bluuebunny/crossref_metadata_2025 huggingface dataset:
Renal and Cardiovascular Effects of Angiotensin-Converting Enzyme Inhibitor Plus Angiotensin II Receptor Antagonist Therapy in Children With Proteinuria
Authors: Lubrano Riccardo , Soscia Francesca , Elli Marco , Ventriglia Flavia , Raggi Claudia , Travasso Elisabetta , Scateni Simona , Di Maio Valeria , Versacci Paolo , Masciangelo Raffaele , Romero Stefano
Published: August 2006

OBJECTIVE. We investigated whether the combination of an angiotensin-converting enzyme inhibitor and an angiotensin II type 1 receptor antagonist offers better control of proteinuria and cardiovascular parameters without causing adverse side effects.

METHODS. We enrolled 10 children (mean age: 12.3 ± 4.06 years) with proteinuria resulting from chronic renal diseases of various causes. The study consisted of 2 phases, 3 months each, for an overall 6-month observation time. During phase 1 (3 months), each child was assigned randomly to treatment with either an angiotensin-converting enzyme inhibitor or an angiotensin II type 1 receptor antagonist alone. During phase 2, each child was advanced to combination therapy with the addition of an angiotensin II type 1 receptor antagonist or an angiotensin-converting enzyme inhibitor, respectively. Renal function tests, echocardiography, and 24-hour ambulatory blood pressure monitoring were performed at the beginning of the study (time 0), at 3 months (time 1), and at 6 months (time 2).

RESULTS. At time 2, proteinuria (change: −80.21 ± 10.75%), interventricular septum index (change: −13.63 ± 18.64%), posterior wall of the left ventricle index (change: −30.71 ± 20.32%), and left ventricular mass index (change: −28.33 ± 24.44%) were reduced significantly, compared with time 0 and time 1. No untoward side effects were detected during the study.

CONCLUSIONS. In the short term, the combination of angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor antagonists for children with proteinuria of renal origin reduced proteinuria significantly, compared with baseline or either drug alone. Furthermore, echocardiographic studies gave evidence of reduction of left ventricular hypertrophy. Additional studies are needed to evaluate long-term results.
Tenofovir Disoproxil Fumarate and an Optimized Background Regimen of Antiretroviral Agents as Salvage Therapy: Impact on Bone Mineral Density in HIV-Infected Children
Authors: Gafni Rachel I. , Hazra Rohan , Reynolds James C. , Maldarelli Frank , Tullio Antonella N. , DeCarlo Ellen , Worrell Carol J. , Flaherty John F. , Yale Kitty , Kearney Brian P. , Zeichner Steven L.
Published: August 2006

OBJECTIVE. Tenofovir disoproxil fumarate, a nucleotide analog HIV reverse transcriptase inhibitor with demonstrated activity against nucleoside-resistant HIV, is approved for use in adults but not children. Metabolic bone abnormalities have been seen in young animals given high-dose tenofovir and HIV-infected adults that were treated with oral tenofovir disoproxil fumarate. However, tenofovir disoproxil fumarate is being used in children despite a lack of bone safety data. We hypothesized that, given the higher rate of bone turnover that is associated with normal skeletal growth, the potential for TDF-related bone toxicity may be greater in children than in adults.

METHODS. Fifteen highly antiretroviral-experienced HIV-infected children who were 8 to 16 years of age (mean ± SD: 12 ± 2) and required a change in therapy received tenofovir disoproxil fumarate 175 to 300 mg/m2 per day (adult dose equivalent) as part of highly active antiretroviral therapy for up to 96 weeks. Bone mineral density of the lumbar spine, femoral neck, and total hip by dual-energy x-ray absorptiometry and blood and urine markers of bone metabolism were measured at 0, 24, 48, 72, and 96 weeks.

RESULTS. Median z score (SD score compared with age, gender, and ethnicity-matched control subjects) of the lumbar spine, femoral neck, and total hip were decreased from baseline at 24 weeks and 48 weeks and then stabilized. Lumbar spine bone mineral apparent density (which estimates volumetric bone mineral density independent of bone size) z scores also decreased at 24 weeks. Absolute decreases in bone mineral density were observed in 6 children; the mean age of these children was significantly younger than the bone mineral density stable group (10.2 ± 1.1 vs 13.2 ± 1.8 years). The change in lumbar spine bone mineral density correlated with decreases in HIV plasma RNA during treatment. Metabolic markers of bone formation and resorption were variable. Two children in whom tenofovir disoproxil fumarate was discontinued because of bone loss that exceeded protocol allowances demonstrated partial or complete recovery of bone mineral density by 96 weeks.

CONCLUSIONS. Tenofovir disoproxil fumarate use in children seems to be associated with decreases in bone mineral density that, in some children, stabilize after 24 weeks. Increases in bone markers and calcium excretion suggest that tenofovir disoproxil fumarate may stimulate bone resorption. Bone turnover is higher in children than in older adolescents and adults because of skeletal growth, potentially explaining the greater effect seen in young children. Decreases in bone mineral density correlate with decreases in viral load and young age, suggesting that young responders may be at greater risk for bone toxicity.
Urinary S100B Protein Concentrations Are Increased in Intrauterine Growth-Retarded Newborns
Authors: Florio Pasquale , Marinoni Emanuela , Di Iorio Romolo , Bashir Moataza , Ciotti Sabina , Sacchi Renata , Bruschettini Matteo , Lituania Mario , Serra Giovanni , Michetti Fabrizio , Petraglia Felice , Gazzolo Diego
Published: August 2006

BACKGROUND. Intrauterine growth retardation is one of the major causes of perinatal mortality and morbidity. To date, there are no reliable methods to detect brain damage in these patients.

METHODS. We conducted a case-control study in tertiary NICUs from December 2001 to December 2003 with 42 intrauterine growth retardation infants and 84 controls. Routine laboratory variables, neurologic outcome at 7-day follow-up, ultrasound imaging, and urine concentrations of S100B protein were determined at 5 time points. Urine S100B levels were measured by an immunoluminometric assay at first urination, 24, 48, and 72 hours, and 7 days after birth. Routine laboratory parameters and neurologic patterns were assessed at the same time as urine sampling.

RESULTS. S100B protein was significantly higher at all of the monitoring time points in urine taken from intrauterine growth retardation newborns than in control infants. When intrauterine growth retardation infants were corrected for the presence of abnormal (group A) or normal (group B) neurologic examination 7 days after birth, S100B was significantly higher at all of the predetermined monitoring time points in group A infants than in group B or controls. At a cutoff of 7.37 multiples of median at first urination, S100B achieved a sensitivity of 95% and a specificity of 99.1% as a single marker for predicting an adverse neurologic outcome. Twenty of 126 patients had neurologic abnormalities, making an overall prevalence of the disease in our population of 15.9% (pretest probability). With respect to the performance of S100B in predicting brain damage, its positive and negative predictive values were 91.0% and 99.0%, respectively.

CONCLUSIONS. Increased urine S100B protein levels in intrauterine growth retardation newborns in the first week after birth suggest the presence of brain damage reasonably because of intrauterine hypoxia. Longitudinal S100B protein measurements soon after birth are a useful tool to identify which intrauterine growth retardation infants are at risk of possible neurologic sequelae.
Median Nerve Conduction Velocity and Central Conduction Time Measured With Somatosensory Evoked Potentials in Thyroxine-Treated Infants With Down Syndrome
Authors: van Trotsenburg A. S. Paul , Smit Bert J. , Koelman Johannes H. T. M. , Dekker-van der Sloot Marijke , Ridder Jeannette C. D. , Tijssen Jan G. P. , de Vijlder Jan J. M. , Vulsma Thomas
Published: August 2006

OBJECTIVE. The aim of this study was to determine whether thyroxine treatment would improve nerve conduction in infants with Down syndrome.

METHODS. A single-center, nationwide, randomized, double-blind, clinical trial was performed. Neonates with Down syndrome were assigned randomly to thyroxine (N = 99) or placebo (N = 97) treatment for 2 years. Daily thyroxine doses were adjusted regularly to maintain plasma thyrotropin levels in the normal range and free thyroxine concentrations in the high-normal range. The outcome measures were nerve conduction velocity and central conduction time, determined through median nerve somatosensory evoked potential recording, at the age of 24 months.

RESULTS. At the age of 24 months, somatosensory evoked potential recordings for 81 thyroxine-treated and 84 placebo-treated infants were available for analysis. Nerve conduction velocity and central conduction time did not differ significantly between the 2 treatment groups (nerve conduction velocity: thyroxine: 51.0 m/second; placebo: 50.1 m/second; difference: 0.9 m/second; central conduction time: thyroxine: 8.83 milliseconds; placebo: 8.73 milliseconds; difference: 0.1 milliseconds).

CONCLUSIONS. Postnatal thyroxine treatment of infants with Down syndrome did not alter somatosensory evoked potential-measured peripheral or central nerve conduction significantly. The absence of favorable effects suggests that pathologic mechanisms other than mild postnatal hypothyroidism underlie the impaired nerve conduction. The absence of adverse effects suggests that longstanding plasma free thyroxine concentrations in the high-normal range are not harmful to nerve maturation.
Preferred Collagen Fiber Orientation in Human Peri-implant Bone After a Short- and Long-term Loading Period: A Case Report
Authors: Traini Tonino , Pecora Gabriele , Iezzi Giovanna , Piattelli Adriano
Published: August 2006

Immediate loading of dental implants offers treatment cost advantages to patients and avoids the functional and psychological problems caused by the wearing of provisional dentures. There is evidence that the amount of transverse collagen fiber orientation in bone is influenced by mechanical stresses and strains. Two osseointegrated dental implants in humans were used in the present study. Two implants inserted in the maxilla were analyzed: 1 short-term implant (implant A) immediately loaded and retrieved after 4 months of loading and 1 long-term implant (implant B) immediately loaded and retrieved after 12 years. We hypothesized that the bone functional strain caused by immediate loading correlated well with the collagen fiber organization occurring after both short- and long-term functional healing. Circularly polarized light (CPL) was used to assess the area fraction extension related to the transverse collagen fiber orientation in the bone matrix. After evaluating a total of 68 digitized images taken at ×50 magnification, birefringence measurements were performed all around the implant surfaces by using 2 central sections from each implant. The results showed that the bone-to-implant contact (BIC) percentage for implant A was 67.9% ± 9.5% (mean ± SD), whereas the BIC percentage for implant B was 74.6% ± 11.2% (mean ± SD). The area fraction extension was 2.7% ± 1.4 % (mean ± SD) for implant A, whereas the area fraction extension was 4.7% ± 1.2% (mean ± SD) for implant B. The CPL measurements of the birefringence for transverse collagen fibers of implant A vs implant B indicated that the bone fraction area difference was not high. In the bone near both dental implants, no differences were found in the amount of transverse collagen fibers. Immediate loading seemed to determine and maintain the collagen fiber's orientation over a long period.
Immediate Implant Placement: A Case Series
Authors: Hoffmann Oliver , Beaumont Christian , Zafiropoulos Gregor-Georg
Published: August 2006

A major drawback of implant therapy is the comparatively long healing period involved. Early and immediate loading of dental implants can significantly decrease the treatment time and thus result in an increase in patients' comfort. In this report, 3 cases of placement and immediate loading of the final implants are presented. In 2 of these cases, where preliminary augmentation was necessary, provisional implants were placed after the procedure and immediate provisional dentures were delivered. With the exception of 1 case, in which 1 implant failed, no adverse events were observed. All cases are in function now for 3 to 5 years after implant placement. The observations from this limited number of cases confirm that immediate loading of implants could be a viable treatment option.
Maxillary Single-tooth Replacement Utilizing a Novel Ceramic Restorative System: Results to 30 Months
Authors: Ormianer Zeev , Schiroli Guido
Published: August 2006

This study reports on the first longitudinal results of an alumina (70%)-zirconia (30%) ceramic restorative system for implant-supported, single-tooth replacement in the anterior maxillary jaw. Eighteen patients (9 men, 9 women, mean age = 42.4 years) were treated with 22 implants placed into 19 extraction sockets and 3 residual ridges. Eight implants were immediately loaded with nonoccluding provisional prostheses. All implants were definitively loaded with fully occluding ceramic restorations after osseointegration and soft tissue maturation. Patients were monitored from 7 to 30 months (mean = 18.1 months) after loading. All implants osseointegrated and were successfully restored. One case of abutment screw loosening occurred because of patient parafunction (bruxing), and another patient reported chewing pain attributed to malocclusion. Both problems were successfully resolved without further incidence. Within the context of this study, single-tooth replacement in the anterior maxillary jaw was successfully achieved with alumina-zirconia ceramic single-tooth restorations with up to 30 months of clinical function.
Centenary of the Discovery of Platinum in the Bushveld Complex
Authors: Cawthorn R. Grant
Published: August 2006

The earliest authenticated scientific report of the occurrence of platinum in rocks from the Bushveld Complex, South Africa, appears to be that of William Bettel on 10th November 1906. Thereafter, prospecting of the chromite-rich rocks for platinum proved frustrating. It is argued that the resurgence of interest by Dr Hans Merensky in 1924 resulted from his realisation that newly panned platinum had a grain size different from that in the chromite layers and indicated a different source rock, which he promptly located as the Merensky Reef.
Electro-Spun, Semiconducting, Oriented Fibres of Supramolecular Quasi-Linear Platinum Compounds
Authors: Fontana Margherita , Caseri Walter , Smith Paul
Published: August 2006

The semiconducting Magnus’salt derivatives [Pt(NH2eh)4][PtCl4] and [Pt(NH2dmoc)4][PtCl4], with eh = (R)-2-ethylhexyl and dmoc = (S)-3,7-dimethyloctyl, are compounds that exhibit a supramolecular structure comprising a backbone of linear arrays of platinum atoms. These compounds behave essentially like ordinary polymers. In this work they were processed into fibres by electrospinning from organic solvents such as toluene. X-ray diffraction patterns indicated that the platinum arrays in the fibres were oriented parallel to the axis of the fibres. Accordingly, the fibres show anisotropic optical and electrical properties. The electrical conductivities observed along the fibre axis were 2 × 10−5 S cm−1 for [Pt(NH2dmoc)4][PtCl4] and 7 × 10−7 S cm−1 for [Pt(NH2eh)4][PtCl4]. These exceeded the values for the respective bulk compounds by 2–3 orders of magnitude, in agreement with comparable observations in oriented semiconducting organic polymers.
Phoscorite-Carbonatite Pipe Complexes
Authors: Fontana Juarez
Published: August 2006

The background to a project in Brazil is described that has found promising concentrations of platinum group elements (PGEs) in phoscorite-carbonatite complexes. Further geochemical and mineralogical research is underway to determine their potential as ore deposits. The well-established industrial demand and current level of prices for the platinum group metals have encouraged the exploration of geological environments other than the layered maficultramafic intrusions that provide the bulk of platinum metals. Environments, such as the Ural-Alaskan Type Complexes (U-ATCs) and the associated placer deposits were for many years the only known sources of the PGEs. This paper attempts to show a connection between platiniferous dunite-pyroxenite pipes in the Ural Platinum Belt and those on the eastern margin of the Bushveld Complex, both being significant PGE producers in the past, and phoscoritecarbonatite pipe (PCP) complexes. PCP complexes may be a promising source of PGEs. Four Brazilian PCP complexes are sampled (Salitre, Tapira, Ipanema and Catalão) as well as the Phalaborwa PCP complex in South Africa.
The Minting of Platinum Roubles
Authors: Rehren Thilo
Published: August 2006

This paper augments a series of articles on Russian roubles in this Journal (–) with a summary of recent research into the manufacturing history and materials characterisation of these coins. The results are not only significant for the identification of genuine roubles issued between 1828 and 1845, ‘Novodel’issues produced in the late 19th century, and outright forgeries of the 20th century, but offer a fascinating insight into the difficulties encountered at the time in the large-scale refining and processing of platinum metal. A range of instrumental methods have been used to elucidate the magnetic properties, chemical composition and low density of genuine roubles, and to reveal their complex internal structure. The resulting new insights into the historical practice of platinum metallurgy are unbiased by concerns about industrial espionage, state secrets, and professional rivalry.
Thermophysical Properties of Palladium
Authors: Cagran Claus , Pottlacher Gernot
Published: August 2006

The results from fast-pulse heating experiments (of duration 60 μs) performed on pure palladium are presented. Thermophysical properties derived include specific enthalpy, enthalpy of fusion, electrical resistivity, isobaric heat capacity, thermal conductivity and thermal diffusivity, over a range of temperatures from the melting transition up to some hundred degrees higher in the liquid state. Additionally, normal spectral emissivity at wavelength 684.5 nm is presented,
Crystallographic Properties of Platinum
Authors: Arblaster J. W.
Published: August 2006

Equations are given to represent the lattice parameter thermal expansion of platinum from 293.15 K to the melting point at 2041.3 K. This treatment is intended to supersede a combination of dilatometric equations with corrections for thermal vacancy effects.
Random Chemistry as a New Tool for the Generation of Small‐Compound Libraries
Authors: Kapková Petra , Heller Eberhard , Kugelmann Eva , Faber Johan , Bringmann Gerhard , Kessler Ulrich , Folkers Gerd , Holzgrabe Ulrike
Published: August 2006

Advances in modern medicinal chemistry have enabled scientists to engineer new pathways aiming at the generation of novel chemical entities. Random chemistry, the serendipitous synthesis of small‐compound libraries by γ‐irradiation of a highly active lead compound or pharmacophoric fragments of active compounds, represents a complementary methodology, which provides both, compounds with resembling molecular structure and rearranged structures not previously known. Since the libraries are likely to be derived from radical chemistry, Fenton's reagent was applied to a methanol/water solution of tacrine to mimic the irradiation. Indeed, the experiment resulted in a similar product spectrum as found for tacrine in water and methanol solutions after 60Co irradiation. However, the application of Fenton's reagent is limited due to its poor solubility in organic solvents. Since the drugs we are aiming for should exhibit high water solubility, this limitation can be regarded as an advantage at the same time. Further extension of the random chemistry approach led to the successful irradiation of non‐active but drugable single fragments and combinations of fragments, i.e. the irradiation of tetrahydroisoquinoline and benzylamine, both being fragments of naphthylisoquinolines with antiplasmodial activity. The obtained isoquinoline derivatives were found to exhibit anti‐infective activities and thus are promising new lead structures.
Performance and microbial analysis of defined and non‐defined inocula for the removal of dimethyl sulfide in a biotrickling filter
Authors: Sercu B. , Boon N. , Beken S. Vander , Verstraete W. , Van Langenhove H.
Published: August 2006

The performance and microbial communities of three differently inoculated biotrickling filters removing dimethyl sulfide (DMS) were compared. The biotrickling filters were inoculated with Thiobacillus thioparus TK‐m (THIO), sludge (HANDS) and sludge + T. thioparus TK‐m + Hyphomicrobium VS (HANDS++), respectively. The criteria investigated were length of the start‐up period, the maximum elimination capacity, and the effects of intermittent loading rates, low pH, peak loading and very low loading rate on the DMS removal efficiency. The HANDS++ reactor exhibited the best performance considering all treatments. HANDS performed almost equally well as HANDS++, except during the determination of the ECmax, while THIO was generally the least efficient. During stable DMS loading at concentrations of 20 ppmv or lower, all reactors exhibited similar and high removal efficiencies (>99%). Denaturing gradient gel electrophoresis (DGGE) analysis showed the establishment of T. thioparus in the biofilm of all reactors, but not of Hyphomicrobium VS. Quantitative monitoring of the introduced bacterial strains was performed with a newly developed real‐time PCR protocol. Initially, the inoculated strains were exclusively found in the reactors in which they were added. Afterwards, however, both strains developed in the biofilm of all three reactors, although T. thioparus attained higher cell densities than Hyphomicrobium. The presence of T. thioparus in THIO was related with the DMS loading rates that were applied, in the sense that intermittent DMS loading and very low DMS loading rates (0.5 ppmv) induced a decrease in gene copy numbers. Real‐time PCR and DGGE both gave consistent results regarding the presence of Hyphomicrobium VS and Thiobacillus thioparus TK‐m in the reactors. Only real‐time PCR could be used to detect bacteria comprising of less than 1.4% of the total bacterial community (∼105 copies ring−1). Biotechnol. Bioeng. 2007;96:661–672. © 2006 Wiley Periodicals, Inc.
Harvesting and concentration of human influenza A virus produced in serum‐free mammalian cell culture for the production of vaccines
Authors: Kalbfuss Bernd , Genzel Yvonne , Wolff Michael , Zimmermann Anke , Morenweiser Robert , Reichl Udo
Published: August 2006

A process scheme for the harvesting and concentration of cell culture‐derived human influenza A virus is presented. The scheme comprises two static filtration steps, chemical inactivation by β‐propiolactone and cross‐flow ultrafiltration. Human influenza A virus A/PR/8/34 (H1N1) was produced in roller bottles with serum‐free medium using MDCK cells as a host. Cultivations resulted in specific hemagglutination (HA) activities of 393 HAU (100 µL)−1 and turbidities of 0.479 OD measured as the extinction of light at 700 nm (mean values are presented). The concentrations of soluble protein and DNA in the harvests were 72 µg/mL and 5.73 µg/mL, respectively. An average product yield of 79% based on HA activity was achieved after clarification by depth (85%) and microfiltration (93%). The turbidities of cell culture supernatants were reduced to 2% of their initial value. Concentration with 750 kDa hollow‐fiber modules by a factor of 20 resulted in 97% recovery of the product when operated at a constant flux of 28 L/(m2 h) and a wall shear rate of 9,500 s−1. The amount of protein and DNA could be reduced to 16% and 33% of their initial amount, respectively. An overall product yield of 77% was achieved. Clarified supernatants and concentrates were further analyzed by non‐reducing SDS–PAGE and agarose gel electrophoresis. Particle volume distributions of concentrates were obtained by dynamic light scattering analysis. From the results it can be concluded that the suggested process scheme is well suited for the harvesting and concentration of cell culture‐derived influenza A virus. Biotechnol. Bioeng. 2007;97:73–85. © 2006 Wiley Periodicals, Inc.
A new method for the joint visualization of vascular structures and connective tissues: Corrosion casting and 1 N NaOH maceration
Authors: Sangiorgi Simone , Manelli Alessandro , Dell'Orbo Carlo , Congiu Terenzio
Published: August 2006

Corrosion casting combined with scanning electron microscopy (SEM) has been widely used to study the morphofunctional aspects of microcirculation in many organs. In this study, we present an optimization of the corrosion casting (CC) technique associating it with NaOH 1 N maceration method to obtain a clear visualization of the relationships existing between the microvascular architecture of an organ and its extracellular matrix. Briefly, experiments were performed macerating the tissue previously injected with a low viscosity acrylic resin in 1 N NaOH and then observing it at SEM. In this study, we present an application of this technique to better evaluate the extracellular components of the vascular wall in medium‐sized and capillary vessels both in skin and in kidney. The results obtained yielded clear images of the three‐dimensional layout of medium‐sized and capillary vessels in comparison with the extracellular environment. Furthermore, detailed information was obtained on the three‐dimensional layout of fibers constituting the walls of venules, arterioles, and capillaries. In addition, the tubular collagenic structures surrounding the excretory tubules of the kidney and the dermal glands of the skin were depicted and their relationships with their vascular supply described in detail. Microsc. Res. Tech. © 2006 Wiley‐Liss, Inc.
Laparoscopic Surgery Principles and Procedures
Authors: Hunt Elizabeth
Published: August 2006

Laparoscopic Surgery Principles and Procedures Edited by Daniel B. Jones, Justin S. Wu, Nathaniel J. Soper 1997, 489 pp $82 hardbound
Patterns of Rogerian Knowing
Authors: King Cecil A.
Published: August 2006

Patterns of Rogerian Knowing Edited by Mary Madrid 1997, 290 pp $25.95 paperback
Goldfishing by gauge theory
Authors: Calogero F. , Langmann E.
Published: August 2006

A new solvable many-body problem of goldfish type is identified and used to revisit the connection between two different approaches to solvable dynamical systems. An isochronous variant of this model is identified and investigated. Alternative versions of these models are presented. The behavior of the alternative isochronous model near its equilibrium configurations is investigated, and a remarkable Diophantine result, as well as related Diophantine conjectures, are thereby obtained.
Side population in adult murine epidermis exhibits phenotypic and functional characteristics of keratinocyte stem cells
Authors: Redvers Richard P. , Li Amy , Kaur Pritinder
Published: August 2006

Based on functional studies in the bone marrow, it has been suggested that the ability to efflux Hoechst 33342 may represent a universal stem cell trait. In this phenotypic and functional characterization of the Hoechst side population (SP) in adult murine epidermis, we demonstrate that these cells are a rare subset of the keratinocyte stem cell-enriched α
6
bri
CD71
dim
fraction comprising SSC
low
/K14
+
/CD34
−
/Oil red O
−
/c-
kit
−
/CD45
−
keratinocytes. Epidermal SPs have the smallest cell and nuclear size but exhibit the highest nuclear-to-cytoplasmic ratio of any fraction examined, consistent with a primitive cell type. Although SPs demonstrated poor cumulative
in vitro
proliferative output, they exhibited sustained epidermal tissue-regenerative activity
in vivo
compared with unfractionated and non-SP cells. Collectively, these results indicate that the epidermal SP contains the most potent keratinocyte stem cell population in skin epithelium.
The violation of the Stokes–Einstein relation in supercooled water
Authors: Chen Sow-Hsin , Mallamace Francesco , Mou Chung-Yuan , Broccio Matteo , Corsaro Carmelo , Faraone Antonio , Liu Li
Published: August 2006

By confining water in nanopores, so narrow that the liquid cannot freeze, it is possible to explore its properties well below its homogeneous nucleation temperature
T
H
≈ 235 K. In particular, the dynamical parameters of water can be measured down to 180 K, approaching the suggested glass transition temperature
T
g
≈ 165 K. Here we present experimental evidence, obtained from Nuclear Magnetic Resonance and Quasi-Elastic Neutron Scattering spectroscopies, of a well defined decoupling of transport properties (the self-diffusion coefficient and the average translational relaxation time), which implies the breakdown of the Stokes–Einstein relation. We further show that such a non-monotonic decoupling reflects the characteristics of the recently observed dynamic crossover, at ≈225 K, between the two dynamical behaviors known as fragile and strong, which is a consequence of a change in the hydrogen bond structure of liquid water.
Myeloid lineage progenitors give rise to vascular endothelium
Authors: Bailey Alexis S. , Willenbring Holger , Jiang Shuguang , Anderson Daniel A. , Schroeder David A. , Wong Melissa H. , Grompe Markus , Fleming William H.
Published: August 2006

Despite an important role in vascular development and repair, the origin of endothelial progenitors remains unknown. Accumulating evidence indicates that cells derived from the hematopoietic system participate in angiogenesis. However, the identity and functional role of these cells remain controversial. Here we show that vascular endothelial cells can differentiate from common myeloid progenitors and granulocyte/macrophage progenitors. Endothelial cells derived from transplanted bone marrow-derived myeloid lineage progenitors expressed CD31, von Willebrand factor, and Tie2 but did not express the hematopoietic markers CD45 and F4/80 or the pericyte markers desmin and smooth muscle actin. Lineage tracing analysis in combination with a Tie2-driven Cre/lox reporter system revealed that, in contrast to bone marrow-derived hepatocytes, bone marrow-derived endothelial cells are not the products of cell fusion. The establishment of both hematopoietic and endothelial cell chimerism after parabiosis demonstrates that circulating cells can give rise to vascular endothelium in the absence of acute radiation injury. Our findings indicate that endothelial cells are an intrinsic component of myeloid lineage differentiation and underscore the close functional relationship between the hematopoietic and vascular systems.
Spectroscopic and electronic structure studies of aromatic electrophilic attack and hydrogen-atom abstraction by non-heme iron enzymes
Authors: Neidig Michael L. , Decker Andrea , Choroba Oliver W. , Huang Fanglu , Kavana Michael , Moran Graham R. , Spencer Jonathan B. , Solomon Edward I.
Published: August 2006

(4-Hydroxy)mandelate synthase (HmaS) and (4-hydroxyphenyl)pyruvate dioxygenase (HPPD) are two α-keto acid dependent mononuclear non-heme iron enzymes that use the same substrate, (4-hydroxyphenyl)pyruvate, but exhibit two different general reactivities. HmaS performs hydrogen-atom abstraction to yield benzylic hydroxylated product (
S
)-(4-hydroxy)mandelate, whereas HPPD utilizes an electrophilic attack mechanism that results in aromatic hydroxylated product homogentisate. These enzymes provide a unique opportunity to directly evaluate the similarities and differences in the reaction pathways used for these two reactivities. An Fe
II
methodology using CD, magnetic CD, and variable-temperature, variable-field magnetic CD spectroscopies was applied to HmaS and compared with that for HPPD to evaluate the factors that affect substrate interactions at the active site and to correlate these to the different reactivities exhibited by HmaS and HPPD to the same substrate. Combined with density functional theory calculations, we found that HmaS and HPPD have similar substrate-bound complexes and that the role of the protein pocket in determining the different reactivities exhibited by these enzymes (hydrogen-atom abstraction vs. aromatic electrophilic attack) is to properly orient the substrate, allowing for ligand field geometric changes along the reaction coordinate. Elongation of the Fe
IV

O bond in the transition state leads to dominant Fe
III

O
•−
character, which significantly contributes to the reactivity with either the aromatic π-system or the C

H σ-bond.
An internally controlled peripheral biomarker for Alzheimer’s disease: Erk1 and Erk2 responses to the inflammatory signal bradykinin
Authors: Khan Tapan K. , Alkon Daniel L.
Published: August 2006

Cognitive impairment has recently been found to correlate with changes in peripheral inflammatory signals such as TNF-α and IL-1β. PKC isozymes regulate levels of TNF-α and IL-6 and the release of other cytokines and also show deficits in Alzheimer’s disease (AD) brains and skin fibroblasts. Here, we investigate MAPK Erk1 and Erk2 phosphorylation in response to the inflammatory agonist bradykinin, which activates PKC pathways. An internally controlled comparison of Erk1 and Erk2 produced an AD index that accurately distinguished fibroblasts of AD from those of normal controls and of non-AD dementias. This accuracy was demonstrated for Coriell Cell Repository (Coriell Institute of Medical Research, Camden, NJ) samples, as well as for samples analyzed on gels with autopsy diagnostic confirmation. AD Erk1 and Erk2 index values were inversely correlated with disease duration, suggesting maximal efficacy for early diagnosis. Finally, the results also demonstrate that, when the AD index agreed with the clinical diagnosis on the presence of AD, there was a high probability of accuracy based on autopsy validation. Thus, this peripheral molecular biomarker, based on differential Erk1 and Erk2 phosphorylation, could have important clinical utility for providing increased certainty in the positive diagnosis of AD, particularly in the early phase of disease progression.
Single-molecule mechanics of mussel adhesion
Authors: Lee Haeshin , Scherer Norbert F. , Messersmith Phillip B.
Published: August 2006

The glue proteins secreted by marine mussels bind strongly to virtually all inorganic and organic surfaces in aqueous environments in which most adhesives function poorly. Studies of these functionally unique proteins have revealed the presence of the unusual amino acid 3,4-dihydroxy-
l
-phenylalanine (dopa), which is formed by posttranslational modification of tyrosine. However, the detailed binding mechanisms of dopa remain unknown, and the chemical basis for mussels’ ability to adhere to both inorganic and organic surfaces has never been fully explained. Herein, we report a single-molecule study of the substrate and oxidation-dependent adhesive properties of dopa. Atomic force microscopy (AFM) measurements of a single dopa residue contacting a wet metal oxide surface reveal a surprisingly high strength yet fully reversible, noncovalent interaction. The magnitude of the bond dissociation energy as well as the inability to observe this interaction with tyrosine suggests that dopa is critical to adhesion and that the binding mechanism is not hydrogen bond formation. Oxidation of dopa, as occurs during curing of the secreted mussel glue, dramatically reduces the strength of the interaction to metal oxide but results in high strength irreversible covalent bond formation to an organic surface. A new picture of the interfacial adhesive role of dopa emerges from these studies, in which dopa exploits a remarkable combination of high strength and chemical multifunctionality to accomplish adhesion to substrates of widely varying composition from organic to metallic.
Regulation of outside-in signaling and affinity by the β2I domain of integrin αLβ2
Authors: Chen JianFeng , Yang Wei , Kim Minsoo , Carman Christopher V. , Springer Timothy A.
Published: August 2006

The adhesiveness of integrin αLβ2is modulated by divalent cations. We mutated three metal ion-binding sites in the β2I domain. The metal ion-dependent adhesion site (MIDAS) and the ligand-induced metal-binding site are required for ligand binding and sufficient for synergism between Ca2+and Mg2+. Adjacent to MIDAS (ADMIDAS) mutants are constitutively active but remain bent, with poor exposure of a β2stalk region epitope. Fluorescence resonance energy transfer between fluorescent protein-fused αLand β2cytoplasmic domains showed that ADMIDAS mutation abrogated ligand binding-induced spatial separation of cytoplasmic domains. Furthermore, ADMIDAS mutation abolished spreading on ligand-bearing substrates. Thus, β2I domain metal ion-binding sites regulate αLI domain affinity, and the ADMIDAS is required for outside-in signaling.
Spermatozoa and spermatids retrieved from frozen reproductive organs or frozen whole bodies of male mice can produce normal offspring
Authors: Ogonuki Narumi , Mochida Keiji , Miki Hiromi , Inoue Kimiko , Fray Martin , Iwaki Takamasa , Moriwaki Kazuo , Obata Yuichi , Morozumi Kazuto , Yanagimachi Ryuzo , Ogura Atsuo
Published: August 2006

Cryopreservation of male germ cells is a strategy to conserve animal species and strains of animals valuable to biomedical research. We tested whether mouse male germ cells could be cryopreserved without cryoprotection by simply freezing epididymides, testes, or whole bodies. The reproductive organs were isolated from killed mice and frozen for 1 week to 1 year at −80°C before spermatozoa and spermatids were collected and injected into mature oocytes. Normal pups were born irrespective of strains tested (ICR and C57BL/6). Epididymides and testes frozen and transported internationally to another laboratory by air could produce pups of inbred C57BL/6 mice. Testicular spermatozoa retrieved from the bodies of male mice (BALB/c nude and C3H/He strains) that had been kept frozen (−20°C) for 15 years could also produce normal offspring by microinsemination. Thus, freezing of either male reproductive organs or whole bodies is the simplest way to preserve male germ cells. Restoration of extinct species could be possible if male individuals are found in permafrost.
Brd4 links chromatin targeting to HPV transcriptional silencing
Authors: Wu Shwu-Yuan , Lee A-Young , Hou Samuel Y. , Kemper Jongsook Kim , Erdjument-Bromage Hediye , Tempst Paul , Chiang Cheng-Ming
Published: August 2006

The E2 protein encoded by human papillomaviruses (HPVs) inhibits expression of the viral E6 oncoprotein, which, in turn, regulates p53 target gene transcription. To identify cellular proteins involved in E2-mediated transcriptional repression, we isolated an E2 complex from human cells conditionally expressing HPV-11 E2. Surprisingly, the double bromodomain-containing protein Brd4, which is implicated in cell cycle control and viral genome segregation, was found associated with E2 and conferred on E2 the ability to inhibit AP-1-dependent HPV chromatin transcription in an E2-binding site-specific manner as illustrated by in vitro reconstituted chromatin transcription experiments. Knockdown of Brd4 in human cells alleviates E2-mediated repression of HPV transcription. The E2-interacting domain at the extreme C terminus and the chromatin targeting activity of a bromodomain-containing region are both essential for the corepressor activity of Brd4. Interestingly, E2–Brd4 blocks the recruitment of TFIID and RNA polymerase II to the HPV E6 promoter region without inhibiting acetylation of nucleosomal histones H3 and H4, indicating an acetylation-dependent role of Brd4 in the recruitment of E2 for transcriptional silencing of HPV gene activity. Our finding that Brd4 is a component of the virus-assembled transcriptional silencing complex uncovers a novel function of Brd4 as a cellular cofactor modulating viral gene expression.
Integrin-linked kinase, a novel component of the cardiac mechanical stretch sensor, controls contractility in the zebrafish heart
Authors: Bendig Garnet , Grimmler Matthias , Huttner Inken G. , Wessels Georgia , Dahme Tillman , Just Steffen , Trano Nicole , Katus Hugo A. , Fishman Mark C. , Rottbauer Wolfgang
Published: August 2006

The vertebrate heart possesses autoregulatory mechanisms enabling it first to sense and then to adapt its force of contraction to continually changing demands. The molecular components of the cardiac mechanical stretch sensor are mostly unknown but of immense medical importance, since dysfunction of this sensing machinery is suspected to be responsible for a significant proportion of human heart failure. In the hearts of the ethylnitros-urea (ENU)-induced, recessive embryonic lethal zebrafish heart failure mutant main squeeze (msq), we find stretch-responsive genes such as atrial natriuretic factor (anf) and vascular endothelial growth factor (vegf) severely down-regulated. We demonstrate through positional cloning that heart failure in msq mutants is due to a mutation in the integrin-linked kinase (ilk) gene. ILK specifically localizes to costameres and sarcomeric Z-discs. The msq mutation (L308P) reduces ILK kinase activity and disrupts binding of ILK to the Z-disc adaptor protein β-parvin (Affixin). Accordingly, in msq mutant embryos, heart failure can be suppressed by expression of ILK, and also of a constitutively active form of Protein Kinase B (PKB), and VEGF. Furthermore, antisense-mediated abrogation of zebrafish β-parvin phenocopies the msq phenotype. Thus, we provide evidence that the heart uses the Integrin–ILK–β-parvin network to sense mechanical stretch and respond with increased expression of ANF and VEGF, the latter of which was recently shown to augment cardiac force by increasing the heart's calcium transients.
Transcriptional Coordination of the Metabolic Network in Arabidopsis
Authors: Wei Hairong , Persson Staffan , Mehta Tapan , Srinivasasainagendra Vinodh , Chen Lang , Page Grier P. , Somerville Chris , Loraine Ann
Published: August 2006

Patterns of coexpression can reveal networks of functionally related genes and provide deeper understanding of processes requiring multiple gene products. We performed an analysis of coexpression networks for 1,330 genes from the AraCyc database of metabolic pathways in Arabidopsis (Arabidopsis thaliana). We found that genes associated with the same metabolic pathway are, on average, more highly coexpressed than genes from different pathways. Positively coexpressed genes within the same pathway tend to cluster close together in the pathway structure, while negatively correlated genes typically occupy more distant positions. The distribution of coexpression links per gene is highly skewed, with a small but significant number of genes having numerous coexpression partners but most having fewer than 10. Genes with multiple connections (hubs) tend to be single-copy genes, while genes with multiple paralogs are coexpressed with fewer genes, on average, than single-copy genes, suggesting that the network expands through gene duplication, followed by weakening of coexpression links involving duplicate nodes. Using a network-analysis algorithm based on coexpression with multiple pathway members (pathway-level coexpression), we identified and prioritized novel candidate pathway members, regulators, and cross pathway transcriptional control points for over 140 metabolic pathways. To facilitate exploration and analysis of the results, we provide a Web site (http://www.transvar.org/at_coexpress/analysis/web) listing analyzed pathways with links to regression and pathway-level coexpression results. These methods and results will aid in the prioritization of candidates for genetic analysis of metabolism in plants and contribute to the improvement of functional annotation of the Arabidopsis genome.
Spatial Imaging, Speciation, and Quantification of Selenium in the Hyperaccumulator PlantsAstragalus bisulcatusandStanleya pinnata
Authors: Freeman John L. , Zhang Li Hong , Marcus Matthew A. , Fakra Sirine , McGrath Steve P. , Pilon-Smits Elizabeth A.H.
Published: August 2006

Astragalus bisulcatus and Stanleya pinnata hyperaccumulate selenium (Se) up to 1% of plant dry weight. In the field, Se was mostly present in the young leaves and reproductive tissues of both hyperaccumulators. Microfocused scanning x-ray fluorescence mapping revealed that Se was hyperaccumulated in trichomes in young leaves of A. bisulcatus. None of 10 other elements tested were accumulated in trichomes. Micro x-ray absorption spectroscopy and liquid chromatography-mass spectrometry showed that Se in trichomes was present in the organic forms methylselenocysteine (MeSeCys; 53%) and γ-glutamyl-MeSeCys (47%). In the young leaf itself, there was 30% inorganic Se (selenate and selenite) in addition to 70% MeSeCys. In young S. pinnata leaves, Se was highly concentrated near the leaf edge and surface in globular structures that were shown by energy-dispersive x-ray microanalysis to be mainly in epidermal cells. Liquid chromatography-mass spectrometry revealed both MeSeCys (88%) and selenocystathionine (12%) inside leaf edges. In contrast, both the Se accumulator Brassica juncea and the nonaccumulator Arabidopsis thaliana accumulated Se in their leaf vascular tissues and mesophyll cells. Se in hyperaccumulators appears to be mobile in both the xylem and phloem because Se-treated S. pinnata was found to be highly toxic to phloem-feeding aphids, and MeSeCys was present in the vascular tissues of a S. pinnata young leaf petiole as well as in guttation fluid. The compartmentation of organic selenocompounds in specific storage areas in the plant periphery appears to be a unique property of Se hyperaccumulators. The high concentration of Se in the plant periphery may contribute to Se tolerance and may also serve as an elemental plant defense mechanism.
Computational Estimation and Experimental Verification of Off-Target Silencing during Posttranscriptional Gene Silencing in Plants
Authors: Xu Ping , Zhang Yuanji , Kang Li , Roossinck Marilyn J. , Mysore Kirankumar S.
Published: August 2006

Successful application of posttranscriptional gene silencing (PTGS) for gene function study in both plants and animals depends on high target specificity and silencing efficiency. By computational analysis with genome and/or transcriptome sequences of 25 plant species, we predicted that about 50% to 70% of gene transcripts in plants have potential off-targets when used for PTGS that could obscure experimental results. We have developed a publicly available Web-based computational tool called siRNA Scan to identify potential off-targets during PTGS. Some of the potential off-targets obtained from this tool were tested by measuring the amount of off-target transcripts using quantitative reverse transcription-PCR. Up to 50% of the predicted off-target genes tested in plants were actually silenced when tested experimentally. Our results suggest that a high risk of off-target gene silencing exists during PTGS in plants. Our siRNA Scan tool is useful to design better constructs for PTGS by minimizing off-target gene silencing in both plants and animals.