bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibitory effects of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin on rat hepatocyte proliferation induced by 2/3 partial hepatectomy
Authors: Bauman J. W. , Goldsworthy T. L. , Dunn C. S. , Fox T. R.
Published: May 2008

To better understand the mode of action of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) induced alterations in hepatic cell proliferation and the potential link to tumour‐promoting activity, we investigated the effects of TCDD on the expression of certain key genes involved in liver cell growth and the effects of TCDD on induced hepatocyte cell proliferation. Gene expression analysis was conducted, by Northern blot hybridization, using RNA isolated from female Sprague‐Dawley rat livers collected at various times during a 14‐day dosing period with TCDD known to produce alterations in cell proliferation. No major changes were observed in the expression of the transforming growth factors TGF‐α and TGF‐β or in oncogenes ras, src and myc. However, the expression of the transcription factors C/EBP, HNF‐1 α and HNF‐4 decreased after 14 days of TCDD treatment. To investigate how TCDD affects hepatic growth, cell proliferation analysis was conducted in rats stimulated to undergo hepatocyte proliferation following either 2/3 partial hepatectomy or lead nitrate treatment. Cell proliferation was quantified by means of immunocytochemical detection of Proliferating Cell Nuclear Antigen (PCNA). Fourteen days of pretreatment with TCDD caused an overall inhibiton of hepatocytes in the growth fraction (G1, S, G2 and M) from 61 ± 3% in the control‐partial hepatectomy group to 41 ± 3% in the TCDD‐partial hepatectomy group. A periportal pattern of cell proliferation was observed in the TCDD‐partial hepatectomy group as compared to the panlobular pattern of cell proliferation in the control‐partial hepatectomy group. TCDD pretreatment also produced an inhibition of cell proliferation induced by the liver mitogen lead nitrate. TCDD‐induced inhibition of hepatocyte proliferation could play a role in TCDD tumour promotion and hepatocarcinogenesis through the creation of a environment whereby preneoplastic cells continue to expand while normal hepatocyte proliferation is inhibited.
Regulation of NIH‐3T3 cell G1 phase transit by serum during exponential growth
Authors: DiSalvo C. V. , Zhang D. , Jacobberger J. W.
Published: May 2008

The proliferation rate of mammalian cells is regulated normally in the G1 phase of the cell cycle. During this phase, it is convenient to assign positive and negative roles to the molecular programs that regulate the duration of G1 and the phase transition from G1 to S phase. Density‐dependent inhibition of cellular proliferation results in an increase in the duration of G1. This form of regulation is due to both secreted factors and cell—cell contact. Serum is mitogenic to a variety of mammalian cell types. Because quiescent cells enter S phase as a result of serum addition to culture media, serum is usually regarded as a source of positive regulatory growth factors. We have measured the length of the G1, S and G2+ M phases of NIH 3T3 cells during exponential growth as a function of cell density and serum concentration. The G1 length increases during exponential growth as a function of density while S and G2+ M are relatively constant. Further, this increase in G1 phase time, or density mediated negative regulation, is inhibited by increasing serum concentration. This phenotype is saturable between 10% to 20% serum. Serum concentrations above 2.5% are able to increase the rate of cell cycling (decrease the G1 phase time) by inhibiting density dependent negative regulation of NIH 3T3.
Laser scanning cytometer (LSC) analysis of fraction of labelled mitoses (FLM)
Authors: Gorczyca W. , Melamed M.R. , Darzynkiewicz Z.
Published: May 2008

Abstract. In this report we describe the successful application of a novel microscope‐based multiparameter laser scanning cytometer (LSC) to measure duration of different phases of cell cycle in HL‐60 human leukaemic cell lines by the fraction of labelled mitoses (FLM) method. Exponentially growing cells were harvested after various time intervals following pulse‐labelling with 5′‐bromo‐2′‐deoxyuridine (BrdUrd), cytocentrifuged, fixed in ethanol, and then exposed to UV light to induce DNA strand breaks at the sites of incorporated BrdUrd. The 3’OH termini of the photolytically generated DNA strand breaks were labelled with BrdUTP in the reaction catalysed by exogenous terminal deoxynucleotidyl transferase (TdT), followed by FITC‐labelled BrdUrd antibodies. DNA was counterstained with propidium iodide (PI). Due to differences in chromatin structure between the interphase and mitotic cells, the LSC identified the latter by virtue of their higher red (PI) fluorescence intensity values among all pixels over the measured cell. To confirm that the cells selected were indeed cells in mitosis, predominantly in metaphase, the recorded X‐Y coordinates of selected cells were used to re‐position the cell for their visual examination. From the time lapse analysis of percentage BrdUrd‐labelled cells progressing through mitosis it was possible to calculate the duration of individual phases of the cell cycle. The duration of S (Ts) and G2+ M (TG2+M) was 8 and 3 h, respectively, and the minimal duration of G2 (TG2) was 2 h. The cell cycle time (Tc) estimated for the cohort of the most rapidly progressing cells was 13 h. The ability to automatically and rapidly discriminate mitotic cells combined with the possibility of their subsequent identification by image analysis makes LSC the instrument of choice for the FLM analysis.
Immortal, non‐tumourigenic mouse mammary outgrowths express high levels of cyclin B1 and activation of cyclin B1/cdc2 kinase
Authors: Said T. K. , Bonnette S. , Medina D.
Published: May 2008

Abstract. Neoplastic transformation of mouse mammary epithelial cells is the result of several identifiable phenotypic changes which presumably require sequential genetic alterations. In our model system, mammary cells progress from a mortal state (virgin duct) to several morphologically distinct intermediate states. The intermediate states are distinct cell populations that are phenotypically identified as immortal, non‐tumourigenic (i.e. EL11), weakly tumourigenic ductal/alveolar hyperplasia (i.e. EL12) and moderately tumourigenic alveolar hyperplasiaa (i.e. TM12) to invasive tumours (i.e. EL12T/TM12T). We have studied the changes in total cyclin A and B1 levels, cyclin A and B1 complexed to cdc2, cyclin B1cdc2 kinase activity and cyclin D proteins in EL11 and EL12 immortalized outgrowth lines. Results revealed increased levels in total cyclin B1(> 5‐fold), cyclin B1/cdc2 (3–4‐fold) and cyclin B1/cdc2 kinase activity (2–3.5‐fold) in EL11 and EL12 phenotypes when compared to control mammary gland (virgin). No changes in the levels of total cyclin A or cycln A associated to cdc2 were observed. Cyclin D1, D2 and D3 protein levels were low in the EL11 immortal ductal outgrowth. Exposure to hormones via a pituitary isograft stimulated the synthesis of cyclin D1 and D2 but not D3 associated to cdk4 as well as total cdk4 proteins. Bromodeoxyuridine (BrdUrd) labelling indices showed marked increases in immortal ductal outgrowths (EL11 and EL12) when compared to virgin, suggesting that epithelial cells are cycling in these cell populations. Even in the presence of hormone stimulation, EL11 outgrowths were not tumourigenic, suggesting that other events are necessary to drive the cells to a tumourigenic phenotype. The results suggest that increased levels of cyclin B1 and cyclin B1‐cdc2 kinase activities are early events and may be an important marker for the immortalized phenotype.
Probing chromatin structure in the early phases of apoptosis
Authors: Ferlini C. , Biselli R. , Scambia G. , Fattorossi A.
Published: May 2008

Abstract. A typical flow cytometric marker of apoptosis is the appearance of a hypodiploid peak. This phenomenon is related to the chromatin fragmentation and loss that occurs during the late stages of the process. We describe herein the changes occurring at the chromatin level in purified nuclei preparations obtained from human peripheral blood mononuclear cells in a time‐course study, including the simultaneous evaluation of nuclear proteins and DNA stainability, light‐scattering properties, and spectrophotometric determination of the protein content. An augmentation of fluoroscein isothiocyanate (FITC) stainability was noticed as early as 1 h after irradiation. As this phenomenon is not correlated to changes in actual protein content, one can conclude that modifications of basic protein accessibility occur from the early phases of the apoptotic process. Also DNA stainability augmented with time, generating the transient appearance of a hyperdiploid peak that preceded the appearance of the hypodiploid peak typical of the late stages of the process, and that shared with the latter the same light‐scattering properties. Chromatin status was further explored by staining apoptotic nuclei using DNA probes with peculiar molecular weight. Propidium iodide (PI) and ethidium bromide (EB), but not the much bulkier 7‐aminoactinomycin D (7‐AAD), identified the nuclei with a transient increase in DNA stainability confirming that an increased dye accessibility to binding sites was responsible for the phenomenon. Remarkably, all dyes identified the same proportion of hypodiploid nuclei when an apoptotic nucleus shed its fragmented chromatin. Control experiments included differential interference contrast and fluorescence microscopy that showed the purity of nuclei preparations and the typical morphological apoptotic features. Finally, the simultaneous evaluation of DNA by PI and nuclear proteins by FITC in a time course study allowed a thorough assessment of changes occurring at the chromatin level in the diverse stages of apoptosis. It is suggested that proteolysis precedes endonucleolysis and probably renders it easier the final endonucleolytic step leading to DNA fragmentation and loss.
Apoptosis and mitosis in oral and oropharyngeal epithelia: evidence for a topographical switch in premalignant lesions
Authors: Birchall M. , Winterford C. , Tripconi L. , Gobé G. , Harmon B.
Published: May 2008

Abstract. Apoptosis (programmed cell death) may play a part in carcinogenesis. The mucosa of the oral cavity, a common site for the development of dysplasia and squamous cell carcinoma, is ideal for the study of carcinogenesis in vivo. Earlier work suggested that apoptosis falls with the development of carcinoma, and that carcinogenesis is preceded by topographical changes in apoptosis. To explore these hypotheses, 72 paraffin sections were obtained: 15 normal (N), nine mild dysplasia (D), 15 severe dysplasia/carcinoma in situ (CIS), 30 squamous cell carcinoma (SCC: power analysis suggested 15 per group). Apoptotic (AI) and mitotic (MI) indices and AI/MI ratio were calculated (1000 cells/slide). These, with age, sex, alcohol and smoking habits, and anatomical subsite, were entered into a regression model with histological group as dependent. Vertical cell position (cp) was plotted, and resultant frequency curves were compared. MI significantly increased (mean N 0.39, 95% confidence interval 0–0.35; D 0.63, 0.23–0.98; SCC 0.86, 0.51–1.21, P <0.0001) and AI/MI significantly decreased (D 0.54, 0.20–0.86; SCC 0.28, 0.05–0.61, P <0.05) progressing from D, through CIS, to SCC. However, after inclusion of all variables, only MI remained significant (P <0.0001). Peak incidence of mitosis shifted downwards in CIS relative to N and D, whilst peak apoptosis shifted upwards. Thus, programmed cell death remains static as mitosis increases in carcinogenesis of the oral cavity. However, there is an alteration in the topographical relationship of these events in CIS which may make homeostatic mechanisms involving apoptosis less efficient.
A mathematical model of glioma growth: the effect of extent of surgical resection
Authors: Woodward D. E. , Cook J. , Tracqui P. , Cruywagen G. C. , Murray J. D. , Alvord E. C.
Published: May 2008

Abstract. We have developed a mathematical model based on proliferation and infiltration of neoplastic cells that allows predictions to be made concerning the life expectancies following various extents of surgical resection of gliomas of all grades of malignancy. The key model parameters are the growth rate and the diffusion rate. These rates were initially derived from analysis of a case of recurrent anaplastic astrocytoma treated by chemotherapies. Numerical simulations allow us to estimate what would have happened to that patient if various extents of surgical resection, rather than chemotherapies, had been used. In each case, the shell of the infiltrating tumour that remains after ‘gross total removal’ or even a maximal excision continues to grow and regenerates the tumour mass remarkably rapidly. By developing a model that allows the growth and diffusion rates to define the distribution of cells at the time of diagnosis, and then varying these rates by about 50%, we created a hypothetical tumour patient population whose survival times show good agreement with the results recently reported by Kreth for treatments of glioblastomas. Tenfold decreases in the rates of growth and diffusion mimic the results reported by many other investigators with more slowly growing gliomas. Thus, the model quantitatively supports the ideas that (i) gliomas infiltrate so diffusely that they cannot be cured by resection alone, surgical or radiological, no matter how extensive that may be; (ii) the more extensive the resection, regardless of the degree of malignancy of the glioma, the greater the life expectancy; and (iii) measurements of the two rates, growth and diffusion, may be able to predict survival rates better than the current histological estimates of the type and grade of gliomas.
TGF‐β1 perturbation of the fibroblast cell cycle during exponential growth: switching between negative and positive regulation*
Authors: Zhang D. , Jacobberger J. W.
Published: May 2008

Abstract. We have demonstrated previously that SV40 T antigen and serum regulate the length of G1 in exponentially growing NIH‐3T3 cells in part by inhibiting density dependent negative cell cycle regulation. In these studies it was suggested that T antigen positively regulated G1 in a density independent manner as well. In this report we show that, 24 h after treatment, TGF‐β1 perturbs the cell cycle of exponentially growing fibroblasts in a manner similar to T antigen. However, prior to 24 h, TGF‐β1 produced a negative response, elongating the Gi phase of the cell cycle that was followed by a positive response, both of which were density independent. This biphasic response was measured between 0 and 12 h post‐treatment and was relative to responses from serum. This switch from an early inhibitory effect to a late stimulatory effect was associated with changes in Rb phosphorylation, the timing and magnitude of which indicated that Rb may be directly regulating TG1 rather than reporting changes in the population. This is further substantiated by abrogation of the inhibitory effect by expression of wild‐type SV40 T antigen and retention of the effect in cells that express an Rb‐binding mutant of T antigen (K1). The biphasic regulatory effects of TGF‐β1 were also displayed in WI‐38 and IMR‐90 human fibroblasts. This suggests that this biphasic effect is a property of fibroblasts.
Growth factors and apoptosis
Authors: Granérus M. , Engström W.
Published: May 2008

Abstract.Apoptosis is nowadays recognized as an important mechanism by which cells can be eliminated from the organism. In particular its role in tissue modelling during embryogenesis has been highlighted. The human teratoma cell line Tera 2, which in several respects acts as a human embryonic stem cell, can be induced to undergo apoptosis by reducing the serum content of the tissue culture medium. We report here that this process can be reversed by replacing serum with the heparin‐binding growth factors, acidic FGF and basic FGF. In contrast, neither of the mammalian transforming growth factors (TGF‐β‐3) managed to exert any effect on growth or apoptosis in Tera 2 cells.
E2F transcription factor action, regulation and possible role in human cancer
Authors: Sladek T. L.
Published: May 2008

E2F transcription factors regulate expression of a panel of cellular genes that control cellular DNA synthesis and proliferation, either by activating or repressing their transcription, largely in a cell cycle‐dependent manner. The ability of E2F proteins to regulate expression of these target genes is, in turn, regulated by other cellular proteins that are important for normal control of cell cycle progression. Together, E2F proteins, their target genes, and the proteins that regulate E2F activity comprise a genetic pathway that is probably the most frequently altered pathway in human cancer. This review examines this genetic pathway and focuses on the role of E2F proteins in its function. Specifically, the target genes regulated by E2F, the likely mechanisms by which activation and repression of target gene transcription is achieved, and the regulation of E2F activity by other proteins in the cell, are discussed.
Prolactin receptor expression by splenocytes from rats in various hormonal states
Authors: Güneş H. , Zawilla S. , Mastro A. M.
Published: May 2008

Prolactin (PRL) is mitogenic for lymphocytes in vitro, but the responsiveness of lymphocytes depends on the in vivo hormonal status of the rats from which the cells were obtained. Lymphocytes from ovariectomized (OVX) rats, but not from rats in oestrus or from male rats, respond to prolactin; administration of oestradiol to OVX rats diminishes the response. In order to determine if a correlation exists between lymphocyte responsiveness to prolactin and levels of cell surface prolactin receptors (PRL‐R) expression, the percentage of splenocytes and each splenocyte subpopulation expressing surface PRL‐R from rats of various hormonal states (OVX, oestradiol‐injected OVX, oestrus and male) was analysed by single‐colour and dual‐colour flow cytometric analysis. We found that approximately 20% of splenocytes expressed surface PRL‐R regardless of hormonal states (n= 16). The majority (85%) of PRL‐R positive splenocytes were B lymphocytes whereas 11.1% and 4.8% of splenocytes expressing the PRL‐R were CD4 positive T‐helper (TH) and CD8 positive T‐cytotoxic (Tc) lymphocytes, respectively. B lymphocytes also stained more brightly than T lymphocytes. This distribution of PRL‐R expression did not show significant alterations on total splenocytes or TH and Tc lymphocytes during various hormonal stages. However, the percentage of PRL‐R‐positive B lymphocytes increased markedly in OVX rats (twofold), compared to rats at oestrus. In summary, no correlation was found between the responsiveness to prolactin as a mitogen and levels of PRL‐R expression by lymphocytes from rats at different hormonal states. This result suggests that sex steroid hormones may control prolactin responsiveness of lymphocytes by affecting the signal transduction pathway through PRL‐R rather than by altering the level of the cell surface receptor expression.
WR‐1065, an active metabolite of the cytoprotector amifostine, affects phosphorylation of topoisomerase IIα leading to changes in enzyme activity and cell cycle progression in CHO AA8 cells
Authors: Murley J. S. , Constantinou A. , Kamath N. S. , Grdina D. J.
Published: May 2008

The effects of WR‐1065 (2‐((aminopropyl)amino)ethanethiol) on cell cycle progression, topoisomerase (topo) IIα activity, and topo IIα phosphorylation in Chinese hamster ovary (CHO) cells have been investigated. Exposure of CHO cells to 0.4 μm of WR‐1065 for 30 min did not effect cell cycle progression nor topo IIaL activity and phosphorylation status. However, concentrations ranging from 4 μm to 4 mm were equally effective in significantly altering these three end points. Cell cycle progression was analysed by flow cytometry. Following a 30 min exposure to this range of concentrations, cells redistributed throughout the cell cycle with the most prominent changes being an accumulation of cells in G2. Topo IIα activity was measured using a kinetoplast DNA (kDNA) decatenation assay. Enzyme activity was reduced by 50% relative to control levels throughout the 4 μm to 4 mm dose range tested. Likewise, topo IIα phosphorylation levels, analysed using an immuno‐precipitation assay and an antibody specific to the 170 kDa band of topo II, decreased between 42% to 48% of control levels. Inhibition of topo IIα activity in cells exposed to WR‐1065 is consistent with the associated observation of WR‐1065 mediated cell cycle progression delay and build‐up of cells in the G2 phase of the cell cycle.
Engagement of DNA polymerases during apoptosis
Authors: Miscia S. , Di Baldassarre A. , Rana R. Alba , Di Pietro R. , Cataldi A.
Published: May 2008

DNA replicative and repair machinery was investigated by means of different techniques, including in vitro nuclear enzymatic assays, immunoelectron microscopy and confocal microscopy, in apoptotic cell lines such as HL‐60 treated with methotrexate, P815 and K562 exposed to low temperatures and Friend cells exposed to ionizing radiation. The results showed a shift of DNA polymerase α and β activities. DNA polymerase α, which in controls was found to be the principal replicative enzyme driving DNA synthesis, underwent, upon apoptosis, a large decrease of its activity being replaced by DNA polymerase β which is believed to be associated with DNA repair. Such a modulation was concomitant with a topographical redistribution of both DNA polymerase α and the incorporation of BrdUrd throughout the nucleus. Taken together, these results indicate the occurrence of a dramatic response of the DNA machinery, through a possible common or at least similar behaviour when different cell lines are triggered to apoptosis. Although this possibility requires further investigation, these findings suggest an extreme attempt of the cell undergoing apoptosis to preserve its nuclear environment by switching on a repair/defence mechanism during fragmentation and chromatin margination.
Gompertzian growth curves in parathyroid tumours: further evidence for the set‐point hypothesis
Authors: Parfitt A. M. , Fyhrie D. P.
Published: May 2008

Background: Clinical and cell kinetic data in parathyroid tumours show that their rate of growth slows down progressively and that tumour size approaches an asymptotic value. The Gompertz equation has been widely used in oncology to model growth retardation in malignant tumours; we describe its first aplication to a benign tumour. Methods: In 41 patients with radiation associated hyperparathyroidism, individual solutions were derived for the Gompertz equation: Nt= Exp[A/a(1–Exp–at)], where A is the rate constant (years‐1) for initial exponential growth and a is the rate constant (years‐1) for exponential decline in A. Input data comprised three estimates of tumour age at surgery, 100%, 75% and 50% of the time since irradiation, cell number estimated from tumour weight, and current tumour growth rate, representing the difference between current cell birth rate, estimated from the prevalence of mitotic figures, and an assumed mean rate of cell loss of 5%. Results: With 100% tumour age, geometric mean values were 2.76 for A, 0.134 for a, and 0.87 g for the growth asymptote. As assumed tumour age decreased, the rate constants increased and the growth asymptotes declined from 22% to 9% greater than the geometric mean tumour weight. Depending on assumed tumour age, the rate constants were about 15–45 times smaller than in myeloma and in testicular tumours, and the growth asymptotes about 2500 and about 60 times smaller, respectively. A and a were highly correlated (r2= 0.993), with a slope of 20.9 and no significant intercept. Depending on assumed tumour age, the geometric mean time from the initial mutation to the first cell division ranged from 39 to 92 days, much longer than in malignant tumours. Conclusions: (1) The Gompertz modelling demonstrates that both the nonprogressive clinical course and the slow growth of parathyroid tumours can be accounted for by a single mutation. (2) The extremely low values for A and a, and consequent very long delay before the first cell division, support the notion that the initial mutation does not affect a growth regulatory gene, but increases growth indirectly via an increase in secretory set‐point, the clone of mutant cells behaving as if they were in a hypocalcaemic environment until the plasma calcium rises to the new set‐point. (3) The clinical characteristics of radiation‐induced parathyroid tumours are modelled more closely if there is a substantial delay between time of irradiation and onset of tumour growth. (4) The rate constants A and a are highly correlated because the variability
Outbreak of exogenous Cushing's syndrome due to unlicensed medications
Authors: Azizi Fereidoun , Jahed Adel , Hedayati Mehdi , Lankarani Mahnaz , Bejestani Hadi Shahrad , Esfahanian Fatemeh , Beyraghi Nargues , Noroozi Alireza , Kobarfard Farzad
Published: May 2008

Objective  Despite the widespread medical use of glucocorticoids, reports of factitious administration of these hormones have been uncommon. We herein report an outbreak of Cushing's syndrome in Tehran among the addicts using Tamgesic (a brand of Buprenorphine) to help them through the narcotic withdrawal stage, without knowledge of the glucocorticoid content of the black‐market drug.

Design and measurements  Case histories of 19 patients with a final diagnosis of iatrogenic Cushing's syndrome were reviewed. Liquid chromatography/mass spectrometry (LC–Mass) method was used to evaluate glucocorticoid existence in the brand. High performance liquid chromatography was used to determine plasma dexamethasone level.

Results  No buprenorphine was present in the vials. Each Tamgesic vial contained 0·4 mg of Dexamethasone disodium phosphate; Heroin was also found in them. The duration of injection abuse and the total dexamethasone intake was 4·5 (1–18) months and 2·6 (0·8–8) mg/day, respectively. Median plasma dexamethasone concentration was 5·8 nmol/l, with a range of 5–8·7. Physical findings of the cases were not different from those of the classic endogenous Cushing's syndrome but their serum cortisol and urinary free cortisol were suppressed. Severe life‐threatening complications were demonstrated in five cases.

Conclusion  Surreptitious use of steroids resulting in Cushing's syndrome may be more common in opium addicts; a high degree of suspicion is needed to uncover this disorder. Whenever facing a cushingoid appearance in addicts, the possibility of using black market drugs with corticosteroid contents should be kept in mind.
Preserving the unpreservable: a lost world rediscovered at Christian Malford, UK
Authors: Wilby Philip R. , Duff Keith , Page Kevin , Martin Susan
Published: May 2008

The small village of Christian Malford, Wiltshire (UK) is known to palaeontologists the world over because of the chance discovery of an astonishing fossil bonanza in the mid‐nineteenth century. Pits in the Jurassic Oxford Clay yielded thousands of specimens of exquisitely preserved ammonites, fish and crustaceans, but became most famous for squid‐like cephalopods and belemnites (collectively termed coleoids) with fossilized soft‐parts. The precise location of the find has remained obscure, until now, and a new attempt is underway to understand the ancient environment that triggered this unusual preservation.
Down‐regulation of MyoD gene expression in rat diaphragm muscle with heart failure
Authors: Lopes Francis da Silva , Carvalho Robson Francisco , Campos Gerson Eduardo Rocha , Sugizaki Mario Matheus , Padovani Carlos Roberto , Nogueira Célia Regina , Cicogna Antonio Carlos , Pai‐Silva Maeli Dal
Published: May 2008

Diaphragm myopathy has been described in patients with heart failure (HF), with alterations in myosin heavy chains (MHC) expression. The pathways that regulate MHC expression during HF have not been described, and myogenic regulatory factors (MRFs) may be involved. The purpose of this investigation was to determine MRF mRNA expression levels in the diaphragm. Diaphragm muscle from both HF and control Wistar rats was studied when overt HF had developed, 22 days after monocrotaline administration. MyoD, myogenin and MRF4 gene expression were determined by RT‐PCR and MHC isoforms by polyacrylamide gel electrophoresis. Heart failure animals presented decreased MHC IIa/IIx protein isoform and MyoD gene expression, without altering MHC I, IIb, myogenin and MRF4. Our results show that in HF, MyoD is selectively down‐regulated, which might be associated with alterations in MHC IIa/IIx content. These changes are likely to contribute to the diaphragm myopathy caused by HF.
Psychosocial effects experienced by grandmothers as primary caregivers in rural Botswana
Authors: THUPAYAGALE‐TSHWENEAGAE G.
Published: May 2008

Studies on the psychosocial effects of grandmothers as primary caregivers in Botswana are non‐existent. The purpose of this study was to close that knowledge gap. Twenty‐five (n = 25) grandmothers who were primary caregivers to their grandchildren in one rural village of Botswana were interviewed twice a week between January and May 2006. A central theme that emerged from the interviews under psychological effects was ‘disenfranchised grief’ with sub themes that included depression, loneliness, blaming and stress. The themes that emerged on social effects included isolation, loss of control, unavailability of mental health services, financial hardships and a sense of failure for some participants. Implications for mental health practitioners and policy makers are given.
Patients' experience of learning and gaining personal knowledge during a stay at a mental hospital
Authors: BORGE L. , HUMMELVOLL J. K.
Published: May 2008

The focus is on voluntarily hospitalized patients' subjective experiences of learning and gaining personal knowledge during a stay at a mental hospital. The aim was to explore and describe patients' learning as personal knowledge acquisition related to the therapeutic process during hospitalization. The study was exploratory and descriptive, with a hermeneutic – phenomenological approach in data collection and analysis. Qualitative interviews were carried out with 15 patients during and after their stay. A re‐analysis was conducted. The results underline the importance of the environmental effects on patients' motivation for learning and self‐esteem in an acknowledging milieu. Moving towards relearning presupposes that the patient's motivation is aroused. Patients must participate in the treatment and the validity of the knowledge must be tested in the individual patient's life. The patients confirmed and helped each other to increase insight through recognizing each other's problems and reactions. Time in itself seemed to increase self‐reflection. Receiving impulses and getting concrete tools through therapy stimulated meaning and hope for future living. The professionals must use a holistic approach including a learning climate in pleasant surroundings and a conjoint contribution from fellow patients and staff. Further research should focus on how to combine therapy with learning – preferably by means of a co‐operative inquiry design.
Aptitude of psychiatric nurses: conceptual considerations and measurement difficulties
Authors: HASPESLAGH M. , DELESIE L. , IGODT P.
Published: May 2008

Patient allocation is common practice in psychiatric nursing. This study investigates nurse aptitude, a sub‐concept of competence, to validate and refine patient allocation. The focus is on operationalizing aptitude for daily management purposes. Aptitude varies in function of the tasks to be performed and the therapeutic relationship of each psychiatric nurse with her individual patients. Time, job context, socio‐cultural context and semantic frame of reference have also to be taken into account when operationalizing aptitude. Self and peer opinions are a basis for aptitude measurement as patient care and its management are shared among a small team of nurses. A meticulous idio‐graphic analysis is necessary. These constraints generate several measurement difficulties that are to be dealt with without too many unrealistic assumptions. The research design enabled reliable aggregation of peer ‘on’ and ‘from’ opinions. These allowed confrontation of opinions and identification of bias in these. Stepwise explorative experimentation led to gauging and calibrating a specific aptitude questionnaire to the context of psychiatric nursing. The final version is now being applied in practice in 14 wards of 11 hospitals in Flanders.
Reproductive protein evolution within and between species: maintenance of divergent ZP3 alleles in Peromyscus
Authors: TURNER LESLIE M. , HOEKSTRA HOPI E.
Published: May 2008

In a variety of animal taxa, proteins involved in reproduction evolve more rapidly than nonreproductive proteins. Most studies of reproductive protein evolution, however, focus on divergence between species, and little is known about differentiation among populations within a species. Here we investigate the molecular population genetics of the protein ZP3 within two Peromyscus species. ZP3 is an egg coat protein involved in primary binding of egg and sperm and is essential for fertilization. We find that amino acid polymorphism in the sperm‐combining region of ZP3 is high relative to silent polymorphism in both species of Peromyscus. In addition, while there is geographical structure at a mitochondrial gene (Cytb), a nuclear gene (Lcat) and eight microsatellite loci, we find no evidence for geographical structure at Zp3 in Peromyscus truei. These patterns are consistent with the maintenance of ZP3 alleles by balancing selection, possibly due to sexual conflict or pathogen resistance. However, we do not find evidence that reinforcement promotes ZP3 diversification; allelic variation in P. truei is similar among populations, including populations allopatric and sympatric with sibling species. In fact, most alleles are present in all populations sampled across P. truei's range. While additional data are needed to identify the precise evolutionary forces responsible for sequence variation in ZP3, our results suggest that in Peromyscus, selection to maintain divergent alleles within species contributes to the pattern of rapid amino acid substitution observed among species.
Genetic spatial structure in a butterfly metapopulation correlates better with past than present demographic structure
Authors: ORSINI L. , CORANDER J. , ALASENTIE A. , HANSKI I
Published: May 2008

The Glanville fritillary butterfly (Melitaea cinxia) has been studied in the Åland Islands in Finland since 1991, where it occurs as a classic metapopulation in a large network of 4000 dry meadows. Much ecological work has been conducted on this species, but population genetic studies have been hampered by paucity of suitable genetic markers. Here, using single nucleotide polymorphisms and microsatellites developed for the Glanville fritillary, we examine the correspondence between the demographic and genetic spatial structures. Given the dynamic nature of the metapopulation, the current genetic spatial structure may bear a signal of past changes in population sizes and past patterns of gene flow rather than reflect the current demographic structure or landscape structure. We analyse this question with demographic data for 10 years, using the Rand index to assess the similarity between the genetic, demographic, and landscape spatial structures. Our results show that the current genetic spatial structure is better explained by the past rather than by the current demographic spatial structure or by the spatial configuration of the habitat in the landscape. Furthermore, current genetic diversity is significantly explained by past metapopulation sizes. The time lag between major demographic events and change in the genetic spatial structure and diversity has implications for the study of spatial dynamics.
New Biomarkers in an Acute Model of Live Escherichia coli‐induced Sepsis in Pigs
Authors: Castellheim A. , Thorgersen E. B. , Hellerud B. C. , Pharo A. , Johansen H. T. , Brosstad F. , Gaustad P. , Brun H. , Fosse E. , Tønnessen T. I. , Nielsen E. W. , Mollnes T. E.
Published: May 2008

We developed a live Escherichia coli model of acute sepsis in pigs with emphasize on biomarkers reflecting the early inflammatory response of sepsis. Healthy pigs, 25–35 kg, were challenged intravenously (IV) (n = 12) or intrapulmonary (n = 6) with live E. coli and observed for 3 and 5 h respectively. Control pigs received culture medium (n = 6 + 3). Haemodynamic parameters and a broad panel of inflammatory mediators were measured. The dose of bacteria was carefully titrated to obtain a condition resembling the early phase of human septic shock. The IV group displayed a pro‐inflammatory response [significant increase in tumour necrosis factor‐α, interleukin (IL)‐6 and IL‐8] and an early anti‐inflammatory response (significant increase in IL‐10). For the first time, we demonstrate a significant increase in IL‐12 and matrix metalloproteinase‐9 (MMP) early in pig sepsis. Coagulation was activated (significant increase in thrombin–antithrombin complexes) and there was a significant decrease in the serum proteins suggesting capillary leakage. Haemodynamic parameters reflected a septic condition with significant decrease in systemic blood pressure, increases in heart rate, pulmonary artery pressure and base deficit. None of these changes was observed in the control group. Interleukin‐1β and vascular endothelial growth factor increased in both groups. Nitric oxide measurements suggested an initial pulmonary vascular endothelial inflammatory response. The intrapulmonary group, which did not resemble septic condition, showed a substantial increase in MMP‐9. In this porcine model of sepsis, IL‐12 and MMP‐9 were detected for the first time. These biomarkers may have an impact in the understanding and future treatment of sepsis.
Statice Virus Y ‐ a Virus related to Bean Yellow Mosaic and Clover Yellow Vein Viruses
Authors: Lesemann D.‐E. , Koenig R. , Hein A.
Published: May 2008

The authors are greatly indebted to the Deutsche Forschungsgemeinschaft for financial support, to Miss B. Murthlm, Mrs. U. Herzberg, Mrs. B. Hane and Miss P. Rahse for reliable technical assistance and to Dr. M. Hollings, Dr. R. O. Hampton and Mr. D. Z. Maat for gifts of antisera.
Mechanical Transmission of Soil‐borne Barley Yellow Mosaic Virus
Authors: Friedt W.
Published: May 2008

Leaves of winter barley (Hordeum vulgare L.) cv. Gerbel were mechanically sap‐inoculated with Barley Yellow Mosaic Virus (BaYMV). Different additives to the inoculation fluid were tested. Whereas the dilution of plant sap by water alone resulted in an infection rate of 43%, the addition of sodium sulphite (80 %) and potassium phosphate‐buffer (89%) increased the proportion of infected plants substantially. Infectivity was further increased by repeated inoculation, when sodium sulphite yielded 96 % and potassium phosphate 100% of infection. The usefulness of the technique in further research and application is discussed.
The Hypersensitive Reaction in Tobacco Leaf Tissue infiltrated with Pseudomonas pisi 5. Inhibition of RNA Synthesis in Mesophyll Cells
Authors: Al‐Issa A. N. , Sigee D. C.
Published: May 2008

The synthesis of mesophyll cell RNA in tobacco leaf tissue infiltrated with the incompatible bacterium Pseudomonas pisi was investigated by light and electron microscope autoradiography of H3‐uridine uptake.

Interpretation of the light microscope quantitative data was complicated by the oscillation in levels of cytoplasmic RNA synthesis that resulted from the physical process of fluid infiltration (seen in the control tissue). Direct comparison with the control showed that the presence of bacteria resulted in a rapid decrease in the synthesis of host cell RNA. This effect was clear within the first 1½h (induction period) of the hypersensitive reaction, where it was particularly marked in the cytoplasm of palisade cells. Electron microscope autoradiography showed that the presence of bacteria did not cause complete cessation of RNA synthesis in mitochondria and chloroplasts.

The early inhibition of RNA synthesis preceeded fine structural (degenerative) change, and should be regarded as one of the primary events associated with the induction of host cell necrosis.
Changes in Respiration of Seedling Roots Inoculated with Phytophthora cinnamomi
Authors: Cahill D. , Weste Gretna
Published: May 2008

An increase in rate of respiration was recorded for intact roots of seven native Australian species 16 h after inoculation with Phytophthora cinnamomi. By 24 h the magnitude of the increase ranged from 2—159% above that of the uninoculated controls and was evidently not related to host susceptibility. A time sequence study of lesion extension and the associated increased respiration rates for both susceptible and tolerant eucalypts demonstrated a difference in response. The rate of respiration in the tolerant species increased 2 % and only at the site of inoculation, whereas in the susceptible species the respiration rate increased in a wave which began at the inoculation site and continued along the root with the advancing fungal invasion. Respiration rate only increased in regions of the root actually inhabited by the pathogen.

The fungal contribution to the total respiration of infected roots was less than 1 % and was determined by measuring respiration of inoculated killed roots.

Respiration rates were measured in the presence of potassium cyanide (KCN) and salicylhydroxamic acid (SHAM). Both KCN‐sensitive and SHAM‐sensitive respiration occurred in normal uninfected E. marginate seedlings. A large proportion of the increase in total respiration rate of infected seedlings compared with uninoculated controls was due to the alternate, SHAM‐sensitive pathway. The physiological implications of these results are discussed.
Natural Occurrence of Helenium Virus S in Impatiens holstii
Authors: Koenig R. , Lesemann D.‐E. , Lockhart B. , Betzold J. A. , Weidemann H. L.
Published: May 2008

Samples of commercially grown Impatiens holstii from several sources in Minnesota contained a carlavirus which serologically was closely related, if not identical with Helenium virus S described earlier in Germany. The two viruses have similar experimental host ranges and caused similar cytopathogenic effects. After mechanical transmission the Impatiens isolate produced less severe symptoms in Impatiens than the Helenium isolate. Only the latter isolate was transmitted by Myzus persicae in the non‐persistent manner.
Antimicrobial Activity of Leaf Extracts of Polyalthia longifolia
Authors: Annapurna Y. , Mitra Sakti , Iyengar D. S. , Rao S. Nagabushan , Bhalerao U. T.
Published: May 2008

Leaf extracts of P. longifolia with different solvents of increasing polarity were tested against some pathogenic fungi and bacteria. The nature of the active compound is briefly discussed in view of the observed activity in methanol extracts.
Effect of Bacillus subtilis on Growth and Protection of Onion against White Rot
Authors: Utkhede R. S. , Rahe J. E.
Published: May 2008

The effect of isolates of Bacillus subtilis applied as seed treatments on plant growth and white rot on three onion cultivars was studied for two seasons on muck soil of Fraser valley of British Columbia. The isolates of B. subtilis provided significant season‐long protection against onion white rot on all three cultivars. The most effective isolate (BACT 2) protected the onion cultivar Autumn spice against onion white rot in both years. plant height, number of leaves per plant, and bulb weight were not affected by treating seeds with the Bacillus isolates. Bulb neck diameter of the cultivar Autumn Spice was significantly reduced by two isolates in both seasons.
Dispersal of Pseudocercosporella herpotrichoides Spores from Infected Wheat Straw
Authors: Fitt B. D. L. , Bainbridge A.
Published: May 2008

Evidence from spore samples collected amongst infected straw spread on fallow ground supported the conclusion that spores of Pseudocercosporella herpotrichoides are dispersed mostly by rainsplash. Most spores travelled a short distance in the larger ballistic splash droplets, although some may have travelled further in smaller airborne droplets.

Weekly spore counts from microscope slides under rainshields, a funnel and an impinger, evaluated as samplers for spores of P. herpotrichoides, showed a similar seasonal pattern. The funnel, as the largest sampler, generally collected most spores, but the impinger collected more spores per unit area of sampling surface. Slides sometimes collected spores when none was recovered from other samplers. Young wheat plants, exposed with the samplers and changed weekly, subsequently developed eyespot symptoms for most of the season.
The Particle Length of an Isolate of Apple Chlorotic Leafspot Virus from Prunus domestica
Authors: Thomas B. J.
Published: May 2008

The modal length of an isolate of apple chlorotic leafspot virus (CLSV) from Prunus domestica was determined by serologically specific electron microscopy. Particles adsorbed from leaf sap extracts (modal length c. 825 nm) were longer than those adsorbed from purified virus preparations (modal length c. 795 nm). Particles of a CLSV isolate from apple, however, had a modal length of only c. 700 nm.
Wirkung von Virushemmstoffen auf die Infektion von Tabakprotoplasten mit dem Tabakmosaik‐Virus
Authors: von Sydow B. , Hein A.
Published: May 2008

Effects of virus inhibitors on the infection of tobacco protoplasts with tobacco mosaic virus

Yeast extract inhibits the infection of Nicotiana glutinosa plants with tobacco mosaic virus (TMV), whereas in N. sandérae yeast extract is not effective. This phenomena was compared with the effect of yeast extract on protoplasts, and on the infection of protoplasts of both tobacco species with TMV. Additionally, skim milk and ribonuclease were included in the experiments as further inhibitors of early stages of virus infection. It was examined whether these inhibitors damage non‐inoculated protoplasts (a), and whether they affect virus infections in protoplasts as they do in cells of intact plants (b).

To investigate protoplast damage by the inhibitors, conductivity measurements of protoplast suspensions containing inhibitors, and the ability of protoplasts for cell wall regeneration after treatment with the inhibitors, were used. Inhibitor concentrations which prevent virus infections in plants did not damage the protoplasts.

The inhibitor effect on the course of infection was investigated by protoplast treatments before, during and after inoculation with TMV, and by addition of the substances to the culture medium. Measurements of virus content in protoplasts after cultivation revealed different results for the three inhibitors, however, there was no difference in the response of protoplasts from the two tobacco species to yeast extract. It is concluded that there are principal differences between the inhibition of plant and protoplast infections. Therefore, it is unlikely that protoplasts are a useful system for the mode of action studies on inhibitors of early stages of virus infection in plants.
Cytopathology of Shoot Apical Meristem of Hop Plants Infected with Hop Stunt Viroid11)
Authors: Momma T. , Takahashi T.
Published: May 2008

Shoot apical meristems of hop plants infected with hop stunt viroid (HSV) were examined for cytopathic changes. No measurable changes in ultrastructure were found in shoot tip 0.2 mm long bearing apical dome and two pairs of the primordia, whereas in the 3rd leaf primordium cell walls were undulate and/or frequently were irregular in thickness. These cell wall abnormalities were not observed in comparable shoot tips of the uninoculated hop plants or HSV‐free hop plants obtained by meristem tip culture.