bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute urethritis caused by Neisseria meningitidis
Authors: KANEMITSU NORIYUKI , HAYASHI ISSEI , SATOH NODOKA , HAYAKAWA TAKAHIRO , MITSUYA HIDEO , HAYASE YOSIMASA , HIRAMOTO KEN , KOJIMA MUNEKADO
Published: May 2003

A 48‐year‐old heterosexual Japanese man visited the outpatient clinic of Nagoya Urology Hospital, complaining of burning pain at voiding and pus discharge from the urethral orifice. These symptoms appeared the day following oral‐genital contact (fellatio) with a commercial sex worker. On the basis of the presumptive clinical diagnosis of gonorrhea because of the microscopic detection of diplococci in the urethral discharge, he was treated with levofloxacin (300 mg per day) for 7 days. His symptoms responded quickly and urinalysis taken 7 days later was normal. Microbiological examinations isolated Neisseria meningitidis in the urethral discharge by culture with the use of enzymatic profiles. Further prevalence of sexually transmitted diseases (STD) through oral‐genital contact would lead to an increase in meningococcal urethritis.
Transition zone biopsy and prediction of extraprostatic extension at radical prostatectomy
Authors: ÖNDER ALI ULVI , YAYCIOGLU OZGUR , ATAUS SULEYMAN , GUL UMIT , DEMIRKESEN OKTAY , YALCIN VELI , SOLOK VURAL
Published: May 2003

Background: There is limited data in the literature that suggests that transition zone (TZ) biopsy might be useful for the prediction of extraprostatic extension (EPE) in clinically localized prostate cancer. We studied the role of TZ biopsy in the prediction of EPE.

Methods: Transition zone biopsies were performed in addition to systematic peripheral zone (PZ) biopsies between November 1995 and December 1999. During this period, 59 patients underwent radical prostatectomy for clinically localized disease. Final pathological results were compared with preoperative clinical and biopsy findings.

Results: Of the 59 patients who underwent radical prostatectomy, 46 had cancer only in the PZ cores and 13 had cancer both in the PZ and the TZ cores at the biopsy. Final histopathological results revealed EPE in 19 (32%) patients and positive surgical margins in 22 (37%). In univariate analysis of age, prostate‐specific antigen (PSA), mean percentage of positive PZ cores, mean biopsy Gleason score and positive TZ biopsy, there was a significant difference for serum PSA levels (P = 0.021), presence of positive TZ cores (P = 0.018) and percentage of positive PZ cores in patients with and without EPE (P < 0.001). In multivariate analysis, the single independent predictor of EPE was the percentage of positive PZ biopsy cores (P = 0.0227). There was agreement between the side of positive TZ biopsy and EPE in seven of eight patients.

Conclusion: Taking two TZ cores in addition to peripheral sextant biopsy did not result in better prediction of EPE. The relationship between TZ involvement and the presence of EPE can be investigated further in radical prostatectomy specimens.
Japan's share of research output in urology and nephrology
Authors: RAHMAN MAHBUBUR , SAKAMOTO JUNICHI , FUKUI TSUGUYA
Published: May 2003

Background: Recent studies have documented Japan's share of articles in different biomedical fields. However, Japan's contribution to urology and nephrology is not known.

Methods: Seven journals in this field with the highest impact factors were selected to obtain relevant data. In June 2002, we searched the Medline database to obtain country affiliation details of articles published in the selected journals during 1991–2000. The proportion of articles with a higher grade of evidence (randomized controlled trials or clinical trials, cohort studies and case‐control studies) were also generated and compared to the average values for all articles published in these journals.

Results: Of the total number of articles (22 232), Japan's share of research output for the selected journals in urology and nephrology was 6% (1335 articles) and it ranked second in the world following the USA (56.5%). The recent increase in the share was statistically significant for Japan, Austria, France, Germany, Spain and Turkey. The proportion of articles with a high grade of evidence was lower for articles originated in Japan than for the total number of articles.

Conclusion: Japan's contribution to urology and nephrology research is within the range of its contribution to other biomedical fields. However, the number of high quality clinical research conducted in Japan in this field was small.
Experience with flexible video cystoscope equipped with built‐in high‐frequency cauterizing element for transurethral resection of the bladder
Authors: KAWAKAMI MASAKO , ISHIKAWA MASAKUNI , FURIHATA MASAYUKI , KONTANI KAZUHIKO , KOBAYASHI SHINYA , IIJIMA KAZUYOSHI , NISHIZAWA OSAMU
Published: May 2003

We successfully treated three patients using the flexible video cystoscope (CYF‐240A, Olympus, Japan) for superficial bladder cancer under local anesthesia and/or spinal anesthesia. The major advantage of this new technique is that surgeons can use digital pictures and high frequency cauterization. This new system provides good quality of life for bladder cancer patients experiencing frequent recurrences.
Molecular and cytological investigations of phosphoglucomutase (PGM1) in the K562 cell line
Authors: TOMKINS J. , FOX M. , LOVEGROVE J. U. , PARRINGTON J. , HOPKINSON D. A. , WHITEHOUSE D. B.
Published: May 2003

Phosphoglucomutase 1 (PGM1) deficiency is a stable characteristic of the erythroleukaemic cell line, K562, whereas the activity of the isozymes of the other two PGM loci (PGM2 and PGM3) is slightly elevated. In this study the molecular basis of PGM1 deficiency was investigated by a combined approach utilising protein electrophoresis, immunodetection, cytogenetic techniques, and DNA and RNA analysis. Isoelectric focusing and activity staining confirmed that K562 has no detectable PGM1 activity. Immunoblot analysis of extracts, separated by isoelectric focusing, starch gel and SDS gel electrophoresis, using monospecific anti‐PGM1 antibodies showed that K562 contained no detectable immunoreactive material. Karyotype analysis revealed the presence of two intact chromosomes 1 and a derivative chromosome 1, der(1)t(1; 11), each of which carried a copy of the PGM1 gene as demonstrated by fluorescence in situhybridization using a PGM1 cosmid as probe. Southern blot analysis using a PGM1 cDNA clone as probe suggested that the PGM1 genes had not been subject to any gross structural rearrangements. We were also able to determine that K562 is type PGM1 2+1+ by restriction endonuclease analysis of genomic DNA. Very low levels of PGM1 mRNA which appeared to be full length transcripts were detected in K562 using a reverse transcriptase PCR technique. We conclude that the most likely cause of PGM1 enzyme deficiency in K562 is abnormal regulation of transcription.
Enrichment of Hepatic Progenitor Cells From Adult Mouse Liver
Authors: Azuma Hisaya , Hirose Tetsuro , Fujii Hideaki , Oe Shoshiro , Yasuchika Kentaro , Fujikawa Takahisa , Yamaoka Yoshio
Published: May 2003

Hepatic progenitor cells (HPCs) have been characterized in several drug–treated rodent models and in the fetal liver; however, their properties have not been fully clarified in the normal adult liver, presumably because of their relatively small population and the existence of mature hepatocytes. In an attempt to resolve this issue, we developed a new enrichment system for HPCs using their cell aggregate formation properties. Nonparenchymal cells (NPCs) derived from enzymatically digested liver cells in normal adult mouse liver were treated in a hypoxic 2–hour suspension culture under constant shaking. This procedure resulted in cell aggregate formation and almost complete elimination of mature hepatocytes. Cell aggregates were formed only in Ca2+–containing medium, suggesting cadherin–dependent cell–cell adhesion. In these cell aggregates, 95% consisted of vascular endothelial cells that expressed VE–cadherin. The remaining 5% consisted of rapidly proliferating, small epithelial cells that expressed α–fetoprotein (AFP), E–cadherin, and albumin but not cytokeratin 19 (CK19), α–smooth muscle actin, or VE–cadherin. These results are consistent with an immature hepatic cell phenotype. When these immature hepatic cells were cultured with 10-7 mol/L dexamethasone and 1% dimethyl sulfoxide, the de novo expression of mature hepatocyte markers such as tryptophan–2,3–dioxygenase (TO) was induced concomitantly with the induction of morphologic characteristics such as mitochondria– and peroxisome–rich cytoplasm and bile canaliculi formation. In conclusion, our methodology allows the enrichment of immature hepatic cells from the normal adult mouse. These cells are capable of growth and maturation along the hepatocyte lineage, indicating that these cells are HPCs.
Steroid–Free Chemotherapy Decreases Risk of Hepatitis B Virus (Hbv) Reactivation in Hbv–Carriers With Lymphoma
Authors: Cheng Ann-Lii , Hsiung Chao A. , Su Ih-Jen , Chen Pei-Jer , Chang Ming-Chih , Tsao Chao-Jung , Kao Woei-Yao , Uen Wu-Ching , Hsu Chih-Hung , Tien Hwei-Fan , Chao Tsu-Yi , Chen Li-Tzong , Whang-Peng Jacqueline
Published: May 2003

Reactivation of hepatitis is one of the most serious complications of chemotherapy in lymphoma patients who are carriers of the hepatitis B virus (HBV). Glucocorticoids are linked to increased risk of HBV reactivation. This study seeks to clarify whether removal of glucocorticoids from chemotherapy regimens may decrease the risk of HBV reactivation. Eligible patients were seropositive for hepatitis B surface antigen (HBsAg) and had histologically proven non–Hodgkin's lymphomas for which intensive chemotherapy was indicated. Patients were randomized to receive either ACE (epirubicin, cyclophosphamide, and etoposide) or PACE (prednisolone + ACE). A total of 50 patients were enrolled, 25 each for the ACE and PACE arms. The cumulative incidence of HBV reactivation at 9 months after starting chemotherapy was 38% and 73% for ACE and PACE arm, respectively (P = .03). The degree of clinical hepatitis was significantly more severe in the PACE arm: 11 patients (44%) in the PACE and 3 patients (13%) in the ACE arm had ALT elevation more than 10–fold of normal (P = .025), and 7 patients (28%) in the PACE and 1 patient (4%) in the ACE arm had icteric hepatitis (P = .049). Complete remission of tumors occurred in 11 (46%) patients in the PACE and 8 (35%) patients in the ACE arm (P = .556). The estimated overall survival rate at 46 months was 68% in the PACE arm and 36% in the ACE arm, respectively (P = .18). In conclusion, steroid–free chemotherapy decreases the incidence and severity of HBV reactivation in HBsAg–positive lymphoma patients. However, further research is needed to evaluate whether steroid–free chemotherapy may confer a less satisfactory control of lymphoma.
Active Immunization Against De Novo Hepatitis B Virus Infection in Pediatric Patients After Liver Transplantation
Authors: Chang Seong-Hwan , Suh Kyung-Suk , Yi Nam-Joon , Choi Seok Ho , Lee Hoan Jong , Seo Jeong Kee , Lee Kuhn Uk
Published: May 2003

The shortage of donor organs occasionally mandates the use of hepatic allografts from anti–HBc (+) donors. HBIG and/or lamivudine are recommended for the prevention of de novo HBV infection in naive patients, but there are attendant problems, such as mutant strain emergence and high cost. Active immunization presents a better alternative than the use of HBIG or lamivudine, if it can be proven to be effective. Accordingly, we investigated the outcome of HBV vaccination in pediatric hepatic transplant recipients. Between July 1999 and October 2001, 19 pediatric recipients were administered HBV vaccinations after liver transplantation at Seoul National University Hospital. Nine patients received a graft from anti–HBc (+) donors and 10 from anti–HBc (-) donors. When steroid was withdrawn, recombinant HBV vaccine was administered. The median follow–up period after vaccination was 10.0 ± 5.2 months. Seventeen of the 19 patients showed a positive response to vaccination. In 9 patients who received grafts from anti–HBc (+) donors, 2 patients showed no response, 4 patients low response (peak HBsAb titer <1,000 IU/L), and 3 patients high response (peak HBsAb titer ≥1,000 IU/L). De novo HBV infection developed in 1 of 2 patients who showed no response to vaccination. In 10 patients who received grafts from anti–HBc (-) donors, 5 showed a low response and 5 a high response. In conclusion, HBV vaccination in pediatric patients after liver transplantation appeared to exhibit some effectiveness at protecting young children that received a graft from anti–HBc (+) donors from de novo HBV infection.
Proteasome Inhibition Potentiates Cyp2e1–Mediated Toxicity in Hepg2 Cells
Authors: Pérez María José , Cederbaum Arthur I.
Published: May 2003

Chronic ethanol consumption causes increased oxidative damage in the liver. Induction of CYP2E1 is one pathway involved in how ethanol produces oxidative stress. Ethanol can cause protein accumulation, decreased proteolysis, and decreased proteasome activity. The objective of this study was to investigate the effect of inhibition of the proteasome activity on CYP2E1–dependent toxicity. HepG2 cells over–expressing CYP2E1 (E47 cells) were treated with arachidonic acid (AA) plus iron, agents important in development of alcoholic liver injury and which are toxic to E47 cells by a mechanism dependent on CYP2E1, oxidative stress, and lipid peroxidation. Addition of various proteasome inhibitors was associated with significant potentiation of the loss of cell viability caused by AA plus iron. Potentiation of toxicity was associated with increased oxidative damage as reflected by an increase in lipid peroxidation and accumulation of oxidized and nitrated proteins in E47 cells and an enhanced decline in mitochondrial membrane potential. Antioxidants prevented the loss of viability and the potentiation of this loss of viability by proteasome inhibition. CYP2E1 levels were elevated about 3–fold by the proteasome inhibitors. Inhibition of proteasome activity also potentiated toxicity of AA alone and toxicity after treatment to remove glutathione (GSH). Similar results were found in hepatocytes from pyrazole–treated rats with high levels of CYP2E1. In conclusion, proteasome activity plays an important role in modulating CYP2E1–mediated toxicity in HepG2 cells by regulating CYP2E1 levels and by removal of oxidized proteins. Such interactions may be important in CYP2E1–catalyzed toxicity of hepatotoxins and in alcohol–induced liver injury.
All Liver Recipients Benefit From the Protocol 10–Year Liver Biopsies
Authors: Sebagh Mylène , Rifai Kinan , Féray Cyrille , Yilmaz Funda , Falissard Bruno , Roche Bruno , Bismuth Henri , Samuel Didier , Reynès Michel
Published: May 2003

The value of late protocol biopsies after liver transplantation remains to be evaluated to highlight the therapeutic policies. The study population was composed of patients who survived with the initial graft and with an available 10–year protocol biopsy (n = 143). The long–term histologic outcome of the graft, particularly the rate of ductopenia in cases with chronic rejection (CR), and Metavir scoring of fibrosis in cases with viral chronic hepatitis (VCH), were assessed. Fibrosis progression (FP) rates were compared over 3 periods (0–5, 5–10, and 0–10 years). At 10 years, histologic abnormalities present in 80% of the patients were not identifiable from liver function tests (LFTs), which were strictly normal in 52% of the patients. Histologic CR occurred in 24% at 10 years, with a mean rate of ductopenia higher at 10 years than at 5 years (49% vs. 34%, P < .001). In cases of VCH, fibrosis worsened, with a median FP rate of 0.20 fibrosis units/year. During the first 5 years, FP was as follows; hepatitis B virus infection was greater than recurrent hepatitis C virus (HCV) infection, which was greater than acquired HCV infection (P = .029). In patients with HCV, FP was higher during the second 5–year period than during the first one (P = .042). In conclusion, given the high prevalence of histologic abnormalities and the lack of sensitivity and specificity of LFTs, late protocol biopsies clearly are justified to adjust treatments, not only in HCV–infected patients in whom FP was fast and not linear, but also in the whole population of recipients.
Glucagon Induces the Plasma Membrane Insertion of Functional Aquaporin–8 Water Channels in Isolated Rat Hepatocytes
Authors: Gradilone Sergio A. , García Fabiana , Huebert Robert C. , Tietz Pamela S. , Larocca Cecilia M. , Kierbel Arlinet , Carreras Flavia I. , LaRusso Nicholas F. , Marinelli Raúl A.
Published: May 2003

Although glucagon is known to stimulate the cyclic adenosine monophosphate (cAMP)–mediated hepatocyte bile secretion, the precise mechanisms accounting for this choleretic effect are unknown. We recently reported that hepatocytes express the water channel aquaporin–8 (AQP8), which is located primarily in intracellular vesicles, and its relocalization to plasma membranes can be induced with dibutyryl cAMP. In this study, we tested the hypothesis that glucagon induces the trafficking of AQP8 to the hepatocyte plasma membrane and thus increases membrane water permeability. Immunoblotting analysis in subcellular fractions from isolated rat hepatocytes indicated that glucagon caused a significant, dose–dependent increase in the amount of AQP8 in plasma membranes (e.g., 102% with 1 μmol/L glucagon) and a simultaneous decrease in intracellular membranes (e.g., 38% with 1 μmol/L glucagon). Confocal immunofluorescence microscopy in cultured hepatocytes confirmed the glucagon–induced redistribution of AQP8 from intracellular vesicles to plasma membrane. Polarized hepatocyte couplets showed that this redistribution was specifically to the canalicular domain. Glucagon also significantly increased hepatocyte membrane water permeability by about 70%, which was inhibited by the water channel blocker dimethyl sulfoxide (DMSO). The inhibitors of protein kinase A, H–89, and PKI, as well as the microtubule blocker colchicine, prevented the glucagon effect on both AQP8 redistribution to hepatocyte surface and cell membrane water permeability. In conclusion, our data suggest that glucagon induces the protein kinase A and microtubule–dependent translocation of AQP8 water channels to the hepatocyte canalicular plasma membrane, which in turn leads to an increase in membrane water permeability. These findings provide evidence supporting the molecular mechanisms of glucagon–induced hepatocyte bile secretion.
Elevated Hepatocyte Levels of the Forkhead Box A2 (Hnf–3β) Transcription Factor Cause Postnatal Steatosis and Mitochondrial Damage
Authors: Hughes Douglas E. , Stolz Donna Beer , Yu Songtao , Tan Yongjun , Reddy Janardan K. , Watkins Simon C. , Diehl Anna Mae , Costa Robert H.
Published: May 2003

The Forkhead box (Fox) transcription factor Foxa2 (HNF–3β) and related family members Foxa1 (HNF–3α) and Foxa3 (HNF–3γ) act in concert with other hepatocyte nuclear factors (HNF) to coordinately regulate liver–specific gene expression. To circumvent the hepatic functional redundancy of the Foxa proteins, we used the T–77 transgenic (TG) mouse line in which the -3–kb transthyretin (TTR) promoter functioned to increase hepatocyte expression of the Foxa2 cDNA. Adult TG mice exhibited reduced hepatic glycogen and progressive liver injury, but maintained normal serum levels of glucose, insulin, and glucagon. In this study, we further characterized the postnatal liver defect in TTR–FoxA2 TG mice. The postnatal TG mice displayed significant reduction in serum glucose levels and in hepatocyte glycogen storage without increased serum levels of ketone bodies and free fatty acid suggesting that they are not undergoing a starvation response. We show that TG liver developed a substantial transient steatosis, which reached a maximum at postnatal day 5 and is associated with increased expression of hepatic genes involved in fatty acid and triglyceride synthesis, lipid β–oxidation, and amino acid biosynthesis. Furthermore, transmission electron microscopy analysis of postnatal TG liver revealed extensive mitochondrial membrane damage, which is likely due to reactive oxygen species generated from lipid β–oxidation. In conclusion, our model proposes that in response to reduction in hepatocyte glycogen storage, the TTR–Foxa2 TG mice survive by maintaining sufficient serum levels of glucose through gluconeogenesis using deaminated amino acids with dicarboxylate products of peroxisomal lipid β–oxidation shuttled through the tricarboxylic acid cycle.
The Global Trend towards Devolution and its Implications
Authors: Rodríguez-Pose Andrés , Gill Nicholas
Published: June 2003

Globalisation has been accompanied by an equally global tendency towards devolution of authority and resources from nation-states to regions and localities that takes on various forms, depending upon which actors are driving the decentralisation efforts. The existence of a general trend towards devolution also has significant implications for efficiency, equity, and administration. The authors outline first the general drive towards devolution and then proceed to examine which countries are experiencing which forms of decentralisation. A theoretical argument emphasising the role of governmental legitimacy across various tiers of government is used to explain the diversity of devolution initiatives, drawing on examples that include Brazil, Mexico, India, China, the USA, and some European countries. Having supported their model of decentralisation, the authors then examine the implications of the widespread downward transfer of power towards regions. Some of the less widely discussed pitfalls of decentralisation are presented; caution in promoting devolutionary efforts is the prescription of this paper.
Attention Affects the Stereoscopic Depth Aftereffect
Authors: Rose David , Bradshaw Mark F , Hibbard Paul B
Published: June 2003

‘Preattentive’ vision is typically considered to include several low-level processes, including the perception of depth from binocular disparity and motion parallax. However, doubt was cast on this model when it was shown that a secondary attentional task can modulate the motion aftereffect (Chaudhuri, 1990 Nature344 60–62). Here we investigate whether attention can also affect the depth aftereffect (Blakemore and Julesz, 1971 Science171 286–288). Subjects adapted to stationary or moving random-dot patterns segmented into depth planes while attention was manipulated with a secondary task (character processing at parametrically varied rates). We found that the duration of the depth aftereffect can be affected by attentional manipulations, and both its duration and that of the motion aftereffect varied with the difficulty of the secondary task. The results are discussed in the context of dynamic feedback models of vision, and support the penetrability of low-level sensory processes by attentional mechanisms.
Does the Bandpass Linear Filter Response Predict Gradient Lightness Induction? A Reply to Fred Kingdom
Authors: Logvinenko Alexander D
Published: June 2003

It is argued that lightness illusions induced by luminance gradient cannot be accounted for by the response of a bandpass linear filter as recently claimed by Kingdom ( Perception28 929–934).
The Venus Effect: People's Understanding of Mirror Reflections in Paintings
Authors: Bertamini Marco , Latto Richard , Spooner Alice
Published: June 2003

We propose the term ‘Venus effect’ for a common phenomenon in picture perception. It occurs when a picture shows an actor and a mirror that are not placed along the observer's line of sight, for instance a Venus admiring herself in a small mirror, and when the actor's reflection in the mirror is visible to the observer. In this situation, observers tend to report, incorrectly, that Venus is also seeing herself in the mirror in the same location as the observer. We discuss this using famous paintings as examples.
Perceived Shifts of Flashed Stimuli by Visible and Invisible Object Motion
Authors: Watanabe Katsumi , Sato Takashi R , Shimojo Shinsuke
Published: June 2003

Perceived positions of flashed stimuli can be altered by motion signals in the visual field—position capture (Whitney and Cavanagh, 2000 Nature Neuroscience3 954–959). We examined whether position capture of flashed stimuli depends on the spatial relationship between moving and flashed stimuli, and whether the phenomenal permanence of a moving object behind an occluding surface (tunnel effect; Michotte 1950 Acta Psychologica7 293–322) can produce position capture. Observers saw two objects (circles) moving vertically in opposite directions, one in each visual hemifield. Two horizontal bars were simultaneously flashed at horizontally collinear positions with the fixation point at various timings. When the movement of the object was fully visible, the flashed bar appeared shifted in the motion direction of the circle. But this position-capture effect occurred only when the bar was presented ahead of or on the moving circle. Even when the motion trajectory was covered by an opaque surface and the bar was flashed after complete occlusion of the circle, the position-capture effect was still observed, though the positional asymmetry was less clear. These results show that movements of both visible and ‘hidden’ objects can modulate the perception of positions of flashed stimuli and suggest that a high-level representation of ‘objects in motion’ plays an important role in the position-capture effect.
Performance of Myzus persicae (Hemiptera: Aphididae) clones on different host-plants and their host preference
Authors: Nikolakakis N.N. , Margaritopoulos J.T. , Tsitsipis J.A.
Published: May 2003

The performance of eighteen clones of Myzus persicae (Sulzer) on pepper and tobacco plants at 20°C and L16:D8 and the choice of young adult apterae between tobacco and pepper leaf-discs were examined. The clones were collected from weeds and peach in two tobacco-growing regions: Katerini, northern Greece and Karditsa, central Greece (only from weeds) and from Lehonia, central eastern Greece where tobacco is not cultivated. All clones did well on both hosts. However, the analysis of data revealed a significant effect of ‘region / host plant origin’ on aphid performance. The mean values of adult weight, intrinsic rate of increase and fecundity of the clones collected in Lehonia and reared on tobacco were significantly lower than the observed values for clones from Katerini and Karditsa. Aphids from Lehonia had significantly higher mean values for developmental time on tobacco than clones from the other regions whereas the opposite was observed when aphids were reared on pepper. Aphids collected in Lehonia performed better on pepper than those originating from the tobacco-growing regions. A choice test revealed differences among the clones originating from different regions. Fifty three percent and 43% of aphids from weeds and peach from Lehonia, respectively, chose pepper. By comparison 41.5% and 40.0% of aphids from peach and weeds from Katerini, respectively and 49.5% of aphids from Karditsa preferred tobacco. The results are discussed in relation to host specialization in M. persicae.
Evidence for host-associated clones of grape phylloxera Daktulosphaira vitifoliae (Hemiptera: Phylloxeridae) in Australia
Authors: Corrie A.M. , van Heeswijck R. , Hoffmann A.A.
Published: May 2003

Grape phylloxera, Daktulosphaira vitifoliae Fitch, is an important pest of grapevines (Vitis vinifera L.) (Vitaceae). Using microsatellite DNA markers it was demonstrated strong associations can exist between D. vitifoliae asexual lineages and vine host type within a vineyard. Also, in excised root bioassays, D. vitifoliae collected from three regions where different genotypic classes predominated showed host-specific differences in life table parameters of reproductive rate and intrinsic rate of increase. Lastly, comparisons of mitochondrial DNA (cytochrome oxidase I) sequences revealed that D. vitifoliae in Australia have paraphyletic origins and fall into two clades partially related to vine host usage. These findings indicate introduction of separate lineages of D. vitifoliae which have close host associations and as such, have important implications for management of this pest in Australia.
Insecticide-treated cattle against tsetse (Diptera: Glossinidae): what governs success?
Authors: Hargrove J.W. , Torr S.J. , Kindness H.M.
Published: May 2003

The distributions of insecticide-treated cattle from sites in Tanzania and Zimbabwe were assessed from interviews with livestock owners, analysis of secondary livestock data and mapping technologies. The time-course of tsetse control operations at these sites were then simulated using a mathematical model that assumed diffusive movement and logistic growth in fly populations. A simulation of a tsetse control operation in Mudzi district, north-east Zimbabwe, was in accord with observations that the use of insecticide-treated cattle was unable to prevent substantial re-invasion of tsetse from Mozambique, consequent on the patchy distribution of cattle. The simulation was also consistent with the observed efficacy of a 10-km wide barrier of insecticide-treated targets deployed evenly at 4 km−2. Simulation of a control operation on Mkwaja Ranch in Tanzania was in accord with the observation that the use of insecticide-treated cattle reduced the tsetse population on the ranch by c. 90%. Insecticide-treated cattle were used to better effect in the Kagera Region of Tanzania. Simulation of this operation predicts that the deployment of 35,000 treated cattle in the area would result in > 99% control of the tsetse population, consistent with the observed decline, by 1–2 orders of magnitude, in cases of trypanosomiasis in the region. The greater success of the Kagera operation was due to the size and shape of the treated area and, particularly, to the restriction of re-invasion to 20% of the perimeter, compared with > 80% on Mkwaja. Simulation was used to assess how tsetse control could have been improved at Mkwaja. The results suggest that splitting herds into smaller, more numerous, units could have achieved some improvement but, in general, the disease problem would not have been solved by the use of insecticide-treated cattle alone. Only by deploying odour-baited targets in ungrazed areas, or in a 1–3-km barrier around the ranch, could substantially better control (99–99.9%) have been achieved. Sensitivity analyses of the Mkwaja simulation showed that the general conclusions were robust to assumptions regarding cattle distribution and the rates of fly movement and growth. Properly managed and appropriately applied insecticide-treated baits are powerful weapons for tsetse control but should not be used without regard to potential levels of re-invasion, consequent largely on considerations of the size and shape of the treatment area and the density and distribution of the baits.
Controlled Damage in Thick Specimens by Multiphoton Excitation
Authors: Galbraith James A. , Terasaki Mark
Published: May 2003

Controlled damage by light energy has been a valuable tool in studies of cell function. Here, we show that the Ti:Sapphire laser in a multiphoton microscope can be used to cause localized damage within unlabeled cells or tissues at greater depths than previously possible. We show that the damage is due to a multiphoton process and made wounds as small as 1 μm in diameter 20 μm from the surface. A characteristic fluorescent scar allows monitoring of the damage and identifies the wound site in later observations. We were able to lesion a single axon within a bundle of nerves, locally interrupt organelle transport within one axon, cut dendrites in a zebrafish embryo, ablate a mitotic pole in a sea urchin egg, and wound the plasma membrane and nuclear envelope in starfish oocytes. The starfish nucleus collapsed ∼1 h after wounding, indicating that loss of compartmentation barrier makes the structure unstable; surprisingly, the oocyte still completed meiotic divisions when exposed to maturation hormone, indicating that the compartmentalization and translocation of cdk1 and its regulators is not required for this process. Multiphoton excitation provides a new means for producing controlled damage deep within tissues or living organisms.
MyoD Distal Regulatory Region Contains an SRF Binding CArG Element Required for MyoD Expression in Skeletal Myoblasts and during Muscle Regeneration
Authors: L'honore Aurore , Lamb Ned J. , Vandromme Marie , Turowski Patric , Carnac Gilles , Fernandez Anne
Published: May 2003

We show here that the distal regulatory region (DRR) of the mouse and human MyoD gene contains a conserved SRF binding CArG-like element. In electrophoretic mobility shift assays with myoblast nuclear extracts, this CArG sequence, although slightly divergent, bound two complexes containing, respectively, the transcription factor YY1 and SRF associated with the acetyltransferase CBP and members of C/EBP family. A single nucleotide mutation in the MyoD-CArG element suppressed binding of both SRF and YY1 complexes and abolished DRR enhancer activity in stably transfected myoblasts. This MyoD-CArG sequence is active in modulating endogeneous MyoD gene expression because microinjection of oligonucleotides corresponding to the MyoD-CArG sequence specifically and rapidly suppressed MyoD expression in myoblasts. In vivo, the expression of a transgenic construct comprising a minimal MyoD promoter fused to the DRR and β-galactosidase was induced with the same kinetics as MyoD during mouse muscle regeneration. In contrast induction of this reporter was no longer seen in regenerating muscle from transgenic mice carrying a mutated DRR-CArG. These results show that an SRF binding CArG element present in MyoD gene DRR is involved in the control of MyoD gene expression in skeletal myoblasts and in mature muscle satellite cell activation during muscle regeneration.
Tumor Necrosis Factor-α Stimulates the Epithelial-to-Mesenchymal Transition of Human Colonic Organoids
Authors: Bates Richard C. , Mercurio Arthur M.
Published: May 2003

An epithelial-mesenchymal transition (EMT) characterizes the progression of many carcinomas and it is linked to the acquisition of an invasive phenotype. Given that the tumor microenvironment is an active participant in tumor progression, an important issue is whether a reactive stroma can modulate this process. Using a novel EMT model of colon carcinoma spheroids, we demonstrate that their transforming-growth factor-β1 (TGF-β)-induced EMT is accelerated dramatically by the presence of activated macrophages, and we identify tumor necrosis factor-α (TNF-α) as the critical factor produced by macrophages that accelerates the EMT. A synergy of TNF-α and TGF-β signaling promotes a rapid morphological conversion of the highly organized colonic epithelium to dispersed cells with a mesenchymal phenotype, and this process is dependent on enhanced p38 MAPK activity. Moreover, exposure to TNF-α stimulates a rapid burst of ERK activation that results in the autocrine production of this cytokine by the tumor cells themselves. These results establish a novel role for the stroma in influencing EMT in colon carcinoma, and they identify a selective advantage to the stromal presence of infiltrating leukocytes in regulating malignant tumor progression.
Direct Interaction with Nup153 Mediates Binding of Tpr to the Periphery of the Nuclear Pore Complex
Authors: Hase Manuela E. , Cordes Volker C.
Published: May 2003

Tpr is a 267-kDa protein forming coiled coil-dominated homodimers that locate at the nucleoplasmic side of the nuclear pore complex (NPC). The proteins that tether Tpr to this location are unknown. Moreover, the question whether Tpr itself might act as a scaffold onto which other NPC components need to be assembled has not been answered to date. To assess Tpr's role as an architectural element of the NPC, we have studied the sequential disassembly and reassembly of NPCs in mitotic cells, paralleled by studies of cells depleted of Tpr as a result of posttranscriptional tpr gene silencing by RNA interference (RNAi). NPC assembly and recruitment of several nucleoporins, including Nup50, Nup93, Nup96, Nup98, Nup107, and Nup153, in anaphase/early telophase is shown to precede NPC association of Tpr in late telophase. In accordance, cellular depletion of Tpr by RNAi does not forestall binding of these nucleoporins to the NPC. In a search for proteins that moor Tpr to the NPC, we have combined the RNAi approach with affinity-chromatography and yeast two-hybrid interaction studies, leading to the identification of nucleoporin Nup153 as the binding partner for Tpr. The specificity of this interaction is demonstrated by its sensitivity to Tpr amino acid substitution mutations that abolish Tpr's ability to adhere to the NPC and affect the direct binding of Tpr to Nup153. Accordingly, cellular depletion of Nup153 by RNAi is shown to result in mislocalization of Tpr to the nuclear interior. Nup153 deficiency also causes mislocalization of Nup50 but has no direct effect on NPC localization of the other nucleoporins studied in this investigation. In summary, these results render Tpr a protein only peripherally attached to the NPC that does not act as an essential scaffold for other nucleoporins.
The AP-1 Clathrin-adaptor Is Required for Lysosomal Enzymes Sorting and Biogenesis of the Contractile Vacuole Complex inDictyosteliumCells
Authors: Lefkir Yaya , de Chassey Benoît , Dubois Annick , Bogdanovic Aleksandra , Brady Rebecca J. , Destaing Olivier , Bruckert Franz , O'Halloran Theresa J. , Cosson Pierre , Letourneur François
Published: May 2003

Adaptor protein complexes (AP) are major components of the cytoplasmic coat found on clathrin-coated vesicles. Here, we report the molecular and functional characterization of Dictyostelium clathrin-associated AP-1 complex, which in mammalian cells, participates mainly in budding of clathrin-coated vesicles from the trans-Golgi network (TGN). The γ-adaptin AP-1 subunit was cloned and shown to belong to a Golgi-localized 300-kDa protein complex. Time-lapse analysis of cells expressing γ-adaptin tagged with the green-fluorescent protein demonstrates the dynamics of AP-1–coated structures leaving the Golgi apparatus and rarely moving toward the TGN. Targeted disruption of the AP-1 medium chain results in viable cells displaying a severe growth defect and a delayed developmental cycle compared with parental cells. Lysosomal enzymes are constitutively secreted as precursors, suggesting that protein transport between the TGN and lysosomes is defective. Although endocytic protein markers are correctly localized to endosomal compartments, morphological and ultrastructural studies reveal the absence of large endosomal vacuoles and an increased number of small vacuoles. In addition, the function of the contractile vacuole complex (CV), an osmoregulatory organelle is impaired and some CV components are not correctly targeted.
p38 Mitogen-Activated Protein Kinase Mediates Cell Death and p21-Activated Kinase Mediates Cell Survival during Chemotherapeutic Drug-induced Mitotic Arrest
Authors: Deacon Karl , Mistry Pratibha , Chernoff Jonathan , Blank Jonathan L. , Patel Rajnikant
Published: May 2003

Activation of the mitotic checkpoint by chemotherapeutic drugs such as taxol causes mammalian cells to arrest in mitosis and then undergo apoptosis. However, the biochemical basis of chemotherapeutic drug-induced cell death is unclear. Herein, we provide new evidence that both cell survival and cell death-signaling pathways are concomitantly activated during mitotic arrest by microtubule-interfering drugs. Treatment of HeLa cells with chemotherapeutic drugs activated both p38 mitogen-activated protein kinase (MAPK) and p21-activated kinase (PAK). p38 MAPK was necessary for chemotherapeutic drug-induced cell death because the p38 MAPK inhibitors SB203580 or SB202190 suppressed cell death. Dominant-active MKK6, a direct activator of p38 MAPK, also induced cell death by stimulating translocation of Bax from the cytosol to the mitochondria in a p38 MAPK-dependent manner. Dominant active PAK suppressed this MKK6-induced cell death. PAK seems to mediate cell survival by phosphorylating Bad, and inhibition of PAK in mitotically arrested cells reduced Bad phosphorylation and increased apoptosis. Our results suggest that therapeutic strategies that suppress PAK-mediated survival signals may improve the efficacy of current cancer chemotherapies by enhancing p38 MAPK-mediated cell death.
Ykt6p Is a Multifunctional Yeast R-SNARE That Is Required for Multiple Membrane Transport Pathways to the Vacuole
Authors: Kweon Youngseok , Rothe Anca , Conibear Elizabeth , Stevens Tom H.
Published: May 2003

Intracellular membrane fusion requires that membrane-bound soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins on both vesicle and target membranes form a highly specific complex necessary to bring the membranes close in space. Ykt6p is a yeast R-SNARE protein that has been implicated in retrograde transport to the cis-Golgi compartment. Ykt6p has been also been found to fractionate with vacuole membranes and participate in a vacuolar SNARE complex in homotypic vacuole fusion. To investigate the role of Ykt6p in membrane traffic to the vacuole we generated temperature-sensitive mutations in YKT6. One mutation produces an early Golgi block to secretion, and overexpression of the SNARE protein Sft1p suppresses the growth and secretion defects of this mutation. These results are consistent with Ykt6p and Sft1p participating in a SNARE complex associated with retrograde transport to the cis-Golgi. A second set of mutations in YKT6 specifically affects post-Golgi membrane traffic to the vacuole, and the effects of these mutations are not suppressed by Sft1p overexpression. Defects are seen in carboxypeptidase Y sorting, alkaline phosphatase transport, and aminopeptidase I delivery, and in one mutant, overexpression of the SNARE protein Nyv1p suppresses the alkaline phosphatase transport defect. By mutationally separating early and late requirements for Ykt6p, our findings have revealed that Ykt6p is a R-SNARE protein that functions directly in the three biosynthetic pathways to the vacuole.
A comparison between linear and exponential schemes in control volume finite element method
Authors: Abbassi H. , Boughamoura A. , Ben Nasrallah S.
Published: May 2003

In this paper, we present a comparison of linear and exponential interpolation functions for control volume finite element method. The exponential interpolation function is expressed in the elemental local coordinate system whereas the classic linear interpolation function is expressed in the global coordinate system. The comparison is achieved in the case of the Green‐Taylor vortex, a flow from which we know the analytical solution. Firstly, the two functions are applied to a triangular element of the domain to compare the results given by each interpolation function to the exact value. Secondly, these two functions are compared when used to solve the discretized equations over the entire domain.
Process modeling of composites by resin transfer molding: practical applications of sensitivity analysis for isothermal considerations
Authors: Henz B.J. , Tamma K.K. , Kanapady R. , Ngo N.D. , Chung P.W.
Published: May 2003

The resin transfer molding process for composites manufacturing consists of either of two considerations, namely, the fluid flow analysis through a porous fiber preform where the location of the flow front is of fundamental importance, and the combined flow/heat transfer/cure analysis. In this paper, the continuous sensitivity formulations are developed for the process modeling of composites manufactured by RTM to predict, analyze, and optimize the manufacturing process. Attention is focused here on developments for isothermal flow simulations, and various illustrative examples are presented for sensitivity analysis of practical applications which help serve as a design tool in the process modeling stages.
Application of the conservation element and solution element method in numerical modeling of heat conduction with melting and/or freezing
Authors: Ayasoufi A. , Keith T.G.
Published: May 2003

The conservation element and solution element (CE/SE) method, an accurate and efficient explicit numerical method for resolving moving discontinuities in fluid mechanics problems, is used for the first time to solve phase change problems. Several isothermal phase change cases are studied and comparisons are made to existing analytical solutions. The CE/SE method is found to be accurate and robust for the numerical modeling of phase change problems.
Study and modelling of a density dependent population using faltung (closed cycle type) equations
Authors: Bordehore Cèsar , Pascual Angela , Pujol Maria J. , Escolano Julio , Manchón Inmaculada , Grimalt Pedro
Published: May 2003

Faltung equations (closed cycle type) have a wide range of biological applications, nonetheless, they are poorly studied. We use a Volterra‐Kostitzin model (which is a Faltung equation) to study the dynamics of a certain species, where the integral term represents a residual action. The complexity of resolution of this non‐linear equation using classical numeric methods is here solved with the Adomian decomposition method. Our method provides the same graphic solution as others do, such as the numeric method Miladie. However, the decomposition method of Adomian has the advantage that neither time nor space are considered discontinuous and that it gives an analytical solution with a reliable approximation.
Effect of space ratio and corrugation angle on convection enhancement in wavy channels
Authors: Comini G. , Nonino C. , Savino S.
Published: May 2003

By neglecting the influence of tubes, this paper adopts a simplified two‐dimensional approach to deal with laminar convection of air through wavy finned‐tube exchangers. Pressure drop and heat transfer characteristics are investigated in the fully developed region of the flow channels between adjacent fins. The solutions are presented for several space ratios (height over length of a module) and two corrugation angles. They concern laminar flows both below and above the onset of the self‐sustained oscillations that precede the transition to turbulence. Fully developed velocity and thermal fields are computed by imposing anti‐periodic conditions at inlet/outlet sections of a single calculation cell. In the range of Reynolds numbers investigated, Nusselt numbers and friction factors first increase with space ratios (up to a value depending on the corrugation angle), then start decreasing with increasing space ratios.
Managing corporate identity: an integrative framework of dimensions and determinants
Authors: Cornelissen Joep P. , Elving Wim J.L.
Published: May 2003

Although there has been an enduring interest in corporate identity and image management, there is relatively little systematic empirical research on the topic. Largely due to the diffuse interpretations and dubious denotation that have characterized the subject of corporate identity so far, the authors present an integrative conceptual framework of dimensions and determinants of corporate identity management. This framework and its constructs specify the concept of corporate identity and can be used on a predictive basis to guide, frame and model empirical research into this area.