bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neurotransmitter release changes induced by low power 830 nm diode laser irradiation on the neuromuscular junctions of the mouse
Authors: Nicolau Renata Amadei , Martinez Manel Santafé , Rigau Josepa , Tomàs Josep 
Published: September 2004

AbstractBackground and ObjectiveTreating patients with a Gallium‐Aluminum‐Arsenide (GaAlAs) infrared (IR) diode laser reduces muscle spasm and increases mobility in the muscles. The effect of low intensity laser irradiation on nerve function, growth, and repair mechanisms is a contentious area of research. We have addressed one aspect of this controversy by systematically examining the influence of 830 nm laser radiation on neurotransmitter release in neuromuscular junctions (NMJ) of the mouse diaphragm.Study Design/Materials and MethodsThirty adult mice were studied. Diode laser GaAlAs 830 nm (4 and 12 J/cm2) was used. Neurotransmitter release was studied by conventional intracellular recording techniques on curarized muscles or high magnesium media. The quantal content, amplitude, and latency of the end‐plate potentials (EPPs) were analyzed. Frequency and amplitude were evaluated for the miniature end‐plate potentials (MEPPs). Facilitation of the neurotransmitter release was also evaluated by paired pulse stimulation.Results and ConclusionsThe irradiated (12 J/cm2) muscles showed a significant reduction in quantal content (P = 0.01) and EPP amplitude (P = 0.04), but the latency, spontaneous transmitter release (MEPPs) and paired pulse facilitation did not change. No alterations were observed in NMJ irradiated with 4 J/cm2. We conclude that 830 nm diode laser irradiation (at a dose of 12 J/cm2) can affect the evoked neurotransmitter release in the mouse motor endplates. Lasers Surg. Med. 35:236–241, 2004. © 2004 Wiley‐Liss, Inc.
Increased brain tumor resection using fluorescence image guidance in a preclinical model
Authors: Bogaards Arjen , Varma Abhay , Collens Sean P. , Lin Aihua , Giles Anoja , Yang Victor X.D. , Bilbao Juan M. , Lilge Lothar D. , Muller Paul J. , Wilson Brian C. 
Published: September 2004

AbstractBackground and ObjectivesFluorescence image‐guided brain tumor resection is thought to assist neurosurgeons by visualizing those tumor margins that merge imperceptibly into normal brain tissue and, hence, are difficult to identify. We compared resection completeness and residual tumor, determined by histopathology, after white light resection (WLR) using an operating microscope versus additional fluorescence guided resection (FGR).Study Design/Materials and MethodsWe employed an intracranial VX2 tumor in a preclinical rabbit model and a fluorescence imaging/spectroscopy system, exciting and detecting the fluorescence of protoporphyrin IX (PpIX) induced endogenously by administering 5‐aminolevulinic acid (ALA) at 4 hours before surgery.ResultsUsing FGR in addition to WLR significantly increased resection completeness by a factor 1.4 from 68±38 to 98±3.5%, and decreased the amount of residual tumor post‐resection by a factor 16 from 32±38 to 2.0±3.5% of the initial tumor volume.ConclusionsAdditional FGR increased completeness of resection and enabled more consistent resections between cases. Lasers Surg. Med. 35:181–190, 2004. © 2004 Wiley‐Liss, Inc.
Peripheral thermal and mechanical damage to dentin with microsecond and sub‐microsecond 9.6 μm, 2.79 μm, and 0.355 μm laser pulses
Authors: Rosa Alfredo Dela , Sarma Anupama V. , Le Charles Q. , Jones Robert S. , Fried Daniel 
Published: September 2004

AbstractBackground and ObjectivesIt is desirable to minimize peripheral thermal damage during laser irradiation, since thermal damage to collagen and mineral compromises the bond strength to restorative materials in dentin and inhibits healing and osteointegration in bone. There were two primary objectives of this study. The first objective was to measure the degree of thermal damage peripheral to incisions in dentin produced with lasers resonant to the specific absorption bands of water, collagen, and hydroxyapatite with varying pulse duration using polarized‐light microscopy (PLM). The second objective was to use synchrotron radiation infrared spectromicroscopy (SR‐FTIR) to identify the specific chemical nature of the optical changes observed under PLM in the respective zones of thermal damage peripheral to the laser incisions.Study Design/Materials and MethodsPrecise incisions were produced in 3×3 mm2blocks of human dentin using CO2(9.6 μm), Er:YSGG (2.79 μm), and Nd:YAG (355 nm) lasers with and without a computer controlled water‐spray. Optical coherence tomography (OCT) was used to obtain optical cross‐sections of each incision to determine the rate of ablation. The peripheral thermal damage zone around each incision was analyzed using PLM and SR‐FTIR.ResultsThermally induced chemical changes to both mineral and the collagen matrix were observed with SR‐FTIR with a 10 μm spatial resolution and those changes were correlated with optical changes observed with PLM. Minimal (<10 μm) thermal damage was observed for pulse durations less than the thermal relaxation time (Tr) of the deposited laser energy, with and without applied water at 9.6 μm and with only applied water at 2.79 μm. For pulse durations greater than Tr, greater peripheral thermal damage was observed for both IR laser wavelengths with and without the water‐spray. There was minimal thermal damage for 355 nm laser pulses less than Trwith and without applied water; however, extensive mechanical damage (cracks) was observed.ConclusionsHigh resolution SR‐FTIR is well suited for characterization of the chemical changes that occur due to thermal damage peripheral to laser incisions in proteinaceous hard tissues. Sub‐microsecond pulsed IR lasers resonant with water and mineral absorption bands ablate dentin efficiently with minimal thermal damage. Similar laser parameters are expected to apply to the ablation of alveolar bone. Lasers Surg. Med. 35:214–228, 2004. © 2004 Wiley‐Liss, Inc.
Laser irradiation of the guinea pig basilar membrane
Authors: Wenzel Gentiana I. , Pikkula Brian , Choi Chul‐Hee , Anvari Bahman , Oghalai John S. 
Published: September 2004

AbstractBackground and ObjectivesThe cochlea is the part of the inner ear that transduces sound waves into neural signals. The basilar membrane, a connective tissue sheet within the cochlea, is tonotopically tuned based on the spatial variation of its mass, stiffness, and damping. These biophysical properties are mainly defined by its constituent collagen fibers. We sought to assess the effect of laser irradiation on collagen within the basilar membrane using histological analysis.Study Design/Materials and MethodsFour excised guinea pig cochleae were stained with trypan blue. From these, two were irradiated with a 600 nm pulsed dye laser and two were used as controls. Collagen organization was visualized using polarization microscopy.ResultsLaser irradiation reduced the birefringence within the basilar membrane as well as within other stained collagen‐containing structures. Larger reductions in birefringence were measured when more laser pulses were given. The effects were similar across all turns of each cochlea.ConclusionsLaser irradiation causes immediate alterations in collagen organization within the cochlea that can be visualized with polarization microscopy. These alterations may affect cochlear tuning. Ongoing research is aimed at analyzing the effect of laser irradiation on cochlear function. It is conceivable that this technique may have therapeutic benefits for patients with high‐frequency sensorineural hearing loss. Lasers Surg. Med. 35:174–180, 2004. © 2004 Wiley‐Liss, Inc.
Laser‐assisted vascular end to end anastomosis of elastin heterograft to carotid artery with an albumin stent: A preliminary in vivo study
Authors: Xie Hua , Bendre Suhas C. , Burke Allen P. , Gregory Kenton W. , Furnary Anthony P. 
Published: September 2004

AbstractBackground and ObjectivesLaser‐assisted end to end vascular anastomosis of an elastin heterograft to native artery may prevent problems associated with currently available vascular synthetic grafts and conventional suture anastomosis.Study Design/Materials and MethodsA total of 21 anastomoses in the carotid arteries of 7 domestic swine were performed with an 800 nm laser and an albumin stent plus solder. There were 5 artery to artery and 16 elastin heterograft to native artery anastomoses. Operative parameters, vascular patency, and histology of the anastomoses were evaluated.ResultsOut of 21 anastomoses, 16 were patent for 3 hours. One artery to artery anastomosis was thrombosed and four elastin heterograft to artery anastomoses were excluded from the study due to heterograft burst. The average amount of applied energy was 212 J for artery to artery anastomosis and 273 J for elastin heterograft to native artery. Histology shows coagulative necrosis of the adventitia, hypereosinophilic contraction band in the media of native arteries and no changes in elastin heterografts.ConclusionsLaser‐assisted vascular anastomosis (LAVA) of elastin heterograft to medium size vessel using an albumin stent is feasible. Chronic studies are warranted to determine long‐term patency and histology of the LAVA. Lasers Surg. Med. 35:201–205, 2004. © 2004 Wiley‐Liss, Inc.
Microarray analysis of prostate cancer progression to reduced androgen dependence: Studies in unique models contrasts early and late molecular events
Authors: Sirotnak F.M. , She Yuhong , Khokhar Nushmia Z. , Hayes Paula , Gerald William , Scher Howard I. 
Published: September 2004

AbstractThree unique variants of the CWR22 human prostate cancer xenograft model (CWR22LD1, LD2, and LD3) with a decrease in dependence on androgens were selected under noncastrate conditions, i.e., by outgrowth after transplantation into male NCR (AT) nu mice without testosterone supplementation. These variants were unable to grow in castrated male mice. For comparison, a second set of variants with even less dependence on androgens (castrate‐resistant) were derived following outgrowth from CWR22 (CWR22Rv1 and RC) or CWRLD1 (CWR22RS) after transplantion in castrated male mice. The androgen receptor (AR) gene in the CWR22LD variants was transcriptionally active and was neither mutated nor significantly overexpressed compared to CWR22. Oligonucleotide microarray analysis showed distinctly different profiles of dysregulated gene expression among the CWR22LD variants. Groups of only 26–41 genes were dysregulated greater than threefold with a different proportion of up versus downregulated genes in each variant. Only one of the castrate‐resistant variants (CWR22Rv1) had a highly overexpressed AR gene but AR in this variant and the two other castrate‐resistant variants, CWR22 RS and RC, was not mutated beyond that seen in CWR22. In contrast to the CWR22LD variants, a total of 342, 295, and 222 genes were dysregulated at least threefold in CWR22Rv1, CWR22RS, and CWR22RC, respectively, differing as well in the proportion of up versus downregulated genes. Many of the genes dysregulated in CWR22LD1, LD2, and LD3 were further dysregulated in CWR22Rv1, RC, or RS. The most downregulated gene was microseminoprotein beta (MSPB). Along with cyclin D1, the most upregulated gene by an order of magnitude compared to other upregulated genes was hepatocyte growth factor (HGF) (scatter factor). These results suggest that the onset in the loss of androgen dependence in CWR22 proceeds through multiple pathways and does not require any direct change in the status of AR. However, upregulation of other survival pathways like that involving HGF in these studies could co‐activate AR signaling. The endogenous overexpression of genes regulating sterol biosynthesis also observed in castrate‐resistant CWR22 variants delineated a clinically relevant, compensatory mechanism for overcoming androgen deprivation reaffirming a central role for AR signaling in this process. © 2004 Wiley‐Liss, Inc.
Pharmacological inhibition of fatty acid synthase (FAS): A novel therapeutic approach for breast cancer chemoprevention through its ability to suppress Her‐2/neu (erbB‐2) oncogene‐induced malignant transformation
Authors: Menendez Javier A. , Mehmi Inderjit , Verma Vishal A. , Teng Poh K. , Lupu Ruth 
Published: September 2004

AbstractWe designed our experiments to evaluate whether fatty acid synthase (FAS), a lipogenic enzyme linked to tumor virulence in population studies of human cancer, is necessary for the malignant transformation induced by Her‐2/neu (erbB‐2) oncogene, which is overexpressed not only in invasive breast cancer but also in premalignant atypical duct proliferations and in ductal carcinoma in situ of the breast. To avoid the genetic complexities associated with established breast cancer cell lines, we employed NIH‐3T3 mouse fibroblasts engineered to overexpress human Her‐2/neu coding sequence. NIH‐3T3/Her‐2 cells demonstrated a significant upregulation of FAS protein expression, which was dependent on the upstream activation of mitogen‐activated protein kinase and phosphatidylinositol 3′‐kinase/AKT pathways. Remarkably, pharmacological FAS blockade using the mycotoxin cerulenin or the novel small compound C75 completely suppressed the state of Her‐2/neu‐induced malignant transformation by inhibiting the ability of NIH‐3T3/Her‐2 cells to grow under either anchorage‐independent (i.e., to form colonies in soft agar) or low‐serum monolayer conditions. Moreover, NIH‐3T3/Her‐2 fibroblasts were up to three times more sensitive to chemical FAS inhibitors relative to untransformed controls as determined by MTT‐based cell viability assays. In addition, pharmacological FAS blockade preferentially induced apoptotic cell death of NIH‐3T3/Her‐2 fibroblasts, as determined by an ELISA for histone‐associated DNA fragments and by the terminal deoxynucleotidyltransferase (TdT)‐mediated nick end labeling assay (TUNEL). Interestingly, the degree of Her‐2/neu oncogene expression in a panel of breast cancer cell lines was predictive of sensitivity to chemical FAS inhibitors‐induced cytotoxicity, while low‐FAS expressing and chemical FAS inhibitors‐resistant MDA‐MB‐231 breast cancer cells became hypersensitive to FAS blockade when they were engineered to overexpress Her‐2/neu. Our observations strongly suggest that inhibition of FAS activity may provide a new molecular avenue for chemotherapeutic prevention and/or treatment of Her‐2/neu‐related breast carcinomas. © 2004 Wiley‐Liss, Inc.
Resources, capabilities, and the performance of industrial firms: A multivariate analysis
Authors: Carmeli Abraham , Tishler Asher 
Published: September 2004

AbstractThis study uses multivariate analysis to assess the basic question asked by resource‐based view researchers: Do organizational resources and capabilities account for variations in firm performance? An analysis of survey responses of 93 industrial enterprises in Israel indicates that superiority of an industrial enterprise, in terms of four performance measures (return on sales, return on equity, market share change, and customer satisfaction), can be explained by a set of four core organizational resources and capabilities (managerial skills, organizational culture, organizational communication, and perceived organizational reputation). The results lend significant support to the premise of the resource‐based view of strategic management. Copyright © 2004 John Wiley & Sons, Ltd.
Compensating for innovation: Do small firms offer high‐powered incentives that lure talent and motivate effort?
Authors: Zenger Todd R. , Lazzarini Sergio G. 
Published: September 2004

AbstractEmpirical studies commonly confirm that small firms enjoy efficiency advantages in generating innovation. However, the origin of this advantage remains poorly understood. This study explores the hypothesis that small firms enjoy advantages over large firms in crafting effective, incentive‐intensive employment contracts that lure top engineering talent and motivate high effort. These hypotheses are tested using data from a sample of R&D engineers in Silicon Valley and the Route 128 area. Copyright © 2004 John Wiley & Sons, Ltd.
Redeployment of corporate resources: A study of acquisition strategies in the US defense industries, 1978–1996
Authors: Anand Jaideep 
Published: September 2004

AbstractHow are excess resources redeployed when an industry declines? These resources can be redeployed within the firm through diversification and across firms through a market interface. Acquisitions can play an important role in either of these mechanisms. First, acquisitions can provide new complementary resources and facilitate the redeployment of excess resources within the firm through recombination. Second, horizontal acquisitions can facilitate consolidation and disposal of excess or redundant resources that can be redeployed elsewhere through a market interface. I study both these kinds of acquisitions in the US defense industries (1978–1996), and explain the choice between the two acquisition strategies on the basis of the business environment, underlying resources of the firm, and to a lesser extent, as a consequence of agency forces within the firm. I derive implications for strategic transformation of firms, and the resource‐based and evolutionary perspectives. Copyright © 2004 John Wiley & Sons, Ltd.
Empirical evidence regarding the tension between knowledge sharing and knowledge expropriation in collaborations
Authors: Heiman Bruce A. , Nickerson Jack A. 
Published: September 2004

AbstractInterfirm collaborations can raise a fundamental dilemma. To create value, collaborators may have to adopt a variety of practices to facilitate knowledge transfer. Deploying these practices may increase the likelihood that economically valuable knowledge, which is (1) beyond the scope of the collaboration, and (2) difficult to legally protect, is expropriated. How can firms manage this dilemma? The purpose of this paper is to empirically examine the veracity of a chain of propositions addressing this dilemma based on a novel joint knowledge‐based view/transaction cost economics framework. A plausible chain of relationships is briefly summarized and explored in detail empirically using unrelated datasets. The chain links two knowledge‐based attributes of collaboration—knowledge tacitness and problem‐solving complexity—to the use of knowledge management practices—high‐bandwidth communication channels and co‐specialized communication codes. These practices are economic responses to knowledge‐sharing difficulties as measured by tacitness and complexity. Increasing knowledge transparency via knowledge management practices, however, gives rise to opportunism hazards, which are safeguarded against via economizing governance choice. Our empirical effort examines the effects that two knowledge attributes of collaborations have on governance choice, first directly and then indirectly through the intervening linkages. Empirical results from both datasets indicate substantial support for the proposed chain of relationships. The results are provocative in that they offer the first preliminary evidence for a plausible reconciliation of two perspectives previously treated exclusively as adversaries. Copyright © 2004 John Wiley & Sons, Ltd.
Organizational choice in R&D alliances: Knowledge‐based and transaction cost perspectives
Authors: Sampson Rachelle C. 
Published: September 2004

AbstractThis study examines how firms choose organizational form for their R&D alliances. Encouraging cooperation in these alliances is often challenging, given the difficulties in knowledge sharing between partners and protecting the property rights over partner knowledge. Interestingly, knowledge‐based and transaction cost perspectives generate different hypotheses on alliance organization choice in this setting. When partner knowledge bases are very different, the risk of unintended transfer or leakage is reduced, yet the need for enhanced communication and knowledge sharing mechanisms remains undiminished. With a sample of 232 R&D alliances, I find more thorough support for the transaction cost hypothesis. Firms more likely select an equity joint venture as partner knowledge bases diverge and knowledge transfer becomes more difficult. When such knowledge bases are very different, however, firms are less likely to choose an equity joint venture over more contractual forms of alliance organization. Thus, these results provide empirical evidence on alliance organization choice and also have important implications for the fundamental question of why firms exist. Copyright © 2004 John Wiley & Sons, Ltd.
Reach out or reach within? Performance implications of alliances and location in biotechnology
Authors: Zaheer Akbar , George Varghese P. 
Published: September 2004

AbstractThe extensive literature on geographical clusters has argued that firms stand to gain from the knowledge spillovers and the easy availability of skills in regional agglomerations. At the same time, the research on strategic alliances, particularly in technology‐intensive industries, views alliances as vehicles for the transfer of technology and knowledge. Does membership in a geographical cluster or a network of alliances—an alliance cluster—benefit firms equally? More importantly, does it matter whether firms form alliances with firms within their geographical cluster, or do they do better by reaching out beyond their cluster? In this paper, we investigate these and other related questions in the context of technology‐intensive industries such as biotechnology and argue that the high‐level knowledge sensing and acquiring needs of firms in such industries may require combinations of both kinds of knowledge‐access mechanisms. We use the BioScan database to obtain 648 alliances for the period 1985–1998 among 248 public companies, and complement it with COMPUSTAT data to examine the effect of clustering and alliances on market value. Our results suggest that merely being part of geographical clusters is not enough, and nor is it adequate for firms to join alliance clusters. Rather, firms gain by forming alliances both within and beyond their geographical clusters, which highlights the complexities of acquiring technology‐intensive knowledge and suggests that the acquisition of knowledge in technology‐intensive settings is best achieved through mechanisms both formal and informal, both proximate and distant. Copyright © 2004 John Wiley & Sons, Ltd.
Competing in groups
Authors: Rowley Tim J. , Baum Joel A. C. , Shipilov Andrew V. , Greve Henrich R. , Rao Hayagreeva 
Published: September 2004

AbstractIn this study, we examine how the characteristics of clique structures affect the performance of firms embedded within the cliques. Although it is generally accepted in organization theory and strategic management that firms are embedded within ego and overarching industry networks that each affect their behavior and performance, there is little evidence on whether cliques are stable features of industry networks or affect firm behavior or performance. We theorize that the value of a clique to its members depends on (1) the network centrality of the clique and (2) the internal structure and organization (heterogeneity and inequality) of the clique. Our analysis of the Canadian investment banking industry from 1952 to 1990 provides empirical evidence of stable cliques, and indicates that while a clique's internal structure and organization materially affect firm‐level benefits of clique membership, its positional embeddedness within the industry network does not. Copyright © 2004 John Wiley & Sons, Ltd.