bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavioral changes associated with suboptimal prey densities for larval American shad
Authors: Ross R. M. , Johnson J. H. , Bennett R. M. , Dropkin D. S.
Published: July 2006

Laboratory studies were conducted to determine the effects of suboptimal prey density and length of prey‐deprivation period on swimming, feeding, and social behavior in larval American shad. Alosa sapidissima. Replicated prey‐density treatments of 1,000, 500, and 0 Artemia nauplii/liter and deprivation periods of 0,2, and 4 days were established for an 8‐day period. The duration or frequency of 11 behavior patterns was quantified with an event recorder during the experiment. Exposure to suboptimal prey densities affected three categories of larval behavior: swimming activities (pivot and dart), interaction with other larvae (escape or avoid), and stereotypical feeding responses (sigmoid and lunge). Location of a food patch, simulated by the sudden introduction of prey to aquaria, affected the frequency of feeding responses more than other categories of behavior. The patch model was supported as a foraging strategy in larvae. The ontogeny of prey deprivation was evidenced primarily by changes in swimming activity (reduced pivot and dart frequencies), though feeding responses (particularly fixate) were also diminished. Deprivation‐induced loss of pivot and fixate was an irreversible, pathological effect of starvation. Deprivation also resulted in greater vertical orientation (head up, 42°) of larvae than non‐deprived larvae (21–29°). These changes in behavior may result in less effective escape from predators, location of food patches, or pursuit and capture of prey items in riverine habitats.
Observations on the reproductive biology of female Hypostomus luetkeni Lacèpéde 1803
Authors: Mazzoni R. , Caramaschi E. P.
Published: July 2006

Abstract— Seasonal observations in the gonadosomatic index and development stages of female ovaries showed that Hypostomus luetkeni has an extended spawning period lasting from September to February. Histological examinations and analysis of oocyte size distributions indicated a fractional spawning. Fecundity was determined in ripe ovaries and indicated that H. luetkeni, as most other Loricariidae, spawn a small number (446‐936 eggs‐ind−1) of large eggs (5.2 mm).
Habitat utilization of juvenile Atlantic salmon (Salmo salar L.), brown trout (Salmo trutta L.) and Arctic charr (Salvelinus alpinus (L.)) in two lakes in northern Norway
Authors: Halvorsen M. , Jergensen L. , Amundsen P. ‐A.
Published: July 2006

Abstract— Habitat utilization of juvenile Atlantic salmon, brown trout and Arctic charr was investigated in two lakes in northern Norway during the icefree season. Both the vertical distribution and the distribution among different habitat types were studied by gillnetting with small mesh sized gillnets (8‐15 mm) in different habitats. Salmon and trout were predominantly caught in the littoral and sublittoral zones (0‐6 m depth). Access to shelter seemed to be the most important factor determining the horizontal distribution of small salmon and trout. Most of these fish were caught in stony or vegetated habitats, while few salmon and trout were caught on sandy locations or in the pelagic zone. In one of the lakes, there were significantly higher catch rates of salmon than of trout in the stony littoral (0‐3 m), while in the other lake there were no significant differences in spatial distribution between these two species. Charr were primarily found in the profundal, sublittoral or pelagic zones of the lakes.
Feeding patterns in five predatory fishes of the high Paranà River floodplain (PR, Brazil)
Authors: de Almeida V. L. L. , Hahn N. S. , Vazzoler A. E. A. de M.
Published: July 2006

Abstract— Between March 1992 and February 1993 five piscivorous fish species, Acestrorhynchus lacustris (Reinhardt, 1874), Hoplias malabaricus (Bloch, 1794), Rhaphiodon vulpinus Agassiz, 1829, Salminus maxillosus, Valenciennes, 1840 and Plagioscion squamosissimus (Heckel, 1840), of the high Paranà River floodplain showed a wide total prey spectrum though only three to four taxa were dominant in their diet. Shrimp, Macrobrachium amazonicum, were also common to the majority of species. Seasonal and spatial variations occurred throughout the study period probably due the availability of prey species. The main resources shared by the predators were also the most abundant in the area, with consumption markedly focused on prey about 5.0 cm long. Detrended correspondence analysis was effective in discriminating two groups of predators species that exploited distinct microhabitats. The predators with the least scores consumed small characids that inhabit mid‐water or the littoral region, whereas those with the largest scores consumed prey associated to the bottom.
Nest site characteristics and male reproductive success in the upland bully, Gobiomorphus breviceps (Eleotridae)
Authors: Hamilton W. J. , Stott M. K. , Poulin R.
Published: July 2006

Abstract— The characteristics of male upland bullies (Gobiomorphus breviceps) and their nest sites were examined in two New Zealand streams as possible determinants of male reproductive success. There was no association between male size, nest site characteristics (depth, distance to shore, river velocity, nest rock size), and male reproductive success. Similarly, the male's parasite load had no detectable influence on reproductive success. Multiple regression analysis revealed that no combination of factors could explain the wide variation in male reproductive success. It may be that the unpredictable nature of the stream habitats of bullies has favored reduced choosiness in females, which could lead to an absence of correlations between male and nest characteristics and reproductive success.
Variability of fish densities in a small catchment
Authors: Danehy R. J. , Ringler N. H. , Stehman S. V. , Hassett J. M.
Published: July 2006

Abstract— Temporal and spatial variability of fish communities were examined within a 91‐km2 catchment in central New York over four years. Riffle‐dwelling species, slimy sculpin Cottus cognatus, longnose dace Rhinichthys cataractae, and young‐of‐the‐year brown trout Salmo trutta, were more strongly affected by flood and drought than pool‐adapted species, adult brown trout, blacknose dace Rhinichthys atratulus, white sucker Catostomus commersoni, and creek chub Semotilus atromaculatus. Canonical correspondence analysis using seven abiotic variables (mean width, residual pool depth, water surface slope, mean Froude number, variance in Froude number, maximum monthly discharge and minimum monthly discharge) separated fish communities among sites and years. The first axis represented a headwater‐to‐valley gradient; the second axis reflected habitat complexity, based on both geomorphic and hydraulic features. Temporal differences in fish densities were related to hydrological factors. Fish communities throughout the catchment showed similar responses to flood and drought.
The Copper Transporter (Ctr) Family of Cu+ Uptake Systems
Authors: Dumay Quentin C. , Debut Aurore J. , Mansour Nahla M. , Saier Jr. Milton H.
Published: July 2006

Copper (Cu+) transporters of the Ctr family are sequence diverse eukaryotic proteins that function by an unknown mechanism of action. We have conducted bioinformatic analyses of sequenced Ctr proteins. Multiple paralogues are found in single organisms, and these may be either closely or distantly related to each other. Protein phylogeny generally correlates with organismal source and protein size with proteins of each cluster being derived from a specific eukaryotic kingdom and exhibiting characteristic domain arrangements. Some homologues exhibit repeats of the basic 3 TMS unit. Regions of conserved hydrophobicity and amphipathicity suggest functional roles, particularly for putative TMSs 2 and 3 which possess a nearly fully conserved M X3 M motif in putative TMS2. We propose that this motif comprises the transmembrane Cu+-binding site in oligomeric channels that take up Cu+ by a passive, membrane potential-dependent mechanism.
Diagnosis of Paroxysmal Nocturnal Hemoglobinuria by Fluorescent Clostridium septicum Alpha Toxin
Authors: Shin Dong-Jun , Cho Duck , Kim Young Ran , Rhee Joon Haeng , Choy Hyon E. , Lee Je-Jung , Hong Yeongjin
Published: July 2006

Paroxysmal nocturnal hemoglobinuria (PNH), a hematopoietic stem cell disorder, is caused by the loss of glycosylphosphatidylinositol (GPI)-anchored proteins on the cell membrane. PNH can be simply diagnosed by flow cytometry using monoclonal antibodies against GPI-anchored proteins or fluorescent-tagged aerolysin, a bacterial toxin that binds GPI anchored proteins. Clostridium septicum alpha toxin is homologous to aerolysin and specifically binds GPI-anchored proteins. Previously, we found that an alpha toxin m45 mutant with two amino acid changes, S189C/S238C, lost cytotoxicity but still possessed binding activity for GPI-anchored proteins. To use this mutant toxin as a diagnostic probe in flow cytometry, we constructed the EGFP-AT(m45) expression vector, comprising a S189C/S238C alpha toxin mutant with EGFP and His tags at the N and C termini, respectively. The recombinant EGFP-AT(m45) was easily purified using single-step affinity chromatography against His tag from Escherichia coli. EGFP-AT(m45) bound to CHO and HeLa cells in a similar manner to monoclonal antibodies against GPI-anchored proteins or aerolysin. In whole blood from a PNH patient, GPI-deficient granulocytes could be differentiated by EGFP-AT(m45) using the same procedure as that employed with commercially available monoclonal antibodies. Therefore, nontoxic EGFP-conjugated C. septicum alpha toxin could be used clinically for PNH diagnosis.
Optimized Growth Kinetics of Pichia pastoris and Recombinant Candida rugosa LIP1 Production by RSM
Authors: Chang Shu-Wei , Shieh Chwen-Jen , Lee Guan-Chiun , Akoh Casimir C. , Shaw Jei-Fu
Published: July 2006

A predictive model for Pichia pastoris expression of highly active recombinant Candida rugosa LIP1 was developed by combining the Gompertz function and response surface methodology (RSM) to evaluate the effect of yeast extract concentration, glucose concentration, temperature, and pH on specific responses. Each of the responses (maximum population densities, specific growth rate (µmax), protein concentration, and minimum lag phase duration) was determined using the modified Gompertz function. RSM and 4-factor-5-level central composite rotatable design (CCRD) were adopted to evaluate the effects of growth parameters, such as temperature (21.6–38.4°C), glucose concentration (0.3–3.7%), yeast extract (0.16–1.84%), and pH (5.3–8.7) on the responses of P. pastoris growth kinetics.Based on ridge maximum analysis, the optimum population density conditions were: temperature 24.4°C, glucose concentration 2.0%, yeast extract 1.5%, and pH 7.6. The optimum specific growth rate conditions were: temperature 28.9°C, glucose concentration 2.0%, yeast extract 1.1%, and pH 6.9. The optimum protein concentration conditions were: temperature 24.2°C, glucose concentration 1.9%, yeast extract 1.5%, and pH 7.6. Based on ridge minimum analysis, the minimal lag phase conditions were: temperature 32.3°C, glucose concentration 2.1%, yeast extract 1.1%, and pH 5.4. For the predicted value, the maximum population density, specific growth rate, protein concentration, and minimum lag phase duration were 15.7 mg/ml, 3.4 h–1, 0.78 mg/ml, and 4.2 h, and the actual values were 14.3 ± 3.5 mg/ml, 3.6 ± 0.6 h–1, 0.72 ± 0.2 mg/ml, and 4.4 ± 1.6 h, respectively.
Management of the Gastrointestinal Tract at the Time of Cystectomy
Authors: Jain S. , Simms M.S. , Mellon J.K.
Published: July 2006

Radical cystectomy impacts on the gastro-intestinal tract in several ways. Clearly there is the need for bowel mobilisation, resection and anastamosis in order to create a urinary diversion, and the use of bowel preparation or antibiotics are controversial topics. Post-operatively ileus is common and there is debate about the routine use of NG tubes. Early enteral feeding is a modern concept but not yet proven. In the long-term there can be problems such as diarrhoea and B12 deficiency. All of these issues are discussed in this review using the latest available evidence.
Split Technique in Horseshoe Kidney Transplantation
Authors: Pedro Renato Nardi , Leitão Victor A. , Myiaoka Ricardo , Fregonesi Adriano , Villas Boas Cláudio C. , Reges Ricardo , Matheus Wagner E. , Netto Jr. Nelson Rodrigues
Published: July 2006

Background/Aims: Nowadays, owing to a greater number of patients waiting for a kidney donation and to a shortage of organs donated, more suitable organ acceptance criteria have been formulated. Horseshoe kidney transplantations have become feasible giving good allograft outcomes. The aim of this paper is to illustrate the split technique in horseshoe kidney transplantation and to report long-term results. Methods: During the period from February 2004 to February 2005, two horseshoe kidneys were harvested from multiple organ retrieval. The surgical features and outcomes of these 2 cases are described separately. Mean follow-up time was 12.3 months. Conclusions: Organs that were previously said to be marginal are being used more regularly and the more suitable selection does not exclude elderly donors with or without underlying diseases. Horseshoe kidney transplantation requires greater skills and experience of the surgeons compared to conventional kidney transplantation. This kind of renal abnormality has to be considered a feasible option for transplantation. Good long-term results are reported.
Significance of Cancer Involvement at the Ureteral Margin Detected on Routine Frozen Section Analysis during Radical Cystectomy
Authors: Lee Sang Eun , Byun Seok-Soo , Hong Sung Kyu , Chang In Ho , Kim Yong June , Gill Myung Chul , Song Sang Hoon , Kim Kwang Taek
Published: July 2006

Introduction: We investigated the clinical significance of preoperatively-unsuspected ureteral involvement of cancer detected on intraoperative frozen section analysis of ureteral margins during radical cystectomy. Patients and Methods: We performed a retrospective study of 115 patients who received radical cystectomy for locally-advanced but node-negative transitional cell carcinoma of the bladder between 1995 and 2002 by reviewing their records. Results: Of 115 total patients, 5 (4.3%) demonstrated carcinoma in situ at the ureteral margin with 2 of 5 having a positive margin on final pathologic analysis. Meanwhile, only 3 of 115 total patients (2.6%) later showed upper urinary tract recurrence at a median interval of 30 months after cystectomy. And all 3 patients had intramural or juxtavesical ureter involvement of disease (p = 0.006), while not demonstrating carcinoma in situ in ureteral margins resected during cystectomy. On multivariate analysis, only the stage and grade of bladder cancer along with pathologic feature of vascular invasion were observed to be independent prognostic predictors of disease-specific survival. Conclusions: Cancer involvement of the distal ureteral margin detected through intraoperative frozen section analysis may not be a significant factor regarding upper tract recurrence and survival of patients with locally-advanced bladder cancer after radical cystectomy. Upper tract recurrence may be more prone to occur in patients with cancer involvement at the intramural or juxtavesical ureter.
Evaluation of p53 Nuclear Accumulation in Low- and High-Grade (WHO/ISUP Classification) Transitional Papillary Carcinomas of the Bladder for Tumor Recurrence and Progression
Authors: Vardar Enver , Gunlusoy Bulent , Minareci Süleyman , Postaci Hakan , Ayder Ali Riza
Published: July 2006

Objectives: To evaluate the association of p53 nuclear accumulation with recurrence and progression in transitional cell carcinomas of the bladder and to examine the distribution of p53 in low-grade and high-grade transitional cell carcinomas according to the World Health Organization/International Society of Urological Pathology classification. Patients and Methods: Nuclear accumulations of p53 were examined in a total of 99 patients with transitional cell carcinoma between May 1995 and October 1999. The mean age was 64 years. There were 94 (95%) men and 5 (5%) women. Following resection, surgical specimens were examined, and p53 accumulation with a 20% cutoff value was accepted as positive staining. Of the 99 patients, 52 (53%) had histologically superficial bladder tumors, and 47 (47%) had invasive tumors. Data concerning grade, stage, number of recurrences, and disease progression were available for each patient. Results: The median follow-up period was 55 months. 60 of the 99 patients (61%) had p53 overexpression. The difference for p53 overexpression between low-grade and high-grade tumors was significant (p < 0.05). In low- and high-grade tumors, there was no significant relationship for recurrence between p53-positive and p53-negative groups. But there was a statistically significant relationship between progression and histological grade of the tumors. p53 had no significant relationship with tumor recurrences (p > 0.05), but its relationship with progression was statistically significant (p < 0.05). Conclusions: We did not find a correlation between tumor recurrence and p53 overexpression, but p53 overexpression has a predictive value in determining tumor progression. High-grade tumors had higher p53-positive values than low-grade tumors. This group of patients should be considered for radical therapies on the basis of other prognostic parameters.
Association of Urokinase Gene 3′-UTR T/C Polymorphism with Bladder Cancer
Authors: Manchanda Parmeet Kaur , Bid Hemant Kumar , Mittal Rama Devi
Published: July 2006

Introduction: Bladder cancer is a disease characterized by multiple recurrences. Some investigators assume urokinase to be involved in the causation of bladder cancer, although there is lack of genetic evidence. Our aim was to evaluate whether polymorphism of the urokinase gene is associated with transitional cell carcinoma (TCC) of the urinary bladder. Materials and Methods: The study included 100 patients (mean age 62.5 ± 10.2 years) with TCC of urinary bladder and 150 healthy controls (mean age 60 ± 11.5 years) living in the same area. Polymerase chain reaction (PCR)-based restriction analysis was used to identify the C/T polymorphism of the urokinase gene. Genotyping distribution and allelic frequencies between patients and controls were compared. Results and Conclusion: There was a significant difference in the frequency distribution of the urokinase gene 3′-UTR C/T polymorphism in bladder cancer patients as compared to the normal control group (p < 0.05), but no significant difference in allelic frequencies or in carriage rates between bladder cancer patients and normal controls were observed. Our study suggests that urokinase gene polymorphism may be associated with bladder cancer and can thus serve as a potential genetic marker in screening for the possible causes of bladder cancer. Perhaps analysis of patients with superficial bladder TCC and mutated urokinase might help clarify this aspect in large cohort studies in different populations.
The Involvement of Glucocorticoids and Interleukin-1 in the Regulation of Brain Prostaglandin Production in Response to Surgical Stress
Authors: Beilin Benzion , Shavit Yehuda , DeKeyser Freda , Itzik Anna , Weidenfeld Joseph
Published: July 2006

Background: This study examined the role of glucocorticoids (GC) and interleukin-1 (IL-1) in regulating the production of brain prostaglandin E2 (PGE2) in response to surgical stress. Methods: Surgical stress was induced in rats by laparotomy or exploration of the carotid. PGE2 ex vivo production was measured in the frontal cortex or central amygdala of adrenalectomized rats, or of rats treated with either the GC type II receptor blocker (RU38486) or synthetic GC (dexamethasone). IL-1 involvement in mediating PGE2 response to surgical stress was examined in IL-1 receptor type I deficient (IL-1rKO) mice. Results: Surgical stress elevated serum corticosterone and increased PGE2 production by the frontal cortex and the central amygdala. A more pronounced PGE2 response was found in adrenalectomized rats and in rats treated with RU38486, whereas administration of dexamethasone inhibited stress-induced PGE2 production. IL-1rKO mice exhibited lower PGE2 production in the frontal cortex under basal condition and failed to increase PGE2 production in response to surgical stress. Conclusions: Surgical stress-induced production of brain PGE2 is specifically regulated by GC via the mediation of type II corticosteroid receptors. Normal IL-1 signaling is required for the production of brain PGE2 under basal conditions and in response to surgical stress.
Analysis of Non-Linear Ion Drift in Spectrometers of Ion Mobility Increment with Cylindrical Drift Chamber
Authors: Elistratov A.A. , Shibkov S.V. , Nikolaev E.N.
Published: July 2006

A model for the drift of ions under a non-uniform, high-frequency electric field in the drift chamber of a spectrometer of ion mobility increment is developed. For the general dependence of the ion mobility on the electric field strength and the general time-dependence of the separating voltage, we suggest a procedure for calculating of the ion peak form. The shape of the peak for the ion focusing and defocusing conditions has been obtained.
Isomerization and Fragmentation Reactions of Gaseous Dimethyl Phenylarsane Radical Cations and Methyl Phenylarsenium Cations. A Study by Tandem Mass Spectrometry and Density Functional Theory Calculations
Authors: Kirchhoff Dirk , Grützmacher Hans-Friedrich , Grützmacher Hansjörg
Published: July 2006

The unimolecular reactions of the radical cation of dimethyl phenylarsane, C6H5As(CH3)2, 1.+, and of the methyl phenylarsenium cation, C6H5As+CH3, 2+, in the gas phase were investigated using deuterium labeling and methods of tandem mass spectrometry. Additionally, the rearrangement and fragmentation processes were analyzed by density functional theory (DFT) calculations at the level UBHLYP/6-311+G(2d,p)//UBHLYP/5-31+G(d). The molecular ion 1.+ decomposes by loss of a •CH3 radical from the As atom without any rearrangement, in contrast to the behavior of the phenylarsane radical cation. In particular, no positional exchange of the H atoms of the CH3 group and at the phenyl ring is observed. The results of DFT calculations show that a rearrangement of 1.+ by reductive elimination of As and shift of the CH3 group is indeed obstructed by a large activation barrier. The mass-analyzed kinetic energy spectrum of 2+ shows that this arsenium cation fragments by losses of H2 and AsH. The fragmentation of the trideuteromethyl derivative 2-d3+ proves that all H atoms of the neutral fragments originate specifically from the methyl ligand. Identical fragmentation behavior is observed for metastable m-tolyl arsenium cation, m-CH3–C6H4As+H, 2tol+. The loss of AsH generates ions C7H7+ which requires rearrangement in 2+ and bond formation between the phenyl and methyl ligands prior to fragmentation. The DFT calculations confirm that the precursor of this fragmentation is the benzyl methylarsenium cation, 2bzl+, and that 2bzl+ is also the precursor ion fo the elimination of H2. The analysis of the pathways for rearrangements of 2+ to the key intermediate, 2bzl+, by DFT calculations show that the preferred route corresponds to a 1,2-H shift of a H atom from the CH3 ligand to the As atom and a shift of the phenyl group in the reverse direction. The expected rearrangement by a reductive elimination of the As atom, which is observed for the phenylarsenium cation and for halogeno phenyl arsenium cations, requires much more activation enthalpy.
Study of a Bisquaternary Ammonium Salt by Atmospheric Pressure Photoionization Mass Spectrometry
Authors: Giuliani A. , Debois D. , Laprévote O.
Published: July 2006

A comprehensive atmospheric pressure photoionization (APPI) mass spectrometry investigation of hexamethonium bromide is reported. This bisquaternary ammonium salt is a model system for the investigation of multiply charged species and elucidation of ion formation processes. It has been used to elucidate the physico–chemical phenomenon occurring when photoionization is carried out at atmospheric pressure. First, the in-source fragmentations were studied for aqueous solutions of the salt with the photoionization lamp switched off, i.e. under thermospray conditions. It is shown that, in this mode of operation, fragmentations are minor and may be classified into two classes, namely dequaternization and charge separation, arising from the two precursors, M2+ and [M + Br]+. Second, the fragmentation patterns have been monitored in dopant-assisted APPI for different dopants (toluene, toluene-d8, anisole and Hexafluorobenzene) at various amounts. At low dopant flow rates, the [M + Br]+ and M2+ ions are still observed. As the flow rate is increased, these precursor ions lose intensity and are finally suppressed for all three dopants. Comparison of toluene and toluene-d8 reveals that H atoms may be transferred from the dopant to the molecular ions, very likely mediated by the solvent. The role of the solvent (water) was also investigated by using heavy water. Apart from the thermospray fragmentations, which are also observed in APPI, several fragmentation pathways appear to be specific to the photoionization process. Photoionization efficiencies are measured by determination of the relative photoionization cross sections with respect to toluene. It is found that, when the ionization efficiencies are taken into account, the depletion of the precursors as a function of the dopant flow rates is the same for all three dopant molecules. This result shows that the precursor ions are depleted by reactions with the photoelectrons released from the dopant. Three additional mechanisms are proposed to account for this effect: electron transfer or H atom transfer from negatively charged water nanodroplets and H atom transfer from the dopant.
Determination of the Non-Constant Component of Ion Mobility Using the Spectrometer of Ion Mobility Increment
Authors: Elistratov A.A. , Shibkov S.V. , Nikolaev E.N.
Published: July 2006

A new method for determination of the non-constant component, α( E), of an ion mobility, k( E), is suggested. The method uses the relationship U C( U S) that can be experimentally obtained with a spectrometer of ion mobility increment with planar drift chamber. ( U C is a compensating voltage, U S is separating voltage amplitude.) A general equation for α( E) has been derived. We have explored the possibility of determination of α( E) from the experimental data for different types of U S( t). In two specific cases, analytical solutions have been obtained.
Structural Characterization of Polyethers Using Matrix-Assisted Laser Desorption/Ionization Quadrupole Ion Trap Time-of-Fight Mass Spectrometry
Authors: Okuno Shoji , Kiuchi Masato , Arakawa Ryuichi
Published: July 2006

Fragmentation of polyethers, such as poly(ethylene glycol) (PEG), poly(propylene glycol) and poly(tetramethylene glycol) was analyzed by matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS) using a quadrupole ion trap time-of-fight mass spectrometer (QIT-ToF). The Li adduct ion provided more abundant fragments than the Na and K adduct ions in the MS/MS spectra. A previous study had demonstrated four series fragments of hydroxyl-, vinyl- and formyl-terminated ions, as well as distonic cations, in high-energy fast atom bombardment MS/MS and MALDI collision-induced dissociation measurements of poly(ethylene glycol). In the present study, the low-energy MS/MS measurements using MALDI-QIT-ToF, showed hydroxyl-, vinyl- and formyl-terminated fragments with or without other fragment groups, but not distonic cations. The fragmentation depended on the types of polyethers examined. MS/MS measurements using MALDI-QIT-ToF are expected to allow structural characterization of unknown components of polyethers.
Mutations in OSTM1 (Grey Lethal) Define a Particularly Severe Form of Autosomal Recessive Osteopetrosis With Neural Involvement
Authors: Pangrazio Alessandra , Poliani Pietro Luigi , Megarbane André , Lefranc Gérard , Lanino Edoardo , Di Rocco Maja , Rucci Francesca , Lucchini Franco , Ravanini Maria , Facchetti Fabio , Abinun Mario , Vezzoni Paolo , Villa Anna , Frattini Annalisa
Published: July 2006

We report three novel osteopetrosis patients with OSTM1 mutations and review two that have been previously described. Our analysis suggests that OSTM1 defines a new subset of patients with severe central nervous system involvement. This defect is also present in the gl mouse, which could represent a good model to study the role of the gene in the pathogenesis of this disease.

Introduction: Autosomal recessive osteopetrosis (ARO) is a severe hereditary bone disease whose cellular basis is in the osteoclast, but with heterogeneous molecular defects. In addition to the TCIRG1 and the ClCN7 genes, whose mutations account for ∼55% and 10% of cases, respectively, the OSTM1 gene has been described thus far in only two ARO patients.

Materials and Methods: We report here three novel ARO patients presenting with severe primary central nervous system involvement in addition to the classical stigmata of severe bone sclerosis, growth failure, anemia, thrombocytopenia, and visual impairment with optic atrophy. In addition we analyzed the brain morphology and histology of the grey lethal mutant mouse.

Results: The analysis of the OSTM1 gene in two patients, both from Kuwait, showed homozygous two nucleotide deletion in exon 2, leading to a frameshift and premature termination. The third (Lebanese) patient showed a single point mutation in exon 1, leading to a nonsense mutation. The clinical neurological evaluation of the two Kuwaiti patients by CT and MRI scans showed a defect in the white matter, with a specific diagnosis of severe cerebral atrophy. The gl brain showed a diffuse translucent appearance with loss of the normal demarcation between the white and the grey matter, features consistent with myelin loss or hypomyelination. Histological and myelin staining analysis evidenced an atrophy of the corpus callosum with loss of myelin fibers, and in cortical areas, loss of the normal lamination consistent with multiple foci of cortical dysplasia.

Conclusions: These findings suggest that OSTM1-dependent ARO defines a new subset of patients with severe central nervous system involvement leading to a very poor prognosis. The fact that central nervous system involvement is also present in the gl mouse mutant suggests that this mouse is a good model to test possible therapies.
Homocysteine Enhances Bone Resorption by Stimulation of Osteoclast Formation and Activity Through Increased Intracellular ROS Generation
Authors: Koh Jung-Min , Lee Young-Sun , Kim Yang Soon , Kim Duk Jae , Kim Hong-Hee , Park Joong-Yeol , Lee Ki-Up , Kim Ghi Su
Published: July 2006

Hyperhomocystinemia is a modifiable risk factor for osteoporosis and fracture. Physiologic concentrations of Hcy directly activate osteoclast formation and activity through stimulation of p38 MAPK and integrin β3. The effects of Hcy were mediated by generation of intracellular ROS.

Introduction: Hyperhomocysteinemia is a modifiable risk factor for osteoporosis and its related bone fractures. It has been reported that bone resorption and turnover rate were increased in hyperhomocystinemia. Using mouse bone marrow cells, we examined the direct effects of homocysteine (Hcy) on osteoclast formation and activity.

Materials and Methods: Osteoclast formation was determined by TRACP staining and TRACP activity. Intracellular reactive oxygen species (ROS) generation was measured using a fluorescent probe, dichlorodihydrofluorescein diacetate. Intracellular signaling cascades of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and NF-κB were measured by Western blotting. Integrin β3 mRNA levels were measured by RT-PCR. Actin ring formation and bone resorption assays were also performed.

Results: Physiologic concentrations of Hcy upregulated TRACP+ multinucleated cells and TRACP activity, stimulated actin ring formation, and increased the number of nuclei per cell and the level of expression of integrin β3 mRNA. In addition, Hcy increased bone resorption and stimulated p38 MAPK activity and intracellular reactive oxygen species (ROS) generation. All of these Hcy-induced changes were blocked by pretreatment with the antioxidant, N-acetyl cysteine.

Conclusions: Hcy directly activates osteoclast formation and activity through increased generation of intracellular ROS. These findings suggest that, in individuals with mild to moderate hyperhomocystinemia, increased bone resorption by osteoclasts may contribute to osteoporosis and that an antioxidant may attenuate bone loss in these individuals.
Expression of Mouse Osteoclast K-Cl Co-Transporter-1 and Its Role During Bone Resorption
Authors: Kajiya Hiroshi , Okamoto Fujio , Li Jing-Ping , Nakao Akihiro , Okabe Koji
Published: July 2006

To assess the role of Cl− transport during osteoclastic bone resorption, we studied the expression and function of K+/Cl− co-transporters (KCCs). KCC1 and chloride channel-7 were found to be expressed in mouse osteoclasts. The KCC inhibitor, R(+)-butylindazone (DIOA), KCC1 antisense oligo-nucleotides, and siRNA suppressed osteoclastic pit formation. DIOA also decreased Cl− extrusion and reduced H+ extrusion activity. These results show that KCC1 provides a Cl− extrusion mechanism accompanying the H+ extrusion during bone resorption.

Introduction: Mice with deficient chloride (Cl−) channels, ClC7, show severe osteopetrosis, resulting from impairment of Cl− extrusion during osteoclastic bone resorption. However, the expression and functional role of Cl− transporters other than ClC7 in mammalian osteoclasts is unknown. The aim of this study was to determine expression of K+/Cl− co-transporters (KCCs) and their functional role for bone resorption in mouse osteoclasts.

Materials and Methods: Mouse osteoclasts were derived from cultured bone marrow cells with macrophage-colony stimulating factor (M-CSF) and RANKL or from co-culture of bone marrow cells and primary osteoblasts. We examined the expression of Cl− transporters using RT-PCR, immunochemical, and Western blot methods. The effects of Cl− transport inhibitors on H+ and Cl− extrusion were assessed by measuring intracellular H+ ([H+]i) and Cl− ([Cl−]i). The effects of inhibitors, antisense oligo-nucleotides, and siRNA for Cl− transporters on bone resorption activities were evaluated using a pit formation assay.

Results and Conclusions: Mouse osteoclasts express not only ClC7 but also K+/Cl− co-transporter mRNA. The existence of KCC1 in the cell membrane of mouse osteoclasts was confirmed by immunochemical staining and Western blot analysis. KCC inhibitors and Cl− channels blockers increased [Cl−]i and [H+]i in resorbing osteoclasts, suggesting that the suppression of Cl− extrusion through KCC and Cl− channels leads to reduced H+ extrusion activity. The combination of both inhibitors greatly suppressed these extrusion activities. KCC inhibitors and Cl− channel blockers also decreased osteoclastic bone resorption in our pit area essay. Furthermore, KCC1 antisense oligo-nucleotides and siRNA suppressed osteoclastic pit formation as well as treatment of ClC7 inhibitors. These results indicate that K+/Cl− co-transporter-1 expressed in mouse osteoclasts acts as a Cl− extruder and plays an important role for H+ extrusion during bone resorption.
Pathogenic Role of Connective Tissue Growth Factor (CTGF/CCN2) in Osteolytic Metastasis of Breast Cancer
Authors: Shimo Tsuyoshi , Kubota Satoshi , Yoshioka Norie , Ibaragi Soichiro , Isowa Sachiko , Eguchi Takanori , Sasaki Akira , Takigawa Masaharu
Published: July 2006

The role of CTGF/CCN2 in osteolytic metastasis by breast cancer cells and its mechanism of action were studied. Osteolytic metastasis accompanied by CCN2 and PTHrP overproduction was efficiently inhibited by an anti-CCN2 antibody. Furthermore, we found that CCN2 was induced by PTHrP through PKA-, PKC-, and ERK-mediated pathways therein.

Introduction: Connective tissue growth factor (CTGF/CCN2) is a mediator of local angiogenesis induced by breast cancer, but its role in osteolytic metastasis has not been evaluated. PTH-related peptide (PTHrP) is another critical factor in the development of the osteolytic metastasis. Using both in vivo and in vitro approaches, we studied whether/how neutralization of CCN2 prevented bone metastasis and how PTHrP signaling is related.

Materials and Methods: A mouse model of bone metastasis by human breast cancer cell line MDA231 was treated with a CCN2-neutralizing antibody, and osteolytic bone metastases were assessed on radiographs and immunohistochemistry. Ccn2 gene expression and transcription were examined by Northern blot and luciferase analysis. Immunoblot analysis and kinase inhibitors were used to identify the signaling pathways implicated. Anti-angiogenic/osteoclastogenic effects of ccn2 downregulation were also evaluated.

Results: Treatment of mice with a CCN2-neutralizing antibody greatly decreased osteolytic bone metastasis, microvasculature, and osteoclasts involved. The antibody also suppressed the growth of subcutaneous tumor in vivo and proliferation and migration of human umbilical vein endothelial cells (HUVECs) in vitro. Downregulation of ccn2 also repressed osteoclastogenesis. CCN2 expression was specifically observed in cancer cells producing PTHrP and type I PTH/PTHrP receptor (PTH1R) invaded the bone marrow, and PTHrP strongly upregulated ccn2 in MDA231 cells in vitro. Activation of protein kinase C (PKC) and protein kinase A (PKA) was necessary and sufficient for the stimulation of ccn2 by PTHrP. Indeed, inhibition of the extracellular signal-regulated kinase (ERK1/2), PKC, or PKA by specific inhibitors counteracted the stimulation of ccn2 expression. Incubation of MDA231 cells with PTHrP induced the activation of ERK1/2. Consistent with these findings, inhibition of PKC prevented PTHrP-induced ERK1/2 activation, whereas 12-O-tetradecanoylphorbol13-acetate (TPA), a stimulator of PKC, upregulated it.

Conclusions: CCN2 was critically involved in osteolytic metastasis and was induced by PKA- and PKC-dependent activation of ERK1/2 signaling by PTHrP. Thus, CCN2 may be a new molecular target for anti-osteolytic therapy to shut off the PTHrP–CCN2 signaling pathway.
Relationship Between Bone Quantitative Ultrasound and Fractures: A Meta-Analysis
Authors: Marín Fernando , González-Macías Jesús , Díez-Pérez Adolfo , Palma Silvia , Delgado-Rodríguez Miguel
Published: July 2006

The relationship between bone QUS and fracture risk was estimated in a systematic review of data from 14 prospective studies of 47,300 individuals and 2350 incident fractures. In older women, low QUS values were associated with overall fracture risk, low-trauma fractures, and with hip, forearm, and humerus fractures separately.

Introduction: Bone quantitative ultrasound (QUS) has emerged as a promising technique to evaluate bone status. The aim of this study was to determine the association between measurements of QUS with the risk of fracture.

Materials and Methods: A meta-analysis of prospective cohort studies published between 1985 and June 2005 with a baseline measurement of QUS and subsequent follow-up for fractures was carried out. Fourteen separate study populations, consisting of about 47,300 individuals (85.4% women), with about 124,000 person-years of observation and over 2350 fractures, including 653 hip, 529 forearm, and 386 humeral fractures, were analyzed. The main outcome measure was the estimated relative risk of fracture for a decrease in bone QUS parameters of 1 SD below sex- and age-adjusted mean in women.

Results: Eleven studies evaluated QUS at the heel, with patella and phalanx (two studies each) and distal radius (one study) being scarcely used. There was not significant heterogeneity among the studies included in the review. Relative risk estimates (95% CI) for overall fractures were 1.55 (1.35–1.78) for each SD decrease in broadband ultrasound attenuation (BUA), 1.63 (1.37–1.93) for speed of sound (SOS), and 1.74 (1.39–2.17) for QUS index/stiffness index (QUI/SI). Risk estimates were similar or slightly higher for hip fractures and low-energy trauma fractures. Humeral and forearm/wrist fractures were also related with lower QUS values.

Conclusions: Measurements of bone QUS are significantly associated with nonspinal fracture risk in older women in a similar degree to DXA. QUS may be a valid alternative to evaluate fracture risk in situations where DXA is not accessible.
Simplified buckling analysis of skeletal structures
Authors: Izzuddin B. A.
Published: July 2006

A simplified approach is proposed for buckling analysis of skeletal structures, which employs a ‘rotational spring analogy’ for the formulation of the geometric stiffness matrix. The benefit of this analogy is that it offers an intuitive framework, which is based on the common notions of linear structural analysis. Assuming that the structural deflections prior to buckling are negligible, a linear eigenvalue problem, utilising the geometric and material stiffness matrices, can be easily formulated and solved for the critical buckling loads. This can be further simplified using an assumed mode, where the rotational spring analogy is shown to provide considerable computational benefits and significant insight into the buckling of various forms of skeletal structure. In this context, the use of different assumed modes can be conceived as a process of probing the structure to establish the most likely mode for buckling and the corresponding critical load. It is also shown that the approximation inherent in the assumed mode approach together with the discrete form of the rotational spring analogy can be significantly improved through modal combinations and increasing the number of elements, respectively, where convergence to the exact buckling solution is demonstrated. Several illustrative examples are provided in this paper, which highlight the simplicity of the proposed approach, its application using a linear structural analysis tool and its ability to shed significant light on important issues in buckling analysis of skeletal structures.
Role of cement content in specifications for concrete durability: aggregate type influences
Authors: Dhir R. K. , McCarthy M. J. , Tittle P. A. J. , Zhou S.
Published: July 2006

In this paper, the second of the series, examining the role of cement content in specifying concrete durability, the influences of aggregate characteristics are considered. As for the first paper, the reported work was carried out within a framework of mix adjustments, required to produce practical concretes, that is, with the inclusion of filler and superplasticising admixture. A total of five UK normalweight aggregates and a lightweight aggregate were examined. It is shown that, for a given w/c ratio and aggregate type, reduction in cement and water contents (and the associated mix adjustments) did not adversely affect concrete properties (fresh, bulk engineering, permeation and durability). Indeed, many aspects of concrete performance were enhanced, with the improvements with cement reduction generally being greatest for aggregates having low absorption. Furthermore, the influence of cement content at a given w/c ratio on durability was found to be less significant than that of a change in aggregate type for the range of UK materials tested. The implications of the study for concrete construction practice are discussed.
Management Entry Into U.S. Agriculture
Authors: Tolley G. S.
Published: July 2006

The view that agriculture is undergoing replacement of one kind of human capital by another is offered as alternative to the traditional view that resources are chronically oversupplied to farming. The hypothesis that high level management farms have experienced favorable cost curve shifts explains farm number declines as primarily replacement of many low management by fewer high management farms. The replacement raises efficiency modestly. Occupational supply behavior relations for management levels lead to inferences about income distribution and future structure of agriculture. A price‐income policy is suggested to compensate outmoded management for obsolescence.
The Investment Behavior of a Farm Firm Operating under Risk
Authors: Sadan Ezra
Published: July 2006

The opportunities facing the investment decision maker in a farm firm operating under risk can be summarized in some cases in terms of “efficiency frontiers,” the dimensions of which are the expected present value and the variance of the farm's future net returns. This article attempts to trace and define these frontiers in terms of deductible algebraic equations in simplified single‐ and multiperiod cases where the farm output level is determined by a single systematic input variable—capital—and a single random factor and where the functional relationship is Cobb‐Douglas. It also attempts to outline, through simulation procedures, the frontiers pertaining to a “real world” case of a growing farm cum household unit.
The Measurement of Efficiency Relative to a Frontier Production Function
Authors: Seitz Wesley D.
Published: July 2006

A method is presented for estimating a frontier production function allowing economies and diseconomies of scale using linear programming techniques. The general applicability of this function is illustrated by considering the neutral and nonneutral cases. Indexes of technical, price, and economic efficiency of production of observations of equal scale are introduced. Three equivalent efficiency indexes are offered which measure the efficiency of alternative scale activities. Utilization of the efficiency indexes in determining the nature of the production function, causes of observed inefficiency, and the degree and nature of technological advance are discussed.
An Experimental Comparison of Pricing in Two Auction Systems
Authors: Frahm Donald G. , Schrader Lee F.
Published: July 2006

Trading and pricing procedures are being increasingly viewed as variables in the marketing system, particularly as the pricing role of central markets declines. Quantification of the effect of pricing systems on price outcome is needed for decisions in this area. English (ascending bid) and Dutch (descending price) auctions are compared in a series of experiments. Specific hypotheses regarding price variation, pattern of price during an auction period, and departure from equilibrium price are tested. The experimental evidence indicates the existence of a significant area of indeterminacy in pricing processes.
Economic Determinants of the Farm and Elevator Trends in the Volume of Corn Artificially Dried
Authors: Hill Lowell D.
Published: July 2006

The trend toward on‐farm drying of corn is not consistent with the economic advantage of the elevator in performing the drying function. This study examines the factors that have influenced this trend, using four related analytical models: (1) an aggregate model using county census data; (2) a profit‐maximization model of individual farmers; (3) a weighted regression of ownership probabilities based on farm and elevator survey data; and (4) a regression model of behavior response by market areas. Results of these models provide a composite picture of the relationships influencing the decision to dry corn on the farm. Three independent sources of data add validity to the overall conclusions.
Impact of Public Land Programs on Local Government Finances
Authors: Barron James C. , Jansma J. Dean
Published: July 2006

Public land ownership is often assumed to adversely affect the fiscal capacity of local governments through removal of part of the property tax base. A method employing multiple regression analysis was developed to test this hypothesis in a forested region of Pennsylvania. Neither higher tax rates on private land nor reduced levels of per capita local government expenditures were found to be associated with large amounts of public land, thereby indicating that local governments are not placed at an economic disadvantage by public land programs. Extended use of this analytical technique could result in better public policy decisions on resource use.