bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ecological significance of net photosynthesis activation by water vapour uptake in Ramalina capitata from rain-protected habitats in central Spain
Authors: Pintado Ana , Sancho Leopoldo G. 
Published: January 2003

AbstractThe reactivation of net photosynthesis and dark respiration from water vapour and from liquid water in the lichen Ramalina capitata var. protecta (H. Magn.) Nimis from sheltered habitats in Central Spain was investigated. CO2 gas-exchange response and thallus water content were measured in the laboratory as dry thalli were allowed to equilibrate by water vapour uptake under different relative humidities, and as saturated thalli dried. Water content of thalli from different habitats was also measured in the field during rainfall. The results show that the lichen is very efficient in using water vapour from the air for photosynthesis. Net photosynthetic rates were measured at very low water potentials (up to – 26-9 Megapascal) with water contents of the thalli below 30% dry weight. Maximum net photosynthetic rates measured after water vapour uptake were in some cases similar to those obtained after hydration by liquid water, while respiration rates were always lower after water vapour uptake, indicating a relatively larger activation of the photobiont. Moreover, photosynthetic rates at thallus water contents below 60% dry weight were higher when hydration was achieved through water vapour uptake than with liquid water. Field measurements had shown that this lichen reached water contents through water vapour absorption of 40% dry weight that would allow a positive balance of CO2 uptake. Possible ecological implications of differences in photosynthetic activation depending on the water source are discussed in terms of the carbon gain under natural conditions of this ombrophobous lichen.
The significance of stemflow chemistry for epiphytic lichen diversity in a dieback-affected spruce forest on Mt Brocken, northern Germany
Authors: Hauck Markus , Hesse Volker , Runge Michael 
Published: January 2003

AbstractEpiphytic lichen diversity in a boggy stand of Norway spruce (Picea abies) was studied in the eastern Harz Mountains, northern Germany. Spruce trees at wet sites were affected by forest dieback, whereas trees on drier sites remained unaffected. Lichen diversity was higher on diebackaffected trees than on healthy ones. The foliose lichen Hypogymnia physodes was significantly more frequent on dead trees, whereas the crustose, extremely toxitolerant Lecanora conizaeoides occurred more frequently on healthy trees. Stemflow concentrations of NH⊂4⊃+, NO⊂3⊃-, PO⊂3⊃-, and SO⊂4⊃2- were lower on affected trees. This is attributed to reduced interception from the atmosphere due to needle loss. Cover of H. physodes decreased with increasing mean SO⊂4⊃2- concentration in stemflow. The total of lichen species per sample tree also decreased with increasing SO⊂4⊃2- concentration in stemflow, indicating that most species reacted in a similar way as H. physodes. Cover of L. conizaeoides increased with increasing SO⊂4⊂2- concentration, but decreased at higher SO⊂4⊃2- concentrations. Bark chemistry had a minor influence on lichen diversity.
The effect of recombinant human osteogenic protein‐1 (bone morphogenetic protein‐7) impregnation on allografts in a canine intercalary bone defect
Authors: Cullinane Dennis M. , Lietman Steven A. , Inoue Nozomu , Deitz Luke W. , Chao Edmund Y. S. 
Published: January 2003

AbstractThe utility of cortical allografts in repairing large bone defects is limited by their slow and incomplete incorporation into host bone. In order to determine the effects of recombinant human osteogenic protein‐1 (rhOP‐1) impregnation on allograft incorporation, we used a canine intercalary bone defect model. Bilateral resection of a 4 cm segment of the femoral diaphysis and reconstruction with structural bone allografts were performed. In one limb, the allograft was soaked in solution with rhOP‐1 for 1 h before implantation. In the other limb, the allograft was soaked in the same solution without rhOP‐1. Dynamic load‐bearing, radiographic analysis, biomechanical testing, and histomorphometric analysis were conducted. Radiographic analysis showed significantly larger periosteal callus area in the rhOP‐1 treated group at week 2. The rhOP‐1 significantly increased allograft bone porosity and significantly increased the number of active osteons in the allografts. There were no significant differences between the rhOP‐1 treated and non‐treated allografts in load bearing and biomechanical analyses. These findings indicate that rhOP‐1 increases intercalary allograft remodeling without deleterious effects in mechanical and functional strength.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Expression of monocyte chemoattractant protein‐1 in primary cultures of rabbit intervertebral disc cells
Authors: Yoshida Masakazu , Nakamura Takafumi , Kikuchi Taro , Takagi Katsumasa , Matsukawa Akihiro 
Published: January 2003

AbstractMacrophages are considered essential for herniated disc resorption, and chemokines may play a role in their recruitment. Here we demonstrate that intervertebral disc cells are capable of producing monocyte chemoattractant protein‐1 (MCP‐1), a CC chemokine that is chemotactic for macrophages. Nucleus pulposus cells and anulus fibrosus cells were harvested from intervertebral discs of healthy rabbits, and the cells were stimulated with either interleukin (IL)‐1β or tumor necrosis factor (TNF)α. Reverse transcriptase polymerase chain reaction demonstrated that IL‐1β and TNFα induced mRNA expression for MCP‐1 in nucleus pulposus and anulus fibrosus cells. Protein concentrations of MCP‐1 in the culture supernatants were quantitated by fluoroim‐munoassay, which showed that nucleus pulposus and anulus fibrosus cells dose‐ and time‐dependently produced MCP‐1 after IL‐1β‐and TNFα‐stimulation, an event that was completely abrogated by IL‐1 receptor antagonist and anti‐TNFα monoclonal antibody, respectively. Nucleus pulposus cells produced significantly higher levels of MCP‐1 than did anulus fibrosus cells. Immunohisto‐chemically, the intensity of MCP‐1 positive cells in nucleus pulposus cells was stronger than that in anulus fibrosus cells. Altogether, our data clearly demonstrated the production of MCP‐1 in intervertebral disc cells, suggesting the possible involvement of disc cells in an early stage of macrophage infiltration.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Wrist kinetics after luno‐triquetral dissociation: the changes in moment arms of the flexor carpi ulnaris tendon
Authors: Tang Jin Bo , Xie Ren Gou , Yu Xiao Wei , Chen Feng 
Published: January 2003

AbstractWrist biomechanics after luno‐triquetral (LT) dissociation is important for understanding the clinical sequelae of the disease and for determining its treatment options. The LT interosseous ligament plays an important role in stabilizing the joint and damage to the ligament would be expected to significantly increase moment arms of tendon of the flexor carpi ulnaris (FCU), the principal ulnar wrist flexor. We investigated the changes in moment arms of FCU tendon after various amounts of sectioning of the ligaments proven to be associated with LT dissociation. In six fresh frozen cadaveric upper extremities, excursions of the FCU tendon were recorded simultaneously with wrist joint angulation during wrist flexion‐extension and radioulnar deviation. Tendon excursions were measured in intact wrists, in wrists with sectioning of the dorsal portion of the LT interosseous ligament, in wrists with sectioning of the entire LT interosseous ligament, and finally in wrists with further sectioning of the dorsal radiotriquetral and intercarpal ligaments. Moment arms of the tendon were calculated from tendon excursions and joint motion angulations and expressed as percentage changes from those in the intact wrist. During wrist flexion‐extension, moment arms of the FCU tendon after sectioning of the entire LT interosseous ligament and after sectioning of the two capsular ligaments were 112 ± 7% and 114 ± 8%, respectively; these values were significantly greater than those in the intact wrist. During radioulnar deviation, the moment arms were 114 ± 11% after sectioning of the dorsal portion of the LT interosseous ligament, 134 ± 15% after sectioning of the entire ligament, and 153 ± 18% after sectioning of the capsular ligaments, again being significantly greater than the normal wrist. Increase in moment arms of the FCU tendon after loss of integrity of the LT interosseous ligament and dorsal capsular ligaments may contribute to clinical sequelae of LT dissociation and difficulty in treating this disorder.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Cyclic compression of cartilage/bone explants in vitro leads to physical weakening, mechanical breakdown of collagen and release of matrix fragments
Authors: Thibault Marc , Robin Poole A. , Buschmann Michael D. 
Published: January 2003

AbstractMechanical loading of articular cartilage can produce catabolic and anabolic changes in tissue metabolism. Most previous studies in this area have focussed on aggrecan. Little information concerning load‐induced collagen modifications has been obtained. We have therefore conducted studies where mechanical loads are applied in vitro to full thickness cartilage explants retaining a thin layer of bone, in order to investigate mechanically induced collagen breakdown and consequent turnover, in addition to aggrecan changes and mechanical property alterations. Tissue explant disks were subjected to unconfined compression and either immediately frozen or kept in static culture for 10 days. Mechanical tests of the disks immediately prior to and just after the cyclic loading period were also performed. They showed a weakening of the collagen network and an increased hydraulic permeability due to the cyclic loading. Load‐induced alterations of the extracellular matrix was then clearly evidenced by an increase in denatured collagen in the disks frozen immediately after loading compared to unloaded controls. Loaded disks maintained in culture for 10 additional days following cyclic loading no longer expressed this increase in denatured collagen suggesting that mechanically denatured collagen II had undergone a removal process which could represent turnover or repair, or the beginning of progressive degradation. Indeed matrix fragments of collagen II and glycosaminoglycans were found to be released to post‐loading culture medium in increased quantities compared to unloaded controls. Our data further demonstrates the ability of mechanical load of articular cartilage to modulate turnover and metabolism of collagen and proteoglycan in a complex and multifactorial manner that may be of particular significance in the pathogenesis of osteoarthritis and in the development of pharmacological agents to modulate its progression.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Tenofovir treatment at 30 mg/kg/day can inhibit cortical bone mineralization in growing rhesus monkeys (Macaca mulatta)
Authors: Castillo Alesha B. , Tarantal Alice F. , Watnik Mitchell R. , Bruce Martin R. 
Published: January 2003

AbstractThe acyclic nucleoside phosphonate analog, 9‐[2‐(R)‐(phosphonomethoxy)propyl]adenine (PMPA; Tenofovir; Gilead Sciences, Inc., Foster City, CA), has been shown to effectively inhibit simian immunodeficiency virus (SIV) replication in rhesus macaques by blocking reverse transcription. However, chronic long‐term tenofovir treatment at 30 mg/kg/day, intended to reduce viral replication and illness, has been shown to result in bone deformities and spontaneous fractures in rhesus monkeys. Based on these findings, we studied the effects of tenofovir treatment and pathogenic SIV infection on cortical bone remodeling in rhesus monkeys. Tibiae from tenofovir‐treated or untreated, SIV‐infected or uninfected, rhesus macaques were evaluated for bone microdamage and remodeling. We found that tenofovir treatment had a significant effect on osteoid (unmineralized bone) seam width in tibial cross‐sections. Regardless of SIV infection status, half of the tenofovir‐treated animals had significantly increased osteoid seam widths in tibial cortical bone resulting in an osteomalacia‐like condition. Pathogenic SIV infection significantly increased tibial resorption cavity density, and this increase was normalized by tenofovir treatment. These results suggest that tenofovir treatment at 30 mg/kg/day inhibits mineralization of newly formed bone. SIV infection results in increased tibial resorption cavity density, while tenofovir treatment tends to minimize this increase. Both defective mineralization of newly formed bone and increased resorption cavity density may result in greater bone fragility.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
CDMP‐2 induces bone or tendon‐like tissue depending on mechanical stimulation
Authors: Forslund Carina , Aspenberg Per 
Published: January 2003

AbstractCartilage derived morphogenetic proteins (CDMPs, also known as growth and differentiation factors, GDFs) are a subgroup of the bone morphogenetic protein (BMP) gene family. As most BMPs, they are known to induce cartilage or bone formation when implanted subcutaneously or intramuscularly on an appropriate carrier. However, similar implantation experiments with CDMPs have also reported the formation of a tendon‐like tissue, without any cartilage or bone. A solution to this apparent contradiction might be offered by the mechanical tissue differentiation theory, suggesting that tissue differentiation depends on the mechanical environment. This study analyzes the response to CDMP‐2 implants at different sites and under different loading conditions in the rat. Collagen sponges carrying CDMP‐2 were implanted subcutaneously, intramuscularly or inside a freshly created defect in the achilles tendon. Large amounts of bone were induced subcutaneously, smaller amounts intramuscularly, and in the tendons, only small amounts of bone or cartilage were seen in few animals. Thus, the amount of bone appeared inversely related to the degree of mechanical stimulus. To confirm this, CDMP was also injected into tendon defects that were either loaded or partially unloaded. All the unloaded tendons showed bone induction after one CDMP‐2 injection, whereas only 4 of 10 loaded ones showed any cartilage or bone (p = 0.0005). Single injections of a similar dose of CDMP‐2 have previously been shown to augment tendon repair by increasing the size of the tendon callus. This study suggests that the response to CDMP‐2 is dependent on the mechanical situation at the site where it is applied.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
In situ strain and stress of nerve conduction blocking in the brachial plexus
Authors: Takai Shinro , Dohno Hidefumi , Watanabe Yoshinobu , Yoshino Nobuyuki , Ogura Taku , Hirasawa Yasusuke 
Published: January 2003

AbstractThe objective of the present study was to determine the in situ strain and stress of nerve conduction blocking in the brachial plexus. The measurement of the in situ tension stress inducing functional failure of the brachial plexus consisted of two steps. Step I (in vivo): The brachial plexus of the rabbit was stretched laterally until electrophysiological conduction blocking occurred. The distance between two dye marks placed on the lower trunk was simultaneously recorded using a video dimensional analyzer system. Step II (in vitro): The lower trunk that was removed was loaded again, and the nerve tension was recorded. The load at complete conduction blocking was determined by a load‐elongation curve. The results showed that when the in situ nerve strain reached 8.1 ± 0.5%, the compound muscle action potential was not evoked. The in situ load and stress were 2.5 ± 0.4 N and 0.89 ± 0.14 MPa, respectively, at complete conduction blocking. These findings should be helpful in understanding the mechanism of brachial plexus traction injury.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Development‐associated differences in integrative cartilage repair: Roles of biosynthesis and matrix
Authors: Giurea Alexander , Dimicco Michael A. , Akeson Wayne H. , Sah Robert L. 
Published: January 2003

AbstractA recurring problem in tissue transplantation therapies for articular cartilage defects is the lack of integration between the implant and the host cartilage. Previous studies have shown that in vitro integration between explants of calf cartilage is markedly higher than that between fetal cartilage, despite similarly high levels of deposition of newly synthesized collagen. The aim of this study was to determine if cellular biosynthesis and extracellular matrix each contribute to these development‐associated differences in integrative repair in vitro. The approach taken was to examine integration between specific combinations of cartilage explants that were apposed for two weeks. The cartilage matrix showed different propensities for repair, as integration of calf live cartilage to calf devitalized cartilage was greater than that of calf live cartilage to fetal devitalized cartilage. An inhibiting factor appeared to be present in fetal cartilage matrix since guanidine treatment of fetal devitalized cartilage was able to enhance its integration. The difference between integration to living cartilage and integration to devitalized cartilage, for calf and fetal tissue, indicated that the biosynthetic contribution to integration by calf cartilage was greater than the biosynthetic contribution by fetal cartilage. Thus, the increasing level of integration between fetal and fetal cartilage, fetal and calf cartilage, and calf and calf cartilage appeared to reflect both biosynthetic and matrix differences. Therapeutic strategies to enhance integration to cartilage may thus target both the extracellular components and the cellular biosynthetic activities of implants and host cartilage.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Are social fears and DSM-IV social anxiety disorder associated with smoking and nicotine dependence in adolescents and young adults?
Authors: Sonntag H. , Wittchen H.U. , Höfler M. , Kessler R.C. , Stein M.B. 
Published: January 2003

SummaryTo investigate associations between social anxiety and smoking behaviour in order to explore whether social anxiety predicts the first onset of cigarette smoking, regular smoking and the development of nicotine dependence.Baseline and four-year follow-up data from the Early Developmental Stages of Psychopathology Study (EDSP), a prospective-longitudinal community study of 3,021 adolescents and young adults, are used. Smoking behaviour and psychopathology were assessed with the M-CIDI and its DSM-IV algorithms. At baseline, 35.7% of the sample were regular smokers, and 18.7% fulfilled criteria for DSM-IV nicotine dependence. Twenty-seven point two percent reported at least one social fear, and 7.2% met criteria for DSM-IV social phobia, most of whom reported first onset of social fear problems clearly prior to smoking initiation. Cross-sectional retrospective baseline analyses based on retrospective reports revealed that social fears and DSM-IV social phobia were both significantly associated with higher rates of nicotine dependence. Prospective-longitudinal analyses that were conducted in an attempt to confirm cross-sectional retrospective results showed that baseline non-users with social fears (OR = 3.85) and baseline non-dependent users with social fears (OR = 1.5) had an increased risk of onset of nicotine dependence during the follow-up period of four years. These findings remained significant even when controlling for co-morbid depressive disorders. Social anxiety was found to be significantly associated with nicotine dependence in both cross-sectional retrospective and prospective-longitudinal analyses. It is suggested that social fears could lead to heavy tobacco use as smoking is a socially acceptable behaviour that relieves anxiety in social situations. Possible differential effects of social anxiety on the early stages of smoking behaviour compared to effects on nicotine dependence are discussed. These findings should stimulate a continued search into potentially causal links between social fear symptoms and the development of tobacco consumption and nicotine dependence in adolescence.
Cognitive aspects of social phobia: a review of theories and experimental research
Authors: Musa C.Z. , Lépine J.P. 
Published: January 2003

SummaryCognitive theories of social phobia have largely been inspired by the information-processing models of anxiety. They propose that cognitive biases can, at least partially, explain the etiology and maintenance of this disorder. A specific bias, conceived as a tendency to preferentially process socially-threatening information, has been proposed. This bias is thought to intervene in cognitive processes such as attention, memory and interpretation. Research paradigms adopted from experimental cognitive psychology and social psychology have been used to investigate these hypotheses. The existence of a bias in the allocation of attentional resources and the interpretation of information seems to be confirmed. A memory bias in terms of better retrieval for threat-relevant information appears to depend on specific encoding activities.
Disability and quality of life in pure and comorbid social phobia. Findings from a controlled study
Authors: Wittchen H.U. , Fuetsch M. , Sonntag H. , Müller N. , Liebowitz M. 
Published: January 2003

SummarySocial phobia is increasingly recognized as a prevalent and socially impairing mental disorder. However, little data is available regarding the general and disease-specific impairments and disabilities associated with social phobia. Furthermore, most studies have not controlled for the confounding effects of comorbid conditions.This study investigates: (a) the generic quality of life; (b) work productivity; and, (c) various other disorder-specific social impairments in current cases with pure (n = 65), comorbid (n = 51) and subthreshold (n = 34) DSM-IV social phobia as compared to controls with no social phobia (subjects with a history of herpes infections).Social phobia cases reported a mean illness duration of 22.9 years with onset in childhood or adolescence. Current quality of life, as assessed by the SF-36, was significantly reduced in all social phobia groups, particularly in the scales measuring vitality, general health, mental health, role limitations due to emotional health, and social functioning. Comorbid cases revealed more severe reductions than pure and subthreshold social phobics. Findings from the Liebowitz self-rated disability scale indicated that: (a) social phobia affects most areas of life, but in particular education, career, and romantic relationship; (b) the presence of past and current comorbid conditions increases the frequency and severity of disease-specific impairments; and, (c) subthreshold social phobia revealed slightly lower overall impairments than comorbid social phobics. Past-week work productivity of social phobics was significantly diminished as indicated by: (a) a three-fold higher rate of unemployed cases; (b) elevated rates of work hours missed due to social phobia problems; and (c) a reduced work performance.Overall, these findings underline that social phobia in our sample of adults, whether comorbid, subthreshold, or pure was a persisting and impairing condition, resulting in considerable subjective suffering and negative impact on work performance and social relationships. The current disabilities and impairments were usually less pronounced than in the past, presumably due to adaptive behaviors in life style of the respondents. Data also confirmed that social phobia is poorly recognized and rarely treated by the mental health system.