bluuebunny/crossref_metadata_2025 huggingface dataset:
Tamoxifen: a novel treatment for primary biliary cirrhosis?
Authors: Reddy A. , Prince M. , James O.F. , Jain S. , Bassendine M.F.
Published: June 2004

Abstract: Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease, which predominantly affects women. It is characterised histologically by necroinflammation of small intrahepatic bile ducts and biochemically by elevated serum alkaline phosphatase, levels of which at diagnosis predict survival. Ursodeoxycholic acid (UDCA) is the only treatment shown to improve liver biochemistry and survival. We report two patients with PBC who show a fall in serum alkaline phosphates levels whilst receiving tamoxifen therapy. Tamoxifen may exert this effect, which warrants further study, either via cholangiocyte estrogen receptors, inhibiting cholangiocyte proliferation and inducing apoptosis or by activating pregnane X receptor, analogous to the mode of action of UDCA.
Hepatitis C virus infection in human liver tissue engrafted in mice with an infectious molecular clone
Authors: Maeda Norio , Watanabe Mamoru , Okamoto Susumu , Kanai Takanori , Yamada Taketo , Hata Jun‐ichi , Hozumi Nobumichi , Katsume Asao , Nuriya Hideko , Sandhu Jasbir , Ishii Hiromasa , Kohara Michinori , Hibi Toshifumi
Published: June 2004

Abstract: Background/aims: Recent advances in molecular cloning of hepatitis C virus (HCV) have enabled us to apply some available HCV molecular clones to experimental studies. However, these investigations have been restricted to chimpanzee models or ‘isolated hepatocytes’ from tree shrews. In this study, we engrafted ‘human liver tissue’ into immunodeficient mice and investigated HCV infection using an infectious molecular clone.

Methods: Human liver tissues from normal (non‐HCV‐infected) liver were transplanted into non‐obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. We then inoculated the mice with sera from HCV‐infected patients or an infectious HCV molecular clone. HCV RNA was assessed using nested reverse‐transcription polymerase chain reaction (PCR), real‐time detection PCR and in situ PCR.

Results: Without any growth support, normal human liver tissues survived in NOD/SCID mice while maintaining the original viable hepatic architecture. HCV RNA was detected in the mice serum until the fourth week after the inoculation. In situ PCR and immunohistochemistry clearly demonstrated positive signals for HCV in the cytoplasm of infected hepatocytes, while the engrafted human liver tissues showed no apparent morphological changes indicative of infection.

Conclusion: Engraftment of human liver tissues into NOD/SCID mice and infection with HCV molecular clones could offer a reverse genetic strategy for HCV infection.
Hepatocyte survival depends on β1‐integrin‐mediated attachment of hepatocytes to hepatic extracellular matrix
Authors: Pinkse Gabriëlle G.M. , Voorhoeve Mathijs P. , Noteborn Mathieu , Terpstra Onno T. , Bruijn Jan Anthonie , De Heer Emile
Published: June 2004

Abstract: Background: A major drawback of allogeneic hepatocyte transplantation is the lack of sustained survival of the transplanted cells in the recipient liver parenchyma. The purpose of this study was to determine the effect of the presence or absence of hepatic extracellular matrix (ECM) molecules on hepatocyte survival and function following hepatocyte isolation for transplantation purposes, and the role of β1‐integrin molecules therein.

Methods: Hepatocytes, either untreated or treated with anti‐β1 integrin antibodies or RGD peptides, were seeded on wells precoated with collagen type I, type IV, laminin, fibronectin or polyhydroxyethylmehacrylate. The extent of attachment and apoptosis was evaluated.

Results: When hepatocytes were added into wells precoated with either fibronectin, or collagen type IV, rapid spreading and prolonged survival occurred, in contrast to hepatocytes that were seeded in wells precoated with collagen type I or polyhydroxyethylmehacrylate. Pretreatment of the cells with anti‐β1‐integrin antibodies resulted in reduction of cell attachment to laminin, fibronectin, collagen I, and collagen IV. Synthetic RGD (arginine–glycine–aspartate)‐peptides and anti‐β1 antibodies inhibited apoptosis of cultured hepatocytes.

Conclusions: Our findings indicate that embedding of hepatocytes within their normal liver ECM surroundings maintains their survival. When detached from their natural surrounding hepatocytes enter into apoptosis, unless treated with anti‐β1‐integrin antibodies or RGD peptides. This knowledge will allow improvement of hepatocyte transplantation efficiency.
Virological, immunological and histological aspects in adult β‐thalassemic patients with chronic hepatitis C virus infection
Authors: Siagris D. , Giannakoulas N. , Christofidou M. , Tsamandas A. , Lekkou A. , Thomopoulos K. , Zoumbos N. , Labropoulou‐Karatza Ch.
Published: June 2004

Abstract: Objectives: Multitransfused adult β‐thalassemic patients constitute a population with high prevalence of hepatitis C virus (HCV) infection, because of transmission of HCV from infected blood donors prior to the introduction of anti‐HCV screening. The aim of this study was to compare them with otherwise normal patients with HCV infection.

Methods: Forty‐two adult multitransfused β‐thalassemics and 49 otherwise normal patients of the same age, with chronic HCV infection were studied. Viral parameters, autoimmunity indices and liver histology were evaluated.

Results: Serum HCV RNA levels were found significantly lower in thalassemic (median: 65 150 international units per milliliter (IU/ml); range: 3 059 380 IU/ml) than in non‐thalassemic (NT) patients (median: 580 000 IU/ml; range: 10 956 000 IU/ml; P=0.001). The most prevalent genotype in thalassemic group was genotype 4 (32.4%) while in NT group was genotype 3a (59.2%). Cryoglobulins were detected in 8/42 (19%) thalassemic patients and in 12/49 (24.5%) NTs. Thalassemic patients had significantly lower levels of C3 and C4 components of complement and higher incidence of anti‐nuclear antibodies than those without thalassemia. In patients with thalassemia a lower grading score was noted in liver biopsy compared with those without thalassemia (4.41±1.98 vs 5.38±2.09, P=0.038). On the contrary, thalassemic patients were found to have a higher staging score (3.08±1.51 vs 2.33±1.34, P=0.024).

Conclusions: Adult β‐thalassemic patients, compared with other patients with HCV infection, present lower necroinflammatory activity and lower viral load but higher staging score. Autoimmune features are marginally different. Age of acquiring the infection, iron overload and modulation of immune system by transfusions are the proposed causes of these differences.
Low Rates of Angiographic and Clinical Restenosis with the New Flexible MedStent for the Treatment of Single Discrete Coronary Lesions
Authors: SEGEV AMIT , CANTOR WARREN J. , COHEN ERIC A. , SEIDELIN PETER H. , NATARAJAN MADHU K. , MARQUIS JEAN‐FRANCOIS , LAZZAM CHARLES , WATSON RANDAL K. , CHISHOLM ROBERT J. , STRAUSS BRADLEY H.
Published: June 2004

The use of enhanced designs of new coronary stents continues to expand the spectrum of coronary anatomy and clinical settings amenable to nonsurgical revascularization. The objectives of this clinical trial were to demonstrate the safety and late angiographic restenosis rate of the new flexible MedStent. The study included 117 patients with stable or unstable angina pectoris and a discrete de novo lesion of a native coronary artery. Procedural success, 6‐month angiographic findings, and 1‐year clinical outcomes were determined. The stent was successfully deployed in all but one patient (99.1%). There were no events in any of the patients within the first 2 weeks after the procedure. At 1 year, a total of 12 patients had 16 clinical events related to the stented artery (1 death, 3 non‐Q‐wave MIs, 10 repeat PTCAs, and 2 CABG procedures). This represents a target vessel revascularization rate (TVR) of 10.3%. The minimal luminal diameter (MLD) at 6 months for the MedStent was 2.04 ± 0.71 mm. The 6‐month binary angiographic restenosis was 20.0% (95% CI, 12.5%–27.5%). The results of the Medstent study in discrete, de novo native coronary lesions demonstrated low incidence of clinical events as well as favorable angiographic restenosis rate. (J Interven Cardiol 2004;17:167–170)
Late Presentation of an Iatrogenic Circumflex to Left Atrial Fistula Closed with a Covered Stent
Authors: JULIAN WILLIAM , HOBBS CAIRD , KUMAR SOMANTH , ROBERTS DAVID HESKETH
Published: June 2004

An anomalous circumflex to left atria fistula following previous excision of an atrial myxoma was successfully occluded percutaneously using a covered stent. The intervention was technically challenging but was possible using a Magnum guide wire via a left radial approach. (J Interven Cardiol 2004;17:179–181)
Atresia of Right Pulmonary Veins with Intact Atrial Septum and Major Aorto‐Pulmonary Collateral Treated with Percutaneous Stent Implantation and Embolization
Authors: USSIA GIAN PAOLO , MARASINI MAURIZIO , RIMINI ALESSANDRO , PONGIGLIONE GIACOMO
Published: June 2004

Unilateral pulmonary vein (PV) atresia is a rare congenital cardiac malformation with evolution toward irreversible pulmonary hypertension. Pneumonectomy or lung transplant is currently the treatment of choice for such a disease. We describe an unusual case of right PV atresia and major aorto‐pulmonary collaterals treated with percutaneous angioplasty, stent implantation, and aorto‐pulmonary collateral embolization. (J Interven Cardiol 2004;17:183–187)
Increased Dosage during Intracoronary Irradiation Due to Overlapped Source Stepping Shows No Long‐Term Adverse Changes in Vessel Morphology
Authors: SYEDA BONNI , YAHYA NABIL , SCHMID RAINER , KIRISITS CHRISTIAN , DENK STEFAN , DERNTL MICHAEL , SCHUKRO CHRISTOPH , POKRAJAC BORIS , POTTER RICHARD , GLOGAR DIETMAR
Published: June 2004

Purpose: The purpose of this analysis was to evaluate if overdosage during intracoronary irradiation due to overlapped source stepping may result in long‐term morphologic changes in vessel anatomy.

Methods: Baseline angiograms of patients with in‐stent restenosis undergoing coronary reintervention followed by intracoronary irradiation with source stepping were analyzed. Overlapping was considered present for the segment with overlapped reference isodose length (RIL) (RIL = segment with ≥90% of reference dose at 1 mm vessel wall depth). Baseline and 6‐months follow‐up volumetric intravascular ultrasound (IVUS) analysis were performed for the overlapped segment and for proximal and distal segments of equal length.

Results: Overlapping was found in six patients (three patients: 32P treatment; three patients: 90Sr/Y treatment); final analysis was performed in four patients. Comparison of the baseline and follow‐up IVUS volumetric parameters revealed no significant change in lumen or vessel volumes at segments of overlaps in comparison to proximal and distal reference segments.

Conclusion: Increased dosage due to overlapping during source stepping is not associated with morphologic changes in vessel anatomy at follow‐up. (J Interven Cardiol 2004;17:143–149)
Mandibular overdentures supported by two Brånemark, IMZ or ITI implants: a 5‐year prospective study
Authors: Meijer Henny J.A. , Batenburg Rutger H.K. , Raghoebar Gerry M. , Vissink Arjan
Published: June 2004

Objectives:

The aim of this prospective comparative study was to evaluate the survival rate and the condition of the peri‐implant tissues of the IMZ implant system (two‐stage cylindertype), the Brånemark implant system (two‐stage screwtype) and the ITI implant system (one‐stage screwtype) supporting a mandibular overdenture during a 5‐year follow‐up period.

Material and Methods: Three groups of 30 edentulous patients were treated with two endosseous implants in the interforaminal region of the mandible. Clinical and radiographic parameters were evaluated immediately after completion of the prosthetic treatment and after 1, 2, 3, 4 and 5 years of functional loading.

Results: The five‐year survival rate is 98.3% for the IMZ group, 98.3% for the Brå group and 100% for the ITI group. Mean scores on indices for plaque, calculus, gingiva and bleeding were very low at all evaluation periods. Mean marginal bone loss over a period of 5 years, was 1.4 mm for the IMZ group, 0.7 mm for the Brå group and 0.9 mm for the ITI group.

Conclusion: It is concluded that two implants placed in the interforaminal region, connected with a bar, supply a proper base for the support of a mandibular overdenture in the edentulous patient. After 5 years no clinically relevant and statistically significant radiographic changes had developed between the three implant systems.
Some risk factors for periodontal bone loss in 50‐year‐old individuals
Authors: Paulander Jörgen , Wennström Jan L. , Axelsson Per , Lindhe Jan
Published: June 2004

Objective: The aim of this 10‐year prospective study of 50‐year‐old individuals was to analyze the incidence of periodontal bone loss and potential risk factors for periodontal bone loss.

Methods: The subject sample was generated from an epidemiological survey performed in 1988 of subjects living in the County of Värmland, Sweden. A randomized sample of 15% of the 50‐year‐old inhabitants in the county was drawn. At the 10‐year follow‐up in 1998, 320 (75%) of the 449 individuals examined at baseline were available for re‐examination, out of which 4 had become edentulous. Full‐mouth clinical and radiographic examinations and questionnaire surveys were performed in 1988 and 1998. Two hundred and ninety‐five individuals (69%) had complete data for inclusion in the analysis of radiographic bone changes over 10 years. Non‐parametric tests, correlations and stepwise multiple regression models were used for statistical analysis of the data.

Results: The mean alveolar bone level (ABL) in 1988 was 2.2 mm (0.05) and a further 0.4 mm (0.57) (p=0.000) was lost over the 10 years. Eight percent of the subject sample showed no loss, while 5% experienced a mean bone loss of 1 mm. Smoking was found to be the strongest individual risk predictor (RR=3.2; 95% CI 2.03–5.15). When including as smokers only those individuals who had continued with the habit during the entire 10‐year follow‐up period, the relative risk was slightly increased (3.6; 95% CI 2.32–5.57). Subjects who had quit smoking before the baseline examination did not demonstrate a significantly increased risk for disease progression (RR=1.3; 95% CI 0.57–2.96). Stepwise multiple regression analysis revealed that smoking, % approximal sites with probing pocket depth 4 mm, number of teeth and systemic disease were significant explanatory factors for 10‐year ABL loss (R2=0.12). For never smokers, statistically significant predictors were number of teeth, mean ABL, % periodontally healthy approximal sites and educational level (R2=0.20).

Conclusion: The inclusion of smokers in risk analysis for periodontal diseases may obstruct the possibility to detect other true risk factors and risk indicators.
Tooth loss during maintenance following periodontal treatment in a periodontal practice in Norway
Authors: Fardal Øystein , Johannessen Anne C. , Linden Gerard J.
Published: June 2004

Background: Periodontal therapy coupled with careful maintenance has been shown to be effective in maintaining periodontal health; however, a small number of teeth are still lost because of progressive periodontitis.

Aim: To investigate factors associated with tooth loss due to periodontal reasons during maintenance following periodontal treatment in patients in a Norwegian specialist periodontal practice. The study also examined how initial prognosis related to actual outcome as measured by periodontal tooth loss.

Methods: Hundred consecutive patients (68 females, 32 males) who had comprehensive periodontal treatment and attended for 9.8 (SD: 0.7), range: 9–11 years of maintenance care, were studied. All teeth classified as being lost due to periodontal disease over the period were identified.

Results: Only 36 (1.5%) of the 2436 teeth present at baseline were subsequently lost due to periodontal disease. There were 26 patients who lost at least one tooth. Logistic regression analysis showed that tooth loss was significantly related to male gender (p=0.049; adjusted odds ratio: 2.8; confidence interval (c.i.): 1.0–8.1), older age, i.e.>60 years (p=0.012; adjusted odds ratio: 4.0; c.i.: 1.3–12.0) and smoking (p=0.019; adjusted odds ratio: 4.2; c.i.: 1.4–13.8). The majority 27 (75%) of the teeth lost due to periodontal disease had been assigned an uncertain, poor or hopeless initial prognosis; however, nine teeth (25%) lost had been assigned a good prognosis at baseline. The prognosis for 202 teeth was judged to have worsened over the period of the study.

Conclusion: Compliance with maintenance following periodontal treatment was associated with very low levels of tooth loss in a referral practice in rural Norway. Male gender, older age (>60 years) and smoking were predictors of tooth loss due to progressive periodontitis.
Plasma antibody levels in periodontitis patients and controls
Authors: Graswinckel J. E. M. , Van Der Velden U. , Van Winkelhoff A. J. , Hoek F. J. , Loos B. G.
Published: June 2004

Background: A major aspect of the adaptive host response in periodontitis is the production of antibodies. Several risk and susceptibility factors for periodontitis, including smoking, age and composition of the subgingival microflora, have also been suggested to influence antibody production.

Aim: The present study was conducted to investigate plasma levels of immunoglobulin (Ig) G, A and M antibodies in periodontitis patients of Caucasian European heritage in relation to disease severity, smoking, diagnosis and prevalence of periodontopathogens.

Methods: In this study, 29 patients with severe periodontitis, 51 with moderate periodontitis and 55 controls without periodontal destruction were enrolled. From the total of 80 patients, 18 were diagnosed with aggressive periodontitis and 62 with chronic periodontitis. Total IgG, IgA and IgM as well as IgG isotypes were analyzed in plasma samples.

Results: Levels of total IgG, IgA and IgM were not different between patients and controls; however, in periodontitis, higher levels of IgG1 and IgG2 were observed. Smoking appeared to be significantly and inversely related to antibody levels in periodontitis, in particular for total IgG and IgG2. The absence of an elevated total IgG and IgG2 in smoking patients was irrespective of severity, prevalence of periodontal pathogens and diagnosis. The elevation of total IgG and IgG1 and IgG2 in non‐smoker periodontitis patients was observed in patients with moderate periodontitis and even greater in patients with severe periodontitis, but was independent whether patients were infected with Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis and independent of diagnosis. Clinically, it was observed that patients who smoked had more periodontal bone loss; the current findings on antibody levels may be one of several mechanisms related to more extensive periodontal breakdown in smoker patients.

Conclusion: The current study shows that non‐smoker periodontitis patients have higher levels of total IgG and IgG2 than smoker periodontitis patients.
Quantification of dental plaque on lingual tooth surfaces using image analysis: reliability and validation
Authors: Smith R.N. , Rawlinson A. , Lath D. , Elcock C. , Walsh T.F. , Brook A.H.
Published: June 2004

Aim: The aim of this study was to increase the versatility and further validate the method reported by Smith et al. (2001) by testing the reliability of plaque measurement against two well‐known dental plaque quantification methodologies using image analysis in a clinical trial.

Method: The teeth of 40 subjects were disclosed before digital images of the labial and lingual surfaces of their upper and lower incisors were acquired. The amount of plaque present was quantified using a modification of the method described by Smith et al. (2001). The method was modified for obtaining images of the lingual surfaces by incorporating the use of orthodontic occlusal mirrors and 5‐mm pieces of moistened blue articulating paper used to enable calibration. Plaque measurements were made from 320 upper and lower anterior teeth from the 40 subjects by two operators. Fliess' coefficient of reliability was used to assess intra‐ and inter‐operator reliability and the independent sample t test was used to assess statistical significance between test and control groups after checking the data for normality. For validation, measurements were recorded using the Turesky et al. (1970) (modification of the Quigley & Hein (1962) plaque index and the Addy et al. (1983) plaque area index. The results were compared with the image analysis method using Pearson's correlation coefficient.

Results: The results for reliability were within Fliess' range of “excellent” for both intra‐operator repeatability and inter‐operator reproducibility. Pearson's correlation coefficients showed highly significant values indicating the close similarity between all three methods.

Conclusions: This method for the measurement of dental plaque on lingual surfaces of anterior teeth proved reliable. The combined results from the labial and lingual surfaces of anterior teeth using image analysis produced trial conclusions comparable with the alternate plaque quantification methods used, with less clinician time and further producing a permanent database of images for future use.
The relationship between tomato intake and congestive heart failure risk in periodontitis subjects
Authors: Wood Nelson , Johnson Roger B.
Published: June 2004

Background: The objective of this study was to investigate the relationship between monthly tomato consumption (MTC) and serum lycopene (sLyco) levels, and a self‐reported history of congestive heart failure (CHF) in individuals with periodontitis using data available in the Third National Health and Nutrition Examination Survey (NHANES III).

Methods: Adult participants in NHANES III were used in this study. Zero to thirty three percent of sites with a periodontal attachment loss (PAL) of >3 mm was considered a healthy periodontium, while greater than >33% of sites with PAL of >3 mm as periodontitis. The outcome variable was the self‐reported history of CHF. MTC and sLyco levels were categorized into quartiles. Data was analyzed by Kruskal–Wallis, anova and multivariate analyses using SPSS®. p<0.05 was used to reject the null hypothesis.

Results: Individuals with periodontitis showed a dose–response relationship between dietary MTC and self‐reported CHF risk; moderate MTC (risk ratio (RR), 3.15; 95% confidence interval (CI), 1.03–9.67), low MTC (RR, 3.31; 95% CI, 1.33–8.24) (p<0.05) and very low MTC (RR, 5.10; 95% CI, 1.67–15.57) (p<0.01), adjusting for confounders of both diseases (periodontitis and CHF). The moderate sLyco level‐healthy periodontium group showed a significant decrease in CHF risk (RR, 0.25; 95% CI, 0.07–0.84) (p<0.05), adjusting for confounders. Significant inverse dose–response relationships were seen between sLyco and C‐reactive protein, and MTC and white blood cell count in periodontitis subjects, respectively (p<0.05). MTC was correlated with sLyco concentration (r=−0.018, p<0.05), adjusting for confounders abolished that significance.

Conclusions: A relationship exists between periodontitis and CHF risk, and high MTC appears to affect this relationship in a positive direction in periodontitis subjects.
The Deletion of the Succinate Dehydrogenase Gene
KlSDH1
in
Kluyveromyces lactis
Does Not Lead to Respiratory Deficiency
Authors: Saliola Michele , Bartoccioni Paola Chiara , De Maria Ilaria , Lodi Tiziana , Falcone Claudio
Published: June 2004

We have isolated a
Kluyveromyces lactis
mutant unable to grow on all respiratory carbon sources with the exception of lactate. Functional complementation of this mutant led to the isolation of
KlSDH1
, the gene encoding the flavoprotein subunit of the succinate dehydrogenase (SDH) complex, which is essential for the aerobic utilization of carbon sources. Despite the high sequence conservation of the
SDH
genes in
Saccharomyces cerevisiae
and
K. lactis
, they do not have the same relevance in the metabolism of the two yeasts. In fact, unlike
SDH1
,
KlSDH1
was highly expressed under both fermentative and nonfermentative conditions. In addition to this, but in contrast with
S. cerevisiae
,
K. lactis
strains lacking
KlSDH1
were still able to grow in the presence of lactate. In these mutants, oxygen consumption was one-eighth that of the wild type in the presence of lactate and was normal with glucose and ethanol, indicating that the respiratory chain was fully functional. Northern analysis suggested that alternative pathway(s), which involves pyruvate decarboxylase and the glyoxylate cycle, could overcome the absence of SDH and allow (i) lactate utilization and (ii) the accumulation of succinate instead of ethanol during growth on glucose.
Suppressors of an Adenylate Cyclase Deletion in the Fission Yeast
Schizosaccharomyces pombe
Authors: Stiefel Jeffrey , Wang Lili , Kelly David A. , Janoo Rozmin T. K. , Seitz Jeffrey , Whitehall Simon K. , Hoffman Charles S.
Published: June 2004

Schizosaccharomyces pombe
utilizes two opposing signaling pathways to sense and respond to its nutritional environment. Glucose detection triggers a cyclic AMP signal to activate protein kinase A (PKA), while glucose or nitrogen starvation activates the Spc1/Sty1 stress-activated protein kinase (SAPK). One process controlled by these pathways is
fbp1
+
transcription, which is glucose repressed. In this study, we isolated strains carrying mutations that reduce high-level
fbp1
+
transcription conferred by the loss of adenylate cyclase (
git2
Δ), including both
wis1
−
(SAPK kinase) and
spc1
−
(SAPK) mutants. While characterizing the
git2
Δ suppressor strains, we found that the
git2
Δ parental strains are KCl sensitive, though not osmotically sensitive. Of 102
git2
Δ suppressor strains, 17 strains display KCl-resistant growth and comprise a single linkage group, carrying mutations in the
cgs1
+
PKA regulatory subunit gene. Surprisingly, some of these mutants are mostly wild type for mating and stationary-phase viability, unlike the previously characterized
cgs1
-
1
mutant, while showing a significant defect in
fbp1-lacZ
expression. Thus, certain
cgs1
−
mutant alleles dramatically affect some PKA-regulated processes while having little effect on others. We demonstrate that the PKA and SAPK pathways regulate both
cgs1
+
and
pka1
+
transcription, providing a mechanism for cross talk between these two antagonistically acting pathways and feedback regulation of the PKA pathway. Finally, strains defective in both the PKA and SAPK pathways display transcriptional regulation of
cgs1
+
and
pka1
+
, suggesting the presence of a third glucose-responsive signaling pathway.
RasC Plays a Role in Transduction of Temporal Gradient Information in the Cyclic-AMP Wave ofDictyostelium discoideum
Authors: Wessels Deborah , Brincks Rebecca , Kuhl Spencer , Stepanovic Vesna , Daniels Karla J. , Weeks Gerald , Lim Chinten J. , Spiegelman George , Fuller Danny , Iranfar Negin , Loomis William F. , Soll David R.
Published: June 2004

To define the role that RasC plays in motility and chemotaxis, the behavior of arasCnull mutant,rasC−, in buffer and in response to the individual spatial, temporal, and concentration components of a natural cyclic AMP (cAMP) wave was analyzed by using computer-assisted two-dimensional and three-dimensional motion analysis systems. These quantitative studies revealed thatrasC−cells translocate at the same velocity and exhibit chemotaxis up spatial gradients of cAMP with the same efficiency as control cells. However,rasC−cells exhibit defects in maintaining anterior-posterior polarity along the substratum and a single anterior pseudopod when translocating in buffer in the absence of an attractant.rasC−cells also exhibit defects in their responses to both the increasing and decreasing temporal gradients of cAMP in the front and the back of a wave. These defects result in the inability ofrasC−cells to exhibit chemotaxis in a natural wave of cAMP. The inability to respond normally to temporal gradients of cAMP results in defects in the organization of the cytoskeleton, most notably in the failure of both F actin and myosin II to exit the cortex in response to the decreasing temporal gradient of cAMP in the back of the wave. While the behavioral defect in the front of the wave is similar to that of themyoA−/myoF−myosin I double mutant, the behavioral and cytoskeletal defects in the back of the wave are similar to those of the S13A myosin II regulatory light-chain phosphorylation mutant. Expression array data support the premise that the behavioral defects exhibited by therasC−mutant are the immediate result of the absence of RasC function.
Genome-Wide Single-Nucleotide Polymorphism Map for
Candida albicans
Authors: Forche Anja , Magee P. T. , Magee B. B. , May Georgiana
Published: June 2004

Single-nucleotide polymorphisms (SNPs) are essential tools for studying a variety of organismal properties and processes, such as recombination, chromosomal dynamics, and genome rearrangement. This paper describes the development of a genome-wide SNP map for
Candida albicans
to study mitotic recombination and chromosome loss.
C. albicans
is a diploid yeast which propagates primarily by clonal mitotic division. It is the leading fungal pathogen that causes infections in humans, ranging from mild superficial lesions in healthy individuals to severe, life-threatening diseases in patients with suppressed immune systems. The SNP map contains 150 marker sequences comprising 561 SNPs and 9 insertions-deletions. Of the 561 SNPs, 437 were transition events while 126 were transversion events, yielding a transition-to-transversion ratio of 3:1, as expected for a neutral accumulation of mutations. The average SNP frequency for our data set was 1 SNP per 83 bp. The map has one marker placed every 111 kb, on average, across the 16-Mb genome. For marker sequences located partially or completely within coding regions, most contained one or more nonsynonymous substitutions. Using the SNP markers, we identified a loss of heterozygosity over large chromosomal fragments in strains of
C. albicans
that are frequently used for gene manipulation experiments. The SNP map will be useful for understanding the role of heterozygosity and genome rearrangement in the response of
C. albicans
to host environments.
Candida albicans
Rim13p, a Protease Required for Rim101p Processing at Acidic and Alkaline pHs
Authors: Li Mingchun , Martin Samuel J. , Bruno Vincent M. , Mitchell Aaron P. , Davis Dana A.
Published: June 2004

Candida albicans
is an important commensal of mucosal surfaces that is also an opportunistic pathogen. This organism colonizes a wide range of host sites that differ in pH; thus, it must respond appropriately to this environmental stress to survive. The ability to respond to neutral-to-alkaline pHs is governed in part by the
RIM101
signal transduction pathway. Here we describe the analysis of
C. albicans
Rim13p, a homolog of the Rim13p/PalB calpain-like protease member of the
RIM101
/
pacC
pathway from
Saccharomyces cerevisiae
and
Aspergillus nidulans
, respectively.
RIM13
, like other members of the
RIM101
pathway, is required for alkaline pH-induced filamentation and growth under extreme alkaline conditions. Further, our studies suggest that the
RIM101
pathway promotes pH-independent responses, including resistance to high concentrations of lithium and to the drug hygromycin B.
RIM13
encodes a calpain-like protease, and we found that Rim101p undergoes a Rim13p-dependent C-terminal proteolytic processing event at neutral-to-alkaline pHs, similar to that reported for
S. cerevisiae
Rim101p and
A. nidulans
PacC. However, we present evidence that suggests that
C. albicans
Rim101p undergoes a novel processing event at acidic pHs that has not been reported in either
S. cerevisiae
or
A. nidulans
. Thus, our results provide a framework to understand how the
C. albicans
Rim101p processing pathway promotes alkaline pH-independent processes.
RBR1
, a Novel pH-Regulated Cell Wall Gene of
Candida albicans
, Is Repressed by
RIM101
and Activated by
NRG1
Authors: Lotz Henrike , Sohn Kai , Brunner Herwig , Mühlschlegel Fritz A. , Rupp Steffen
Published: June 2004

The transcription factor Rim101p of
Candida albicans
has been shown to play a major role in pH-dependent gene regulation. Rim101p is involved in cell wall biosynthesis, since it regulates
PHR1
and
PHR2
, two almost functionally redundant cell wall glycosidases important for adaptation to either neutral or acidic habitats within the human host. To identify additional cell wall components regulated by Rim101p, we performed transcriptional profiling with a cell wall-specific DNA microarray. We showed that Rim101p contributes to the activation of known hypha-specific genes such as
HWP1
and
RBT1
but is also required for repression of the previously uncharacterized potential cell wall genes
RBR1
,
RBR2
, and
RBR3
. Further characterization of
RBR1
revealed that it encodes a small glycosylphosphatidyl inositol protein that is expressed under acidic conditions predominantly at low temperature. Deletion of the gene resulted in a filamentation defect at low pH. Most interestingly,
NRG1
, a transcriptional repressor of hyphal growth in
C. albicans
, was required for
RBR1
expression. The apparently activating effect of
NRG1
observed in this study has not been described before. In addition, we showed that expression of
NRG1
is not only temperature but also pH dependent.
Sequence Elements Necessary for Transcriptional Activation ofBAD1in the Yeast Phase ofBlastomyces dermatitidis
Authors: Rooney Peggy J. , Klein Bruce S.
Published: June 2004

Blastomyces dermatitidisis a dimorphic fungal pathogen that converts from mycelia or conidia to a host-adapted yeast morphotype upon infection. Conversion to the yeast form is accompanied by the production of the virulence factor BAD1. Yeast-phase-specific expression of BAD1 is transcriptionally regulated, and its promoter shares homology with that of the yeast-phase-specific geneYPS3ofHistoplasma capsulatum. Serial truncations of theBAD1upstream region were fused to thelacZreporter to define functional areas in the promoter. Examination of PBAD1-lacZfusions inB. dermatitidisindicated thatBAD1transcription is upregulated in the yeast phase. The 63-nucleotide box A region conserved in theYPS3upstream region was shown to be an essential component of the minimalBAD1promoter. A matched PYPS3-lacZconstruct indicated that this same region was needed for minimalYPS3promoter activity inB. dermatitidistransformants. Reporter activity inH. capsulatumtransformants similarly showed a requirement for box A in the minimalBAD1promoter. Several putative transcription factor binding sites were identified within box A ofBAD1. Replacement of two of these predicted sites within box A—a cAMP responsive element and a Myb binding site—sharply reduced transcriptional activity, indicating that these regions are critical in dictating the yeast-phase-specific expression of this crucial virulence determinant ofB. dermatitidis.
Simple sequence repeat diversity in diploid and tetraploid Coffea species
Authors: Moncada Pilar , McCouch Susan
Published: June 2004

Thirty-four fluorescently labeled microsatellite markers were used to assess genetic diversity in a set of 30 Coffea accessions from the CENICAFE germplasm bank in Colombia. The plant material included one sample per accession of seven East African accessions representing five diploid species and 23 wild and cultivated tetraploid accessions of Coffea arabica from Africa, Indonesia, and South America. More allelic diversity was detected among the five diploid species than among the 23 tetraploid genotypes. The diploid species averaged 3.6 alleles/locus and had an average polymorphism information content (PIC) value of 0.6, whereas the wild tetraploids averaged 2.5 alleles/locus and had an average PIC value of 0.3 and the cultivated tetraploids (C. arabica cultivars) averaged 1.9 alleles/locus and had an average PIC value of 0.22. Fifty-five percent of the alleles found in the wild tetraploids were not shared with cultivated C. arabica genotypes, supporting the idea that the wild tetraploid ancestors from Ethiopia could be used productively as a source of novel genetic variation to expand the gene pool of elite C. arabica germplasm.Key words: Coffea spp., microsatellite markers, genetic diversity.
Development of microsatellite markers in Fragaria, their use in genetic diversity analysis, and their potential for genetic linkage mapping
Authors: Hadonou A M , Sargent D J , Wilson F , James C M , Simpson D W
Published: June 2004

We have developed 21 new microsatellites in the model diploid perennial species Fragaria vesca from an enriched genomic library developed using F. vesca 'Ruegen'. The transferability of the primer pairs to other Fragaria species was high; all 31 primer pairs produced amplicons in 3 accessions of the octoploid strawberry Fragaria × ananassa, whereas 24 (77%) amplified a product in 7 other diploid Fragaria species. We analysed the allelic variation among 15 F. vesca accessions using the 21 microsatellites reported here and 10 F. vesca microsatellites described previously. The level of polymorphism detected at these microsatellite loci was high; five loci were monomorphic. Only two microsatellites were required to unambiguously discriminate among the 15 F. vesca accessions. A preliminary survey of segregation in an F2 progeny indicates that 20 of the 26 polymorphic loci (77%) could be mapped.Key words: Fragaria, genetic fingerprinting, microsatellites.
Diversification within grapevine cultivars goes through chimeric states
Authors: Hocquigny S , Pelsy F , Dumas V , Kindt S , Heloir M-C , Merdinoglu D
Published: June 2004

Vitis vinifera 'Pinot' clones were analysed at 50 microsatellite loci to assess intravarietal genetic diversity. When analysing leaf tissue DNAs, polymorphism mainly resulted from the appearance of a third allele when two were expected for heterozygous loci in a diploid species. The sequencing of the three microsatellite alleles at two loci has confirmed their simultaneous presence in the leaf tissues. A hypothesis explaining the triallelic profiles at a locus is the presence of a periclinal chimera meristem structure, in which genetically different cell layers coexist. The periclinal chimeric state of two Vitis vinifera 'Pinot gris' clones was confirmed by splitting and analysing the genotypes resulting from L1 and L2 cell layers in progeny derived from self-fertilization, in root tissues, and in plants regenerated from somatic embryogenesis. Prevalence of chimerism in polymorphic clones observed in a collection of 145 accessions belonging to 'Pinot gris', 'Pinot noir', Pinot blanc', 'Pinot meunier', and 'Pinot moure' cultivars was demonstrated. The accumulation of somatic mutations and cell layer rearrangements allowed us to deduce the relationships between the various genotypes and to open a way for understanding the diversification process and the phylogeny in the 'Pinot' group.Key words: microsatellite, diversity, somatic mutation, chimerism, Vitis vinifera L., 'Pinot'.
Identification of AFLP makers linked to non-seed shattering locus (sht1) in buckwheat and conversion to STS markers for marker-assisted selection
Authors: Matsui K , Kiryu Y , Komatsuda T , Kurauchi N , Ohtani T , Tetsuka T
Published: June 2004

Shattering habit in buckwheat has two forms: brittle pedicel and weak pedicel. Brittle pedicel is observed in wild buckwheat, but not in cultivated buckwheat. Brittle pedicel in buckwheat is produced by two complementary, dominant genes, Sht1 and Sht2. The sht1 locus is linked to the S locus; almost all common buckwheat cultivars possess the allele sht1. To detect molecular makers linked to the sht1 locus, we used amplified fragment-length polymorphism (AFLP) analysis in combination with bulked segregant analysis of segregating progeny of a cross between a non-brittle common buckwheat and a brittle self-compatible buckwheat line. We screened 312 primer combinations and constructed a linkage map around the sht1 locus by using 102 F2plants. Five AFLP markers were linked to the sht1 locus. Two of these, e54m58/610 and e55m46/320, cosegregated with the sht1 locus without recombination. The two AFLP markers were converted to STS markers according to the sequence of the AFLPs. The STS markers are useful for marker-assisted selection of non-brittle pedicel plants and provides a stepping-stone for map-based cloning and characterization of the gene encoding non-brittle pedicel.Key words: Fagopyrum esculentum, brittle pedicel, self-compatibility, bulked segregant analysis.
Gypsy-like retrotransposons in Pyrenophora: an abundant and informative class of molecular markers
Authors: Taylor Emily J.A , Konstantinova Pavlina , Leigh Fiona , Bates Jayne A , Lee David
Published: June 2004

This paper describes the development of S-SAP (sequence-specific amplified polymorphism) using a primer derived from the LTR (long terminal repeat) of the Pyggy retrotransposon isolated from Pyrenophora graminea. Fragments were amplified by S-SAP from different Pyrenophora spp., indicating the presence of Pyggy-like sequences in these genomes. The bands were highly polymorphic between isolates and the number of bands differed by as much as 10-fold between species, demonstrating the potential of this method for genetic analysis in fungi. The phylogenetic relationship among the isolates as deduced using S-SAP data is presented, and shows evidence of genetic exchange between P. graminea and P. teres.Key words: Pyrenophora, retrotransposon, molecular markers, S-SAP.
DNA–Feulgen cytophotometric determination of genome size for the freshwater-invading copepod Eurytemora affinis
Authors: Rasch Ellen M , Lee Carol Eunmi , Wyngaard Grace A
Published: June 2004

Variation in nuclear DNA content within some eukaryotic species is well documented, but causes and consequences of such variation remain unclear. Here we report genome size of an estuarine and salt-marsh calanoid copepod, Eurytemora affinis, which has recently invaded inland freshwater habitats independently and repeatedly in North America, Europe, and Asia. Adults and embryos of E. affinis from the St. Lawrence River drainage were examined for somatic cell DNA content and the presence or absence of embryonic chromatin diminution, using Feulgen–DNA cytophotometry to determine a diploid or 2C genome size of 0.6–0.7 pg DNA/cell. The majority of somatic cell nuclei, however, have twice this DNA content (1.3 pg/nucleus) in all of the adults examined and possibly represent a population of cells arrested at the G2 stage of the cell cycle or associated with some degree of endopolyploidy. Both suggestions contradict assumptions that DNA replication does not occur in adult tissues during the determinate growth characteristic of copepods. Absence of germ cell nuclei with markedly elevated DNA values, commonly found for species of cyclopoid copepods that show chromatin diminution, indicates that E. affinis lacks this trait. The small genome size and presumed absence of chromatin diminution increase the potential utility of E. affinis as a model for genomic studies on mechanisms of adaptation during freshwater invasions.Key words: copepod, genome size, DNA–Feulgen, calanoid, Eurytemora.
Paraoxical relationship between protein content and nucleolar activity in mammalian cardiomyocytes
Authors: Anatskaya Olga V , Vinogradov Alexander E
Published: June 2004

It was recently demonstrated that polyploidization of the avian myocardium is associated with a reduction of cardiac aerobic capacity evaluated by the heart mass to body mass ratio (heart index). To investigate possible cellular correlates of polyploidization, the protein content and nucleolar activity per cell and per genome were examined by image cytometry in 21 mammalian species, differing in the degree of heart polyploidization and heart index. We found that average cardiomyocyte ploidy level correlates negatively with the animal heart index (r = –0.75, p < 10–4), i.e., the large heart of athletic mammals is polyploidized to a lesser degree than the relatively smaller heart of sedentary species, which confirms the picture observed in birds. The protein content per genome decreased with the elevation of cardiomyocyte ploidy level. This inverse correlation was especially pronounced with the removed effect of body mass (r = –0.79, p < 10–4). Surprisingly, these changes were accompanied by the increase of nucleolar activity per genome (r = 0.61, p < 10–3). In the two species, for which the microarray gene expression data were available (human and mouse), this increase was paralleled by the elevated expression of ribosomal protein genes (but there was no increase in the expression of tissue-specific genes). Thus, in the polyploid cardiomyocytes there is a misbalance between protein content per genome and ribosome biogenesis. The reduction of protein content (per genome) of polyploid cardio my ocytes should further curtail heart functionality (in addition to reduction of heart index), because it is known that cardio myocyte protein content consists of more than 90% contractile proteins. This finding makes doubtful a widespread notion that polyploidization is necessary for cell function. Because somatic polyploidization is associated with stressful conditions and impaired energetics, we suppose that additional genomes can serve for cell regeneration and as a defense against oxidative damage in the organs that work at the limit of their metabolic capacity.Key words: somatic polyploidy, heart, functional capacity, protein–DNA ratio.
Ancestral genome duplication in rice
Authors: Guyot Romain , Keller Beat
Published: June 2004

The recent availability of the pseudochromosome sequences of rice allows for the first time the investigation of the extent of intra-genomic duplications on a large scale in this agronomically important species. Using a dot-matrix plotter as a tool to display pairwise comparisons of ordered predicted coding sequences along rice pseudochromosomes, we found that the rice genome contains extensive chromosomal duplications accounting for 53% of the available sequences. The size of duplicated blocks is considerably larger than previously reported. In the rice genome, a duplicated block size of >1 Mb appears to be the rule and not the exception. Comparative mapping has shown high genetic colinearity among chromosomes of cereals, promoting rice as a model for studying grass genomes. Further comparative genome analysis should allow the study of the conservation and evolution of these duplication events in other important cereals such as rye, barley, and wheat.Key words: rice, genome duplication, genome evolution.
MULTI-GRAVITON THEORY FROM A DISCRETIZED RS BRANE-WORLD AND THE INDUCED COSMOLOGICAL CONSTANT
Authors: COGNOLA GUIDO , ZERBINI SERGIO , ELIZALDE EMILIO , NOJIRI SHIN'ICHI , ODINTSOV SERGEI D.
Published: June 2004

We propose a multi-graviton theory with non-nearest-neighbor couplings in the theory space. The resulting four-dimensional discrete mass spectrum reflects the structure of a latticed extra dimension. For a plausible mass spectrum motivated by the discretized Randall–Sundrum brane-world, the induced cosmological constant turns out to be positive and may serve as a quite simple model for the dark energy of our accelerating universe.
SPIN POLARON IN A QUANTUM DOT OF THE DILUTED MAGNETIC SEMICONDUCTORS
Authors: GNANASEKAR K. , NAVANEETHAKRISHNAN K.
Published: June 2004

Theoretical investigations of spin polaron in a quantum dot in the "spin doping" superlattice systems Cd 1 - X in Mn X in Te/Cd 1 - X out Mn X out Te are presented. We estimated the donor ionization energy by variational technique and the spin polaronic shift using the mean field theory with modified Brillouin function. Our results show that significant enhancement of donor ionization energy and spin polaronic shift occur in a dot when compared to a quantum well, wire and bulk systems.