 kg should not be delayed unnecessarily to perform preservative reduction or to utilize PRBC units of a specific age, as hyperkalemia of the primed ECLS circuit is not associated with systemic hyperkalemia in the patient post-initiation of ECLS.
Myocardial protective effects of nicorandil, an opener of potassium channels on senile rat heart
Authors: Liu Jinping , Long Cun , Ji Bingyang , Zhang Hongjia , Wen Fuxing
Published: April 2006

The purpose of this study was to investigate the cardio-protective effects of nicorandil, an opener of potassium channels, on senile rat hearts from ischemic reperfusion injury.

A modified working model of isolated perfused hearts of senile rats was used. After isolation, the hearts underwent 60 min of global hypothermic ischemia treatment, followed by 30 min of reperfusion. These hearts were distributed into three groups, each receiving different cardioplegic solutions: (1) St. Thomas’ solution (Group S), (2) 100 μmol/L nicorandil (Group N), (3) St. Thomas’ solution combined with 100 μmol/L nicorandil (Group S+N). The pre- and post-ischemic myocardial function were assessed by the percentage recovery of the heart rate (HR), ±dp/dtmax (maximal rate of change of left ventricular pressure) and cardiac output (CO). Upon reperfusion, the cardioplegic solution was collected from the coronary sinus and tested for lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) activity.

During 30 min of reperfusion, the percentage recovery of HR, +dp/dt and left ventricular stroke work (LVSW) were significantly higher in Group S+N than in Group S and Group N ( p < 0.05). The percentage of recovery in CO was higher in Group N and Group S+N than in Group S. The electrical activities arresting time (EAT) and mechanical activities arresting time (MAT) were longer in Group N than in Group S and Group N+S( p < 0.01). There were no statistical significance between Group S and Group N+ S( p > 0.05). There were no significant differences in the levels of LDH and CK-MB. Electron microscopic examination revealed better preservation of the ultra-structures of the myocardial tissue in Group N+S than the other two groups.

These results indicate that nicorandil combined with St. Thomas’ solution can improve the left ventricular function of the post-ischemic senile rat and offer a better myocardial protective effect on the ischemic senile myocardium.
Molecular Design of a Calix[6]arene-Based Super-Uranophile with C3 Symmetry. High UO22+ Selectivity in Solvent Extraction
Authors: Araki Koji , Hashimoto Norifumi , Otsuka Hideyuki , Nagasaki Takeshi , Shinkai Seiji
Published: April 2006

Calix[6]arene bearing three carboxylate groups arranged in C3 symmetry formed a 1 : 1 complex with UO22+ and showed much more excellent selectivity factors for UO22+ in solvent extraction than calix[6]arene bearing six carboxylate groups. This establishes that the essence of “super-uranophiles” is related to the molecular design of C3 symmetry.
Synthesis of the Tetrahydropyran Ring Part of a Marine Toxin Polycavernoside-A
Authors: Fujiwara Kenshu , Amano Seiji , Oka Takahiro , Murai Akio
Published: April 2006

Construction of the tetrahydropyran ring part of polycavernoside A, which has been isolated as one of toxic principles from the red alga Polycavernosa tsudai, is described starting from (S)-(−)- and (R)-(+)-glycidols.
Pd-Catalyzed Cycloaddition of Vinylcyclopentenes with Trimethylenemethane. Substituent Effect on [4+3] vs [3+2] Selectivity
Authors: Trost Barry M , Yamazaki Shoko
Published: April 2006

The Pd-catalyzed reaction of 2-vinylcyclopentenes 2 and 3 with trimethylenemethane gave [4+3] and [3+2] cycloadducts. Derivatization of 2-vinylcyclopentenones with bulky ketal substituents served to enhance seven-membered ring formation.
Effects of Calcitonin on Subchondral Trabecular Bone Changes and on Osteoarthritic Cartilage Lesions After Acute Anterior Cruciate Ligament Deficiency
Authors: Behets Catherine , Williams James M , Chappard Daniel , Devogelaer Jean-Pierre , Manicourt Daniel-Henri
Published: April 2006

Because SBM may contribute to cartilage breakdown in OA, experimental OA was induced in dogs by transecting the anterior cruciate ligament of the knee and treating with either CT or a placebo. CT significantly reduced both SBM and cartilage lesions. This study supports the use of CT in the treatment of canine experimental OA.

Introduction: Because subchondral bone remodeling (SBM) may contribute to cartilage breakdown in osteoarthritis (OA), we evaluated to what extend calcitonin (CT) might affect cartilage and bone changes in the early stages of canine experimental OA.

Materials and Methods: Twelve dogs underwent transection of the anterior cruciate ligament (ACLT) of the right knee. After ACLT, each animal received a daily nasal spray delivering either 400 U of CT (CT-treated group; n = 6) or a placebo (PL-treated group; n = 6). At day 84 after surgery, animals were killed, and cartilage changes were graded. BMD and volume fraction (BVF) were assessed by pQCT in different regions of interest (ROIs) of the subchondral cancellous bone of tibial plateaus (TPs). Statistics included a 2 × 2 factorial analysis with ±CT as one factor and ±ACLT as the other.

Results and Conclusions: Nonoperated (N-OP) knees were normal in both groups. In the PL-treated group, ACLT knees all exhibited OA changes, which predominated in the medial knee compartment. Furthermore, compared with N-OP knees, the BMD and BVF of ACLT joints were both markedly reduced in medial TP but not in lateral TP. In contrast, in the CT-treated group, cartilage OA lesions of ACLT knees were significantly reduced, and there was no difference in BMD and BFV between N-OP and ACLT knees. These findings suggest that the loss of subchondral trabeculae contributes to cartilage breakdown, possibly by enhancing cartilage deformation on joint loading. By counteracting bone loss, CT reduced cartilage OA lesions, and thus, might be useful in the treatment of OA in cruciate-deficient dogs.
Decreased Collagen Organization and Content Are Associated With Reduced Strength of Demineralized and Intact Bone in the SAMP6 Mouse
Authors: Silva Matthew J , Brodt Michael D , Wopenka Brigitte , Thomopoulos Stavros , Williams Derek , Wassen Maurice HM , Ko Mike , Kusano Nozomu , Bank Ruud A
Published: April 2006

To examine the link between bone material properties and skeletal fragility, we analyzed the mechanical, histological, biochemical, and spectroscopic properties of bones from a murine model of skeletal fragility (SAMP6). Intact bones from SAMP6 mice are weak and brittle compared with SAMR1 controls, a defect attributed to reduced strength of the bone matrix. The matrix weakness is attributed primarily to poorer organization of collagen fibers and reduced collagen content.

Introduction: The contribution of age-related changes in tissue material properties to skeletal fragility is poorly understood. We previously reported that bones from SAMP6 mice are weak and brittle versus age-matched controls. Our present objectives were to use the SAMP6 mouse to assess bone material properties in a model of skeletal fragility and to relate defects in the mechanical properties of bone to the properties of demineralized bone and to the structure and organization of collagen and mineral.

Materials and Methods: Femora from 4- and 12-month-old SAMR1 (control) and SAMP6 mice were analyzed using bending and torsional mechanical testing of intact bones, tensile testing of demineralized bone, quantitative histology (including collagen fiber orientation), collagen cross-links biochemistry, and Raman spectroscopic analysis of mineral and collagen.

Results: Intact bones from SAMP6 mice have normal elastic properties but inferior failure properties, with 60% lower fracture energy versus SAMR1 controls. The strength defect in SAMP6 bones was associated with a 23% reduction in demineralized bone strength, which in turn was associated with poorer collagen fiber organization, lower collagen content, and higher hydroxylysine levels. However, SAMP6 have normal levels of collagen cross-links and normal apatite mineral structure.

Conclusions: Bones from SAMP6 osteoporotic mice are weak and brittle because of a defect in the strength of the bone matrix. This defect is attributed primarily to poorer organization of collagen fibers and reduced collagen content. These findings highlight the role of the collagen component of the bone matrix in influencing skeletal fragility.
CCR1 Acts Downstream of NFAT2 in Osteoclastogenesis and Enhances Cell Migration
Authors: Ishida Norihiro , Hayashi Koji , Hattori Asuka , Yogo Keiichiro , Kimura Toru , Takeya Tatsuo
Published: April 2006

We found that a chemokine receptor gene, CCR1, acts downstream of NFAT2 in RANKL-stimulated RAW264 and bone marrow cells. The upstream regulatory region of CCR1 showed RANKL-dependent and CsA-suppressible promoter activity. Downregulation of the expression and function of CCR1 suppressed cell migration.

Introduction: We previously reported that the expression of NFAT2 induced by RANKL is a key process for progression to multinucleated cells in an in vitro osteoclastogenesis system. Identifying the target genes of NFAT2 would thus be informative about the differentiation process. We focused here on chemokine and chemokine receptor genes that act downstream of NFAT2 in RAW264 cells as well as osteoclast precursors prepared from bone marrow cells.

Materials and Methods: RAW264 mouse monocyte/macrophage line cells were cultured with or without cyclosporin A (CsA) in the presence of RANKL or glutathione S-transferase (GST). Osteoclast precursors were prepared from bone marrow cells. RANKL-inducible and CsA-suppressible genes were searched for by microarray analysis, and expression was confirmed by quantitative RT-PCR. Promoter activity was measured by luciferase gene reporter assay. Short interfering (si)RNA for CCR1 was introduced in RAW264 cells. Cell migration activity was examined using a Boyden chamber assay.

Results and Conclusions: We identified the chemokine receptor gene CCR1 as a gene showing significant differential expression profiles in osteoclastogenesis in the presence versus the absence of CsA, an inhibitor of NFAT. This property was unique to CCR1 among the chemokine and chemokine receptor genes examined in both RAW264 and bone marrow cells. The upstream regulatory region was isolated from CCR1, and its RANKL-dependent and CsA-suppressible promoter activity was confirmed. The functional significance of CCR1 was assessed by monitoring the migration of cells in a transwell migration assay, and this activity was abolished when either CsA- or CCR1 siRNA-treated cells were used. Moreover, treatment with a Gα inhibitor pertussis toxin (PTX) or methiolynated-regulated on activation, normal T cells expressed and secreted (Met-RANTES), an antagonist of CCR1, suppressed multinucleated cell formation in the bone marrow cell system. Together, these results suggest that the CCR1 signaling cascade is under the control of NFAT2 and seems to enhance the migration of differentiating osteoclasts.
A Novel Tetracycline Labeling Schedule for Longitudinal Evaluation of the Short-Term Effects of Anabolic Therapy With a Single Iliac Crest Bone Biopsy: Early Actions of Teriparatide
Authors: Lindsay Robert , Cosman Felicia , Zhou Hua , Bostrom Mathias P , Shen Victor W , Cruz JoAnn D , Nieves Jeri W , Dempster David W
Published: April 2006

We describe a quadruple tetracycline labeling method that allows longitudinal assessment of short-term changes in bone formation in a single biopsy. We show that 1 month of hPTH(1-34) treatment extends the bone-forming surface, increases mineral apposition rate, and initiates modeling-based formation.

Introduction: Iliac crest biopsy, with histomorphometric evaluation, provides important information about cellular activity in bone. However, to obtain longitudinal information, repeat biopsies must be performed. In this study, we show the capability to obtain short-term longitudinal information on bone formation in a single biopsy using a novel, quadruple labeling technique.

Materials and Methods: Two tetracycline labels were administered using a standard 3 days on, 12 days off, 3 days on format. Four weeks later, the tetracycline labeling was repeated using the same schedule but with a different tetracycline that can be distinguished from the first by its color under fluorescent light. Iliac crest biopsies were performed 1 week later and prepared undecalcified for histomorphometry. Indices of bone formation 1 month apart were measured and calculated using the two sets of labels. We used this method to investigate the early effects of teriparatide [hPTH(1-34)] treatment on bone formation. The results were compared with those from a group of control subjects who were quadruple-labeled, but did not receive hPTH(1-34).

Results: Treatment with hPTH(1-34) dramatically stimulated bone formation on cancellous and endocortical surfaces. This was achieved by both an increase in the linear rate of matrix apposition and extension of the bone-forming surface. New bone was deposited on previously quiescent surfaces (i.e., modeling-based formation), but a proportion of this could occur by encroachment from adjacent resorption cavities.

Conclusions: A single transiliac crest bone biopsy, after sequential administration of two sets of tetracycline labels is a useful approach to study the short-term effects of anabolic agents on human bone. One month of hPTH(1-34) treatment extends the bone-forming surface, increases mineral apposition rate, and initiates modeling-based formation.
Short-Term Intravenous Bisphosphonates in Prevention of Postmenopausal Bone Loss
Authors: Heikkinen Jorma E. , Selander Katri S. , Laitinen Kalevi , Arnala Ilkka , Dr. Väänänen H. Kalervo
Published: April 2006

This study was performed to test the efficacy of short-term intravenous clodronate and etidronate in the prevention of postmenopausal bone loss. Healthy postmenopausal women, exhibiting a decreasing trend in bone mineral density, were randomized to five groups (clodronate at doses of 150, 300, and 600 mg; etidronate at a dose of 300 mg; and a placebo group) of 21–22 subjects. The drugs were administered intravenously three times with 1-week intervals, followed by regular evaluation for up to 24 months. During the first year, 300 mg of clodronate retarded bone loss significantly in the lumbar spine and femoral neck, where significant protection still persisted after 24 months. Other doses of clodronate (150 and 600 mg) were not bone protective. Etidronate (300 mg) retarded bone loss significantly in the lumbar spine up to 24 months, relative to placebo. Serum concentrations of procollagen I carboxy-terminal propeptide and urinary Ca2+ and hydroxyproline excretion decreased in all bisphosphonate groups during the first month after treatment, but the values returned later toward baseline. In the etidronate-group, serum osteocalcin concentrations also decreased significantly during the first 3 months of the study. Otherwise, no uniform serum responses to bisphosphonate-treatment were detected in circulating markers of bone formation, alkaline phosphatase, or osteocalcin. No significant differences in the serum concentrations of cross-linked carboxy-terminal telopeptide of type I collagen were detected between the groups. Patient acceptance of both bisphosphonates was excellent, and no drug-related adverse side effects were detected. These results suggest that infrequently repeated intravenous treatment with bisphosphonates may effectively counteract postmenopausal bone loss.
Bone Microdamage and Skeletal Fragility in Osteoporotic and Stress Fractures
Authors: Burr David B. , Forwood Mark R. , Fyhrie David P. , Martin R. Bruce , Schaffler Mitchell B. , Turner Charles H.
Published: April 2006

The accumulation of bone microdamage has been proposed as one factor that contributes to increased skeletal fragility with age and that may increase the risk for fracture in older women. This paper reviews the current status and understanding of microdamage physiology and its importance to skeletal fragility. Several questions are addressed: Does microdamage exist in vivo in bone? If it does, does it impair bone quality? Does microdamage accumulate with age, and is the accumulation of damage with age sufficient to cause a fracture? The nature of the damage repair mechanism is reviewed, and it is proposed that osteoporotic fracture may be a consequence of a positive feedback between damage accumulation and the increased remodeling space associated with repair.
Increased Adipogenesis and Myelopoiesis in the Bone Marrow of SAMP6, a Murine Model of Defective Osteoblastogenesis and Low Turnover Osteopenia
Authors: Kajkenova Oumitana , Lecka-Czernik Beata , Gubrij Igor , Hauser Simon P. , Takahashi Kenshirou , Parfitt A. Michael , Jilka Robert L. , Manolagas Stavros C. , Lipschitz David A.
Published: April 2006

Bone formation and hematopoiesis are anatomically juxtaposed and share common regulatory mechanisms. However, little is known about the interrelationship between these two processes. We have previously shown that the senescence accelerated mouse-P6 (SAMP6) exhibits decreased osteoblastogenesis in the bone marrow that is temporally linked with a low rate of bone formation and decreased bone mineral density. Here we report that in contrast to decreased osteoblastogenesis, ex vivo bone marrow cultures from SAMP6 mice exhibited an increase in the number of colony-forming unit adipocytes, as well as an increase in the number of fully differentiated marrow adipocytes, compared with SAMR1 (nonosteopenic) controls. Further, long-term bone marrow cultures from SAMP6 produced an adherent stromal layer more rapidly, generated significantly more myeloid progenitors and produced more IL-6 and colony-stimulating activity. Consistent with this, the number of myeloid cells in freshly isolated marrow from SAMP6 mice was increased, as was the number of granulocytes in peripheral blood. The evidence that SAMP6 mice exhibit decreased osteoblastogenesis, and increased adipogenesis and myelopoiesis, strongly suggests that a switch in the differentiation program of multipotential mesenchymal progenitors may underlie the abnormal phenotype manifested in the skeleton and other tissues of these animals. Moreover, these observations support the contention for the existence of a reciprocal relationship between osteoblastogenesis and adipogenesis that may explain the association of decreased bone formation and the resulting osteopenia with the increased adiposity of the marrow seen with advancing age in animals and humans.
Cloning and Characterization of a Calcium-Sensing Receptor from the Hypercalcemic New Zealand White Rabbit Reveals Unaltered Responsiveness to Extracellular Calcium
Authors: Butters Robert R. , Chattopadhyay Naibedya , Nielsen Palle , Smith Craig P. , Mithal Ambrish , Kifor Olga , Bai Mei , Quinn Steven , Goldsmith Paul , Hurwitz Shmuel , Krapcho Karen , Busby James , Brown Edward M.
Published: April 2006

The extracellular Ca2+ (Ca   0 2+ )-sensing receptor (CaR) recently cloned from mammalian parathyroid, kidney, brain, and thyroid plays a central role in maintaining near constancy of Ca   0 2+ . We previously showed that the hypercalcemia normally present in New Zealand white rabbits is associated with an elevated set point for Ca   0 2+ -regulated PTH release (the level of Ca   0 2+ half-maximally inhibiting hormonal secretion). This observation suggested an alteration in the Ca   0 2+ -sensing mechanism in the rabbit parathyroid, a possibility we have now pursued by isolating and characterizing the rabbit homolog of the CaR. The cloned rabbit kidney CaR (RabCaR) shares a high degree of overall homology (>90% amino acid identity) with the bovine, human, and rat CaRs, although it differs slightly in several regions of the extracellular domain potentially involved in binding ligands. By Northern analysis and/or immunohistochemistry, a similar or identical receptor is also expressed in parathyroid, thyroid C cells, small and large intestine, and in the thick ascending limb and collecting ducts of the kidney. When expressed transiently in HEK293 cells and assayed functionally through CaR agonist-evoked increases in Ca   i 2+ , the rabbit CaR shows apparent affinities for Ca   0 2+ , Mg   0 2+ , and Gd   0 3+ that are indistinguishable from those observed in studies carried out concomitantly using the human CaR. Therefore, at least as assessed by its ability to increase Ca   i 2+ when expressed in HEK293 cells, the intrinsic functional properties of the rabbit CaR cannot explain the hypercalcemia observed in vivo in the New Zealand white rabbit.
Long-Term Changes in Bone Mineral and Biomechanical Properties of Vertebrae and Femur in Aging, Dietary Calcium Restricted, and/or Estrogen-Deprived/-Replaced Rats
Authors: Jiang Yebin , Zhao Jenny , Genant Harry K. , Dequeker Jan , Geusens Piet
Published: April 2006

To study the long-term effect of aging, low calcium diet (LCD) and/or ovariectomy (OVX), and estrogen replacement therapy (+E) on rat bone quality of both trabecular and cortical bone, 150 female Wistar rats of 4.5 months were divided into baseline, sham-operation (sham), sham + LCD, OVX, OVX + E, OVX + LCD, OVX + LCD + E, and were observed for 3, 6, and 9 months postsurgery. The bone mineral density (BMD) of the lumbar spine L1–L4, the femoral neck, the midshaft, and the distal metaphysis were determined using dual-energy X-ray absorptiometry (DXA) in vitro. Biomechanical tests of the L1 vertebral body and the left femur were performed. The right femoral midshaft and neck were processed undecalcified for determining cross-sectional moments of inertia (CSMIs). BMD in all groups increased rapidly with aging in the femoral midshaft composed only of cortical bone at 3 months post-OVX and stabilized or decreased thereafter, but decreased at all observation periods in the distal femoral metaphysis, consisting mostly of trabecular bone. L1 maximum compressive strength and stiffness increased as a function of aging in sham and sham + LCD but not in OVX and OVX + LCD. The order of loss in BMD at all sites and in L1 strength and stiffness was: OVX + LCD > OVX > LCD. LCD reduced while OVX improved the total femoral area, CSMIs in the femoral midshaft, and the torsional strength. Estrogen treatment preserved BMD and prevented OVX-induced loss in L1 strength. The BMD and biomechanical properties were greater in OVX + E than in OVX + LCD + E. Loss in BMD and CSMIs was greater in the femoral neck than in the midshaft. The data suggest that rat cortical bone might not be matured until 7.5 months of age. It would be more appropriate to consider rats at peak bone mass as a model of mature rat and to perform OVX at that time. LCD and OVX have a great potential for weakening the bone quality of cortical bone and trabecular bone, respectively, and have an additive effect when combined. Estrogen prevents only OVX-induced bone loss.
The Functional Block of TNF but Not of IL-6 Prevents Bone Loss in Ovariectomized Mice
Authors: Kimble Robert B. , Bain Steve , Pacifici Roberto
Published: April 2006

Considerable evidence supports the hypothesis that estrogen prevents bone loss by blocking the bone marrow cell production of pro-osteoclastogenic cytokines. However, controversy remains on the role of candidate factors, such as tumor necrosis factor (TNF) and interleukin-6 (IL-6). To investigate the contribution of these cytokines to the pathogenesis of ovariectomy (OVX)-induced bone loss, OVX mice were treated with either TNF binding protein (TNFbp), an inhibitor of TNF, the anti–(IL-6) antibody (Ab) 20F3, or estrogen for the first 2 weeks after surgery. OVX caused a rapid decrease in trabecular bone volume (TBV) and an increase in in vivo bone resorption, as assessed by bone histomorphometry. Treatment with TNFbp completely prevented bone loss and the increase in both osteoclast formation and bone resorption induced by OVX, but had no effects in sham-operated controls. In contrast, treatment with anti–IL-6 antibody failed to prevent bone loss, and the increase in bone resorption and osteoclastogenesis induced by OVX. These data demonstrate that in nongenetically manipulated mice, the estrogen-regulated cytokine that plays a central role in the mechanism by which estrogen deficiency causes bone loss is not IL-6, but rather TNF.
Attitudes and Beliefs of Family Physicians and Gynecologists in Relation to the Prevention and Treatment of Osteoporosis
Authors: Suarez-Almazor Maria , Homik Joanne E. , Messina Daniel , Davis Paul
Published: April 2006

The objective of this study was to evaluate the attitudes and beliefs of primary care physicians (PCPs) and obstetricians/gynecologists (O&Gs) in relation to the prevention and treatment of osteoporosis (OP) in postmenopausal women. A survey was mailed to a random sample of PCPs and to all O&Gs registered in the province of Alberta (Canada). The survey evaluated their practice patterns using closed-ended questions, Likert scaled items, and two case studies. Cases 1 and 2 were 52-year-old and 62-year-old healthy postmenopausal women, respectively, with no known risks for OP. Neither had received hormone replacement therapy (HRT). One hundred fifty-seven PCPs and 57 O&Gs participated in the study. Thirty-eight percent of the PCPs and 32% of the O&Gs stated that they never requested bone mineral density measurements (BMDm) in early postmenopausal women. Most would request BMDm only in the presence of risk factors. The most important criteria to request BMDm were chronic glucocorticoid use and recent fractures. For case 1, 7% of the PCPs and 11% of the O&Gs would request BMDm; 76% of the PCPs and 80% of the O&Gs would recommend HRT. For case 2, 29% of the PCPs and 47% of the O&Gs would request BMDm (p = 0.01); 43% of the PCPs and 49% of the O&Gs would prescribe HRT. In general, O&Gs were more inclined to intervene in relation to BMDm and HRT. O&Gs were also more likely to be influenced by clinical trials than PCPs (p < 0.001). Our findings show variations in the patterns of practice of physicians in relation to the prevention of OP. In general, use of densitometry appears to be low. The results of the case studies suggest that individual physician perceptions may be more influential than patient characteristics when requesting BMDm and prescribing HRT, particularly in older postmenopausal women. This group of healthy older women have approximately equal odds of being offered versus not being offered BMDm and HRT according to the physician they consult.
Site of Osteodensitometry in Perimenopausal Women: Correlation and Limits of Agreement Between Anatomic Regions
Authors: Abrahamsen B. , Hansen T. B. , Jensen L. Bjørn , Hermann A. P. , Eiken P.
Published: April 2006

Because the bone mineral density (BMD) in different anatomic regions is heterogenous the number of women who fulfill the World Health Organization definition of osteopenia or osteoporosis increases with the number of regions examined. The purpose of this study was to investigate the agreement between measurements of the spine, femur, forearm, and whole body following menopause. Two thousand and five healthy, perimenopausal women, mean age 50.6 years, were studied using Hologic QDR-1000/W and QDR-2000 densitometers. Though the BMD of different anatomic regions were correlated (r = 0.40–0.77, p < 0.01), the variability in each patient regarding T and Z scores between regions was considerable. For example, despite a high correlation (r = 0.67, p < 0.01) and no systematic difference between the T scores for total femoral and lumbar BMD, the limits of agreement (mean difference ± 2 SD) for the comparison were −1.89 to 1.87. Femoral neck T scores were 0.5 SD lower than those of the other regions, confirming reports that the young adult reference for this measurement is disproportionally high. The prevalence of osteoporosis was 1.2% when femur total BMD was considered alone and 5.9% when lumbar and ultradistal forearm results were included. However, as many as 7.9% showed osteoporosis of the femoral neck when the Hologic T score was used, compared with 0.7% using National Health and Nutrition Examination Survey (NHANES) values. The choice of anatomic region and availability of appropriate young adult reference data has considerable impact on the apparent prevalence of osteoporosis. Given the heterogeneity between regions, a combination of spinal and femoral densitometry should be used in diagnosing osteoporosis, though this increases the prevalence of osteoporosis by 50% or more in perimenopausal women.
Hip Fracture Prediction in Elderly Men and Women: Validation in the Rotterdam Study
Authors: De Laet Chris E. D. H. , Van Hout Ben A. , Burger Huibert , Weel Angelique E. A. M. , Hofman Albert , Pols Huibert A. P.
Published: April 2006

The aim of our study was to validate a hip fracture risk function, composed of age and femoral neck bone mineral density (BMD). This estimate of the 1-year cumulative risk was previously developed on the basis of Dutch hip fracture incidence data and BMD in men and women. A cohort of 7046 persons (2778 men) aged 55 years and over was followed for an average of 3.8 years. The 1-year hip fracture risk estimate was calculated for each participant according to the risk function and categorized as low (<0.1%), moderate (0.1 to <1%), or high (≥1%). Observed first hip fracture incidence was then analyzed for each of these risk categories by age and gender. Additionally, we calculated the relative risk per standard deviation (SD) decrease in femoral neck BMD in this population. At baseline, 2360 individuals were categorized as low risk, 2567 as moderate risk, and 378 as high risk. During follow-up, 110 first hip fractures were observed corresponding to an incidence rate of 4.1/1000 person-years (pyrs) (95% confidence interval 3.4–5.0). The observed incidence rate in the low risk group was 0.2/1000 pyrs (0.1–0.9), 2.7/1000 pyrs (1.8–3.9) in the moderate risk group, and 18.4/1000 pyrs (12.4–27.2) in the high risk group. Below the age of 70 years, incidence was low in all categories, and very few individuals were considered at high risk. Above the age of 70 years, the observed incidence was high in the high risk group, while in the low and moderate risk groups, the incidence remained low even over 80 years of age. In women, the age-adjusted relative risk for hip fractures was 2.5 per SD decrease in femoral neck BMD (1.8–3.6), while in men this relative risk was 3.0 per SD (1.7–5.4). In conclusion, we observed a similar relation of hip fracture with femoral neck BMD in men and women and were able to predict accurately hip fracture rates over a period of almost 4 years.
Pre- and Postmenopausal Women Have Different Bone Mineral Density Responses to the Same High-Impact Exercise
Authors: Dr. Bassey E. J. , Rothwell M. C. , Littlewood J. J. , Pye D. W.
Published: April 2006

The effects of a vertical jumping exercise regime on bone mineral density (BMD) have been assessed using randomized controlled trials in both pre- and postmenopausal women, the latter stratified for hormone replacement therapy (HRT). Women were screened for contraindications or medication likely to influence bone. The premenopausal women were at least 12 months postpartum and not lactating; the postmenopausal women had been stable on, or off, HRT for the previous 12 months and throughout the study. BMD was measured blind using dual-energy X-ray absorptiometry at the spine (L2–L4) and the proximal femur. The exercise consisted of 50 vertical jumps on 6 days/week of mean height 8.5 cm, which produced mean ground reactions of 3.0 times body weight in the young women and 4.0 times in the older women. In the premenopausal women, the exercise resulted in a significant increase of 2.8% in femoral BMD after 5 months (p < 0.001, n = 31). This change was significantly greater (p < 0.05) than that found in the control group (n = 26). In the postmenopausal women, there was no significant difference between the exercise and control groups after 12 months (total n = 123) nor after 18 months (total n = 38). HRT status did not affect this outcome, at least up to 12 months. It appears that premenopausal women respond positively to this brief high-impact exercise but postmenopausal women do not.