bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear accumulation of Saccharomyces cerevisiae Mcm3 is dependent on its nuclear localization sequence
Authors: Young Michael R. , Suzuki Katsunori , Yan Hong , Gibson Susan , Tye Bik K.
Published: November 2003

Background:

The proteins of the Mcm2‐7 family are required for the initiation of DNA replication. In Saccharomyces cerevisiae the nuclear envelope does not break down during the mitotic phase of the cell cycle. Large nuclear proteins, such as the Mcm proteins, which accumulate in the nucleus during specific portions of the cell cycle, must have regulated mechanisms to direct their entry into the nucleus.

Results:

We have identified a nuclear localization sequence (NLS) in Mcm3, and demonstrated that it is necessary for the translocation of Mcm3 into the nucleus and sufficient for directing Escherichia coliβ‐galactosidase to the nucleus. Immediately adjacent to the nuclear localization sequence are four potential sites for phosphorylation by Cdc28. Mutagenesis of all four sites has no immediate phenotypic effect on cell growth or viability, nor does it affect nuclear accumulation of Mcm3, although two‐dimensional protein gel analysis has shown that at least some of these sites are normally phosphorylated in vivo. Substitution of the Mcm3 NLS by the SV40 large T‐antigen NLS also directs the nuclear accumulation of the Mcm3‐T‐antigen protein, although cell growth is compromised. Replication activity in cells bearing either the Mcm3‐Cdc28 phosphorylation site mutations or the Mcm3 T‐antigen NLS substitution, as measured by plasmid stability assays, is comparable to activity in wild‐type cells.

Conclusions:

The Mcm3 protein is imported into the nucleus by a specific NLS. The cell cycle specific nuclear accumulation of Mcm3 appears to be a result of nuclear retention or nuclear targeting, rather than nuclear import regulated through the NLS.
Replication profile of Saccharomyces cerevisiae chromosome VI
Authors: Friedman Katherine L. , Brewer Bonita J. , Fangman Walton L.
Published: November 2003

Background:

An understanding of the replication programme at the genome level will require the identification and characterization of origins of replication through large, contiguous regions of DNA. As a step toward this goal, origin efficiencies and replication times were determined for 10 ARSs spanning most of the 270 kilobase (kb) chromosome VI of Saccharomyces cerevisiae.

Results:

Chromosome VI shows a wide variation in the percentage of cell cycles in which different replication origins are utilized. Most of the origins are activated in only a fraction of cells, suggesting that the pattern of origin usage on chromosome VI varies greatly within the cell population. The replication times of fragments containing chromosome VI origins show a temporal pattern that has been recognized on other chromosomes—the telomeres replicate late in S phase, while the central region of the chromosome replicates early.

Conclusions:

As demonstrated here for chromosome VI, analysis of the direction of replication fork movement along a chromosome and determination of replication time by measuring a period of hemimethylation may provide an efficient means of surveying origin activity over large regions of the genome.
Management of pseudomyxoma peritonei with repeated laparoscopic laser ablation
Authors: Boulos A. , Gorgy A. , Meniru G. , Craft I.
Published: November 2003

Pseudomyxoma peritonei is an intra‐abdominal neoplasm with obscure origin and an indolent but relentless course. The cause of death is usually malignant cachexia and/or metastasis following repeated laparotomy to evacuate the intraperitoneal mucinous material. Different combinations of treatment modalities including surgery, chemotherapy and radiotherapy have failed to effect a cure or proper control of the disease. We have evaluated the feasibility of laser therapy in two cases. The disease is well under control and the patients are well. Our recommendation is that repeated laparoscopic laser ablation should have a role in the treatment of pseudomyxoma peritonei.
The declining place of abdominal hysterectomy in Australia
Authors: Wood C. , Maher P. , Hill D.
Published: November 2003

Between 1990 and 1995 in Australia, the use of abdominal hysterectomy decreased from 78 to 57% of all hysterectomies. This was due to an increase in the use of vaginal hysterectomy from 22 to 35% and the introduction of laparoscopic hysterectomy, which accounted for 8% of cases in 1994–95. Surgeons skilled in hysterectomy techniques perform abdominal hysterectomy in less than 10% of cases, because of their high rates of use of vaginal or laparoscopic hysterectomy or of both. At 4–8%, general utilization of laparoscopic hysterectomy is low in the UK, USA and Australia, and limitations in learning laparoscopic hysterectomy technique are evident. Strategies to simplify the technique have developed but their general application has yet to be demonstrated.
Vaginally assisted laparoscopic hysterectomy: a technique suited for large uteri
Authors: Roushdy M.
Published: November 2003

Objective To assess the feasibility and safety of performing vaginally assisted laparoscopic hysterectomy (VALH) on enlarged uteri up to gestation size of 26 weeks. Design A prospective observational study. Setting Cairo University Hospital and author's private practice. Subjects A total of 16 women with enlarged uteri 18–26 weeks' gestation size. Intervention VALH is essentially a laparoscopic hysterectomy that is assisted at the start of the procedure by dealing with the lower pedicles and ligaments vaginally, followed by closure of the vaginal cuff before turning to laparoscopy. Main outcome measures These include uterine size and weight, surgical outcome, estimated blood loss, operative time, complications, duration of hospital stay. Results The mean weight of removed uteri was 1403 ± 582 g (range 790–2850). All procedures were successfully completed. The operating time was 133 ± 12 min (range 105–205) and was largely dependent upon the weight of the uterus. The manual morcellation of 1 kg of tissue took 55 ± 12 min. Estimated blood loss was 280 ± 10 ml (range 150–530). The duration of hospitalization was 46 ± 17 h (range 22–70). Conclusion VALH is a safe and effective technique for performing a hysterectomy in patients with large uteri up to the weight of 2850 g.
p53‐protein and Ki‐67‐antigen expression are both reliable biomarkers of prognosis in thick stage I nodular melanomas of the skin
Authors: VOGT T. , ZIPPERER K‐H. , VOGT A. , HÖLZEL D. , LANDTHALER M. , STOLZ W.
Published: November 2003

The maximum tumour thickness is the most important prognostic factor in malignant melanomas of the skin. However, the clinical outcome of thick nodular melanomas remains unpredictable. Therefore, we investigated possible prognostic markers in this subset of melanomas. From a melanoma data base, 12 patients with thick (> 3 mm) stage I nodular melanomas of the skin were identified, who were still without signs of progression after five years of follow‐up. These tumours were compared to a randomly selected series of 12 cases, who did not survive the first five years after removal of the tumours. We performed immunostaining for the p53‐protein and the proliferation associated Ki‐67‐antigen. For quantification of immunostaining the tumours were entirely scanned. In addition, all tumours were investigated for any differences with conventionally applied prognostic features: the tumour thickness; the level of invasion; the prognostic index (tumour thickness multiplied by mitotic count); and the mean volume‐weighted mean nuclear volume. We demonstrated significant differences between survivors and non‐survivors exclusively in respect of the staining‐indices for p53 and Ki‐67 (P < 0.03 and 0.02, respectively). With both antibodies the tumours of survivors showed lower counts as compared to non‐survivors. However, within both groups we found no significant correlations between the p53‐ and Ki‐67‐staining results. We conclude that immunostaining for p53‐protein and Ki‐67‐antigen is helpful to identify individuals with thick nodular melanomas who are at risk of metastatic disease.
Activated cytotoxic lymphocytes in lymph nodes from human immunodeficiency virus (HIV) 1‐infected patients: a light and electronmicroscopic study
Authors: SUNILA I. , VACCAREZZA M. , PANTALEO G. , FAUCI A.S. , ORENSTEIN J.M.
Published: November 2003

Persistent generalized lymphadenopathy often develops during HIV‐infection. It is characterized by follicular hyperplasia which progresses over time to follicular involution and finally lymphocyte depletion. To determine whether activated cytotoxic T cells (CD8+) are present in the hyperplastic germinal centres, light and electronmicroscopic immunogold labelling with monoclonal antibodies were used to localize two cytotoxic molecules, perforin and TIA‐1. Perforin and TIA‐1‐positive cells were detected in the follicles and paracortex of lymph nodes from HIV‐infected patients, whereas labelling was seen only in cells of the paracortex in the hyperplastic lymph nodes from HIV‐negative patients. Cytotoxic granules, staining positive for perforin and TIA‐1, were identified by transmission electronmicroscopy, often in proximity to follicular dendritic cells within the hyperplastic germinal centres of only HIV‐positive patients. These cytotoxic cells may play a role in the follicular dendritic cell loss and concomitant follicular involution that occur during the evolution of HIV disease.
Systemic mastocytosis following a malignant ovarian germ cell tumour
Authors: DELACRÉTAZ F. , STALDER M. , MEUGÉ‐MORAW C. , SCHMIDT P.M. , JORIS F. , KURT A.‐M. , DE WERRA P.
Published: November 2003

Cases of mediastinal germ cell tumours associated with haematological disorders (two cases of systemic mastocytosis included) have been reported previously. This combination is more frequent than would be expected by chance alone. We report the case of a 30‐year‐old woman, who presented with a systemic mastocytosis following a malignant ovarian germ cell tumour which was treated by chemo‐ and radiotherapy. The patient predominantly complained of skeletal pains, which led to an erroneous radiological diagnosis of fibrous dysplasia for years. An aggressive variant of systemic mastocytosis was diagnosed on bone marrow examination. Systemic mastocytosis was confirmed by splenectomy, liver biopsy and finally autopsy. The present case is unique because of the ovarian location of the germ cell tumour. We suggest our observation could be related to the broad group of haematological malignancies associated with germ cell tumours.
Angiosarcomas of the breast developing post radiotherapy
Authors: PARHAM D.M. , FISHER C.
Published: November 2003

Aims: This paper describes two contrasting cases of post‐radiotherapy angiosarcomas of the breast. They illustrate the spectrum of malignant vascular tumours that may occur in the breast. These tumours are extremely rare and knowledge of their natural history is limited. The prognosis suggested by the few published cases of poorly or moderately differentiated angiosarcomas suggest a poor prognosis often with a fatal outcome. Methods and results: This was confirmed by our first case a poorly differentiated angiosarcoma, occurring 10 years after radiotherapy for breast carcinoma with death occurring from metastatic angiosarcoma 6 months later. Our second, more recently diagnosed case, was a well‐differentiated angiosarcoma, occurring 5 years post radiotherapy for breast cancer. She remains well 12 months after the diagnosis of sarcoma but her long‐term outlook is more problematic to predict. Only five previous cases of well‐differentiated post‐radiotherapy angiosarcoma of the breast have been reported with limited follow‐up (average 2 years). Conclusions: Communication with the authors of four of the papers since their publication has provided valuable additional information and indicates a potentially good outlook for this woman in the longer term. A second cellular component was also found in these malignant vascular tumours. These spindle cells distinct from the malignant endothelial cells have not to our knowledge been described previously and their possible nature is discussed.
Clear cell dermatofibroma
Authors: WAMBACHER‐GASSER B. , ZELGER B. , ZELGER B.G. , STEINER H.
Published: November 2003

This series presents six cases of a rare variant of dermatofibroma, characterized by marked clear cell change. All lesions occurred on the lower extremities of middle‐aged adults (four women, two men), mostly with the clinical diagnosis of fibrohistiocytic lesion. Histological examination revealed well circumscribed, faintly stained dermal to subcutaneous lesions which were due to the overwhelming presence of clear cells (<90%), some with prominent PAS‐positive cytoplasmic granulation. Overlying epidermal hyperplasia as well as storiform arrangement of spindle cells, sclerotic collagen and some interspersed lympho‐histiocytic infiltrate at the periphery of the lesion indicated the fibrohistiocytic origin. Individual histopathological peculiarities included : bizarre giant cells in two cases, prominent perivascular lympho‐histiocytic response, perifollicular arrangement and haemangiopericytoma‐like features with iron deposition in one case each. Immunohistochemically three of four lesions showed moderate reactivity for factor XIIIa and two of four with an anti‐metallothionen marker E9, but were otherwise negative with a broad panel of markers. Electronmicroscopy in two cases revealed large pools of glycogen beside focal, prominent endoplasmic reticulum and lysosomes in some granular cells, but only optically translucent cells in cases of clear cells. Recognition of clear cell dermatofibroma is important as the differential diagnosis includes some entities with more serious outcome/considerations such as metastases of renal cell carcinoma, xanthogranulomatous reactions, balloon cell naevus/melanoma and clear cell sarcoma.
Interleukin‐12 induces cytotoxic NK1+αβ T cells in the lungs of euthymic and athymic mice
Authors: ANZAI R. , SEKI S. , OGASAWARA K. , HASHIMOTO W. , SUGIURA K. , SATO M. , KUMAGAI K. , TAKEDA K.
Published: November 2003

We recently reported that interleukin‐12 (IL‐12) stimulated hepatic NK1.1 Ag+αβ T cells with intermediate T‐cell receptor (TCR; NK1+ TCRint cells) and enhanced their NK1 expression (NK1high TCRint), and that these cells acquire strong major histocompatibility complex (MHC) unrestricted cytotoxicity in C57BL/6 mice, both +/+ and nu/nu. In the present study, we find that although murine lung normally has few NK1+ TCRint cells, NK1high TCRint cells are induced in +/+ and nu/nu mice after systemic administration of IL‐12; these cells exhibit strong MHC unrestricted cytotoxicity against NK‐sensitive and ‐resistant targets. A small number of NK1high TCRint cells was also found in peripheral blood after increased amounts of IL‐12 were administered. Cytotoxicity tests in vitro revealed that the cytotoxic activity of the lung mononuclear cells (MNC) of C57BL/6 mice induced by IL‐12 was abrogated by the depletion of either NK1+ or CD3+ cells, but not of CD8+ cells, as reportedly was the case of hepatic MNC, suggesting that NK1high TCRint cells are an antimetastatic population not only in the liver but also in the lung of mice. IL‐12 injection into mice markedly elevates serum interferon‐γ (IFN‐γ) levels. However, although IL‐12‐induced cytotoxicity of NK1high TCRint cells was significantly reduced by anti‐IFN‐γ antibody injection (which decreased serum IFN‐γ to an undetectable level), the appearance of NK1high TCRint cells in the lung and liver was not so affected. These results suggest that IFN‐γ is an important mediator of the cytotoxicity of NK1high TCRint cells but is not an essential factor for induction of these cells. We also added data showing that IL‐12 has a broad antimetastatic effect against various liver and lung metastatic tumours intravenously injected into several strains of mice, including NK‐deficient bg/bg mice. It can be considered that, in addition to NK cells, CD8+ cytotoxic T cells and γδ T cells, NK1+ TCRint cells can be categorized as one of the cytotoxic effector populations. These novel type cells distinct from regular T cells may play an important role in monitoring intra‐ and perivascular areas.
T‐cell cytokines may control the balance of functionally distinct macrophage populations
Authors: TORMEY V. J. , FAUL J. , LEONARD C. , BURKE C. M. , DILMEC A. , POULTER L. W.
Published: November 2003

As monocytes differentiate into mature macrophages, subsets emerge that exhibit stimulatory, suppressive or phagocytic potential. These functionally distinct subsets can be discriminated using monoclonal antibodies RFD1 and RFD7. As examples of all these subsets have been repeatedly identified within the macrophage pool in a variety of organs the overall functional capacity of this pool will depend on the relative balance of these subpopulations. This study investigates whether this balance present in mature macrophage populations can be regulated by the local influence of T‐cell‐derived cytokines. The dose‐dependent effect of cytokines interferon‐γ (IFN‐γ), interleukins (IL) IL‐2, IL‐4 and IL‐10 on the phenotype and function of monocyte‐derived macrophages was determined. Subsets of mature cells were quantified by identifying RFD1+ RFD7− stimulatory cells (D1+); RFD1− RFD7+ phagocytes (D7+) and RFD1+ RFD7+ suppressive cells (D1/D7+). IFN‐γ and IL‐4 increased the relative proportions of D1+ stimulatory cells and upregulated HLA‐DR expression. IFN‐γ also increased the capacity of the mature macrophage pool to stimulate T‐cell proliferation. IL‐10 reduced the proportions of D1+ stimulatory cells while promoting the differentiation of D7+ phagocytes and D1/D7+ suppressive cells. IL‐10 induced changes also reduced the functional capacity of the mature populations to stimulate T cells in auto and allogenic mixed lymphocyte reactions (MLR). IL‐2 had no effect on differentiation of monocytes. Thus IL‐4 and IFN‐γ are seen to induce the development of stimulatory macrophages while IL‐10 promotes differentiation of monocytes to mature phagocytes and suppressive macrophages. It is concluded that mature macrophage phenotype is ‘plastic’ and under the control of T‐cell‐derived mediators. Furthermore, within the differentiating monocytes, phenotypic change appears to carry with it functional change, thus retaining the relationship between antigen expression and activity in the mature macrophage populations.
Freeze shattering: a simple and effective method for permeabilizing higher plant cell walls
Authors: Wasteneys G. O. , Willingale‐Theune J. , Menzel D.
Published: November 2003

This article describes a practical technique for permeabilization of higher plant cell walls, which is usually one of the first steps required for immunolocalization of cellular components (and other cytological methods) in plant cell studies. Our strategy involves shattering the walls of cells while the tissues are frozen in liquid nitrogen. It replaces the use of wall degrading enzymes or the need to employ laborious sectioning or other mechanical means for providing access of probes to cells. Freeze‐shattering retains the integrity of whole tissues and cells surprisingly well and thus is especially useful when used in conjunction with confocal laser scanning microscopy for recording the three‐dimensional arrangement of cytoskeletal elements in relation to cell shape. In this article, we demonstrate the effectiveness of this technique for anti‐tubulin and anti‐actin immunofluorescence and for rhodamine phalloidin labelling of the cytoskeleton in various higher plant tissues including onion root tip and bulb scale epidermis, Tradescantia stamen hairs and Arabidopsis leaf epidermis and mesophyll cells.
Backscattered electron imaging of cultured cells: application to electron probe X‐ray microanalysis using a scanning electron microscope
Authors: FERNÁNDEZ‐SEGURA E. , CAÑIZARES F. J. , CUBERO M. A. , REVELLES F. , CAMPOS A.
Published: November 2003

We report a simple method to study the elemental content in cultured human adherent cells by electron probe X‐ray microanalysis with scanning electron microscopy. Cells were adapted to grow on polycarbonate tissue culture cell inserts, washed with distilled water, plunge‐frozen with liquid nitrogen and freeze‐dried. Unstained, freeze‐dried cultured cells were visualized in the secondary and backscattered electron imaging modes of scanning electron microscopy. With backscattered electron imaging it was possible to identify unequivocally major subcellular compartments, i.e. the nucleus, nucleoli and cytoplasm. X‐ray microanalysis was used simultaneously to determine the elemental content in cultured cells at the cellular level. In addition, we propose some improvements to optimize backscattered electron and X‐ray signal collection. Our findings demonstrate that backscattered electron imaging offers a powerful method to examine whole, freeze‐dried cultured cells for scanning electron probe X‐ray microanalysis.
Specialized scanning ion‐conductance microscope for imaging of living cells
Authors: Korchev Y. E. , Milovanovic M. , Bashford C. L. , Bennett D. C. , Sviderskaya E. V. , Vodyanoy I. , Lab M. J.
Published: November 2003

A specialized scanning ion conductance microscope (SICM) for imaging living cells has been developed from a conventional patch‐clamp apparatus, which uses a glass micropipette as the sensitive probe. In contrast with other types of scanning probe microscope, the SICM probe has significant advantages for imaging living cells: it is most suitable for imaging samples immersed in water solutions; and since the probe senses ion current and does not need physical contact with the sample during the scan, any preliminary preparation of cells (fixation or adherence to a substrate) is unnecessary. We have successfully imaged murine melanocytes in growth medium. The microscope images the highly convoluted surface structures without damaging or deforming them, and reveals the true, three‐dimensional relief of the cells. This instrument has considerable ability to operate, potentially simultaneously, in applications as diverse as real‐time microscopy, electrophysiology, micromanipulation and drug delivery.
Far‐field characterization of small apertures
Authors: Petrov N. I. , Woo G. M. , Lee M. B.
Published: November 2003

A far‐field method for characterizing apertures based on the relationship between the relative intensity of propagating modes in a given medium and a small aperture illuminated with a light beam is proposed. A simple optical set‐up based on computer‐generated holograms and spatial filters is suggested to measure the relative strength of modes and provide axial intensity measurements in the far‐field zone. It is shown that the minimal size of a spot that may be measured decreases with an increase in the refractive index of a medium into which light propagates and with the use of high‐order spatial mode filters. The intensities transmitted through tapered optical fibre tips have been measured and their aperture diameters determined using window‐type spatial filters. The results have been compared with measurements using scanning electron microscopy.
Image analysis of X‐ray microtomograms of soft materials during convective drying
Authors: Leonard A. , Blacher S. , Marchot P. , Pirard J. P. , Crine M.
Published: November 2003

X‐ray microtomography is used to explore the textural evolution that soft materials undergo during a drying treatment. An original image processing algorithm is applied to vertical projections and reconstructed cross‐section images in order to quantify the texture at different stages of drying. Measurements are performed both on grey‐level and on binary images. It is shown that X‐ray microtomography is a very promising tool in the field of drying investigations. It can be used to determine internal moisture profiles, and to follow crack development and shrinkage in an accurate and non‐destructive way. This information is crucial to validate drying models. Waste‐water sludges are used as test materials to assess the validity of the proposed methodology. The management of these sludges, often including a drying stage, will become a challenge in the forthcoming years in accordance with environmental regulations. Samples collected in two waste‐water treatment plants are investigated. Their analysis by X‐ray microtomography brings to the fore two different drying behaviours, illustrating that sludge drying is a complex unit operation very sensitive to the way the material is produced.
Distribution and fitness of isolates of Botrytis cinerea with multiple fungicide resistance in Spanish greenhouses
Authors: RAPOSO R. , DELCAN J. , GOMEZ V. , MELGAREJO P.
Published: November 2003

Forty‐nine greenhouses of vegetable crops were surveyed in southeast Spain at the beginning of the disease season in December 1992 to estimate frequencies of resistance to benzimidazoles, dicarboximides and N‐phenylcarbamates (NPC) in B. cinerea. Out of 261 isolates collected, 28% were sensitive to both benzimidazoles and dicarboximides, 15% were benzimidazole‐resistant and dicarboximide‐sensitive, 8% were benzimidazole‐sensitive and dicarboximide‐resistant and 46% were benzimidazole‐ and dicarboximide‐resistant. Resistance to benzimidazole, dicarboximide and N‐phenylcarbamate was determined by measuring the ability of each isolate to grow in the presence of carbendazim, procymidone and diethofencarb fungicides respectively. Carbendazim‐ or procymidone‐ resistant isolates were found in all surveyed greenhouses. Three isolates were found with resistance to carbendazim, procymidone and diethofencarb collected in two adjacent greenhouses that were sprayed with the carbendazim and diethofencarb mixture. All other isolates were sensitive to the mixture because they were either sensitive to carbendazim and resistant to diethofencarb or vice versa. Fitness of 31 isolates of B. cinerea was determined in vivo by measuring their sporulation and lesion growth rate on leaf disks. No fitness costs were associated with resistance to iprodione (dicarboximide) and benomyl (benzimidazole). Isolates with EC50 values higher than 101 mg/L for benomyl and 1.6 mg/L for iprodione were considered to be field resistant (they caused visible lesions on cucumber leaf disks treated with each fungicide).
The major extracellular proteinases of the silverleaf fungus, Chondrostereum purpureum, are metalloproteinases
Authors: MCHENRY J. Z. , CHRISTELLER J. T. , SLADE E. A. , LAING W. A.
Published: November 2003

The fungus Chondrostereum purpureum, the causal agent of silverleaf, when grown in liquid culture or on agar, secreted extracellular proteinases into the medium. Proteinase activity in the mycelium itself was barely detectable. At least 95% of caseinolytic activity in the extracellular fluid (ECF) was inhibited by chelating agents. Fluid dialysed against EDTA was activated by metal ions, confirming the presence of metalloproteinases. Caseinolytic activity of ECF was also largely abolished by sulphydryl compounds and reagents. Superdex G75 chromatography and SDS–PAGE analysis of the proteinases present in concentrated ECF indicated at least four components with proteolytic activity. In addition to the major metalloproteinases, a very low level of a chymotrypsin‐like activity was detected as well as high levels of the exopeptidase, leucine aminopeptidase. A wide range of caseinolytic activity levels was found when 29 C. purpureum isolates from New Zealand were grown in liquid culture, but much less variation was observed on agar. Proteinase activity was found throughout the infection zone of silverleaf‐susceptible plants but could only be detected at the wounding site of resistant cultivars. The possible roles of these proteinases in infection and growth of the pathogen are discussed.
Effect of density and age of lesions on sporulation capacity and infection efficiency in wheat leaf rust (Puccinia recondita f.sp. tritici )
Authors: SACHE I.
Published: November 2003

The effects of lesion ageing and crowding on spore production and infection efficiency of an isolate of wheat leaf rust (caused by Puccinia recondita f.sp. tritici ) were studied under controlled conditions. Spore production per lesion per day decreased exponentially with increasing lesion density for lesions older than 13 days after inoculation. Spore production of younger lesions was not affected by crowding. A synthetic formula relating the accumulated spore production to lesion age and density was derived, allowing the evaluation of spore production per lesion on a daily basis. Infection efficiency was comparatively much less affected by lesion ageing and crowding than was spore production. The most efficient spores were produced by ‘mature’ lesions (14 to 21 days old). At high density, there was no compensation for reduced spore production by an increase in infection efficiency, except for 14‐day‐old lesions. The Daily Multiplication Factor (the product of spore production per lesion and infection efficiency) was higher at low lesion density and may contribute to a rapid increase of populations of sporulating rust lesions in wheat fields. The detrimental effect of lesion crowding, occurring later in the course of the epidemics, may have negligible effects on disease progress.
A model of plant virus disease epidemics in asynchronously‐planted cropping systems
Authors: HOLT J. , CHANCELLOR T.C.B.
Published: November 2003

A mathematical model was developed of the dynamics of a plant virus disease within a spatially‐referenced lattice of fields of a host crop. The model can be applied to crops in continuous, contiguous cultivation such as tropical irrigated rice. Disease progress in each field of the host crop was assumed to be logistic and determined by incidence within the field itself as well as incidence in neighbouring fields, depending on the gradient of disease spread. The frequency distribution of planting dates (represented by the proportion of the total number of fields planted in successive months) was assumed to follow a normal distribution and the variance of planting date was used as a measure of cropping asynchrony. Analysis of the model revealed that disease incidence within the lattice (i.e. mean incidence over all fields) depended upon the infection efficiency, the slope of the dispersal gradient, and the variance in planting date. Disease endemicity depended mainly on planting date variance and disease persisted in the lattice if this variance exceeded a certain threshold. Above the threshold for persistence, the response of mean disease incidence to planting date variance was non‐linear and the region of greatest sensitivity was closest to the threshold. Thus, disease systems that show moderate rather than high cropping asynchrony are more likely to be influenced by changes in the variance of planting date. Implications for the area‐wide management of rice tungro virus disease are discussed.
Measurements of spatial patterns of disease in winter wheat crops and the implications for sampling
Authors: PARKER S. R. , SHAW M. W. , ROYLE D. J.
Published: November 2003

Over a period of three crop seasons the spatial patterns of some common diseases of winter wheat were investigated at growth stages (GS) 31/33 and 59/61. A large‐scale sampling procedure, using randomly positioned transects and based on the theory of autocorrelation analysis, is described. This novel technique enables valid tests of significance to be made on the autocorrelation coefficients calculated. The most complete data obtained were for Septoria tritici blotch which was found to have a near random pattern on scales between 31 cm and 31 m at the growth stages investigated. However, the severity of S. tritici blotch was found to be autocorrelated at scales below 1 m in some fields. With the exceptions of powdery mildew at GS 31/33 and yellow rust at GS 59/61, the other diseases also exhibited a near random pattern. Therefore, almost any convenient sampling pattern, with reasonable overall coverage, will be adequate to obtain samples for monitoring winter wheat at growth stages 31 and 59.
Transmission of grapevine leafroll‐associated closteroviruses by Pseudococcus longispinus and P. calceolariae
Authors: PETERSEN C. L. , CHARLES J. G.
Published: November 2003

The transmission of two closteroviruses associated with grapevine leafroll, GLRaV‐1 and GLRaV‐3, from grapevine to grapevine by the mealybugs, Pseudococcus longispinus and P. calceolariae (Homoptera: Pseudococcidae) was studied. Controlled transmission experiments using the first and third instars of each insect were conducted twice during the 1993–94 growing season to investigate the consequence of virus accumulation within the donor vine leaf tissue on the incidence of virus transmission to healthy recipient vines. Transmission of GLRaV‐1 and GLRaV‐3 was determined by ELISA testing recipient vines in July 1994 and March 1995. GLRaV‐3 was transmitted to recipient vines by P. longispinus and P. calceolariae first instars only. An increase in virus titre within the season did not significantly alter the transmission rate of GLRaV‐3 by either P. longispinus or P. calceolariae first instars. P. longispinus and P. calceolariae failed to transmit GLRaV‐1 to recipient vines.
Detection and identification of phytoplasmas in yellows‐diseased weeds in Italy
Authors: MARCONE C. , RAGOZZINO A. , SEEMÜLLER E.
Published: November 2003

Yellows‐diseased plants of Crepissetosa (hawksbeard), Knautiaarvensis (field scabious), Convolvulusarvensis (field bindweed), Picrisechioides (bristly oxtongue), Echiumvulgare (blueweed) and Calendulaofficinalis (pot marigold) collected in central and southern Italy were examined for phytoplasma infection by means of polymerase chain reaction (PCR) technology using universal phytoplasma primers directed to ribosomal sequences. The detected phytoplasmas were characterized and differentiated using restriction fragment length polymorphism analysis of PCR‐amplified DNA. The phytoplasma detected in diseased pot marigold plants was identified as a member of the aster yellows group and proved indistinguishable from a strain of the American aster yellows phytoplasma. The phytoplasma identified in diseased field bindweed plants is a putative new type of the stolbur group that differed from the typical stolbur phytoplasma. Phytoplasmas detected in diseased hawksbeard, blueweed and field scabious plants are all putative new members of the sugarcane white leaf group while the phytoplasma detected in diseased bristly oxtongue plants represents a new member of the faba bean phyllody group. For hawksbeard and field scabious this is the first report on the occurrence of phytoplasma diseases, whereas phytoplasmas infecting bristly oxtongue and blueweed have never been characterized before.
Carbohydrate Recognition on MUC1‐Expressing Targets Enhances Cytotoxicity of a T Cell Subpopulation
Authors: BÖHM C. M. , MULDER M. C. , ZENNADI R. , NOTTER M. , SCHMITT‐GRÄFF A. , FINN O. J. , TAYLOR‐PAPADIMITRIOU J. , STEIN H. , CLAUSEN H. , RIECKEN E. O. , HANSKI C.
Published: November 2003

The influence of the epithelial mucin MUC1 on T cell‐mediated lysis was analysed using lymph node lymphocytes (LNL) from patients with colorectal carcinoma. LNL were stimulated with allogeneic, MUC1‐transfected B cells and the bulk cultures were cloned. Alloreactive cytotoxic T cell clones were obtained which preferentially lysed MUC1‐expressing targets. The majority was CD4+ and MHC‐class II‐restricted, and a minor group was CD8+ and MHC‐class I‐restricted. All the clones expressed CD3 and TCRαβ, and were CD56−. The capacity to preferentially kill MUC1‐expressing targets was stable in several clones for up to 6 months in culture. The enhancing effect of MUC1 on the lysis was investigated in more detail. It was only seen after inhibition of O‐linked glycosylation in the targets. Furthermore, this effect was completely abrogated by the monoclonal antibody 3C9, directed against the Thomsen–Friedenreich antigen (T‐antigen, Galβ1–3GalNAc bound α1–3 to Ser/Thr) as well as by the soluble disaccharide Galβ1–3GalNAc, but not by other similar disaccharides. The authors conclude that in their system the preferential killing of MUC1‐expressing targets is due to the recognition of an internal carbohydrate epitope accessible on underglycosylated MUC1, possibly T‐antigen, by an auxiliary receptor molecule on T cells.
Differential Role for IL‐2 and IL‐15 in the Inhibition of Apoptosis in Short Term Activated Human Lymphocytes
Authors: LORENZ H.‐M. , HIERONYMUS T. , GRÜNKE M. , MANGER B. , KALDEN J. R.
Published: November 2003

Interleukin (IL)‐15 is a newly described cytokine with properties similar to IL‐2. Even though it does not share sequence homology with IL‐2, both cytokines bind to the same receptor with the noted exception of a cytokine specific α‐chain. In this study the authors compared IL‐2 and IL‐15 to determine their ability to rescue short term activated lymphocytes (phytohaemagglutinin stimulation of peripheral blood mononuclear cells for 6 days, followed by expansion in medium containing IL‐2 for 2 days) from apoptotic cell death. The authors found that both IL‐2 and IL‐15 can inhibit induction of apoptosis in this experimental model with similar time and dose kinetics. On mRNA or protein levels induction of pro‐ and anti‐apoptotic gene products like fasL, bcl‐2, or bax with minor effects on fas/Apo‐1 or bcl‐xL was observed under culture conditions with both IL‐2 and IL‐15. Next, it was found that phytohaemagglutinin (PHA) blasts were less responsive (in terms of cellular proliferation and prevention from apoptosis) to IL‐2 if signals through the α‐chain were blocked, with no effect on β‐chain specific monoclonal antibodies (MoAb). By contrast, IL‐15 was less effective in induction of cellular proliferation and prevention of apoptosis if IL‐2R β‐chain specific MoAb were added to cell cultures. Testing intracellular signalling induced by IL‐2 or IL‐15, the authors found identical changes in tyrosine phosphorylation patterns in PHA blasts cultured in medium or under IL‐2 or IL‐15 stimulation. By contrast, they found consistent differences if PHA stimulated peripheral blood mononuclear cells (PBMC) were expanded in medium containing IL‐15 (instead of IL‐2). These IL‐15 expanded PHA blasts showed a significantly increased percentage of apoptosis after growth factor withdrawal. Furthermore, IL‐2 was more efficient than IL‐15 in rescuing IL‐15 expanded PHA blasts from apoptosis. In IL‐15 expanded PHA blasts expression of IL‐2R α‐chain was lower than that in IL‐2 expanded PHA blasts. A model presenting a differential role for IL‐2 and IL‐15 in inhibition of apoptosis in vivo is discussed.
Dual‐Receptor T Cells Expressing One Self‐Restricted TCR
Authors: SMILEY S. T. , GRUSBY M. J.
Published: November 2003

During thymic development, T cells rearrange and express genes encoding clonotypic T‐cell receptors (TCR), and undergo selective events involving interactions between TCR and thymic major histocompatibility complex (MHC) molecules. Recent studies indicate that up to 30% of peripheral T cells may express two TCR, that both TCR on these cells are functional, and that dual‐specific T cells can promote autoimmunity. Here we demonstrate that dual‐receptor T cells are readily generated in class II‐deficient (class II−) mice expressing the class II‐restricted AND TCR transgene (TCRtg). While this TCRtg is unable to promote positive selection in class II− mice, T cells arise in class II−TCR+tg mice by co‐expressing non‐transgenic endogenous TCR that permit positive selection on class I molecules. Our findings indicate that when a rearranged TCR fails to promote positive selection on self MHC molecules, expression of a second receptor can rescue the developing T cell. Accordingly, many dual‐receptor T cells may actually be mono‐specific in vivo, possessing only one self MHC‐restricted TCR, and therefore should not require unique regulatory controls to prevent autoreactivity.
CD40 Ligation Inhibits IL‐2 and SAC+IL‐2 Induced Proliferation in Chronic Lymphocytic Leukaemia Cells
Authors: SÖDERBERG O. , CHRISTIANSEN I. , CARLSSON M. , NILSSON K.
Published: November 2003

This paper reports on differences between B cell‐type chronic lymphocytic leukaemia (B‐CLL) and normal B cells in their response to IL‐2+thioredoxin (Trx), Staphylococcus aureus Cowan strain 1 (SAC)+IL‐2+Trx, and to CD40 ligation of IL‐2+Trx and SAC+IL‐2+Trx stimulation. The authors found that Trx acted synergistically with IL‐2 and SAC+IL‐2 in inducing DNA synthesis in B‐CLL cells, but not in the normal B cells. Interestingly, IL‐2+Trx alone was found to induce proliferation in B‐CLL cells from patients with advanced stages of disease. In addition, we also found that IL‐2+Trx and SAC+IL‐2+Trx‐induced DNA synthesis of B‐CLL cells was inhibited by CD40 activation (by soluble anti‐CD40 MoAb and anti‐CD40 MoAb presented on irradiated CD32L cells). In clear contrast, SAC+IL‐2+Trx‐induced DNA synthesis of normal B cells was not inhibited by soluble anti‐CD40 MoAb. The authors therefore conclude that B‐CLL cells differ from normal B cells in their response to IL‐2 (IL‐2+Trx) and CD40 ligation.
Clinical Progression of HIV Infection: Role of NK Cells
Authors: BRUUNSGAARD H. , PEDERSEN C. , SKINHØJ P. , PEDERSEN B. K.
Published: November 2003

The purpose of the study was to examine how immune parameters related to non‐major histocompatibility complex (MHC) restricted cytotoxicity changed with respect to progression and duration of human immunodeficiency virus (HIV) infection. Forty‐one HIV seropositive subjects with a known time for seroconversion were included. The major finding was that a low percentage and number of natural killer (NK) cells were found in the group who had a rapid progression to acquired immune deficiency syndrome (AIDS) (less than 70 months following seroconversion) compared with those progressing more slowly to AIDS (more than 70 months following seroconversion). Furthermore, a significant correlation was found between the number of months from seroconversion to the diagnosis of AIDS and percentages of CD16+ cells (rs = 0.811, P < 0.01), CD56+ cells (rs= 0.647, P < 0.05), and CD16+CD56+ cells (rs= 0.839, P < 0.01) as well as the concentration of CD16+CD56+ cells in the blood (rs= 0.699, P < 0.05). No differences were found in percentages and concentrations of NK cell subsets between subjects with a long history (more than 6 years) versus a short history (less than 6 years) of HIV infection without AIDS. Furthermore, no negative correlations were found between the concentration of any NK subsets and the number of months since seroconversion in HIV seropositive individuals without AIDS. The total concentration of CD16+, CD56+, and CD16+ CD56+ cells was lower in the group of HIV seropositive subjects compared with HIV seronegative subjects (age and sex matched), and the concentration of CD16+ cells was lower in those with AIDS than in those without AIDS. In conclusion, low concentration of NK cells in the blood was associated with a more rapid disease progression, indicating that defective non‐MHC restricted cytotoxicity may be associated with HIV disease progression.
The plasma turnover of transfused antithrombin concentrate in patients with acquired antithrombin deficiency
Authors: Harper P. L. , Park G. R. , Carrell R. W.
Published: November 2003

Antithrombin concentrate, prepared from human plasma, has been used as replacement therapy in 35 patients with acquired antithrombin deficiency. The inhibitory activity of the concentrate, measured by chromogenic assay, correlates well with the manufacturer's quoted activity. The mean in vivo recovery of the product was 0.0124 iu mL −1 per iu of antithrombin (AT) concentrate administered by kilogram body weight. The recovery was similar in all diagnostic groups studied and did not vary during the course of treatment. Consumption of the antithrombin concentrate was monitored by measuring the production of thrombin–antithrombin complexes and the loss of plasma antithrombin activity. The mean concentration of thrombin–antithrombin complexes was elevated (23 ng mL −1) at the time of admission to the intensive care unit and fell progressively over the next 4 days. The mean time for the decay of half the antithrombin activity was 23 h during the first 24 h of therapy and rose to 42.1 h after day 1. The recovery and half‐life measurements are necessary to plan an appropriate dosage regimen for the administration of this antithrombin concentrate in acquired deficiency states.
Medical messages in the media – barriers and solutions to improving medical journalism
Authors: Larsson Anna , Oxman Andrew D , Carling Cheryl , Herrin Jeph
Published: November 2003

Context  Medical issues are widely reported in the mass media. These reports influence the general public, policy makers and health‐care professionals. This information should be valid, but is often criticized for being speculative, inaccurate and misleading. An understanding of the obstacles medical reporters meet in their work can guide strategies for improving the informative value of medical journalism.

Objective  To investigate constraints on improving the informative value of medical reports in the mass media and elucidate possible strategies for addressing these.

Design  We reviewed the literature and organized focus groups, a survey of medical journalists in 37 countries, and semi‐structured telephone interviews.

Results  We identified nine barriers to improving the informative value of medical journalism: lack of time, space and knowledge; competition for space and audience; difficulties with terminology; problems finding and using sources; problems with editors and commercialism. Lack of time, space and knowledge were the most common obstacles. The importance of different obstacles varied with the type of media and experience. Many health reporters feel that it is difficult to find independent experts willing to assist journalists, and also think that editors need more education in critical appraisal of medical news. Almost all of the respondents agreed that the informative value of their reporting is important. Nearly everyone wanted access to short, reliable and up‐to‐date background information on various topics available on the Internet. A majority (79%) was interested in participating in a trial to evaluate strategies to overcome identified constraints.

Conclusion  Medical journalists agree that the validity of medical reporting in the mass media is important. A majority acknowledge many constraints. Mutual efforts of health‐care professionals and journalists employing a variety of strategies will be needed to address these constraints.
Involving users in low back pain research
Authors: Ong Bie Nio , Hooper Helen
Published: November 2003

Objective  To involve users in the design of a research project that aims at describing a 12‐month course of low back pain in an adult population sample (epidemiological strand), and to determine how patient and professional perceptions of low back pain and its treatment relate to the use of health‐care and to subsequent outcome (qualitative strand).

Design  Three focus groups were organized in the preparatory phase of the project with general practitioners, other health professionals and low back pain sufferers. Issues pertaining to the experience of living with, or treating low back pain were explored and users were asked to identify relevant research questions for consideration within the study.

Findings  The focus groups revealed tensions between involving users as co‐researchers for design issues and their role as sufferers and health professionals who want to share their narrative accounts of low back pain. The group discussions produced a wealth of material for analysis, but no explicitly stated research topics. Three key themes and the process of user involvement in the focus groups are discussed.

Conclusions  The focus group format could be restrictive in that it allows for detailed exchange between participants, but is insufficiently geared towards the production of a research agenda. We draw conclusions as to possible approaches for user involvement in health services research design.