bluuebunny/crossref_metadata_2025 huggingface dataset:
Low dose beta‐blocker prevents ovariectomy‐induced bone loss in rats without affecting heart functions
Authors: Bonnet N. , Benhamou C.L. , Malaval L. , Goncalves C. , Vico L. , Eder V. , Pichon C. , Courteix D.
Published: August 2008

Findings from animal studies have suggested that bone remodeling is under beta‐adrenergic control. However, the level of adrenergic inhibition required to achieve the most favorable effects on the skeleton remains unknown. To address this question, we compared the effects of low (0.1 mg/Kg/day), medium (5 mg/Kg/day) or high (20 mg/Kg/day) doses of propranolol given 5 days per week for 10 weeks in ovariectomized (OVX) rats. Characteristics of bone microarchitecture, biomechanical properties and bone turnover were investigated, whilst heart functions were assessed by echocardiography and catheterization of the left ventricle. We first confirmed the expression of Adrβ2R and the absence of Adrβ1R on osteoblasts by PCR and confocal microscopy. We then showed that low dose propranolol prevented OVX induced bone loss by increasing bone formation (+30% of MAR vs. placebo, P = 0.01) and decreasing bone resorption (−52% of osteoclast surface on bone surface vs. placebo, P = 0.01). Consequently, rats receiving 0.1 mg/kg/day propranolol displayed higher stress (+27%), intrinsic energy (+28.7%) and Young's Modulus in compression versus placebo (all, P < 0.05). No significant effects on heart hemodynamic parameters were found in rats receiving this dose. In contrast, medium and high doses of propranolol had a negative effect on heart functions but no significant protective effects on bone mass in ovariectomized rats. These results, consistent with the dominant nature of the high bone mass phenotype and normal heart function of Adrβ2R‐deficient mice, suggest that low doses of β‐blockers may have a therapeutic utility in the treatment of osteoporosis with high selectivity for bone tissues. J. Cell. Physiol. 217: 819–827, 2008. © 2008 Wiley‐Liss, Inc.
Calpain‐mediated androgen receptor breakdown in apoptotic prostate cancer cells
Authors: Yang Huanjie , Murthy Shalini , Sarkar Fazlul H. , Sheng Shijie , Reddy G. Prem‐Veer , Dou Q. Ping
Published: August 2008

Since androgen receptor (AR) plays an important role in prostate cancer development and progression, androgen‐ablation has been the frontline therapy for treatment of advanced prostate cancer even though it is rarely curative. A curative strategy should involve functional and structural elimination of AR from prostate cancer cells. We have previously reported that apoptosis induced by medicinal proteasome‐inhibitory compound celastrol is associated with a decrease in AR protein levels. However celastrol‐stimulated events contributing to this AR decrease have not been elucidated. Here, we report that a variety of chemotherapeutic agents, including proteasome inhibitors, a topoisomerase inhibitor, DNA‐damaging agents and docetaxel that cause cell death, decrease AR levels in LNCaP prostate cancer cells. This decrease in AR protein levels was not due to the suppression of AR mRNA expression in these cells. We observed that a proteolytic activity residing in cytosol of prostate cancer cells is responsible for AR breakdown and that this proteolytic activity was stimulated upon induction of apoptosis. Interestingly, proteasome inhibitor celastrol‐ and chemotherapeutic drug VP‐16‐stimulated AR breakdown was attenuated by calpain inhibitors calpastatin and N‐acetyl‐L‐leucyl‐L‐leucyl‐L‐methioninal. Furthermore, AR proteolytic activity pulled down by calmodulin‐agarose beads from celastrol‐treated PC‐3 cells showed immunoreactivity to a calpain antibody. Taken together, these results demonstrate calpain involvement in proteasome inhibitor‐induced AR breakdown, and suggest that AR degradation is intrinsic to the induction of apoptosis in prostate cancer cells. J. Cell. Physiol. 217: 569–576, 2008. © 2008 Wiley‐Liss, Inc.
The effect of differentiation on 1,25 dihydroxyvitamin D‐mediated gene expression in the enterocyte‐like cell line, Caco‐2
Authors: Cui Min , Klopot Anna , Jiang Yan , Fleet James C.
Published: August 2008

We examined 1,25 dihydroxyvitamin D (1,25(OH)2D3)‐induced expression of 25‐hydroxyvitamin D3 24‐hydroxylase (CYP24) and apical calcium channel (TRPV6) mRNA levels in 2‐, 9‐, and 15‐day cultures Caco‐2 cells that model proliferating, post‐proliferative, and differentiated enterocytes. 1,25(OH)2D3‐induced (10 nM, 8 h) CYP24 and TRPV6 mRNA levels were significantly greater in differentiated and post‐proliferative than proliferating Caco‐2 cells (>16X and >3X, respectively). Neither CYP24 mRNA half‐life nor induction of a −298 bp rat CYP24 promoter‐luciferase reporter construct (10 nM 1,25(OH)2D3, 24 h) were different between proliferating and post‐proliferating Caco‐2 cells. We next tested whether the blunted response of natural genes to 1,25(OH)2D3 in proliferating Caco‐2 cells is due to altered chromatin remodeling. VDR and coactivator protein levels do not increase with differentiation but the level of the co‐repressor Alien falls by 50% with differentiation. Over‐expression of Alien reduced 1,25(OH)2D3‐induced activity of a minimal VDRE containing promoter‐luciferase construct by more than 60% in differentiated Caco‐2 cells while siRNA knockdown of Alien in proliferating Caco‐2 cells increased 1,25(OH)2D3‐induced CYP24 mRNA level by 40%. These observations suggest that Alien is a regulator of VDR‐mediated gene transcription in Caco‐2 cells. In addition, we found that 1,25(OH)2D3‐induced association of VDR with chromatin and with the CYP24 promoter was lower in proliferating cells. This suggests that decreased recruitment of VDR to vitamin D response elements also contributes to the blunted transcriptional responsiveness to 1,25(OH)2D3 in proliferating Caco‐2 cells. J. Cell. Physiol. 218: 113–121, 2009. © 2008 Wiley‐Liss, Inc.
Composition and significance of detergent resistant membranes in mouse spermatozoa
Authors: Nixon Brett , Bielanowicz Amanda , Mclaughlin Eileen A. , Tanphaichitr Nongnuj , Ensslin Michael A. , Aitken R. John
Published: August 2008

Mammalian spermatozoa acquire the ability to fertilize an oocyte as they ascend the female reproductive tract. This process is characterized by a complex cascade of biophysical and biochemical changes collectively know as “capacitation.” The attainment of a capacitated state is accompanied by a dramatic reorganization of the surface architecture to render spermatozoa competent to recognize the oocyte and initiate fertilization. Emerging evidence indicates that this process is facilitated by molecular chaperone‐mediated assembly of a multimeric receptor complex on the sperm surface. However, the mechanisms responsible for gathering key recognition molecules within this putative complex have yet to be defined. In this study, we provide the first evidence that chaperones partition into detergent resistant membrane fractions (DRMs) within capacitated mouse spermatozoa and co‐localize in membrane microdomains enriched with the lipid raft marker, GM1 ganglioside. During capacitation, these microdomains coalesce within the apical region of the sperm head, a location compatible with a role in sperm–zona pellucida interaction. Significantly, DRMs isolated from spermatozoa possessed the ability to selectively bind to the zona pellucida of unfertilized, but not fertilized, mouse oocytes. A comprehensive proteomic analysis of the DRM fractions identified a total of 100 proteins, a number of which have previously been implicated in sperm–oocyte interaction. Collectively, these data provide compelling evidence that mouse spermatozoa possess membrane microdomains that provide a platform for the assembly of key recognition molecules on the sperm surface and thus present an important mechanistic insight into the fundamental cell biological process of sperm–oocyte interaction. J. Cell. Physiol. 218: 122–134, 2009. © 2008 Wiley‐Liss, Inc.
First‐trimester prenatal sonographic diagnosis of omphalocele‐exstrophy‐imperforate anus‐spinal defects complex
Authors: Wax Joseph R. , Pinette Michael G. , Smith Rosemarie , Cartin Angelina , Blackstone Jacquelyn
Published: August 2008

We describe a case of omphalocele‐exstrophy‐imperforate anus‐spinal defects (OEIS) diagnosed at 13 weeks' gestation by ultrasound detection of a large multilocular ventral wall mass into which inserted the umbilical cord, and thoracic hemivertebrae with kyphoscoliosis. Subsequent sonographic examinations at 16 and 19 weeks revealed evolution of the ventral wall mass into a classic omphalocele. Clinicians should recognize the significance of a large multicystic ventral wall mass, which should lead to a search for other anomalies suggestive of OEIS complex. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Reappraisal of endosonography of ampullary tumors: Correlation with transabdominal sonography, CT, and MRI
Authors: Chen Chien‐Hua , Yang Chi‐Chieh , Yeh Yung‐Hsiang , Chou Der‐Aur , Nien Chiu‐Kue
Published: August 2008

Purpose.

To reappraise the accuracy of transabdominal sonography (US), CT, MRI, and endosonography (EUS) in the diagnosis and staging of ampullary tumors.

Method.

We reviewed the medical records and the images of 41 consecutive patients with ampullary tumors. Tumor detection rate and accuracy of TNM (tumor–node–metastasis) staging of malignant tumors were determined. Imaging findings were correlated with histopathologic findings.

Results.

The detection rates for ampullary tumors were 97.6% for EUS, 81.3% for MRI, 28.6% for CT, and 12.2% for US (p < 0.001 for EUS versus CT; p < 0.001 for EUS versus US; p > 0.05 for EUS versus MRI). The accuracy in T staging for ampullary carcinomas was 72.7% for EUS, 53.8% for MRI, and 26.1% for CT (p < 0.01 for EUS versus CT; p > 0.05 for EUS versus MRI). The accuracy in N staging for ampullary carcinomas was 66.7% for EUS, 76.9% for MRI, and 43.5% for CT with no statistically significant difference between the 3 modalities. The sensitivity in detecting malignant lymph nodes was 46.7% for EUS, 25.0% for MRI, and 0% for CT (p < 0.01 for EUS versus CT; p > 0.05 for EUS versus MRI; p > 0.05 for MRI versus CT). Transpapillary stenting, advanced tumor extension (>T2), large tumor size (>2 cm), tumor differentiation, and endoscopic appearance of tumor growth did not significantly influence EUS accuracy in T or N staging (p > 0.05).

Conclusion.

EUS was superior to CT and was equivalent to MRI for tumor detection and T and N staging of ampullary tumors. Neither indwelling stents nor tumor size, differentiation, or endoscopic appearance affected the staging accuracy of EUS. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Sustained baculovirus‐mediated expression in myogenic cells
Authors: Shen Heng‐Chun , Yeh Chia‐Ni , Chen Guan‐Yu , Huang Shiu‐Feng , Chen Chi‐Yuan , Chiu Yung‐Chung , Hu Yu‐Chen
Published: August 2008

Background

Baculovirus has emerged as a promising gene delivery vector due to its low cytotoxicity and nonreplication nature in mammalian cells. However, baculovirus‐mediated expression is transient and generally lasts less than 14 days, which could restrict its application in the treatment of diseases requiring stable transgene expression.

Methods

We transduced myoblast cell lines C2C12, Sol 8 and primary myoblasts with a baculovirus expressing the enhanced green fluorescent protein (EGFP) under the control of cytomegalovirus immediate‐early promoter and measured the transduction efficiency by flow cytometry. Myogenic differentiation was induced after transduction and the longevity of EGFP expression was monitored by fluorescence microscopy. The myogenic differentiation was confirmed by reverse transcription‐polymerase chain reaction (RT‐PCR). The persistence of the egfp DNA and transcripts was monitored by real‐time PCR and quantitative real‐time RT‐PCR.

Results

Baculovirus efficiently transduced C2C12, Sol 8 and the primary myoblasts. The transgene expression persisted for a prolonged period of time (at least 63 days) in the cells differentiating into myotubes, but was transient in HeLa cells (<7 days). The sustained expression paralleled the myogenic differentiation and stemmed from the intracellular persistence of egfp DNA and mRNA.

Conclusions

The transgene delivered by baculovirus persists in the myotubes and endows sustained expression, which is distinct from its rapid degradation and transient expression in other cell types. These findings justify the future use of baculovirus for muscle‐based gene therapy. Copyright © 2008 John Wiley & Sons, Ltd.
Triangulations and the Hajós conjecture
Authors: Rödl Vojtěch , Zich Jan
Published: August 2008

In his recent work Thomassen [J Combin Theory Ser B 93 (2005), 95–105] discussed various refinements of Hajós conjecture. Shortly after Mohar [Electr J Combin 12 (2005), N15] provided an answer to Thomassen's Conjecture 6.5, and proposed a possible extension. The aim of this article is to address Mohar's suggestion. In particular, we prove that, for infinitely many integers m, there exists a graph on m vertices forming a triangulation of an orientable surface so that it does not contain a subdivision of a clique of size $O(m^{1/2})$ , and its chromatic number is at least $m^{{2/3} + o(1)}$. The main part of the proof is to show that the random graph can be almost covered by oriented triangles which do not contain certain forbidden configurations. We use a technique similar to the ones of Archdeacon and Grable [Discrete Math 142(1–3)(1995), 21–37] and Thomas and the first author [Random Struct Algorithms 6(1) (1995), 1–12]. We obtain a strengthening by replacing the “nibble” method by “random bites” used by Alon et al. [Israel J Math 100 (1997), 171–187]. © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 293–325, 2008
The size of edge chromatic critical graphs with maximum degree 6
Authors: Luo Rong , Miao Lianying , Zhao Yue
Published: August 2008

In 1968, Vizing [Uaspekhi Mat Nauk 23 (1968) 117–134; Russian Math Surveys 23 (1968), 125–142] conjectured that for any edge chromatic critical graph ${{G}} = ({{V}}, {{E}})$ with maximum degree $\Delta$, $|{{E}}| \geq {{{1}}\over {{2}}}\{(\Delta {{- 1}})|{{V}}| + {{3}}\}$. This conjecture has been verified for $\Delta \leq {{5}}$. In this article, by applying the discharging method, we prove the conjecture for $\Delta = {{6}}$. © 2008 Wiley Periodicals, Inc. J Graph Theory 60: 149–171, 2009
Development of 99mTc‐thioflavin‐T derivatives for detection of systemic amyloidosis
Authors: Serdons K. , Verduyckt T. , Cleynhens J. , Bormans G. , Verbruggen A.
Published: August 2008

In a search for a 99mTc‐labelled tracer agent for imaging of amyloid plaques in patients with systemic amyloidosis (SA), we have conjugated three bifunctional chelating ligands, namely S‐benzyl‐mercaptoacetyl‐l‐aspartyl(tBu)‐glycine, HYdrazinoNICotinic acid and nitrilotriacetic acid, to the 2‐phenylbenzothiazole core of thioflavin‐T (ThT), which has known affinity for amyloid. The compounds were successfully synthesized and labelled with technetium‐99m. Their structure was confirmed by radio‐LC‐MS analysis. After i.v. injection in normal mice, all three 99mTc‐labelled ThT derivatives were excreted almost exclusively via liver and intestines. This indicates that the new tracer agents have not the required biokinetics for application as a probe for detection of SA in the abdominal region. Copyright © 2008 John Wiley & Sons, Ltd.
A human spinal cord cell promotes motoneuron survival and maturation in vitro
Authors: Rouleau Caroline , Mersel Marcel , de Weille Jan , Rakotoarivelo Clovis , Fabre Christine , Privat Alain , Langley Keith , Petite Didier
Published: August 2008

Primary cultures of motoneurons represent a good experimental model for studying mechanisms underlying certain spinal cord pathologies, such as amyotrophic lateral sclerosis and spinal bulbar muscular atrophy (Kennedy's disease). However, a major problem with such culture systems is the relatively short cell survival times, which limits the extent of motoneuronal maturation. In spite of supplementing culture media with various growth factors, it remains difficult to maintain motoneurons viable longer than 10 days in vitro. This study employs a new approach, in which rat motoneurons are plated on a layer of cultured cells derived from newborn human spinal cord. For all culture periods, more motoneurons remain viable in such cocultures compared with control monocultures. Moreover, although no motoneurons survive in control cultures after 22 days, viable motoneurons were observed in cocultures even after 7 weeks. Although no significant difference in neurite length was observed between 8‐day mono‐ and cocultures, after 22 and 50 days in coculture motoneurons had a very mature morphology. They extended extremely robust, very long neurites, which formed impressive branched networks. Data obtained using a system in which the spinal cord cultures were separated from motoneurons by a porous polycarbonate filter suggest that soluble factors released from the supporting cells are in part responsible for the beneficial effects on motoneurons. Several approaches, including immunocytochemistry, immunoblotting, and electron microscopy, indicated that these supporting cells, capable of extending motoneuron survival and enhancing neurite growth, had an undifferentiated or poorly differentiated, possibly mesenchymal phenotype. © 2008 Wiley‐Liss, Inc.
Mitochondrial dysfunction disrupts trafficking of Kir4.1 in spiral ganglion satellite cells
Authors: Zou Jing , Zhang Ya , Yin Shankai , Wu Hao , Pyykkö Ilmari
Published: August 2008

The inward‐rectifier K+channel Kir4.1 is responsible for maintaining cochlear homeostasis and restoring neural excitability. The large‐conductance calcium‐activated K+channel (BKCa) plays a key role in phase locking signals in the mammalian inner ear. To evaluate the influence of mitochondrial dysfunction on the expression and subcellular localization of these channels, 3‐nitropropionic acid (3‐NP) was administered to rat round window membranes for 30 min. Auditory brainstem response was measured both before and 2 hr after 3‐NP administration. Immunofluorescent confocal microscopy was used to measure the expression and subcellular localization of Kir4.1 and BKCa. Alexa Fluor 568‐labeled bovine serum albumin (BSA) was applied to round window membranes as a tracer to explore the cochlear distribution of drug delivery and was detected in the lateral wall, spiral ganglion, cochlear nerve, and organ of Corti. Hearing loss of 23 (±4.4 SE) and 58 (±6.7 SE) dB developed in rats treated with 0.3 and 0.5 mol/liter of 3‐NP, respectively. BKCawas visualized in the cellular membrane and cytoplasm in the upper and middle region of inner hair cells, and it was not affected by 3‐NP. Kir4.1 was detected in intermediate cells of the stria, Deiter's cells, and spiral ganglion satellite cells. Kir4.1 failed to reach the perineural cytoplasm of the satellite cells after 3‐NP treatment. The results of this study suggest that mitochondrial dysfunction disrupts trafficking of Kir4.1 in spiral ganglion satellite cells. © 2008 Wiley‐Liss, Inc.
Increases in transient receptor potential vanilloid‐1 mRNA and protein in primary afferent neurons stimulated by protein kinase C and their possible role in neurogenic inflammation
Authors: Xu Xijin , Wang Peng , Zou Xiaoju , Li Dingge , Fang Li , Lin Qing
Published: August 2008

A recent study by our group demonstrates pharmacologically that the transient receptor potential vanilloid‐1 (TRPV1) is activated by intradermal injection of capsaicin to initiate neurogenic inflammation by the release of neuropeptides in the periphery. In this study, expression of TRPV1, phosphorylated protein kinase C (p‐PKC), and calcitonin gene‐related peptide (CGRP) in dorsal root ganglion (DRG) neurons was visualized by using immunofluorescence, real‐time PCR, and Western blots to examine whether increases in TRPV1mRNA and protein levels evoked by capsaicin injection are subject to modulation by the activation of PKC and to analyze the role of this process in the pathogenesis of neurogenic inflammation. Capsaicin injection into the hindpaw skin of anesthetized rats evoked increases in the expression of TRPV1, CGRP and p‐PKC in mRNA and/or protein levels and in the number of single labeled TRPV1, p‐PKC, and CGRP neurons in ipsilateral L4‐5 DRGs. Coexpressions of TRPV1with p‐PKC and/or CGRP in DRG neurons were also significantly increased after CAP injection. These evoked expressions at both molecular and cellular levels were significantly inhibited after TRPV1receptors were blocked by 5′‐iodoresiniferatoxin (5 μg) or PKC was inhibited by chelerythrine chloride (5 μg). Taken together, these results provide evidence that up‐regulation of TRPV1mRNA and protein levels under inflammatory conditions evoked by capsaicin injection is subject to modulation by the PKC cascade in which increased CGRP level in DRG neurons may be related to the initiation of neurogenic inflammation. Thus, up‐regulation of TRPV1receptors in DRG neurons seems critical for initiating acute neurogenic inflammation. © 2008 Wiley‐Liss, Inc.
The development and evaluation of a soil moisture index
Authors: Hunt Eric D. , Hubbard Kenneth G. , Wilhite Donald A. , Arkebauer Timothy J. , Dutcher Allen L.
Published: August 2008

Soil water is an important parameter in the hydrological balance and is essential for understanding land–surface interactions. While spatial coverage of soil water observations is poor across most of the United States, impedance probes have been used to measure soil water throughout Nebraska in the Automated Weather Data Network (AWDN) since 1999. With 8 years of continuous data at selected sites, we were able to derive a Soil Moisture Index (SMI) that is based on an actual water content (θ) and a known field capacity and wilting point. The SMI is a continuous function and is scaled from 5.0 to − 5.0, with 5.0 representing θ at field capacity and − 5.0 representing θ at wilting point. Since the inception of the soil water network in 1999, periodic episodes of drought have affected all areas of Nebraska. Thus, the SMI was used in this study to analyse growing seasons (1 April to 1 October) from 1999 to 2006 at six selected sites throughout Nebraska. The SMI proved to be effective at depicting the onset of drought and at identifying soil recharge, or lack thereof, when heavy rainfall events followed a significant dry spell. Copyright © 2008 Royal Meteorological Society
Human hypertrophic nonunion tissue contains mesenchymal progenitor cells with multilineage capacity in vitro
Authors: Iwakura Takashi , Miwa Masahiko , Sakai Yoshitada , Niikura Takahiro , Lee Sang Yang , Oe Keisuke , Hasegawa Takumi , Kuroda Ryosuke , Fujioka Hiroyuki , Doita Minoru , Kurosaka Masahiro
Published: August 2008

Hypertrophic nonunion usually results from insufficient fracture stabilization. Therefore, most hypertrophic nonunions simply require the stabilization of the nonunion site. However, the reasons why union occurs without treating the nonunion site directly is not well understood biologically. In this study, we hypothesized that the intervening tissue at the hypertrophic nonunion site (nonunion tissue) could serve as a reservoir of mesenchymal progenitor cells and investigated whether the cells derived from nonunion tissue had the capacity for multilineage mesenchymal differentiation. After nonunion tissue was obtained, it was cut into strips and cultured. Homogenous fibroblastic adherent cells were obtained. Flow cytometry revealed that the adherent cells were consistently positive for mesenchymal stem cell related markers CD13, CD29, CD44, CD90, CD105, CD166, and negative for the hematopoietic markers CD14, CD34, CD45, and CD133, similar to control bone marrow stromal cells. In the presence of lineage‐specific induction factors, the adherent cells differentiated in vitro into osteogenic, chondrogenic, and adipogenic cells. These results demonstrated for the first time that hypertrophic nonunion tissue contains multilineage mesenchymal progenitor cells. This suggests that hypertrophic nonunion tissue plays an important role during the healing process of hypertrophic nonunion by serving as a reservoir of mesenchymal cells that are capable of transforming into cartilage and bone forming cells. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:208–215, 2009
Changes of femoral periprosthetic bone mineral density 6 years after treatment with alendronate following total hip arthroplasty
Authors: Arabmotlagh Mohammad , Pilz Mathias , Warzecha Jörg , Rauschmann Michael
Published: August 2008

Earlier osteodensitometric results of femoral periprosthetic bone showed that postoperative antiresorptive treatment with alendronate following total hip arthroplasty (THA) reduces the periprosthetic bone loss that commonly occurs in the first months after surgery. However, whether alendronate can prevent periprosthetic bone loss over the long term, or if bone loss occurs after discontinuing alendronate is unknown. Femoral periprosthetic bone mineral density (BMD) was assessed in 49 patients 6 years after cementless total hip arthroplasty using dual energy X‐ray absorptiometry. Twenty‐nine patients were treated postoperatively with alendronate and 20 control patients received no treatment. All patients were followed up at 12 months after surgery in a prospective randomized study. The bone mineral density was evaluated in 7 regions of interest according to the Gruen protocol. Six years after total hip arthroplasty, no significant changes were detected in femoral periprosthetic BMD when compared with results at 1 year, and the bone loss in patients with postoperative alendronate treatment was still significantly less than those without treatment. These results suggest that the prevention of femoral periprosthetic bone loss following THA achieved by postoperative antiresorptive treatment with alendronate is of long‐standing effect, and further bone loss does not occur after the first postoperative year. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:183–188, 2009
Kunststoffe mit dem Laser beschriften
Authors: Faißt Birgit
Published: August 2008

Der Laser als Markierwerkzeug ist aus der Industrie nicht mehr wegzudenken. Automobil, Elektronik sowie Medizintechnik sind nur einige wenige Industriezweige, in denen der Laser aufgrund seiner Flexibilität und Vielseitigkeit anderen Verfahren zum Beschriften vorgezogen wird. Die Nachfrage nach Markierlasern steigt, die Gründe dafür sind vielfältig.
Selektives Lasersintern
Authors: Exner Horst , Ebert Robby
Published: August 2008

Das Selektive Lasersintern (SLS) hat sich seit nunmehr 20 Jahren zu einem industriell etablierten Verfahren entwickelt. Mit ihm lassen sich schnell und präzise Bauteile aus verschiedensten Materialien generieren. Kunststoff und Metall werden bereits in großer Vielfalt verarbeitet – die Verarbeitung von Keramik steht noch in den Startlöchern.
Measuring tissue heat penetration by scattered light measurements
Authors: Ben‐David M. , Cantor R. , Balbul N. , Yehuda M. , Gannot I.
Published: August 2008

Background and Objectives

The monitoring of tissue morphological changes during clinical procedure such as laser thermotherapy, laser hair removal and others is important in order to prevent damage to healthy tissue. An optical system and method for the assessment of real time in vivo tissue morphological changes is proposed.

Materials and Methods

We used ex vivo chicken breast as tissue samples. The samples were irradiated by CO2 laser to create thermal structural changes. The optical properties of the tissue samples were measured using an integrating sphere method. We measured the tissue heat penetration and the scattered light from the tissue and compared the results to Monte‐Carlo simulation.

Results

Thermal interaction causes structural changes in the tissue. Therefore changing (increasing) the scattering properties of the tissue. We relate the structural changes to the scattered light pattern and proposed a method for controlling the thermal interaction.

Conclusion

It is possible to design a real time in vivo controlling system for laser tissue thermal interaction that utilizes the changes in the scattered light pattern. Lesers Surg. Med. 40:494–499, 2008. © 2008 Wiley‐Liss, Inc.
Topical delivery of methotrexate via skin pretreated with physical enhancement techniques: low‐fluence erbium:YAG laser and electroporation
Authors: Lee Woan‐Ruoh , Shen Shin‐Chuan , Fang Chia‐Lang , Zhuo Rou‐Zi , Fang Jia‐You
Published: August 2008

Background and Objective

The high hydrophilicity and molecular weight of methotrexate (MTX) make it difficult to deliver via the skin route for treating psoriasis or rheumatoid arthritis. The objective of this study was to enhance and optimize the skin permeation of MTX using two physical techniques: an erbium:yttrium‐aluminum‐garnet (Er:YAG) laser and electroporation.

Methods

In vitro skin permeation was performed using horizontal side‐by‐side diffusion cells. The animal model utilized nude mice. The skin where epidermal hyperproliferation was reproduced by repeated barrier abrogation was also used as a permeation barrier for MTX delivery.

Results

Application of the laser and electroporation significantly enhanced the permeation of MTX. The enhancing effect was more pronounced after applying the laser. Er:YAG laser pretreatment on the skin produced a 3‐ to 80‐fold enhancement dependent upon the magnitude of the laser fluence. Using electroporation, treatment with 10 pulses resulted in a twofold increase in MTX flux. A combination of laser pretreatment and subsequent electroporation for 10 minutes resulted in a higher drug permeation than either technique alone. However, this synergistic effect was only observed when the lower laser fluence (1.4 J/cm2) was applied. Hyperproliferative skin generally showed a greater variability of MTX flux and lower permeation.

Conclusion

The results shown in the present study encourage further investigation of laser‐ and electroporation‐assisted topical drug delivery. Lesers Surg. Med. 40:468–476, 2008. © 2008 Wiley‐Liss, Inc.
Effects of laser repetition rate on corneal tissue ablation for 193‐nm excimer laser light
Authors: Shanyfelt Leia M. , Dickrell Pamela L. , Edelhauser Henry F. , Hahn David W.
Published: August 2008

Background and Objective

The goal of the present work is to assess whether bovine corneal ablations generated at laser repetition rates of up to 400 Hz are comparable to ablations performed at rates consistent with current clinical laser systems.

Study Design/Materials and Methods

A combination of experiments was used to assess a comprehensive range of ablation parameters, including ablation plume dynamics via imaging and transmission, corneal ablation profiles via scanning interferometry, and high‐resolution electron microscopy of collagen structure following ablation.

Results

Using white‐light interferometry analysis, no statistical difference was found between corneal ablation profiles created at 60 and 400 Hz, with an average rate of 0.94 µm/pulse at 60 Hz versus 0.92 µm/pulse at 400 Hz. In addition, based on plume imaging and transmission studies, the bulk ablation plume was found to dissipate on a time‐scale less than the pulse‐to‐pulse separation for a laser repetition rate up to about 400 Hz. A persistent, diffuse gas‐phase component of the ablation products was observed and concluded to be comparable at both repetition rates. Finally, SEM and TEM analysis revealed no signs of differential thermal tissue damage, including collagen fibril analysis, for laser repetition rates up to 400 Hz.

Conclusions

In summary, investigation of the relative effects of excimer laser repetition rate on the overall corneal ablation metrics revealed no measurable difference under conditions typical of clinical refractive procedures. This study suggests that increases in ArF laser repetition rates for clinical applications (up to ∼400 Hz) appear feasible. Lesers Surg. Med. 40:483–493, 2008. © 2008 Wiley‐Liss, Inc.
Low density, non‐ablative fractional CO2laser rejuvenation
Authors: Christiansen Kaare , Bjerring Peter
Published: August 2008

Background and Objectives

Fractional skin rejuvenation has gained increased interest since its introduction in 2003. Both non‐ablative and ablative lasers as well as different treatment techniques have been devised. Recent clinical studies indicate that a paradigm of low spot density combined with high fluences tend to produce better clinical results and less risk of post‐inflammatory hyperpigmentation in darker skin types. The present study is focused on investigations of the clinical outcome by non‐ablative fractional CO2treatments with a single pass with low spot density.

Methods and Materials

A CO2laser was equipped with a scanner enabling it to perform fractional treatments with 36, 64 or 100 microthermal zones (MTZ)/cm2. Twelve patients participated in the study. The perioral area was treated three times with 1‐month intervals using a spot density of 64 MTZ/cm2, a spot diameter of 0.5 mm, a micro‐beam energy of 36–60 mJ, and a pulse duration of 3–5 milliseconds. Follow‐up was performed 3 months after the last treatment.

Results

At the 3‐month follow‐up 72.7% of the volunteers had obtained improvement in ultrasonographically determined dermal density, and the average improvement was 40.2% (SD: 48.0%). This improvement was statistically significant (P<0.006). Eighty percent of the volunteers rated the reduction in visible perioral wrinkles to be fair, good or excellent. For reduction of irregular pigmentation, fair, good or excellent clearance was reported by 62.5% of the volunteers.

Conclusions

The present study demonstrates subjective improvements in wrinkles, skin texture and mottled pigmentation as well as statistically significant objectively measured improvements in ultrasonographical dermal density after three non‐ablative fractional CO2laser treatments. Lesers Surg. Med. 40:454–460, 2008. © 2008 Wiley‐Liss, Inc.
A possible mechanism for visible light‐induced wound healing
Authors: Lipovsky Anat , Nitzan Yeshayahu , Lubart Rachel
Published: August 2008

Background and Objectives

Chronic wounds resistant to conventional therapy have been treated successfully with low energy lasers and light emitting diodes (LEDs) in the visible and near IR region. It has been proposed that production of low level reactive oxygen species (ROS) following illumination is the first step of photobiomodulation. It was also shown that white light (400–800 nm) has similar stimulatory effects as lasers and LEDs. ROS at higher levels are toxic to cells and bacteria.

Study Design/Materials and Methods

In the present study, we examined the phototoxicity of broadband (400–800 nm, 120 J/cm2) visible light on the survival of several pathogenic bacteria:Staphylococcus aureus 195,Pseudomonas aeruginosa 1316,Escherichia coli 1313, andSerratia marcescens. These bacteria were chosen due to their high prevalence in infected wounds. The survival of bacterial cells following illumination was monitored by counting the number of colony forming units before and after exposure to light.

Results

Illumination with white light, 120 J/cm2, caused a reduction of 62%, 83%, and 56% in the colony count ofE. coli 1313,S. aureus 195andS. marcescens, respectively, though no reduction in the viability ofP. aeruginosa 1316was demonstrated. The phototoxic effect was found to involve induction of ROS production by the bacteria. It was also found that illumination ofS. aureus 195andE. coli 1313in the presence of pyocyanin, known to be secreted byP. aeruginosa, had a stronger bactericidal effect compared to illumination alone.

Conclusion

Visible light at high intensity can kill bacteria in infected wounds. Thus, illumination of infected wounds with intense visible light, prior to low intensity illumination for stimulating wound closure, may reduce infection and promote healing. Lesers Surg. Med. 40:509–514, 2008. © 2008 Wiley‐Liss, Inc.
Fluoroelastomer Copolymers Incorporating Polyhedral Oligomeric Silsesquioxane
Authors: Seurer Bradley , Coughlin Edward Bryan
Published: August 2008

The aggregation of polyhedral oligomeric silsesquioxane (POSS) in copolymers was studied by incorporation of POSS into fluorinated copolymers, namely poly(octafluoropentyl acrylate) elastomers. The aggregation of POSS in copolymers affords unique materials. Studies of these novel polymers show POSS aggregates in these copolymers with both the phenyl and isobutyl peripheries, as the chain‐repulsive fluorinated chains help drive this aggregation. The isooctylPOSS copolymers, however, do not have POSS aggregation. Thermal studies of these copolymers also show an increase in the decomposition temperature by incorporation of POSS, which is directly dependent on the POSS periphery.

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Uniformly computable aspects of inner functions: estimation and factorization
Authors: McNicholl Timothy H.
Published: August 2008

The theory of inner functions plays an important role in the study of bounded analytic functions. Inner functions are also useful in applied mathematics. Two foundational results in this theory are Frostman's Theorem and the Factorization Theorem. We prove a uniformly computable version of Frostman's Theorem. We then show that the Factorization Theorem is not uniformly computably true. We then show that for an inner function u with infinitely many zeros, the Blaschke sum of u provides the exact amount of information necessary to compute the factorization of u. Along the way, we prove some uniform computability results for Blaschke products; these results play a key role in the analysis of factorization. We also give some computability results concerning zeros and singularities of analytic functions. We use Type‐Two Effectivity as our foundation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rose‐Like Microstructures of Polyaniline by Using a Simplified Template‐Free Method under a High Relative Humidity
Authors: Zhu Ying , He Haiyong , Wan Meixiang , Jiang Lei
Published: August 2008

3‐D rose‐like microstructures of polyaniline (PANI), which are self‐assembled from 2‐D nanosheets consisted of 1‐D nanofibers, were synthesized by a template‐free method in the presence of ammonium peroxydisulfate (APS) as both oxidant and dopant under a high relative humidity of 80% for the first time. When the relative humidity increases from 25 to 80%, not only morphology of the micro/nanostructured PANI undergoes a change from 1‐D nanofibers to 2‐D nanosheets to 3‐D rose‐like microstructures, but also increase in crystallinity. It is proposed that a cooperation effect of the oriented water molecules at the vapor–water interface and difference in hydrogen bonding energies between the interface and the bulk induced by the relative high humidity results in the formation of the 3‐D rose‐like microstructures self‐assembled from 2‐D nanosheets. Moreover, the method reported may provide a simple approach for understanding self‐assembly of complex micro/nanostructures of PANI.

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Macromol. Rapid Commun. 17/2008
Authors: Nebhani Leena , Sinnwell Sebastian , Inglis Andrew J. , Stenzel Martina H. , Barner‐Kowollik Christopher , Barner Leonie
Published: August 2008

Back Cover: The image depicts the efficient conversion of RAFT functionalized microspheres via a hetero Diels‐Alder reaction introducing narrow polydispersity polycaprolactone onto their surface. The transformation is accompanied by a decolorization of the spheres as thiocarbonyl functions are transformed into 3,6‐dihydro‐2H‐thiopyran rings that constitute the linkage points on the microspheres. Further details can be found in the article by L. Nebhani, S. Sinnwell, A. J. Inglis, M. H. Stenzel,* C. Barner‐Kowollik,* and L. Barner* on page 1431.
Susceptibility gradient mapping (SGM): A new postprocessing method for positive contrast generation applied to superparamagnetic iron oxide particle (SPIO)‐labeled cells
Authors: Dahnke Hannes , Liu Wei , Herzka Daniel , Frank Joseph A. , Schaeffter Tobias
Published: August 2008

Local susceptibility gradients result in a dephasing of the precessing magnetic moments and thus in a fast decay of the NMR signals. In particular, cells labeled with superparamagnetic iron oxide particles (SPIOs) induce hypointensities, making the in vivo detection of labeled cells from such a negative image contrast difficult. In this work, a new method is proposed to selectively turn this negative contrast into a positive contrast. The proposed method calculates the susceptibility gradient and visualizes it in a parametric map directly from a regular gradient‐echo image dataset. The susceptibility gradient map is determined in a postprocessing step, requiring no dedicated pulse sequences or adaptation of the sequence before and during image acquisition. Phantom experiments demonstrated that local susceptibility differences can be quantified. In vivo experiments showed the feasibility of the method for tracking of SPIO‐labeled cells. The method bears the potential also for usage in other applications, including the detection of contrast agents and interventional devices as well as metal implants. Magn Reson Med 60:595–603, 2008. © 2007 Wiley‐Liss, Inc.
Image‐based coronary tracking and beat‐to‐beat motion compensation: Feasibility for improving coronary MR angiography
Authors: Dewan Maneesh , Hager Gregory D. , Lorenz Christine H.
Published: August 2008

A method to reduce the effect of motion variability in MRI of the coronary arteries is proposed. It involves acquiring real‐time low‐resolution images in specific orthogonal orientations, extracting coronary motion from these images, and then using this motion information to guide high‐resolution MR image acquisition on a beat‐to‐beat basis. The present study establishes the feasibility and efficacy of the proposed approach using human motion data in an offline implementation, prior to future online implementation on an MRI scanner. To track the coronary arteries in low‐resolution real‐time MR images in an accurate manner, a tracking approach is presented and validated. The tracking algorithm was run on real‐time images acquired at 15–20 frames per second in four‐chamber, short‐axis, and coronal views in five volunteers. The systolic and diastolic periods in the cardiac cycles, computed from the extracted motion information, had significant variability during the short time periods typical of cardiac MRI. It is also demonstrated through simulation analysis using human tracked coronary motion data that accounting for this cardiac variability by adaptively changing the trigger delay for acquisition on a beat‐to‐beat basis improves overall motion compensation and hence MR image quality evaluated in terms of SNR and CNR values. Magn Reson Med 60:604–615, 2008. © 2008 Wiley‐Liss, Inc.
Magnetization transfer induced biexponential longitudinal relaxation
Authors: Prantner Andrew M. , Bretthorst G. Larry , Neil Jeffrey J. , Garbow Joel R. , Ackerman Joseph J.H.
Published: August 2008

Longitudinal relaxation of brain water 1H magnetization in mammalian brain in vivo is typically analyzed on a per‐voxel basis using a monoexponential model, thereby assigning a single relaxation time constant to all 1H magnetization within a given voxel. This approach was tested by obtaining inversion recovery (IR) data from gray matter of rats at 64 exponentially spaced recovery times. Using Bayesian probability for model selection, brain water data were best represented by a biexponential function characterized by fast and slow relaxation components. At 4.7T, the amplitude fraction of the rapidly relaxing component is 3.4% ± 0.7% with a rate constant of 44 ± 12 s−1 (mean ± SD; 174 voxels from four rats). The rate constant of the slow relaxing component is 0.66 ± 0.04 s−1. At 11.7T, the corresponding values are 6.9% ± 0.9%, 19 ± 5 s−1, and 0.48 ± 0.02 s−1 (151 voxels from four rats). Several putative mechanisms for biexponential relaxation behavior were evaluated, and magnetization transfer (MT) between bulk water protons and nonaqueous protons was determined to be the source of biexponential longitudinal relaxation. MR methods requiring accurate quantification of longitudinal relaxation may need to take this effect explicitly into account. Magn Reson Med 60:555–563, 2008. © 2008 Wiley‐Liss, Inc.
Inferring multiple maxima in intravoxel white matter fiber distribution
Authors: Canales‐Rodríguez Erick Jorge , Melie‐García Lester , Iturria‐Medina Yasser , Martínez‐Montes Eduardo , Alemán‐Gómez Yasser , Lin Ching‐Po
Published: August 2008

A new methodology is introduced that characterizes the intravoxel orientation distribution function (ODF) based on a single‐fiber model of the diffusion MRI signal. Using a Bayesian framework the probability of finding a fiber in a specific orientation is obtained. The proposed ODF estimation relies on a cigar‐like diffusion tensor model, the methodology is thus denominated Bayesian cigar‐like diffusion tensor (BCDT). This work makes two major contributions: 1) the study of single‐fiber models in detecting fibers with different volume fractions in a voxel, and 2) the introduction of the Nth‐root correction to improve the detection of fibers with smaller volume fractions, where N is the number of diffusion MRI measurements. It is demonstrated that the incomplete signal modeling fails to reconstruct the relative fiber volume fractions, especially when the intravoxel diffusion profiles have dissimilar contributions to the diffusion MRI signal. In this situation the fibers with smaller contributions are hardly detectable. The BCDT method proposed here reduces this effect by introducing the Nth‐root correction, making multiple fibers estimable. The performance of the new methodology is illustrated using synthetic and real data, as well as the data from a phantom of intersecting capillaries. Magn Reson Med 60:616–630, 2008. © 2008 Wiley‐Liss, Inc.
Rapid radiofrequency field mapping in vivo using single‐shot STEAM MRI
Authors: Helms Gunther , Finsterbusch Jürgen , Weiskopf Nikolaus , Dechent Peter
Published: August 2008

Higher field strengths entail less homogeneous RF fields. This may influence quantitative MRI and MRS. A method for rapidly mapping the RF field in the human head with minimal distortion was developed on the basis of a single‐shot stimulated echo acquisition mode (STEAM) sequence. The flip angle of the second RF pulse in the STEAM preparation was set to 60° and 100° instead of 90°, inducing a flip angle‐dependent signal change. A quadratic approximation of this trigonometric signal dependence together with a calibration accounting for slice excitation‐related bias allowed for directly determining the RF field from the two measurements only. RF maps down to the level of the medulla could be obtained in less than 1 min and registered to anatomical volumes by means of the T2‐weighted STEAM images. Flip angles between 75% and 125% of the nominal value were measured in line with other methods. Magn Reson Med 60:739–743, 2008. © 2008 Wiley‐Liss, Inc.