bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction in Mucosa of IgG and IgA Antibodies against Parenterally Administered Soluble Immunogens
Authors: Decroix N. , Hocini H. , Quan C. P. , Bellon B. , Kazatchkine M. D. , Bouvet J.‐P.
Published: March 2003

The induction of a mucosal immunity provides an additional principle of vaccination by preventing the entry of pathogens in the body. Albeit the fact that intensive research has been conducted on local vaccines, the major mucosal vaccine commercially available for human use remains the oral polio vaccine. We have previously demonstrated that parenteral vaccination in humans with tetanus toxoid (TT) results in a genital immunoglobulin (Ig)G antibody (Ab) response. Here, we show that injections of TT with no adjuvant induces an anti‐TT response in the mucosal tissues of normal BALB/c mice. The response is multiregional, involves both IgG and IgA isotypes, and is long‐lasting. Similarly, injections of haptens coupled to TT or to other diffusible proteins may induce mucosal Abs. These results led us to immunize normal BALB/c mice with a viral peptide coupled to TT by disulfide bridging. The hapten was a 17 amino acid peptide containing the ELDKWA sequence of human immunodeficiency virus (HIV)‐1 gp41. A significant IgG and IgA Ab response to the immunizing peptide was induced in various mucosal tissues despite the presence of a suboptimal Ab response in the spleen. The results indicate that mucosal immunity to peptides that are candidates for human vaccinations may be achieved by parenteral adjuvant‐free immunization with peptide coupled to TT.
Effect of Maternal Antibodies on Influenza Virus‐Specific Immune Response Elicited by Inactivated Virus and Naked DNA
Authors: Radu D. L. , Antohi S. , Bot A. , Miller A. , Mirarchi A. , Bona C.
Published: March 2003

While vaccines are effective in adults, they are less successful in newborns and infants. Neonatal unresponsiveness to vaccines could be owing to immaturity of lymphocytes and/or to inhibition by maternal antibodies. Unresponsiveness of newborn to vaccines can be overcame by genetic immunization. In the present study we investigated the effect of maternal antibodies on the anti‐influenza virus protective response in progeny born to dams immunized with plasmid containing the hemagglutinin gene or UV‐inactivated virus. The effect of maternal antibodies was studied in plasmid immunized F1 mice born to BALB/c dams, previously immunized with virus or plasmid and crossed with C57BL/6 males, as well as in offspring born to BALB/c dams immunized with plasmid and then immunized with UV‐inactivated WSN virus. We have found that the inhibition period of the anti‐HA antibody response in offspring born to dams immunized with DNA is shorter than that of offspring born to dams immunized with virus. Furthermore, there is a persistent inhibitory effect on B cells from offspring born to dams immunized with virus or injected with antiviral monoclonal antibodies (MoAb), after the decline of maternal antibody titers. The analysis of the haemagglutinin‐specific clonotype reactivity pattern of offspring born to dams immunized with inactivated influenza virus or with a plasmid showed that clonotypes producing antibodies specific for the immunizing virus strain were predominant in offspring born to dams immunized with DNA compared to those born to dams immunized with virus. Maternal antibodies do not affect cell‐mediated immunity. These findings might be used to design efficient vaccination schedules for newborns and infants.
Cytokine Gene Expression in Healing and Non‐Healing Cases of Cutaneous Leishmaniasis in Response to In vitro Stimulation with Recombinant gp63 Using Semi‐Quantitative RT–PCR
Authors: Habibi G. R. , Khamesipour A. , McMaster W. R. , Mahboudi F.
Published: March 2003

Objectives of this study were to test the cytokine gene expression in peripheral blood mononuclear cells (PBMCs) from cases with nonhealing and healing cutaneous leishmaniasis (CL) in response to in vitro stimulation of recombinant gp63 (rgp63) and soluble Leishmania antigen (SLA). Healing and nonhealing cases are, respectively, defined as recovered from disease and refractory to various treatments. To evaluate the type of immunological response, mRNA transcription level for interleukin (IL)‐4, IL‐10, IL‐12 and interferon (IFN)‐γ were determined using semiquantitative reverse transcription–polymerase chain reaction (RT–PCR) technique in PBMCs of these volunteers. The results clearly demonstrated a high level of IL‐4 expression in nonhealing cases of CL and a low expression level of transcripts for IFN‐γ and IL‐12. In contrast, a high level of IFN‐γ and IL‐12 expression and a low level of IL‐4 and IL‐10 expression were detected in the healing cases. These findings not only support the balance of Th1/Th2 cytokines in the inducing predominant profile in healing and nonhealing cases, but it may also show the potential of rgp63 as a proper immunogen which might induce protective responses.
Neonatal Pattern of VH Gene Utilization in Nonobese Diabetic Mice Does not Correlate with Development of Insulitis
Authors: Rietz C. , Screpanti V. , Brenden N. , Fernández C.
Published: March 2003

The nonobese diabetic (NOD) mouse model is a model of human autoimmune insulin dependent diabetes, IDDM. The effector cells of the disease have been shown to be T cells, but also B cells seem to contribute. Adult NOD mice have been shown to display a bias in their utilization of immunoglobulin (Ig) variable heavy (VH) genes. In this study the analysis of VH gene utilization in NOD mice protected from insulitis by transgenic insertion of a major histocompatibility complex (MHC) class II Eα gene, point out that the bias in VH gene expression is not correlated to disease development. The aberrant VH gene utilization pattern in mice with the NOD genetic background is instead suggested to be a consequence of a deregulation of the apoptosis inhibiting gene bcl‐2. We also investigated if prolonged in vitro survival of NOD lymphocytes is correlated to disease development. The Eα transgenic NOD mice were shown to display a prolonged in vitro survival of spleen T cells, similar to normal NOD mice. These results indicate that defective death mechanisms of T cells may not be primarily involved in the development of autoimmune disease in these mice. However, in contrast to results from other groups, no difference in in vitro survival could be detected for B cells from mice with NOD genetic background compared to C57BL/6 mice.
Genesis of Progressive T‐Cell Deficiency Owing to a Single Missense Mutation in the Common Gamma Chain Gene
Authors: Goldman A. S. , Palkowetz K. H. , Rudloff H. E. , Dallas D. V. , Schmalstieg F. C.
Published: March 2003

Patients with a moderate X‐linked combined immunodeficiency (XCID) owing to a single missense mutation in the common gamma chain (γc) gene (L→Q271) were found to have a progressive T‐cell deficiency. Blood T cells from four older subjects with XCIDL→Q271 were studied to ascertain the basis of that progression. Few CD4+ T cells displayed the phenotype (CD45RA+ CD62L+) or deletion circles from T‐cell receptor (TCR) Vβ‐gene rearrangements found in recent thymic emigrants. These deficiencies were more severe in older males with XCIDL→Q271. Relative frequencies of fresh CD4+ and CD8+ T cells that bound annexin V, an early indicator of programmed cell death, or propidium iodide, an indicator of cell necrosis, were greater in XCIDL→Q271 T cells than in normal fresh T cells. The binding of annexin V and propidium iodide to XCIDL→Q271 T cells increased marginally after stimulation with anti‐CD3, but binding by fresh or stimulated XCIDL→Q271 T cells exceeded that found in normal stimulated T cells. Also, telomeres from XCIDL→Q271 CD4+ T cells were shortened in these patients compared to normal young adults. It therefore appears that the thymus is dysfunctional and that mature T cells are not effectively rescued from apoptosis or replication senescence via γc‐mediated pathways in XCIDL→Q271.
Increased Expression of Fas Ligand in Human Tuberculosis and Leprosy Lesions: a Potential Novel Mechanism of Immune Evasion in Mycobacterial Infection
Authors: Mustafa T. , Bjune G. , Jonsson R. , Hernandez Pando R. , Nilsen R.
Published: March 2003

To study the location and mechanism of apoptosis within the human tuberculosis (TB) and leprosy lesions, parallel sections were analyzed for mycobacterial antigens (M.Ag), Fas ligand (FasL), Fas, CD68 and Mac387 by immunohistochemistry, and apoptotic cells by the terminal deoxynucleotidyl‐transferase‐mediated dUTP‐digoxigenin nick end labelling method. Cutaneous leishmaniasis and foreign body granulomas were analyzed for comparison. The heavily infected macrophages in multibacillary TB and leprosy granulomas very strongly expressed FasL, indicating that a mycobacterial infection can induce an increased expression of FasL in a population of infected macrophages, which may protect them from the attack of Fas‐expressing lymphocytes. However, macrophages with high levels of leishmania amastigotes did not selectively express FasL, suggesting that this phenomenon is specific for the mycobacteria. Interestingly, in the well‐formed TB granulomas, 84% of the multinucleated giant cells strongly expressed FasL. The expression of Fas was weak (34%) or absent. A higher number (33%) of epithelioid cells expressed FasL than Fas (23%). Lymphocytes were scanty among the epithelioid cells. The frequency of apoptotic cells was higher in the epithelioid cells (0.25%) than the mononuclear cells in the mantle zone (0.14%). Thus, the epithelioid cells and the multinucleated giant cells by virtue of the increased expression of FasL may make these granulomas an immune privileged site for mycobacteria.
The Effect of IgM‐Enriched Human Ig and Rabbit Antithymocyte Globulin on the Stimulation of Mononuclear Cells
Authors: Eiermann T. H. , Sahm H. , Freitag C. , Zander A. R.
Published: March 2003

Whether IgM‐enriched intravenous Ig (pentaglobin) is a useful adjunct treatment for graft versus host disease (GvHD) prophylaxis in allogeneic stem‐cell transplantation is unclear. Clinical data with the use of a five‐agent GvHD prevention regimen, including pentaglobin and antithymocyte globulin (ATG), are encouraging. In vitro both have been reported to modulate alloreactive T cells. We compared their inhibitory effect on the phytohemagglutinin‐induced lymphocyte proliferation. ATG blocked the proliferation of lymphocytes at lower doses and much stronger than pentaglobin. The combination of both was not different from ATG alone. In pentaglobin, glucose used as stabiliser, caused the effect. Starting at a concentration of 40 mg/dL glucose, glucose alone showed a dose‐dependent inhibition of phytohemaglutinin (PHA)‐induced proliferation. For the in vivo application of pentaglobin, the results suggest that pentaglobin does not inhibit the proliferation of T cells.
Degranulation of Primary and Secondary Granules in Adherent Human Neutrophils
Authors: Xu X. , Håkansson L.
Published: March 2003

The aim of this study was to investigate whether neutrophil adhesion to extracellular matrix proteins like fibronectin, fibrinogen, and albumin influence the release proteins from primary and secondary granules of neutrophils stimulated by phorbol‐myristate‐acetate (PMA) and formyl‐methionyl‐leucyl‐phenylalanine (f‐MLP). Isolated granulocytes plated on wells coated with fibronectin, fibrinogen, and albumin were stimulated with f‐MLP (10−7 mol/l), PMA (10−9 mol/l), Mn2+ (5 mmol/l), or combinations of these stimuli, and the degree of adhesion to protein‐coated surfaces and the amount of granule proteins released was quantified during 90 min of incubation. PMA, in combination with Mn2+, induced a maximum release of ∼80% of the intracellular content of lactoferrin and human neutrophil lipocalin (HNL) and 15–20% of the myeloperoxidase (MPO) content regardless of the protein used. PMA or f‐MLP alone induced 30–40% release of lactoferrin and HNL depending on the protein that the cells were plated on. Adhesion and release of lactoferrin and HNL were quantitatively related when induced by PMA and PMA plus Mn2+, but not by f‐MLP. The mean release of lactoferrin and HNL showed a significant negative relationship to the viability of the cells. In conclusion, adhesion modulates neutrophil degranulation, but it is not always quantitatively related or related in time.
Some Hints Concerning the Shape of T‐Cell Receptor Structures
Authors: Rubin B. , Alibaud L. , Huchenq‐Champagne A. , Arnaud J. , Toribio M.‐L. , Constans J.
Published: March 2003

Several models are proposed for T‐cell antigen receptor (TCR) assembly and structure. However, there is little experimental data favouring directly either one or the other(s). The minimal complex appears to be composed of a TCRαβ/CD3δε,γε/ζ2 structure but at the cell membrane, multimers of this minimal structure may be formed. Quantitative cytofluometry has suggested three CD3ε chains for two TCRβ (or TCRδ) chains/complex. Such data should be repeated with monoclonal antibodies (MoAb) against extracellular (EC) parts of CD3δ or CD3γ chains. In the present review, we have compared the TCR/CD3 assembly of pre‐TCR, TCRγδ and TCRαβ containing complexes, and analysed the reactivity of antibodies (Abs) against the EC part of CD3δ chains. Our data suggest an alternative assembly pathway and structure of TCR/CD3 complexes.
The Thymus Gland: a Target Organ for Growth Hormone
Authors: Savino W. , Postel‐Vinay M. C. , Smaniotto S. , Dardenne M.
Published: March 2003

Increasing evidence has placed hormones and neuropeptides among potent immunomodulators, in both health and disease. Herein, we focus on the effects of growth hormone (GH) upon the thymus. Exogenous GH enhances thymic microenvironmental cell‐derived secretory products such as cytokines and thymic hormones. Moreover, GH increases thymic epithelial cell (TEC) proliferation in vitro, and exhibits a synergistic effect with anti‐CD3 in stimulating thymocyte proliferation, which is in keeping with the data showing that transgenic mice overexpressing GH or GH‐releasing hormone exhibit overgrowth of the thymus. GH also influences thymocyte traffic: it increases human T‐cell progenitor engraftment into the thymus; augments TEC/thymocyte adhesion and the traffic of thymocytes in the lymphoepithelial complexes, the thymic nurse cells; modulates in vivo the homing of recent thymic emigrants, enhancing the numbers of fluroscein isothiocyanate (FITC)+ cells in the lymph nodes and diminishing them in the spleen. In keeping with the effects of GH upon thymic cells is the detection of GH receptors in both TEC and thymocytes. Additionally, data indicate that insulin‐like growth factor (IGF)‐1 is involved in several effects of GH in the thymus, including the modulation of thymulin secretion, TEC proliferation as well as thymocyte/TEC adhesion. This is in keeping with the demonstration of IGF‐1 production and expression of IGF‐1 by TEC and thymocytes. Also, it should be envisioned as an intrathymic circuitry, involving not only IGF‐1, but also GH itself, as intrathymic GH expression is seen both in TEC and in thymocytes, and that thymocyte‐derived GH could enhance thymocyte proliferation. Finally, the possibility that GH improve thymic functions, including thymocyte proliferation and migration, places this molecule as a potential therapeutic adjuvant in immunodeficiency conditions associated with thymocyte decrease and loss of peripheral T cells.
Kinase‐Deficient CMVpp65 Triggers a CMVpp65 Specific T‐Cell Immune Response in HLA‐A*0201.Kb Transgenic Mice after DNA Immunization
Authors: Gallez‐Hawkins G. , Lomeli N. A. , L. Li X. , Yao Z. Q. , La Rosa C. , Diamond D. J. , Zaia J. A.
Published: March 2003

CMVpp65, a candidate component of human cytomegalovirus (CMV) vaccines, has phosphokinase (PK) activity that could affect vaccine safety. A mutated form of CMVpp65 substituting asparagine for lysine at the adenosine triphosphate (ATP)‐binding site (CMVpp65mII) is kinase‐deficient. Using DNA immunizations in a transgenic human leucocyte antigen (HLA)A*0201.Kb mouse model, the mutated CMVpp65 induced cytotoxic T lymphocytes (CTL) immunity similarly to native CMVpp65. Murine CTL lines generated from these immunizations killed human cells either after sensitization with CMVpp65‐specific peptides or after infection with either CMV‐Towne strain or rvac‐pp65. It is proposed that CMVpp65mII be evaluated in candidate vaccines for CMV.
Beyond Self and Nonself: Fuzzy Recognition of the Immune System
Authors: LENG Q. , BENTWICH Z.
Published: March 2003

Self–nonself discrimination of the immune system is a widely accepted principle of immunology; however, abundant existing and physiologic functions of harmless autoimmunity as well as degeneracy of antigen recognition expose the over‐simplification of the two‐valued doctrine. Here, based on infinite‐value fuzzy logic, we propose that the immune repertoire, as a consequence of central tolerance, is able to recognize both self and nonself antigens to a certain degree, compensating for the inadequacy of the two‐valued self–nonself doctrine. Subthreshold recognition of self antigens is necessary for the generation of regulatory T cells, survival of both naive and memory T cells and other physiologic functions. The kind and magnitude of the immune response depend on the affinity between the antigen (self and foreign) and the T‐cell receptor, and microenvironmental and cellular threshold. The outcome of self–nonself discrimination is influenced fundamentally by central tolerance and further dynamic regulation of threshold molecules both in time and space. Understanding the fuzzy feature of the immune system may shed light on mechanisms of autoimmune diseases, cancers and other chronic diseases, and lead to the design of novel vaccines or immunotherapies.
Bcl‐2‐Mediated Regulation of CD69‐Induced Apoptosis of Human Eosinophils: Identification and Characterization of a Novel Receptor‐Induced Mechanism and Relationship to CD95‐Transduced Signalling
Authors: FOERSTER M. , HAEFNER D. , KROEGEL C.
Published: March 2003

Elimination of the eosinophils from the airways by selective induction of apoptosis represents a therapeutic approach for asthma. Here we report on a possible target molecule, the surface receptor CD69. To simulate an asthmatic response, segmental allergen challenge in mild asthmatics was performed. Eosinophil numbers increased in bronchoalveolar lavage (BAL) at 18 h. In contrast to blood cells, BAL eosinophils expressed the activation marker CD69. Purified blood eosinophils stimulated with granulocyte/macrophage colony‐stimulating factor (GM‐CSF) or interferon‐γ (IFN‐γ) expressed CD69 and showed prolonged viability. Only IFN‐γ enhanced constitutive CD95 expression. Coincubation with anti‐CD69 or anti‐CD95 monoclonal antibody (MoAb) induced apoptosis, as revealed by propidium iodide incorporation, membrane blebbing and nuclear fragmentation. Additionally, both anti‐CD69 and anti‐CD95 MoAb reduced cytokine‐enhanced Bcl‐2 expression. In conclusion, CD69 transduces a Bcl‐2‐dependent death signal when ligated by a specific antibody. As, in contrast to the ubiquitous death‐inducer CD95, the function of CD69 appears to be restricted to activated eosinophils, it represents an ideal target for therapeutic intervention in asthma.
Circulating, Interferon‐Producing Plasmacytoid Dendritic Cells Decline During Human Ageing
Authors: Shodell M. , Siegal F. P.
Published: March 2003

Increased frequency and severity of infections in the elderly have been taken as indicative of declining immune function. Dendritic cells (DCs), the most important antigen‐presenting cells, play a central role in initiating and modulating immune responses. One type, DC2, arises from precursor plasmacytoid DCs (pDCs), a rare population of circulating blood cells, whose hallmark function is rapid and copious production of interferon‐α (IFN‐α) upon microbial challenge. We found significant decreases of the circulating pDCs during ageing in healthy adult humans, as defined both by flow cytometry and IFN‐α generation. Mean pDC/mm3 in peripheral blood declined from 7.8 for the youngest age group (18–39 years) to 4.2 for the oldest (60–91 years; P = 0.017). IFN‐α generation declined similarly, from 3537 to 1201 IU/ml, respectively (P = 0.006). There was also a slight decline over the age range in the amount of IFN generated per pDC (slope = −0.0087; P = 0.046). CD4+ T cells decreased by approximately 20% over the same age range (P = 0.001), while there was no change in the total lymphocyte or monocyte counts.
Macrophage‐Stimulating Protein and RON Receptor Tyrosine Kinase: Potential Regulators of Macrophage Inflammatory Activities
Authors: Wang M.‐H. , Zhou Y.‐Q. , Chen Y.‐Q.
Published: March 2003

Macrophage‐stimulating protein (MSP) is a serum protein belonging to the plasminogen‐related growth factor family. The specific receptor for MSP is the RON (recepteur d'origine nantais) receptor tyrosine kinase – a member of the MET proto‐oncogene family. Activation of RON by MSP exerts dual functions on macrophages. The stimulatory activities include the induction of macrophage spreading, migration and phagocytosis. However, MSP also inhibits lipopolysaccharide (LPS)‐induced production of inflammatory mediators, including inducible nitric oxide and prostaglandins. These suppressive effects are mediated by RON‐transduced signals that block LPS‐induced enzymatic cascades that activate nuclear factor kappa‐B (NFκB) pathways. Recent in vivo studies demonstrated that inactivation of the RON gene results in increased inflammatory responses and susceptibility to LPS‐induced septic death in mice, suggesting that RON expression is required for attenuating the extent of inflammatory responses in vivo. Thus, MSP and RON are potential regulators that control macrophage activities during bacterial infection in vivo.
Transfer of Macrophage‐Derived Mycobacterial Antigens to Dendritic Cells Can Induce Naïve T‐Cell Activation
Authors: Girvan A. , Aldwell F. E. , Buchan G. S. , Faulkner L. , Baird M. A.
Published: March 2003

Mycobacteria are capable of surviving and replicating in host macrophages, where they can release antigenic material into the environment. However, unlike dendritic cells (DCs), macrophages do not appear to be capable of activating naïve T cells. Therefore, this work investigated antigen transfer between macrophages and DCs. We generated culture supernatants from bacille Calmette–Guérin (BCG)‐infected and uninfected macrophages and then determined whether DCs could present these extracellular mycobacterial antigens to T cells. Here, we show that DCs pulsed with antigens released from BCG‐infected macrophages can stimulate primed T cells in vitro and initiate naïve T‐cell responses in vivo. These results suggest that antigen transfer can occur between macrophages and DCs.
Umbilical Cord Mannan‐Binding Lectin and Infections in Early Childhood
Authors: Kielgast S. , Thiel S. , Henriksen T. B. , Bjerke T. , Olsen J. , Jensenius J. Chr.
Published: March 2003

To investigate whether mannan‐binding lectin (MBL) in umbilical cord blood (UCB) is associated with the incidence rate of hospitalizations for infections during early childhood. A follow‐up study from birth to 31 months of age, with endpoint data from the Danish National Hospital Discharge Registry. The concentration of MBL and immunoglobulin A (IgA) in UCB was measured in a time‐resolved immunofluorometric assay. Information on possible confounding factors was obtained from questionnaires completed by mothers during their pregnancy, and characteristics of the child at birth were registered by a midwife on a structured coding sheet. A total of 2104 infants born in the period between 1 February 1990 and 25 May 1991 to mothers living in the municipality of Aarhus. Concentration of MBL and IgA in UCB, gestational age, birth weight, number of siblings less than 3 years old, mother's smoking habits, alcohol and coffee consumption, educational and marital status and previous spontaneous abortions and stillbirths. Of 2104 children, 626 were hospitalized at least once, and 346 of these were hospitalized with infection. The hazard ratio (HR) of hospitalization with infections in children with low levels of MBL (<120 ng/ml) was 1.4 (95% confidence interval (CI), 1.0–1.8), which was similar to our findings on hospitalization because of other diseases. The HR of hospitalization for viral infections was 2.8 (CI, 1.3–5.9). Low levels of MBL in UCB were associated with hospitalization in general and particularly with hospitalization for viral infections.
Carbonate sediment transport pathways based on foraminifera: case study from Frank Sound, Grand Cayman, British West Indies
Authors: Li Chun , Jones Brian , Kalbfleisch William B.C.
Published: March 2003

Foraminifera can be used to determine the source(s) of carbonate sediment and the directions of sediment transport in shallow, coastal lagoons such as Frank Sound on the south‐central coast of Grand Cayman. These determinations, based on the distribution of foraminiferal assemblages and ‘tracer species’ (numerically abundant species that live in known physiographic units and/or ecological conditions), show that the lagoonal sediments are a mixture of grains that originated in the lagoon and forereef. The variable proportions of these foraminifera throughout the lagoon reflects the dynamic processes that control lagoonal sedimentation.

Amphistegina gibbosa, Discorbis rosea, and Asterigerina carinata lived in the forereef environment. The fact that these ‘tracer species’ are found throughout Frank Sound and in the beach sands, shows that they were transported across the reef crest and the lagoon. Abrasion‐resistant Archaias angulatus, a‘tracer species’ indicative of a lagoonal setting, forms up to 50% of foraminiferal assemblages found in the lagoonal sediments. Preferential winnowing of small tests from these populations indicates sorting under high energy conditions. The vertical distribution of the forereef and lagoonal foraminifera in the sediment blanket that covers the floor of Frank Sound indicates that these processes are temporally persistent.

Transportation of forereef foraminifera into and around the lagoon and sorting of the lagoonal foraminifera cannot take place under ‘normal’ conditions when the tranquil lagoon is characterized by weak currents. Storms and/or hurricanes, however, generate short‐lived high‐energy events that can move and sort the sediment and foraminifera. At the height of a storm, water and sediment are moved over the reef and then piled and held onshore by the onshore winds and the constant flow of water over the reef and across the lagoon. These currents can mix some of the lagoonal and forereef sediments. As a storm wanes, however, the ‘piled water’ flows offshore via strong rip currents that pass into the ocean through the channels which transect the reef. These currents winnow and/or strip sediment from the lagoon and may transport lagoonal sediments into the forereef area. As a result, residual lagoonal sediment is commonly characterized by larger and abrasion‐resistant foraminifera.
On the efficiency of vertical array aeolian field traps
Authors: RASMUSSEN KELD R. , MIKKELSEN HARALD E.
Published: March 2003

The efficiency of three vertical array field traps for measuring the distribution of aeolian mass transport with height was compared with measurements with an isokinetic trap. The vertical traps seem to work adequately (efficiency > 80%) at heights greater than ≈15 mm above the bed. Closer to the bed, however, the open array trap catches about 70%, the two continuous arrays only about 50%. Because most of the transport takes place close to the surface, the overall efficiency of the field traps ranges from 50 to 70%.

Based on these wind tunnel tests, we have developed a low single‐compartment wedge‐shaped trap. Its shape, in combination with flow straighteners at the entrance, minimizes stagnation effects, so that the efficiency is ≈80%. Our data indicate that with the wedge trap used in combination with the vertical array Aberdeen trap, we can sample mass transport in the field during periods with unidirectional winds with an overall efficiency of the order of 80%.
Diagenesis of the Newark Rift Basin, Eastern North America
Authors: TABAKH  , SCHREIBER
Published: March 2003

Late Triassic nonmarine strata in the Newark Rift Basin, eastern North America, accumulated in a subsiding half‐graben prior to opening of the Atlantic Ocean. These strata consist, in ascending order, of the Stockton, Lockatong, and Passaic formations. Although different in specific lithology, these formations all exhibit diagenetic fabrics dominated by authigenic albite and analcime. These same minerals have a similar presence in Late Triassic (Newark Supergroup) strata of other rift‐related basins to the north, suggesting that related authigenesis is not simply a result of local diagenetic factors.

The basal deposit, the Stockton Formation, is composed of fluvial sandstones and overbank mudstones, with nodular pedogenic calcite (calcrete). During burial, original micrite was first recrystallized into sparry calcite and then later subjected to partial replacement by authigenic albite, which is also present as overgrowths and void fillings in overbank mudstones. The Lockatong Formation contains organic‐rich shales, carbonates, and evaporative mudstones deposited under cyclic conditions in laterally extensive lacustrine environments. Analcime comprises up to 40% of these strata by volume, occurring within the matrix, as a replacement of original carbonates and evaporites, and as fillings in macrovoids. The overlying Passaic Formation is made up of massive red mudstones, evaporites, and local calcareous lacustrine sequences. Evaporites are replaced by coarse‐grained anhydrite together with some authigenic albite.

A central question concerns the source for the Na, Si, and Al required for albite and analcime authigenesis. It is suggested that, in addition to alteration of primary siliciclastic material, sodium in particular was supplied in two ways: (1) from high concentrations in original evaporative brines and groundwaters (Lockatong and Passaic formations); and (2) from dissolution of associated sodium‐bearing evaporites (Lockatong and Passaic Formation) during diagenesis. It is proposed here that basin‐sourced, Na‐enriched brines circulated through the section over time. As albite is more stable at elevated temperatures relative to analcime, it developed in the lowermost strata of the basin (Stockton Formation). Analcime is more prevalent in the overlying Lockatong Formation.
Continental margin sedimentation, with special reference to the north‐east Atlantic margin
Authors: Weaver Philip P. E. , Wynn Russell B. , Kenyon Neil H. , Evans Jeremy
Published: March 2003

The north‐east Atlantic continental margin displays a wide range of sediment transport systems with both along‐slope and down‐slope processes. Off most of the north‐west African margin, south of 26°N, upwelling produces elevated accumulation rates, although there is little fluvial input. This area is subject to infrequent but large‐scale mass movements, giving rise to debris flows and turbidity currents. The turbidity currents traverse the slope and deposit thick layers on the abyssal plains, while debris flows deposit on the continental slope and rise. From the Atlas Mountains northwards to 56°N, the margin is less prone to mass movements, but is cut by a large number of canyons, which also funnel turbidity currents to the abyssal plains. The presence of a lithospheric plate boundary off SW Iberia is believed to have led to high rates of sediment transport to the deep sea. Even larger quantities of coarse sediments have fed the canyons and abyssal plains in the Bay of Biscay as a result of drainage from melting icecaps. Bottom currents have built sediment waves off the African and Iberian margins, and created erosional furrows south of the Canaries. The Mediterranean outflow is a particularly strong bottom current near the Straits of Gibraltar, depositing sand waves and mud waves in the Gulf of Cadiz. North of 56°N, the margin is heavily influenced by glacial and glaciomarine processes active during glacial times, which built glacial trough‐mouth fans, such as the North Sea Fan, and left iceberg scour marks on the upper slope and shelf. Over a long period, especially during interglacials, this part of the margin has been greatly affected by along‐slope currents, with less effect by turbidity currents than on the lower latitude margins. Large‐scale mass movements are again a prominent feature, particularly off Norway and the Faeroes. Some of these mass movements have occurred during the Holocene, although high glacial sedimentation rates may have contributed to the instability.
Storm deposits and storm‐generated coarse carbonate breccias on a pelagic outer shelf (South‐East Basin, France)
Authors: Seguret Michel , Moussine‐Pouchkine Alexis , Gabaglia Guilherme Raja , Bouchette Frederic
Published: March 2003

Uppermost Jurassic limestones of the South‐East Basin (France) are organized into four facies associations that were deposited in four distinct zones: (1) peritidal lagoonal limestones; (2) bioclastic and reefal limestones; (3) pelagic lime mudstones; (4) lime mudstones/calcarenites/coarse breccias. Calcarenite deposits of zone 4 exhibit sedimentary structures that are diagnostic of deposition under wave‐induced combined flow. In subzone 4a, both vertical and lateral transitions from lime mudstone/calcarenite to breccia indicate in situ brecciation under wave‐cyclic loading. Breccias were produced by heterogeneous liquefaction of material previously deposited on the sea floor. Deposits in subzone 4a record relatively long periods (>400 kyr) of sedimentation below wave base, alternating with periods of deposition under wave‐induced currents and periods of in situ deformation. In this zone, storm waves were attenuated by wave–sediment interaction, and wave energy was absorbed by the deformation of soft sediment. With reference to present‐day wave attenuation, water depths in this zone ranged between 50 and 80 m. Landwards of the attenuation zone, in zone 3, storm waves were reduced to fair‐weather wave heights. Storm wave base was not horizontal and became shallower landwards. As a consequence, water depth and wave energy were not linearly related. On a small area of the seaward edge of subzone 4a, cobbles were removed by traction currents and redeposited in subzone 4b. There, they formed a 100‐m‐thick wedge, which prograded over 3 km and was built up by the stacking of 5‐ to 20‐m‐thick cross‐stratified sets of coarse breccia. This wedge records the transport and redeposition of cobbles by a high‐velocity unidirectional component of a combined flow. The increase in flow velocity in a restricted area is proposed to result from flow concentration in a channel‐like structure of the downwelling in the gulf formed by the basin. In more distal subzone 4c, the hydrodynamic effect of wave‐induced currents was quasi‐permanent, and brecciation by wave–sediment interaction occurred only episodically. This indicates that, seawards of the attenuation zone, hydrodynamic storm wave base was deeper than mechanical storm wave base. Uppermost Jurassic carbonates were deposited and soft‐sediment deformed on a hurricane‐dominated ramp of very gentle slope and characterized by a zone of storm wave degeneration, located seawards of a zone of sedimentation below wave base.
Pinch‐out style and position of tidally influenced strata in a regressive–transgressive wave‐dominated deltaic sandbody, Twentymile Sandstone, Mesaverde Group, NW Colorado
Authors: Seidler Lars , Steel Ron
Published: March 2003

The Upper Cretaceous Twentymile Sandstone of the Mesaverde Group in NW Colorado, USA, has been analysed with respect to its pinch‐out style and the stratigraphic position of tidally influenced facies within the sandstone tongue. Detailed sedimentological analysis has revealed that the Twentymile Sandstone as a whole is a deltaic shoreface sandstone tongue up to 50 m thick proximally. Facies change character vertically from very fine‐grained, storm wave‐dominated shelf sandstones and mudstones to fine‐grained, wave‐dominated sandstones and, finally, to fine‐ to coarse‐grained tidally dominated sandstones. The pinch‐out style is characterized by a basinward splitting of the massive proximal sandbody into seven coarsening‐upward fourth‐order sequences consisting of a lower shaly part and an upper sandy part (sandstone tongue). These are stacked overall to reflect the regressive‐to‐transgressive development of the tongue. Each of the lower sandstone tongues 1–3 are gradationally based, very fine‐grained and dominated by hummocky cross‐stratification and were deposited on the lower to upper shoreface. Sandstone tongues 4 and 5 prograded further basinwards than the underlying tongues, are erosively based, fine‐ to coarse‐grained and mainly hummocky, herringbone and trough cross‐stratified. Especially in tongue 5, tidal indicators, such as bipolar foresets and double mud drapes, are common. These tongues were deposited as upper shoreface and tidal channel sandstones respectively. Sandstone tongues 6 and 7 retrograded in relation to tongue 5, are very fine‐ to fine‐grained and hummocky cross‐stratified. These tongues were deposited in lower shoreface to offshore transition environments. The two lower fourth‐order sequences were deposited during normal regressions during slowly rising or stable relative sea level and represent the highstand systems tract. The three succeeding fourth‐order sequences, which show succeedingly increasing evidence of tidal influence, were deposited during falling and lowstand of relative sea level and represent the falling stage (forced regressive) and lowstand systems tracts. The uppermost two fourth‐order sequences were deposited during rapidly rising sea level in the transgressive systems tract. The maximum tidal influence occurred during lowstand progradation, in contrast to most other published examples reporting maximum tidal influence during transgression.
Plagioclase dissolution related to biodegradation of oil in Brent Group sandstones (Middle Jurassic) of Gullfaks Field, northern North Sea
Authors: Ehrenberg S. N. , Jakobsen K. G.
Published: March 2003

Brent Group sandstones from the north side of the Gullfaks Oilfield contain mostly 5–8% albitic plagioclase, whereas plagioclase is almost absent in the same strata in the southern part of the field. Absence of plagioclase throughout the entire vertical extent of the Brent Group in the southern wells seems to rule out provenance as the principal explanation for differing plagioclase content, which is therefore interpreted as the result of diagenesis. Hypotheses for the nature of the inferred leaching event include epigenetic meteoric diagenesis and mesogenetic release of acid components from clay minerals or kerogen, but these explanations are unable to account for the observed spatial distribution of the plagioclase‐bearing and plagioclase‐free sandstone intervals. However, overall correspondence between the area lacking plagioclase and oil compositions having both anomalously high CO2 and organic geochemical indications of advanced biodegradation suggest a link between plagioclase dissolution and biodegradation of the present oil column. It is, therefore, proposed that acid components from biodegradation selectively reacted with albitic plagioclase to form kaolin, releasing sodium bicarbonate into the residual water. The plagioclase‐free sandstones contain more kaolin than the plagioclase‐bearing sandstones, as would be expected due to aluminium conservation. However, the wide and overlapping ranges of kaolin content in both groups suggest that most of the kaolin originated from processes other than biodegradation‐driven plagioclase alteration, potentially including both epigenetic and mesogenetic dissolution, as well as deposition of detrital kaolin and kaolin precursors.
Celestite formation, bacterial sulphate reduction and carbonate cementation of Eocene reefs and basinal sediments (Igualada, NE Spain)
Authors: Taberner Conxita , Marshall James D. , Hendry James P. , Pierre Catherine , Thirlwall M. F.
Published: March 2003

Petrographic and geochemical studies of an Upper Eocene reef and associated basinal sediments from the mixed carbonate–siliciclastic fill of the south‐eastern Pyrenean foreland basin near Igualada (NE Spain) provide new insights into the evolution of subsurface hydrology during the restriction of a marine basin. The reef deposits are located on delta‐lobe sandstones and prodelta marls, which are overlain by hypersaline carbonates and Upper Eocene evaporites. Authigenic celestite (SrSO4) is an important component in the observed diagenetic sequences. Celestite is a significant palaeohydrological indicator because its low solubility constrains transportation of Sr2+ and SO42− in the same diagenetic fluid. Stable isotopic analyses of carbonates in the reef indicate that meteoric recharge was responsible for aragonite stabilization and calcite cementation. Sulphur and oxygen isotope geochemistry of the celestite demonstrates that it formed from residual sulphate after bacterial sulphate reduction, but also requires that there was a prior episode of sulphate recycling. Meteoric water reaching the reef and basinal areas was most probably charged with SO42− from the dissolution of younger Upper Eocene marine evaporites. This sulphate, combined with organic matter present in the sediments, fuelled bacterial sulphate reduction in the meteoric palaeoaquifer. Strontium for celestite precipitation was partly derived in situ from dissolution of aragonite corals in the reef and basinal counterparts. However, 87Sr/86Sr data also suggest that Sr2+ was partly derived from dissolution of overlying evaporites. Mixing of these two fluids promoted celestite formation. The carbonate stable isotopic data suggest that the local meteoric water was enriched in 18O compared with that responsible for stabilization of other reefs along the basin margin. Furthermore, meteoric recharge at Igualada post‐dated evaporite deposition in the basin, whereas other parts of the same reef complex were stabilized before evaporite formation. This discrepancy resulted from the spatial distribution of continental siliciclastic units that acted as groundwater conduits.
Late Pleistocene–Holocene deposits of the Rhône inner continental shelf (France): detailed mapping and correlation with previous continental and marine studies
Authors: Marsset T. , Bellec V.
Published: March 2003

Very‐high‐resolution seismic data acquired on the Rhône continental shelf were used to address the detailed morphology of Late Pleistocene and post‐glacial units (from 18 000 yr BP to the present). Two groups of units can be distinguished. (1) Lower units that are mainly the product of variations in relative sea level. They comprise the last Pleistocene regressive deposits made of alluvial sheets (U0, U1) and, above, transgressive deposits that can be divided into: backstepping transgressive units (U3 and U4a), deposited during the landward retreat of the river mouth and transgressive units (U4b, U4c) laid down during the inundation of the shelf. A prograding littoral/lagoon system (U5/U6) indicating a fluctuation during the rise in sea level caps the transgressive units. This work has emphasized the complexity of these depositional environments, mainly related to a river system situated near the current Petit‐Rhône. (2) Upper units that make up the recent Rhône delta and correspond to the current highstand systems tract (HST) developed since the stabilization of relative sea level. Seven prodeltaic lobes have been identified (U7–U13). Two of them are bilobate (U7 and U8) and date from a period when the delta was split as a result of the fluviatile system being progressively divided into several channels. Other prodeltaic lobes (U9, U10) are stacked in front of the distributary's outlet, recording several periods of outflow. The results show a strong correlation with studies on land. The distribution of recent prodeltaic lobes was constrained by canalization of the Rhône river to prevent the effects of climatic crises or other natural disasters.
Geometry and grain‐size sorting of ripples on low‐energy sandy beaches: field observations and model predictions
Authors: Doucette Jeffrey S.
Published: March 2003

ABSTRACT There are very few field measurements of nearshore bedforms and grain‐size distribution on low‐energy microtidal beaches that experience low‐amplitude, long‐period waves. Field observations are needed to determine grain‐size distribution over nearshore bedforms, which may be important for understanding the mechanisms responsible for ripple development and migration. Additional nearshore field observations of ripple geometry are needed to test predictive models of ripple geometry. Ripple height, length and sediment composition were measured in the nearshore of several low‐energy beaches with concurrent measurements of incident waves. The distribution of sediment sizes over individual ripples was investigated, and the performance of several models of ripple geometry prediction was tested both spatially and temporally. Sediment samples were collected from the crest and trough of 164 ripples. The sand‐sized sediment was separated from the small amount (generally <3%) of coarser material (>2 mm) that was present. Within the sand‐sized fraction, the ripple crests were found to be significantly coarser, better sorted and more positively skewed than the troughs. Overall, the troughs were finer than the crests but contained a greater proportion of the small fraction of sediment larger than 2 mm. The field model of Nielsen (1981) and the model of Wiberg & Harris (1994) were found to be the most accurate models for predicting the wavelength of parallel ripples in the nearshore of the low‐energy microtidal environments surveyed. The Wiberg & Harris (1994) model was also the most accurate model for predicting ripple height. Temporal changes in ripple wavelength appear to be dependent on the morphological history of the bed.