bluuebunny/crossref_metadata_2025 huggingface dataset:
Bone marrow stromal dysfunction in mice administered cytosine arabinoside
Authors: Ben‐Ishay Zina , Barak Vivian
Published: March 2003

Abstract: Objective: The aim of the study was to investigate ex‐vivo the bone marrow (BM) stroma of mice under conditions of low‐ and high‐dose cytosine arabinoside (Ara‐C), a cycle‐specific drug (S‐phase) and to assess possible stromal damage, apart from the killing of hematopoietic cells. Stroma consists of mesenchymal elements generally not in the cell cycle; therefore it could not be a target for the killing effect of Ara‐ C. Materials and Methods: The stromal function was studied by the following: the incidence of stromal stem cells, i.e. CFU‐F; formation of stromal layers under growth conditions of long‐term culture (LTC) followed by irradiation and overlayering of test cells in contact and non‐contact co‐cultures; subsequent culture of the test cells in a semi‐solid medium to assay the incidence of hyperproliferative potential cells (HPPC); production of GM‐CSF, IL‐3, IL‐4, IL‐6 and IFNγ in the conditioned medium (CM) of confluent stromal layers. All tests and assays were carried out on BM specimens, 1–4 d after Ara‐C administration and on controls. Results: Low‐dose Ara‐C induces a marked decrease of CFU‐F, compensated by cycle induction of pre‐CFU‐F, young‐type stromal stem cells. High‐dose Ara‐C causes a CFU‐F decrease to almost zero level. The time length to layer confluency is normal after low‐dose Ara‐C (∼10 d) and prolonged after a high dose (∼30 d). The confluent layers from mice receiving low‐ or high‐dose Ara‐C support hematopoiesis adequately. Among the growth factors and cytokines assayed, only IL‐6 is detected in CM layers. IL‐6 decreases after a low dose of Ara‐C and increases after a high dose. The cause of IL‐6 fluctuations is yet to be investigated. It is, however, evident that IL‐6 is not an essential factor in support of hematopoiesis. Conclusions: Taken together, the current study in mice indicates that Ara‐C administration, in particular a high dose, induces bone marrow stromal damage and/or disfunction. The long period of time to reach layer confluency after a high Ara‐C dose might reflect the in‐vivo situation of slow stromal regeneration.
Cyclosporin A in the treatment of refractory immune thrombocytopenia purpura in children
Authors: Gesundheit Benjamin , Cividalli Gabriel , Freeman Arnold , Yatziv Shaul , Koren Gideon , Baruchel Sylvain
Published: March 2003

Abstract: Patients with refractory autoimmune thrombocytopenia do not respond to standard therapy with high‐dose corticosteroids, intravenous immunoglobulin, and splenectomy. We describe the cases of two patients with refractory autoimmune thrombocytopenia treated with oral cyclosporin A (CsA) to evaluate the efficacy of this alternative therapy. Blood pressure and hepatic and renal function were in the normal range before initiation of treatment. Induction therapy with pulses of high‐dose methylprednisolone was used for 3 consecutive days to improve the initial immune suppression. Gradual dose reduction of CsA, according the platelet count, minimized the long‐term adverse effects of CsA. Oral CsA with pulses of high‐dose methylprednisolone induced remission of the thrombocytopenia. Gradual weaning of CsA over months, according the platelet count, produced no observable adverse effects of the CsA. Rapid dose reduction caused thrombocytopenia, which resolved with higher dosages of CsA. Our cases show the efficacy of CsA for refractory immune thrombocytopenia. This therapeutic option with oral CsA as an additional salvage option may avoid splenectomy and the adverse effects of long‐term corticosteroids. Larger clinical investigations are necessary to establish the indications and therapeutic regimen for CsA in immune thrombocytopenia.
Drugs elevating extracellular adenosine promote regeneration of haematopoietic progenitor cells in severely myelosuppressed mice: their comparison and joint effects with the granulocyte colony‐stimulating factor
Authors: Hofer Michal , Pospı´šil Milan , Znojil Vladimı´r , Vacek Antonı´n , Weiterová Lenka , Holá Jiřina , Vácha Jiřı´
Published: March 2003

Abstract:We tested capabilities of drugs elevating extracellular adenosine and of granulocyte colony‐stimulating factor (G‐CSF) given alone or in combination to modulate regeneration from severe myelosuppression resulting from combined exposure of mice to ionizing radiation and carboplatin. Elevation of extracellular adenosine was induced by joint administration of dipyridamole (DP), a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), serving as an adenosine prodrug. DP + AMP, G‐CSF or all these drugs in combination were administered in a 4‐d treatment regimen starting on day 3 after induction of myelosuppression. Comparable enhancements of haematopoietic regeneration due to elevation of extracellular adenosine or to action of G‐CSF were demonstrated as shown by elevated numbers of haematopoietic progenitor cells for granulocytes/macrophages (GM‐CFC) and erythrocytes (BFU‐E) in the bone marrow and spleen in early time intervals after termination of the drug treatment, i.e. on days 7 and 10 after induction of myelosuppression. Coadministration of all the drugs further potentiated the restoration of progenitor cell pools in the haematopoietic organs. The effects of the drug treatments on progenitor cells were reflected in the peripheral blood in later time intervals of days 15 and 20 after induction of myelosuppression, especially as significantly elevated numbers of granulocytes and less pronounced elevation of lymphocytes and erythrocytes. The results substantiate the potential of drugs elevating extracellular adenosine for clinical utilization in myelosuppressive states, e.g. those accompanying oncological radio‐ and chemotherapy.
Incidence of apoptosis and cell proliferation in multiple myeloma
Authors: Chaidos Aristeidis I. , Bai Maria C. , Kamina Sevasti A. , Kanavaros Panayiotis E. , Agnantis Niki J. , Bourantas Konstantinos L.
Published: March 2003

Abstract: We evaluated the in vivo incidence of apoptosis and cell proliferation in multiple myeloma (MM) and investigated the correlation of both cellular events with histological tumour stage and grade, bcl‐2 protein expression, serum IL‐6 and sIL‐6R. Material and methods: The TUNEL method was used to assess apoptosis and immunohistochemistry to assess the expression of proliferating cell nuclear antigen (PCNA) and bcl‐2 protein in 30 bone marrow biopsy specimens. The apoptotic index (AI) and proliferative index (PI) were defined as the percentage of TUNEL and PCNA positive plasma cells, respectively. Results: The mean AI was 0.162% and the mean PI 27.44%. A positive correlation between AI and PI was found (r = 0.44, P = 0.017). PI was also correlated with tumour grade (P = 0.015). The mean bcl‐2 protein expression was 70% and did not correlate with AI or PI, but was higher in specimens taken at first diagnosis than in specimens taken after response to treatment (P = 0.035). The mean serum IL‐6 and sIL‐6R values were 9.43 pg mL−1 and 47.27 ng mL−1, respectively. These parameters did not correlate with AI or PI. Conclusions: The results indicate that MM might be among the malignancies with very low incidence of apoptosis. Proliferative activity increased in parallel with tumour histological grade. A positive correlation between apoptosis and proliferation was observed, but the incidence of these two cellular events seems not to be related to the bcl‐2 protein expression and the serum levels of IL‐6 and sIL‐6R.
Fatal reactivation of hepatitis B virus following cytotoxic chemotherapy for acute myelogenous leukemia: fibrosing cholestatic hepatitis
Authors: Kojima H. , Abei M. , Takei N. , Mukai Y. , Hasegawa Y. , Iijima T. , Nagasawa T.
Published: March 2003

Abstract: Hepatitis B virus (HBV) is a well known pathogen that sometimes causes fulminant hepatitis in patients undergoing cytotoxic chemotherapy. Fibrosing cholestatic hepatitis (FCH) is a recently recognized unique variant of viral hepatitis, which has been occasionally reported in HBV‐infected recipients of liver, renal, or bone marrow transplantation. We present here a 48‐yr‐old male in whom HBV was reactivated during post‐remission chemotherapy for acute myelogenous leukemia, which resulted in rapidly fatal outcome. He manifested with deterioration of liver function in association with enormous replication of HBV. Liver biopsy showed marked ballooning of hepatocytes, cholestasis, and periportal fibrosis with minimum infiltrates. Immunostaining revealed that hepatocytes were strongly positive for hepatitis B surface antigen. Under the diagnosis of FCH, he was treated with lamivudine and interferon β, which was not effective. Autopsy showed severe atrophy of the liver and marked degeneration of hepatocytes. Hematologists should be aware that FCH is a fatal complication that can develop under post‐chemotherapy immunosuppressed conditions. Although there is no convincing evidence, prophylactic administration of lamivudine seems to be a reasonable strategy.
Deoxycytidine kinase expression and activity in patients with resistant versus sensitive acute myeloid leukemia
Authors: Veuger Marjan J. T. , Honders M. Willy , Willemze Roel , Barge Renée M. Y.
Published: March 2003

Abstract: Resistance to cytarabine (AraC) is a major problem in treatment of patients with acute myeloid leukemia (AML). In contrast to in vitro AraC resistance, deoxycytidine kinase (dCK) mutations are rarely found in patients with refractory or relapsed AML. Previously we have demonstrated alternatively spliced dCK mRNA predominantly expressed in leukemic blasts from patients with resistant AML. In this study we investigated wild‐type (wt) dCK expression and activity to elucidate the possible role of decreased dCK expression or activity in unresponsiveness to AraC in patients with AML. No alterations in dCK mRNA and protein expression or in dCK activity were detected between patients with clinically resistant vs. sensitive AML. In addition, wt dCK expression and activity were not reduced in leukemic blasts expressing alternatively spliced dCK forms as compared to blasts with only wt dCK. Also, no major differences in wt dCK expression and activity were observed between samples obtained from patients with AML and bone marrow or peripheral blood samples from healthy donors. These data implicate that in our patient group of refractory or relapsed AML cases, alterations in dCK expression and/or activity cannot explain unresponsiveness to chemotherapy including AraC.
Fibroblasts surrounding melanoma express elevated levels of matrix metalloproteinase‐1 (MMP‐1) and intercellular adhesion molecule‐1 (ICAM‐1) in vitro
Authors: Wandel E. , Graßhoff A. , Mittag M. , Haustein U. F. , Saalbach A.
Published: March 2003

Abstract: Tumour growth and metastasis involve the degradation of extracellular matrix components by matrix degrading enzymes produced by tumour cells and stromal fibroblasts. In this study, fibroblasts were obtained from biopsies on the border (TB) and 1 cm distant from the melanoma (TD) and cultured separately. Similar studies were performed with fibroblasts surrounding melanocytic nevi as control. The expression of matrix metalloproteinase‐1 (MMP‐1) mRNA and tissue matrix metalloproteinase inhibitor 1 (TIMP‐1) were studied by Northern blot analysis. The activation antigen intercellular adhesion molecule‐1 (ICAM‐1) in TB‐ and TD‐fibroblasts was investigated by flow cytometry. In melanoma, TB‐fibroblasts showed an increased expression of MMP‐1 mRNA mainly in fibroblasts obtained from tumours with extended invasive growth demonstrated by Clark level whereas the expression of the major specific inhibitor TIMP‐1 was unaltered. In contrast, fibroblasts surrounding benign melanocytic nevi did not express elevated levels of MMP‐1. The upregulation of MMP‐1 in TB‐fibroblasts compared to TD‐fibroblasts was maintained during cultivation. Furthermore, MMP‐1 mRNA expression and MMP‐1 total protein amount in normal fibroblasts were increased by melanoma cell conditioned medium. We demonstrated an increased expression of ICAM‐1 in TB‐fibroblasts compared to TD‐fibroblasts in vitro depending on the amount of inflammatory infiltrate in situ. The differences of ICAM expression disappeared during continued cell culture. These results support the idea that fibroblasts surrounding melanoma are activated and are possibly involved in the degradation of matrix proteins surrounding the tumour.
Connexins: a connection with the skin
Authors: Richard Gabriela
Published: March 2003

Abstract: The intercellular signaling system mediated by connexin channels is crucial for maintaining tissue homeostasis, growth control, development, and synchronized response of cells to stimuli. This review summarizes the structure, assembly, and properties of the components of the complex and diverse connexin system, and their biological functions in skin. The importance of gap junctional intercellular communication for normal development and differentiation of human epidermis as well as the hearing function of the inner ear is illustrated by the examples of erythrokeratodermia variabilis and palmoplantar keratoderma associated with hearing loss. These autosomal dominant inherited disorders are caused by germline mutations in the connexin genes GJB3 (encoding connexin‐31) and GJB2 (encoding connexin‐26), respectively. Recent functional studies of individual connexin mutations suggest that they may exert a dominant inhibitory effect on normal connexin channel function and perturb gap junctional intercellular communication, resulting in phenotypic manifestation in patients with these disorders.
Alopecia mice derived from albino ddY mice: breeding, histological and ultrastructural studies
Authors: Kagoura M. , Morohashi M.
Published: March 2003

Abstract: Sparse‐haired (SH) mice arose spontaneously in a stock of sib‐mated albino ddY mice. Hair loss in the skin of SH mice begins at 3 weeks of age and progresses with age. On the basis of breeding studies between SH mice and albino ddY mice, the phenotype of SH mice is identified as autosomal recessive inheritance. Histological examination shows that numerous pilary canals begin to widen and the outer root sheath becomes thin at 1 week of age. The inner root sheath and the hair were separated. Ultrastructural examination reveals that electron dense materials which formed coalesced and irregularly coiled chains are seen at the level of firm attachment of the hair to its inner root sheath. At the level of hair and inner root sheath separation, linear materials with high electron density are observed in the exocuticle of the hair cuticle. These results suggest that the appearance of electron dense materials is closely related to the mechanism of hair loss in SH mice and SH mice may be useful as an animal model in human hypotrichosis.
VEGF production, cell proliferation and apoptosis of human IGR 1 melanoma cells under nIFN‐α/β and rIFN‐γ treatment
Authors: Bölling Brigitte , Fandrey Joachim , Frosch Peter J. , Acker Helmut
Published: March 2003

Abstract: The effect of natural and recombinant interferons (nIFN, rIFN) on cell growth, apoptosis and the production of vascular endothelial growth factor (VEGF) was investigated in the human melanoma cell line IGR 1. We determined cell proliferation, cell vitality, DNA synthesis, apoptosis, intracellular oxygen radicals (ROS) and VEGF‐mRNA as well as VEGF‐protein levels. rIFN‐γ significantly inhibited growth by decreasing DNA synthesis and increasing apoptosis. Less pronounced was the growth inhibitory effect of nIFN‐β because an increased rate of apoptosis was outweighed by enhanced DNA synthesis. nIFN‐α only had minor effects on cell growth parameters. Under long‐term incubation (144 h) nIFN‐β decreased, but rIFN‐γ increased production of the angiogen VEGF. Our data underscore the multiple effects of IFNs on melanoma cells and may contribute to the understanding of ambivalent results of melanoma therapy by IFNs. Particularly, the increased VEGF production under long‐term treatment with serum IFN levels between 100 and 1200 IU/ml should be kept in mind.
Alterations in cytokine regulation in aged epidermis: implications for permeability barrier homeostasis and inflammation
Authors: Ye J. , Garg A. , Calhoun C. , Feingold K. R. , Elias P. M. , Ghadially R.
Published: March 2003

Abstract: Acute disruption of the cutaneous permeability barrier with either solvents or tape‐stripping stimulates a homeostatic metabolic response in the subjacent nucleated layers of the epidermis that results in a rapid restoration of normal permeability barrier function. When the aged epidermal permeability barrier is stressed, it reveals a diminished capacity for recovery, in comparison to young epidermis, analogous to other organs in the aged when stressed. Although the signals that regulate this homeostatic response by the epidermis have not yet been resolved, acute permeability barrier disruption stimulates release of prestored IL‐1α, and increased production of potentially regulatory cytokines, including IL‐1α and TNFα in the epidermis. In these studies, we addressed the hypothesis that cytokine dysregulation explains the permeability barrier abnormality in aged epidermis, assessing the regulation of IL‐1 and TNF signaling in aged vs young mice. To determine whether the IL‐1 family of cytokines plays a key role in the permeability barrier abnormality of the aged, permeability barrier recovery rates were compared in transgenic mice lacking the functional IL‐1 type 1 receptor vs wild‐type mice at various ages. Knockout of the IL‐1 type 1 receptor exacerbates the defect in permeability barrier homeostasis that is seen in age‐matched, wild‐type counterparts. Furthermore, the sluggish permeability barrier recovery in aged epidermis is associated with, and at least in part attributable to, altered expression of the IL‐1 family of cytokines and receptors both under basal conditions and after acute barrier perturbations. Whereas modulations in cytokine expression with epidermal permeability barrier perturbation are qualitatively similar in aged epidermis, they greatly differ quantitatively. In contrast, examination of TNFα mRNA and protein basally, and following barrier perturbation revealed no alterations in aged epidermis. Together, these results show that selective alterations in the IL‐1 family of cytokines occur with aging and that defects in IL‐1 signaling may contribute to the epidermal permeability barrier abnormality of aged skin.
Sebaceous glands in acne patients express high levels of neutral endopeptidase
Authors: Toyoda M. , Nakamura M. , Makino T. , Kagoura M. , Morohashi M.
Published: March 2003

Abstract: Acne is a complex, chronic and common skin disorder of pilosebaceous units. Although it is known that exacerbation of acne results from emotional stress, the nature of the association between stress and acne remains unclear. This is due in part to the lack of substantial evidence regarding the participation of cutaneous neurogenic factors in the pathogenesis of acne. To examine the possible involvement of neurogenic factors in the etiology of acne, we used immunohistochemistry to compare the distribution of SP‐containing nerve fibers around sebaceous glands and the expression of neutral endopeptidase in sebaceous acini of the facial skin of acne patients and of healthy subjects. More numerous substance P immunoreactive nerve fibers in close apposition to the sebaceous glands and an increase in expression of neutral endopeptidase in sebaceous acini were observed in acne patients compared with the controls. Immunoelectron microscopy revealed that the subcellular localization of neutral endopeptidase was restricted to the Golgi apparatus and the endoplasmic reticulum within sebaceous germinative cells. In addition, in vitro experiments using an organ culture system demonstrated that substance P induced expression of neutral endopeptidase in sebaceous glands in a dose dependent manner. This study reveals that substance P and its degrading enzymes are involved in the pathogenesis of acne, which in turn might partially explain the pathologic significance of neurogenic and psychogenic aspects in the disease process.
A large conductance [Ca2+]i‐independent K+ channel expressed in HaCaT keratinocytes
Authors: Nguyen V. H. , Markwardt F.
Published: March 2003

Abstract: Patch‐clamp recordings were carried out in the inside‐out configuration in human keratinocytes of the cell line HaCaT. Patch pipettes were filled with 150 mM KCl, 1 mM CaCl2 and 10 mM HEPES. In symmetrical KCl solutions, single channel currents from a large conductance channel (about 170 pS) were measured. Replacement of 120 mM KCl by K‐aspartate had only a minor influence on the single channel conductance and on the reversal potential. In intracellular solution in which K+ has been replaced by Na+ or NMDG+, the reversal potential shifted to >+ 40 mV indicating K+ as the main charge carrier. The channels were neither dependent on intracellular Ca2+ (between 0.8 nM and 10 µM), ATP (at 0 and 1 mM) nor Mg2+ (at 0 and 0.5 mM). The mean current showed an outward rectification that can be mainly attributed to the voltage dependence of the open probability. The channels displayed bursting kinetics with a mean open time of about 2 ms and closed times of about 0.2, 2 and 20 ms. The mean open probability was usually low (0.05) but increased occasionally (0.6) mainly due to a lower probability of long closings. We conclude that these K+ channels contribute to the resting potential of human keratinocytes which may control the Ca2+ influx and thereby their proliferation and differentiation.
Effect of the transcriptional repressor Mad1 on proliferation of human melanoma cells
Authors: Ohta Yukinori , Hamada Yuko , Saitoh Norimitsu , Katsuoka Kensei
Published: March 2003

Abstract: Mad1 is a Myc antagonist that heterodimerizes with Max and functions as a transcriptional repressor. We studied the effects of Mad1 on cell growth and malignant phenotype in human melanoma cells. To perturb the activity of c‐Myc, which is involved in the progression of melanoma, we overexpressed Mad1 protein with liposomal‐mediated transfection of cytomegalovirus promoter‐driven expression vector containing the human Mad1 gene, pcMad‐1. The growth characteristics and malignant potential of two Mad1 transfectants of the FEM human melanoma cell line, overexpressing Mad1 stably and the respective vector control were analysed both in vitro and in a nude mice xenograft model in vivo. Two Mad1 transfectants exhibited up to 2.8 times longer doubling time, less proliferation rate (50% inhibition), increased G0/G1 accumulation in cell‐cycle distribution, and active melanin synthesis, compared with vector controls in vitro. In the mice model, the volume of tumors that arose from Mad1 transfected clones was 4–5 times less than those arising from vector control FEM cells. Histopathologically, tumors that arose from Mad1 transfectants showed altered round‐shaped morphology with less pleomorphism compared with control FEM cells. Our results indicating that Mad1 gene transfer inhibits the proliferation of human melanoma cells suggest that Mad1 could be a potentially useful candidate for the modification of genes against malignancies.
Genes that are differentially expressed in rat vibrissa follicle germinative epithelium in vivo show altered expression patterns after extended organ culture
Authors: Whitehouse C. Jenna , Huckle James W. , Demarchez Michel , Reynolds Amanda J. , Jahoda Colin A. B.
Published: March 2003

Abstract: Hair growth depends on maintenance of signalling between the dermal papilla and the germinative epithelium (GE), from which the differentiated layers of the hair fibre originate. Because no molecular studies have been reported which concentrate specifically on GE cells either in vivo or in vitro, we prepared a cDNA library enriched for messages which were highly expressed in GE cells to identify genes that may be involved in hair growth control. Of 35 subtracted library clones sequenced, 23 shared extensive homology with previously determined cDNA sequences, including LEF‐1 and id4. Hair follicle organ culture models are often used to investigate the molecular basis of hair growth, although hair growth arrest occurs relatively rapidly in vitro. As an indicator of their role in follicle activities, we compared the expression of GE‐specific clones in different regions of freshly isolated vibrissa follicles, with the corresponding regions of growth arrested, cultured follicles. Changes in the expression of some of these clones indicates that they could be related to fundamental cellular activities in the follicle. A library enriched for GE‐specific clones therefore provides a useful source of candidate molecules for studies of follicular epithelial cell behaviour, both in vivo and in vitro.
Neutrophil gelatinase‐associated lipocalin is a marker for dysregulated keratinocyte differentiation in human skin
Authors: Mallbris Lotus , O'Brien Kevin P. , Hulthén Anna , Sandstedt Bengt , Cowland Jack B. , Borregaard Niels , Ståhle‐Bäckdahl Mona
Published: March 2003

Abstract: Neutrophil gelatinase‐associated lipocalin (NGAL) is a 25‐kDa protein initially isolated from the specific granules of human neutrophils. It is a member of the highly heterogeneous lipocalin protein family, which shares a common tertiary structure. Its synthesis is induced in gastrointestinal epithelium in association with inflammation and malignancy. To gain insight into its potential role in other epithelia we have investigated the expression of NGAL in human skin embryonic development, in normal adult skin, and in skin associated with inflammation and neoplastic transformation. In the present study we report that the embryonic expression of NGAL appears to be regulated in a spatio‐temporal pattern. It was induced in the interfollicular epidermis at 20–24 weeks of gestational age but thereafter progressively receded towards the hair follicles. In normal adult skin, NGAL was detected solely in association with hair follicles. However, strong induction of NGAL in the epidermis was seen in a variety of skin disorders characterized by dysregulated epithelial differentiation such as psoriasis, pityriasis rubra and squamous cell carcinoma. In these tissues production of NGAL was confined to spatially distinct subpopulations of keratinocytes underlying areas of parakeratosis, whereas skin samples lacking parakeratotic epithelium such as lichen ruber planus, acute contact eczema and basal cell carcinoma were negative for NGAL. Consistent with being a marker for disturbed terminal differentiation, NGAL immunoreactivity showed an inverse pattern when compared with that of the differentiation marker filaggrin. The biologic functions of NGAL in epithelia are not fully known, although an immunomodulatory role in host defense has been proposed. In addition, the transient interfollicular NGAL expression during skin embryogenesis along with the induction of NGAL in adult parakeratotic epidermis suggests it play a role in epithelial differentiation pathways.
Do spatial models of growth rate potential reflect fish growth in a heterogeneous environment? A comparison of model results
Authors: Tyler J. A. , Brandt S. B.
Published: March 2003

Abstract
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Spatial models of fish growth rate potential have been used to characterize a variety of environments including estuaries, the North American Great Lakes, small lakes and rivers. Growth rate potential models capture a snapshot of the environment but do not include the effects of habitat selection or competition for food in their measures of environment quality. Here, we test the ability of spatial models of fish growth rate potential to describe the quality of an environment for a fish population in which individual fish may select habitats and local competition may affect per capita intake. We compare growth rate potential measurements to simulated fish growth and distributions of model fish from a spatially explicit individual‐based model of fish foraging in the same model environment. We base the model environment on data from Lake Ontario and base the model fish population on alewife in the lake. The results from a simulation experiment show that changes in the model environment that caused changes in the average growth rate potential correlated extremely highly (r2≥0.97) with changes in simulated fish growth. Unfortunately, growth rate potential was not a reliable quantitative predictor of simulated fish growth nor of the fish spatial distribution. The inability of the growth rate potential model to quantitatively predict simulated fish growth and fish distributions results from the fact that growth rate potential does not consider the effects of habitat selection or of competition on fish growth or distribution, processes that operate in our individual‐based model and presumably also operate in nature. The results, however, do support the use of growth rate potential models to describe the relative quality of habitats and environments for fish populations.
Is scuba sampling a relevant method to study fish microhabitat in lakes? Examples and comparisons for three European species
Authors: Brosse S. , Laffaille P. , Gabas S. , Lek S.
Published: March 2003

Abstract – We compared fish microhabitat use patterns in the littoral zone of a lake using a new direct method (point abundance sampling by scuba, PASS) and the widely used point abundance sampling by electrofishing technique (PASE). We collected microhabitat data for age 0+ roach (Rutilus rutilus L.), perch (Perca fluviatilis L.), and pike (Esox lucius L.). The two methods yielded different results for fish assemblage structure and microhabitat patterns. Using PASE, fish were mainly found in “shelter habitats” such as shallow waters and dense vegetation. It is likely that this behavior is caused by the disturbance of the observer stamping around. Using PASS, fish escapement behavior was rarely observed. Therefore, we concluded that this direct and nondestructive sampling technique can be used to provide an accurate microhabitat estimation of a fish community and is assumed to be more suitable than PASE for fish habitat studies.
Influence of site characteristics on fish community patterns in French reservoirs
Authors: Irz P , Laurent A , Messad S , Pronier O , Argillier C
Published: March 2003

Abstract – The objectives of this paper are to describe the fish assemblages in French reservoirs and to relate them to the sites' characteristics. The results of 43 fishing surveys were collected and completed with environmental descriptors. Fish assemblages differ between salmonids‐dominated mountain sites and lowland ones. The latter show higher species diversity and a distinction between rheophilic‐ and limnophilic‐type communities. This distinction can be explained by the reservoir age, location in the catchment and depth. The response of fish communities to these variables was investigated by canonical correspondence analysis. It shows that rheophilic species are typically abundant in upper basin, deep and recently created reservoirs. The fish community response to the aging process corresponds to an addition of lowland standing waters species and an extinction of the native riverine ones. The structuring role of the sites' depth, location and age is discussed, considering their relationship with the water body trophic status.
The differential effects ofLigula intestinalis(L.) plerocercoids on host growth in three natural populations of roach,Rutilus rutilus(L.)
Authors: Loot G. , Poulin R. , Lek S. , Guégan J.‐F.
Published: March 2003

Abstract – This study reports the differential effect of the pseudophyllidean cestode,Ligula intestinalis, on the growth rates of three fish populations of the roach,Rutilus rutilus, under field conditions. Here, we show that only one host‐population is affected by parasite‐induced gigantism in the first 2 years of host life. Paradoxically, this increase in fish growth is strongly correlated with the parasitic load in plerocercoid stages, in that only the roach population subjected to the heaviest parasitic pressure shows an enhanced growth of cestode‐parasitized individuals. This host gigantism observed in only one locality is associated with parasite‐induced fish mortality occurring, on average, one year earlier in this fish population when compared to other populations. We discuss the different reasons for this differential parasite effect on growth enhancement across host‐population in natural settings. Whether the growth effects represent an adaptive response by the host or a manipulation byL. intestinalisof the host, remains to be elucidated.
Influence of eastern hemlock (Tsuga canadensis L.) on fish community structure and function in headwater streams of the Delaware River basin
Authors: Ross R. M. , Bennett R. M. , Snyder C. D. , Young J. A. , Smith D. R. , Lemarie D. P.
Published: March 2003

Abstract –  Hemlock (Tsuga canadensis) forests of the eastern U.S. are in decline due to invasion by the exotic insect hemlock woolly adelgid (Adelges tsugae). Aquatic biodiversity in hemlock ecosystems has not been documented; thus the true impact of the infestation cannot be assessed. We compared ichthyofaunal assemblages and trophic structure of streams draining hemlock and hardwood forests by sampling first‐ and second‐order streams draining 14 paired hemlock and hardwood stands during base flows in July 1997 at the Delaware Water Gap National Recreation Area of Pennsylvania and New Jersey. Over 1400 fish of 15 species and 7 families were collected, but hemlock and hardwood streams individually harbored only one to four species. Brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were two to three times as prevalent in hemlock than hardwood streams. Insectivorous fishes occurred in significantly higher proportion in streams of hardwood (0.90) than hemlock (0.46) stands, while piscivores occurred more often in hemlock (0.85) than hardwood (0.54) stands. Functional (trophic) diversity of fishes in hemlock and second‐order streams was numerically greater than that of hardwood and first‐order streams. Species composition also differed by stream order and terrain type. Biodiversity is threatened at several levels within hemlock ecosystems at risk to the hemlock woolly adelgid in eastern U.S. forests.
Cultured tumor cells of murine submandibular gland origin: a model to investigate pHi regulation of salivary cells
Authors: Trzaskawka Estelle , Vigo Jean , Egea Jean‐Christophe , Goldsmith Marie‐Christine , Salmon Jean‐Marie , Deville De Periere Dominique
Published: March 2003

Intracellular pH (pHi) and several ion transport mechanisms in cultured murine salivary gland cells (SCA‐9) were studied using a videomicrofluorometric method and the H+‐specific probe C‐SNARF‐1. The aim of this study was to test SCA‐9 cells' pHi regulation mechanisms and evaluate if this cell line is representative of submandibular gland cells. Resting pHi in unstimulated cells was estimated to be 7.17±0.07. To investigate the presence of Na+/H+ and Cl−/HCO3− antiports as well as Na+/K+/2Cl− symports in SCA‐9 cells, we used different specific blockers, dimethyl‐amiloride, disulfonic stilbene, bumetanide and furosemide. In order to study SCA‐9 cell capacity to regulate their pHi in response to alkaline and acid loads, we applied the NH4Cl prepulse method to all these blockers. The results showed that SCA‐9 cells possess both antiports and symports involved in pHi regulation, and that this cell line can be used as a convenient model to study pHi regulatory mechanisms in salivary cells.
Changes in function and in pain‐related and cognitive‐behavioral variables after arthroscopy of temporomandibular joints
Authors: Dahlstro¨m Lars , Widmark Göran , Carlsson Sven G.
Published: March 2003

The purpose was to prospectively evaluate changes in clinical, pain, and cognitive‐behavioral variables in a structurally homogenous group of patients with painful temporomandibular joints (TMJ), who had undergone an identical intervention, arthroscopy. Twenty‐six consecutive patients who had previously undergone unsuccessful conservative treatment participated. They were evaluated with the Craniomandibular Index (CMI), pain‐related measures on visual analogue scales (VASs) for 1 wk, questionnaires, and the Multidimensional Pain Inventory (MPI). The mean CMI decreased significantly, from 0.28 to 0.18, 3 months after surgery. Pain measures also decreased significantly as rated on questionnaires, and “at worst” and “most of the time” on VASs. Intrapsychic variables related to pain also decreased significantly, while interpersonal and activity measures remained unchanged. An overall MPI dysfunctional variable correlated significantly with pain. Few further changes were observed at 12 months. Lysis and lavage of the upper TMJ compartment appears to effectively alleviate persisting functional and pain‐related symptoms with low morbidity, in line with previous findings. Recoveries seem to be accompanied by changes in certain pain‐related cognitive‐behavioral variables within a limited sphere. Biological and intrapsychic features may interact with interpersonal factors in a complicated way in patients with orofacial pain.
Water characteristics associated with the occurrence of Legionella pneumophila in dental units
Authors: Zanetti Franca , Stampi Serena , De Luca Giovanna , Fateh‐Moghadam Pirous , Bucci Sabattini Maria Antonietta , Checchi Luigi
Published: March 2003

This study evaluated the incidence of Legionella pneumophila in dental unit water samples and investigated how the occurrence of these bacteria may be related to some physical, chemical and bacteriological characteristics of the water. The samples were taken from the incoming tap water, oral rinsing cup, air–water syringe, ultrasonic scaler, and the turbine of 23 dental units of private and public institutions. Apart from L. pneumophila(serogroup 1 and 3) isolated in 22 out of the101 (21.8%) water samples tested, two other species were found: L. bozemanii and L. dumoffii. The highest densities and frequency of L. pneumophila were observed in the water coming into the units and in the dental units of public institutions. A negative association between L. pneumophila and 36°C and 22°C heterotrophic total plate counts and other Gram‐negative bacteria was found. An inverse association between the concentration of L. pneumophila and water temperature was also observed. The values of pH and total hardness did not show any significant difference in the L. pneumophila‐positive and ‐negative dental unit waters. Finally, the chemical oxygen demand (COD) and residual chlorine were found to correlate positively with L. pneumophila.
Biological mercury measurements before and after administration of a chelator (DMPS) and subjective symptoms allegedly due to amalgam
Authors: Schuurs Albert , Exterkate Rob , Ten Cate Bob
Published: March 2003

The aim of the study was to explore multivariately the relationship between subjective symptoms allegedly due to amalgam and mercury measurements before and after administration of a chelator. Of 120 participants, the mercury concentrations in urine (U‐Hg) and plasma (P‐Hg) before and after a chelating agent or placebo were determined as were the numbers of fillings and symptoms allegedly due to subjective symptoms. The dental status was charted. Blood was analysed on 13 parameters. The analysis revealed neither the parameters in blood nor the subjective symptoms to be associated with a dimension dominated by ‘mercury indicators’. The final analysis was therefore performed with ‘number of subjective symptoms’ and enabled to distinguish two subsamples. One subsample was characterised by >2 subjective “symptoms”, highest scores for U‐Hg, P‐Hg and filled surfaces, and chewing gum for >1 h a day. The other subsample comprised the subjects with few filled surfaces and low U‐Hg and P‐Hg, but was not characterised by “no subjective symptoms”. The chelator was considered neither to invalidate nor to improve these findings and was concluded not to be helpful in diagnosing “symptoms”. The chelator caused side effects in 42% of the subjects and the placebo in 27%. A relationship between amalgam fillings and subjective symptoms could not be shown. Therefore, the mere fact of knowing to have amalgam fillings was assumed to be the reason why subjective symptoms were attributed to amalgam and side effects were ascribed to the treatment.
Immunohistochemical and ultrastructural evaluation of the effects of phosphoric acid etching on dentin proteoglycans
Authors: Oyarzún Alejandro , Rathkamp Hermann , Dreyer Erik
Published: March 2003

It has been reported that phosphoric acid (PA) produces structural and molecular alterations in dentin collagen fibrils; however, no relevant information exists on the influence of etching with PA on dentin non‐collagenous macromolecules. The present study investigated, by immunohistochemistry and ultrastructural histochemistry, the behavior of dentin proteoglycans (PG) after etching human dentin samples with 35% PA gel (thickened with colloidal silica) or with a 35% PA liquid for 15, 30 and 120 s. Immunolabeling with a mouse monoclonal anti‐chondroitin sulfate antibody demonstrated that glycosaminoglycans (GAG) were preserved within dentinal tubules opened to the surface after etching with PA gel. In addition, the cationic tracer polyethyleneimine, used for the ultramicroscopic localization of PG anionic sites, revealed that treatment of dentin samples with PA gel preserved the polyanionic peritubular PG in the etched area. On the other hand, etching with the PA liquid produced loss of peritubular GAG and PG anionic sites in the etched dentin surface. The results obtained indicated that similar concentrations of PA in gel or liquid formulations differently affect the organization of dentin PG. The clinical significance of these in vitro findings and the structural and molecular interactions of dentin PG with adhesive systems are still unknown.
Treatment of inflamed ferret dental pulps with recombinant bone morphogenetic protein‐7
Authors: Rutherford R. Bruce , Gu Keni
Published: March 2003

Recombinant human BMP‐7 (bone morphogenetic protein‐7, osteogenic protein‐1) is osteogenic, dentinogenic and cementogenic when implanted into the appropriate tissue in vivo. However, most studies characterizing the induction of these tissues have implanted BMP‐7 into freshly surgerized, clinically healthy tissues. To determine if BMP‐7 is dentinogenic in inflamed dental pulps, we applied BMP‐7 to inflamed ferret pulps. A single application of 5 μg of a commercial preparation of lipopolysaccharide (LPS) from Salmonella typhimurium directly to the coronal pulp induced a reversible mixed inflammatory exudate of moderate intensity within 3 d. Treatment with a single application of 2.5, 7.5 or 25 μg recombinant human BMP‐7/mg collagen (2 mg total mass/tooth) induced reparative dentinogenesis in controls but not LPS treated dental pulps. These data reveal that a single application of up to 50 μg/tooth of exogenous recombinant BMP‐7 is insufficient to induce reparative dentinogenesis in ferret teeth with reversible pulpitis. Given that pulp cells in the inflamed tissues likely retain the capacity to respond to exogenous BMP‐7, it is possible that insufficient active recombinant protein is available to induce tissue formation in experimentally inflamed dental pulps.
Effect of experimental diabetes on mandible growth in rats
Authors: Giglio Máximo Juan , Lama Maria Anabel
Published: March 2003

The aim of the present work was to assess the effects of experimental diabetes on mandible growth in rats. Experimental diabetes was induced in rats, aged 26 d, by a single dose of 100 mg/kg b.w. of Streptozotocin (STZ). Thirty‐one d post STZ or vehicle injection, the animals were killed. Mandibles were resected to determine Mandibular Skeletal Units dimensions (MSU) and overall mandible growth. Statistical analysis of results revealed, for STZ treated animals as compared to the control group: 1) a decrease in b.w.; 2) an increase in food intake; 3) an increase in glucemia (200%); 4) normal hemoglobin, creatinine and plasma urea values; 5) a reduction in growth of symphyseal (9%), coronoid (16%), and alveolar (13%) heights, condyloid (11%), angular (8%), and base (3%) lengths, and condyloid width (8%). Mandibular length (4%), height (8%) and length of base (6%) were significantly lower in diabetic animals as compared to the control group. No significant differences in length of symphyseal process, alveolar length and height of base were found between groups. Rats on a restricted diet, resulting in a decreased b.w., and the control group exhibited similar mandibular dimensions. These data show that STZ‐induced diabetes reduces mandibular growth, resulting in some deformity of the structure.
Detection of artificially induced vertical radicular fractures using Tuned Aperture Computed Tomography
Authors: Nair Madhu K. , Nair Uma Devi P. , Gröndahl Hans‐Göran , Webber Richard L. , Wallace James A.
Published: March 2003

This study compared the accuracy of three imaging modalities for the detection of artificially induced vertical root fractures (VRF) on teeth in cadaver mandibles. Fifty‐four single‐rooted, endodontically treated mandibular teeth being prepared to carry posts were evaluated using direct digital radiography (DDI) with a Schick sensor, unprocessed Tuned Aperture Computed Tomography® (TACT‐U) images and iteratively restored TACT (TACT‐IR) images. Twenty‐eight of these teeth had been subjected to fracture induction using an apically driven force. Nine basis images were used for each TACT image generation. Eight observers used a five‐point confidence rating scale to record the confidence with which they considered a fracture to be present or not. Sensitivity and specificity values were computed and receiver operating characteristic (ROC) curves were generated. The areas under the curves (Az) used as an indication of the diagnostic accuracy of the imaging system were as follows: DDI: 0.37; TACT‐U: 0.77 and TACT‐IR: 0.81. DDI was significantly inferior to the TACT modalities. Differences in detection efficacy based on observers and observation sessions were noted on ANOVA and post‐hoc Tukey's tests. This study indicates that TACT is the imaging modality of choice for VRF in endodontically treated teeth.
Separation of the outer membrane and identification of major outer membrane proteins from Porphyromonas gingivalis
Authors: Murakami Yukitaka , Imai Masashi , Nakamura Hiroshi , Yoshimura Fuminobu
Published: March 2003

The outer membrane of Porphyromonas gingivalis, an oral strict anaerobe, was isolated by sucrose density gradient centrifugation. The outer membrane obtained by the differential detergent extraction method, previously reported, showed an essentially similar protein pattern on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE), confirming that the latter method is suitable for the study of outer membrane proteins in this organism. N‐terminal amino acid sequence analysis revealed that major outer membrane proteins in this organism included Arg‐gingipain, Lys‐gingipain, RagA (a TonB‐linked receptor), and putative porins that were homologous to Escherichia coli OmpA.