bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of nicotine on bone mass and strength in aged female rats
Authors: Akhter M. P. , Iwaniec U. T. , Haynatzki G. R. , Fung Y. K. , Cullen D. M. , Recker R. R. 
Published: December 2002

AbstractThis study investigated the effects of nicotine on bone mass and biomechanical properties in aged, estrogen‐replete (sham‐operated) and estrogen‐deplete (ovariectomized) female rats. Eight month old, retired breeder, sham‐operated and ovariectomized Sprague‐Dawley rats were left untreated for 12 weeks to establish cancellous osteopenia in the ovariectomized group. The animals were then administered saline, low dose nicotine (6.0 mg/kg/day) or high dose nicotine (9.0 mg/kg/day) via osmotic minipumps for 12 weeks. Vertebrae and femora were collected at necropsy for determination of bone mass and strength. As expected, ovariectomy had a negative effect on most endpoints evaluated. Vertebral body bone mineral content (BMC) and density (BMD) and the structural (ultimate load and yield load) and material (ultimate stress, yield stress, and flexural modulus of elasticity) strength properties were lower in the OVX rats than in the sham‐operated rats. Femoral diaphysis BMC, BMD, ultimate load, and flexural modulus were also lower in the OVX rats than in the sham‐operated rats. The nicotine doses administered resulted in serum nicotine levels that averaged 1.5–4.5‐fold greater than those observed in heavy smokers. Despite the high doses used, nicotine had no effect on vertebral BMC, BMD, or any of the structural and material strength properties in either the OVX or the Sham rats. In addition, nicotine had no effect on femoral diaphysis BMC, BMD, ultimate load, stiffness, ultimate stress, or flexural modulus. Femoral yield load and stress were lower in low dose nicotine‐treated rats than in vehicle‐treated rats. However, differences were not detected between the high dose nicotine‐ and vehicle‐treated rats for either femoral yield load or stress. The results suggest that tobacco agents other than nicotine are responsible for the decreased bone density and increased fracture risk as observed in smokers.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The role of emergency obstetric care in preventing maternal deaths: an historical perspective on European figures since 1751
Authors: Papiernik E. 
Published: December 2002

AbstractA review of the time‐relationships is provided between the introduction of obstetric techniques and organization of obstetric care in Europe and the decrease of maternal death rates from 1751 to 1980. Published figures were used to discover the evolution of maternal deaths in Europe for the last 250 years, and to propose a parallel analysis of major modifications of obstetric care. The teaching of obstetrics to midwives and general practitioners, introduction of forceps and of low‐segment cesarean section technique, disappearance of home deliveries, antibiotics, anesthesia and blood banks are among the addressed techniques. Even if a causal relationship cannot be proposed, the major inflection in the rate of reduction of maternal deaths is related to the introduction of low segment cesarean section in the first years of the 20th century. This progress was also related to the progressive transfer of birth sites, from home to specialized units.
Traditional birth attendants in Bangladeshi villages: cultural and sociologic factors
Authors: Rozario S. 
Published: December 2002

AbstractWorld Health Organization policy for some years has emphasized working through traditional birth attendants as the best path to improving the appalling level of maternal and child mortality and illness in much of the Third World. The universal appropriateness of this strategy has begun to be called into question. Recent research on childbirth in rural Bangladesh, as elsewhere in South Asia, suggests that the concept of the ‘traditional birth attendant’ in the context of this region needs to be reexamined. The dai typically have tittle training and low status, due to their close association with the removal of birth pollution. A policy based on converting them into modern health professionals faces serious obstacles. In practice, neither the poorly‐trained village dai nor such biomedically‐trained practitioners as are available at the village level are able to deliver competent health care. Their effectiveness is further compromised by the cultural and material environment within which they operate. A more adequate approach to care for birthing women in the village still has to be developed.
Protective effects of intermittent hydrostatic pressure on osteoarthritic chondrocytes activated by bacterial endotoxin in vitro
Authors: Lee Mel S. , Ikenoue Takashi , Trindade Michael C. D. , Wong Neal , Goodman Stuart B. , Schurman David J. , Smith R. Lane 
Published: December 2002

AbstractThe role of continuous passive motion (CPM) in the management of septic arthritis and inflammatory arthritis remains of interest. CPM produces cyclic variations in intraarticular pressure that facilitates transport of fluid, nutrients, and solutes within and/or across the joint and stimulates chondrocyte metabolism. However, the precise mechanisms mediating the responses of chondrocytes to joint motion remain unclear. This study tested the hypothesis that dynamic mechanical loading counteracts effects of bacterial lipopolysaccharide (LPS), an inflammatory mediator, on chondrocyte metabolism. Intermittent hydrostatic pressure (IHP) (10 MPa for 4 h) was applied to human chondrocytes pretreated with LPS (1 μg/ml for 18 h). LPS activation of chondrocytes decreased mRNA signal levels of type II collagen by 67% and aggrecan by 56% and increased nitric oxide by 3.1‐fold, monocyte chemotactic protein‐1 mRNA signal levels by 6.5‐fold, and matrix metalloproteinase‐2 mRNA signal levels by 1.3‐fold. Application of IHP to LPS‐activated chondrocytes decreased nitric oxide synthase mRNA signal levels and nitric oxide levels in the culture medium. Exposure of LPS‐activated chondrocytes to IHP upregulated type II collagen and aggrecan mRNA signal levels by 1.7‐fold, relative to chondrocytes activated by LPS and maintained without loading. In addition, application of IHP decreased the upregulation in signal levels of monocyte chemotactic factor‐1 and matrix metalloproteinase‐2 following LPS activation by 45% and 15%, respectively. These data show that mechanical loading counteract effects of inflammatory agents, such as bacterial LPS, and suggest that postinfection sequelae are influenced by the presence or absence of joint loading.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The fate of soft callus chondrocytes during long bone fracture repair
Authors: Ford Joanna L. , Robinson Derek E. , Scammell Brigitte E. 
Published: December 2002

AbstractFollowing fracture, the cartilaginous tissue of the soft callus is eventually replaced by bone. Removal of the cartilage is a critical part of the bone healing process but information concerning the changes in chondrocytes during this process is sparse. The aim of the study was to investigate the fate of chondrocytes in the soft callus during the bone repair process using a rabbit tibial fracture model. Fracture tissue was processed for collagen I‐III and keratan sulphate immunohistochemistry to study changes in matrix composition and the TUNEL technique (terminal deoxynucleotidyl transferase medicated dUTP nick‐end labelling) to identify death of soft callus chondrocytes. Transmission electron microscopy (TEM) was also carried out to investigate the ultrastructure of chondrocytes within the soft callus. Results showed that the size of the cartilage area decreased over time and that cartilage matrix was replaced with new matrix rich in collagen I and III. Chondrocytes became engulfed in the new matrix and appeared to stop producing cartilage matrix. Chondrocyte cell death was seen at the border of the soft callus, just within the newly produced matrix. TEM revealed that these dying/dead cells were not typically apoptotic in appearance. In conclusion, results indicate that chondrocytes of the soft callus die as a result of the progressive production of bone matrix which eventually engulfs them and leads to the remodelling of the area and eventual bone repair.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Epigallocatechin‐3‐gallate selectively inhibits interleukin‐1 β‐induced activation of mitogen activated protein kinase subgroup c‐Jun N‐terminal kinase in human osteoarthritis chondrocytes
Authors: Singh Rashmi , Ahmed Salahuddin , Malemud Charles J. , Goldberg Victor M. , Haqqi Tariq M. 
Published: December 2002

AbstractActivation of mitogen activated protein kinases (MAPK) is a critical event in pro‐inflammatory cytokine‐induced signaling cascade in synoviocytes and chondrocytes that lead to the production of several mediators of cartilage damage in an arthritic joint. Green tea (Camellia sinensis) is a widely consumed beverage and we earlier showed that polyphenols present in green tea (GTP) inhibit the development of inflammation and cartilage damage in an animal model of arthritis. In this study we evaluated the role of epigallocatechin‐3‐gallate (EGCG), a green tea polyphenol which mimics its anti‐inflammtory effects, in modulating the IL‐1β‐induced activation of MAPK's in human chondrocytes. We discovered that EGCG inhibited the IL‐1β‐induced phosphorylation of c‐Jun N‐terminal kinase (JNK) isoforms, accumulation of phospho‐c‐Jun and DNA binding activity of AP‐1 in osteoarthritis (OA) chondrocytes. Also IL‐1β, but not EGCG, induced the expression of JNK p46 without modulating the expression of JNK p54 in OA chondrocytes. In immunecomplex kinase assays, EGCG completely blocked the substrate phosphorylating activity of JNK but not of p38‐MAPK. EGCG had no inhibitory effect on the activation of extracellular signal‐regulated kinase p44/p42 (ERKp44/p42) or p38‐MAPK in OA chondrocytes. EGCG or IL‐1β did not alter the total non‐phosphorylated levels of either p38‐MAPK or ERKp44/p42 in OA chondrocytes. These are novel findings and indicate that EGCG may be of potential benefit in inhibiting IL‐1β‐induced catabolic effects in OA chondrocytes that are dependent on JNK activity.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Expanded phenotypically stable chondrocytes persist in the repair tissue and contribute to cartilage matrix formation and structural integration in a goat model of autologous chondrocyte implantation
Authors: Dell'Accio Francesco , Vanlauwe Johan , Bellemans Johan , Neys Johan , De Bari Cosimo , Luyten Frank P. 
Published: December 2002

AbstractAutologous chondrocyte implantation (ACI) is an established technique to repair joint surface defects. Although there is some indirect evidence that the expanded chondrocytes are required to achieve proper healing, the role they play in the repair process is not clear yet. To monitor the persistence and the phenotype of the injected chondrocytes in the repair tissue (RT) we have optimized a fluorescent labeling protocol for articular chondrocytes, which allows cell tracking in vivo for up to 14 weeks, using the fluorescent dye PKH26. We have combined in vivo cell tracking, with the immune‐detection of collagen type II protein in a goat model of ACI. Our data indicate that the implanted cells can persist for at least 14 weeks in the defects, can participate in the integration with the surrounding tissues, and become structural part of the RT, rich in collagen type II and sulfated proteoglycans. Albeit with a small number of samples, our data provide proof of principal that the implanted chondrocytes can contribute to structural cartilage repair in a goat model of ACI.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
MicroCT evaluation of normal and osteoarthritic bone structure in human knee specimens
Authors: Patel Vikas , Issever Ahi Sema , Burghardt Andrew , Laib Andres , Ries Michael , Majumdar Sharmila 
Published: December 2002

AbstractAlthough trabecular bone structure has been evaluated, variation with knee compartment and depth from joint surface is not completely understood. Cadaver knees were evaluated with microcomputed tomography analysis for these variations. Objective differences were compared between: medial vs. lateral compartments; femoral vs. tibial bone; and normal vs. arthritic knees. Depth dependent changes in the parameters were observed for the first 6 mm of the cores in normal knees: BV/TV, Tb.N and Conn.D gradually decrease, while Tb.Sp and SMI increase. In the first 6 mm of the normal tibia BV/TV, Tb.N, and Tb.Th are greater than in the femur on both the medial and lateral compartments while Tb.Sp, SMI, and Conn.D are lower. The medial compartment values for BV/TV, Tb.N, Tb.Th and Conn.D are generally greater than for the lateral in both the femur and tibia while Tb.Sp and SMI are lower. In comparison of normal vs. arthritic knees significant differences are observed in the first 6 mm of the medial tibia. With arthritis BV/TV and Tb.Th are lower, while SMI and Tb.Sp are higher. Tb.N and Conn.D show no statistically significant difference. The bone structure variations are, thus, most prominent in the first 6 mm of depth and medial compartment bone is generally more structurally sound than lateral. Severely arthritic bone changes are most prominent in the medial compartment of the tibia and bone structure is less sound in severe arthritis.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Quantification of expression levels of cellular differentiation markers does not support a general shift in the cellular phenotype of osteoarthritic chondrocytes
Authors: Gebhard Pia Margarethe , Gehrsitz Angelika , Bau Brigitte , Söder Stephan , Eger Wolfgang , Aigner Thomas 
Published: December 2002

AbstractMany studies have shown increased anabolic activity in osteoarthritic cartilage and have suggested changes in the cellular phenotypes of articular chondrocytes. Most of these studies relied on non‐quantitative technologies, which did not allow the estimation of the relative importance of the different differentiation phenomena. In the present study, we developed and used quantitative PCR assays for collagen types I, II(total), IIA, III, and X as marker genes indicating cellular synthetic activity (collagen type II) as well as differentiation pattern of chondrocytes (collagen types I, IIA, III, and X) and quantified these genes in normal, early degenerative, and late stage osteoarthritic cartilage in parallel.At first sight, our results confirmed previously published data showing hardly any expression of collagen genes in normal and significantly enhanced expression in osteoarthritic cartilage. This included collagen types II, III, and IIA, but also collagen types I(α1) and X. However, if one considers the ratios of the various markers of chondrocytic differentiation in comparison to collagen type II, the main synthetic product of differentiated chondrocytes, no shift in the cellular phenotype was detectable. In fact, expression ratios remained constant or were even decreased in osteoarthritic cartilage.Our results confirm that normal adult human articular chondrocytes display hardly any expression activity of the collagen types investigated, whereas osteoarthritic chondrocytes show very increased synthetic activity. The largely unchanged ratios of collagen subtypes investigated indicate that no general shift in the cellular phenotype does occur in osteoarthritic cartilage as suggested by previous investigations.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
A novel two‐step method for the formation of tissue‐engineered cartilage by mature bovine chondrocytes: The alginate‐recovered‐chondrocyte (ARC) method
Authors: Masuda Koichi , Sah Robert L. , Hejna Michael J. , Thonar Eugene J.‐M. A. 
Published: December 2002

AbstractMost attempts to tissue‐engineer cartilage have involved seeding of cultured cells into a biological or synthetic scaffold. We have developed a novel two‐step culture approach that makes possible the in vitro formation of cartilaginous‐like tissue by mature adult bovine chondrocytes without the aid of a synthetic matrix. The first step consists of culturing chondrocytes under conditions that maintain their rounded shape and their molecular phenotype as assessed by type II collagen and aggrecan production. This step was accomplished by culturing the isolated chondrocytes in alginate beads until the cells have reestablished a proteoglycan‐rich cell‐associated matrix (CM). The second step consists of culturing the cells with their CM, after recovery from the beads, on a tissue culture insert with a porous membrane. In this study, young adult bovine articular chondrocytes were cultured in alginate beads in the presence of 10% or 20% fetal bovine serum (FBS). After 7 days of culture, the alginate beads were dissolved by incubating the beads for 20 min in sodium citrate buffer, a calcium chelator. Following a brief centrifugation, the cells with their CM were recovered, resuspended in medium containing 10% or 20% FBS and seeded onto a tissue culture insert. After 1 week of culture on the insert, the individual cells with their CM progressively became incorporated into a mass of cartilaginous tissue. Culture with 20% FBS resulted in the best formation of tissues. These tissues, easily recovered from the insert, were then subjected to biochemical and histological analyses. The biochemical results showed that the chondrocytes remain phenotypically stable in the tissues. The de novo tissue has a relatively high ratio of PG/collagen. Histological examination of the tissue revealed it contained a cartilage‐like matrix strongly stained with toluidine blue. This scaffold‐free system appears ideal to study, in vitro, the development of transplantable cartilaginous tissue.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The national maternal mortality study of Egypt 1992–1993
Authors: Kassas M. , Hefni M. , Hanafi A. , Campbell O. 
Published: December 2002

AbstractThe study was designed as a population‐based sample of all maternal deaths over a one‐year period in 21 governorates. A sample of 7487 deceased women of reproductive age was selected. During pregnancy, delivery, or in the puerperium, there were 825 772 maternal deaths and 53 from incidental causes. Of the maternal deaths, 69.5% were due to direct obstetric causes while 26.9 and 3.6% were due to indirect and unknown causes, respectively. The national maternal mortality ratio was 174 maternal deaths per 100 000 live births.
Birth control counseling for HIV seropositive pregnant women
Authors: Piya‐Anant M. , Atisook R. , Ratananikom P. 
Published: December 2002

AbstractTesting for HIV antibody at the antenatal clinic in Siriraj Hospital started on 1 July 1991. It was found that the percentage of HIV seropositive pregnant women rapidly increased from 1.2% in 1992 to 1.9% in 1993. During those 2 years, 487 seropositive women were admitted for delivery or abortion; 23.8% were adolescents and 47.0%, young adults. Prevention of HIV transmission from mother‐to‐baby was birth control; 95 women (19.5%) chose to abort their pregnancy. After termination of all pregnancies by abortion or delivery, 83% requested sterilization, 12.9% accepted Norplant, 1.8% the pill and only 2.3% refused anything at all. Condoms were used regularly for prevention of HIV infection by 29.4% of men although Thai men generally do not accept them for birth control. Seropositive Norplant users had more bleeding than general Norplant users but treatments were the same.
Nerve conduction and microanatomy in the rabbit sciatic nerve after gradual limb lengthening–distraction neurogenesis
Authors: Yokota Atsushi , Doi Munekazu , Ohtsuka Hisashi , Abe Muneaki 
Published: December 2002

AbstractTo clarify how the peripheral nerve adapts to elongation during gradual limb lengthening, electrophysiological and histomorphometric examinations were performed on the sciatic nerves in 18 rabbits. External fixators were used to lengthen the right femora by 30 mm (30%), at a daily rate of 0.5 mm (Group 1) or 2.0 mm (Group 2). Examinations were performed immediately after the limb lengthening procedure. Electrophysiologically, mild conduction slowing was observed in Group 1; a conduction block was evident in Group 2. Histologically, the mean diameter of myelinated fibers was unchanged in Group 1, but a significantly decreased diameter was observed in Group 2. Electron microscopy revealed that mild degenerative change of unmyelinated axons occurred sporadically in two cases in Group 2, but neither group showed evidence of thinning of myelin sheath of myelinated fibers. The mean internodal length (between nodes of Ranvier) of teased fibers was 1216 ± 295 μm in the control contralateral side, 1484 ± 347 μm in Group 1, and 1467 ± 322 μm in Group 2. Thus the internodes were lengthened by 22.1% (Group 1) and 20.7% (Group 2) in comparison with those of the controls. Straightening of the geometry of paranodal myelin sheath was significantly correlated with the rate of distraction. These results indicate that myelinated nerve fibers adapt to gradual elongation by lengthening each Schwann cell body, not by proliferation of Schwann cells.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Two distinct cellular mechanisms of osteoclast formation and bone resorption in periprosthetic osteolysis
Authors: Sabokbar A. , Kudo O. , Athanasou N. A. 
Published: December 2002

AbstractPurpose: TNFα and IL‐1α are proinflammatory cytokines that are abundant in periprosthetic tissues. These cytokines stimulate bone resorption and have recently been shown to directly induce osteoclast formation in mouse marrow cultures. We examined whether TNFα and IL‐1α can directly induce osteoclast formation from human arthroplasty‐derived (CD14+) macrophages by a mechanism independent of RANKL‐induced osteoclastogenesis.Methods: TNFα and M‐CSF (±IL‐1α) were added to cultures of magnetically sorted (CD14+) and unsorted (CD14+/CD14−14) cells isolated from the pseudomembrane of loosened hip arthroplasties. Osteoprotegerin (OPG), RANK:Fc and antibodies to TNF receptors (p55 and p75) were added to these cultures to distinguish the pathway of osteoclastogenesis. Osteoclast differentiation was assessed by expression of tartrate‐resistant acid phosphatase (TRAP), vitronectin receptor (VNR) and lacunar resorption.Results: The addition of TNFα (±IL‐1α) resulted in differentiation of CD14+ macrophages into TRAP+ and VNR+ multinucleated cells capable of extensive lacunar resorption. Both OPG and RANK:Fc (which inhibit RANKL‐induced osteoclastogenesis) did not block osteoclastogenesis. The addition of antibodies directed against the p55 receptor subunit of TNF resulted in significant inhibition of osteoclast formation and lacunar resorption.Conclusions: Our results indicate that, in the presence of M‐CSF, TNFα is sufficient for inducing human osteoclast differentiation from arthroplasty macrophages and that TNFα acts synergistically with IL‐1α to stimulate lacunar resorption. This process is distinct from the RANK/RANKL signalling pathway and is likely to operate in periprosthetic tissues when there is heavy wear particle deposition and cytokine production.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Rethinking the role of the risk approach and antenatal care in maternal mortality reduction
Authors: Yuster E.A. 
Published: December 2002

AbstractIn developing countries where most women are not delivered in health facilities, screening for obstetric risk is neither a cost‐effective nor efficient strategy for maternal mortality reduction. Antenatal care can contribute to preventing such deaths when used for identifying early obstetric complications, educating women to identify obstetric danger signs, and motivating them and their families to seek appropriate referral care.