bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new approach for improving the birefringence analysis of dental enamel mineral content using polarizing microscopy
Authors: SOUSA F. B. , VIANNA S. S. , SANTOS‐MAGALHÃES N. S. 
Published: February 2006

SummaryThe main problem in interpreting birefringence of dental enamel under polarizing microscopy is the lack of physical constants able to allow the Wiener equation to be applied directly to the composition of such tissue. The present study introduces a new approach to circumvent this constraint. Because the nonmineral phase of enamel is heterogeneous, its refractive index can be computed in terms of its components (namely, water, which is partially replaced by the immersion medium, and organic matter), thereby providing a more acceptable refractive index to be used in the Wiener equation. Furthermore, the enamel mineral volume is ordinarily calculated on the basis of the density 3.15 g cm−3. The density 2.99 g cm−3 has been, however, reported to be more accurate for enamel hydroxyapatite, so enamel mineral volumes from selected published data were converted using such a density. The birefringence of mature enamel computed by the Wiener equation, taking into account the above refinements, matched, for the first time, published experimental birefringence values. The theoretical water and organic contents were also consistent with published experimental data. Thus, a direct application of the Wiener equation to the enamel composition has now been achieved. It is speculated that quantitative data on the mineral, the water and the organic contents of mature dental enamel can be derived from interpretation of birefringence in two immersion media (obtained before and after extraction of the organic matter) with this new approach.
The quantitative analysis of thin specimens: a review of progress from the Cliff‐Lorimer to the new ζ‐factor methods
Authors: WATANABE M. , WILLIAMS D. B. 
Published: February 2006

SummaryA new quantitative thin‐film X‐ray analysis procedure termed the ζ‐factor method is proposed. This new ζ‐factor method overcomes the two major limitations of the conventional Cliff‐Lorimer method for quantification: (1) use of pure‐element rather than multielement, thin‐specimen standards and (2) built‐in X‐ray absorption correction with simultaneous thickness determination. Combined with a universal, standard, thin specimen, a series of ζ‐factors covering a significant fraction of the periodic table can be estimated. This ζ‐factor estimation can also provide information about both the detector efficiency and the microscope–detector interface system. Light‐element analysis can also be performed more easily because of the built‐in absorption correction. Additionally, the new ζ‐factor method has several advantages over the Cliff‐Lorimer ratio method because information on the specimen thickness at the individual analysis points is produced simultaneously with compositions, thus permitting concurrent determination of the spatial resolution and the analytical sensitivity. In this work, details of the ζ‐factor method and how it improves on the Cliff‐Lorimer approach are demonstrated, along with several applications.
Three times out of Asia Minor: the phylogeography of Arabis alpina L. (Brassicaceae)
Authors: KOCH MARCUS A. , KIEFER CHRISTIANE , EHRICH DOROTHEE , VOGEL JOHANNES , BROCHMANN CHRISTIAN , MUMMENHOFF KLAUS 
Published: February 2006

Abstract Arabis alpina is a characteristic plant in arctic‐alpine habitats and serves as a classical example to demonstrate biology, ecology and biogeography of arctic‐alpine disjuncts. It has a wider distribution than most other arctic‐alpine plants, covering all European mountain systems, the Canary Islands, North Africa, the high mountains of East Africa and Ethiopia, the Arabian Peninsula and mountain ranges of Central Asia in Iran and Iraq. Additionally it is found in the northern amphi‐Atlantic area including northeastern North America, Greenland, Iceland, Svalbard and northwestern Europe. We used markers from the nuclear (internal transcribed spacer of ribosomal DNA) and chloroplast genome (trnL‐F region) to reconstruct its phylogeographic history. Both markers revealed clear phylogeographic structure. We suggest that A. alpina originated in Asia Minor less than 2 million years ago based on synonymous mutation rates of different genes (plastidic matK, nuclear adh and chs). From the Asian ancestral stock one group migrated via the Arabian Peninsula to the East African high mountains. A second group gave rise to all European and northern populations, and also served as source for the northwest African populations. A third group, which is still centred in Asia, migrated independently southwards and came into secondary contact with the East African lineage in Ethiopia, resulting in high genetic diversity in this area. In the Mediterranean regions, the genetic diversity was relatively high with numerous unique haplotypes, but almost without geographic structure. In contrast, the populations in the northern amphi‐Atlantic area were extremely depauperate, suggesting very recent (postglacial) expansion into this vast area from the south.
Ecological and evolutionary genomics of Saccharomyces cerevisiae
Authors: LANDRY CHRISTIAN R. , TOWNSEND JEFFREY P. , HARTL DANIEL L. , CAVALIERI DUCCIO 
Published: February 2006

Abstract Saccharomyces cerevisiae, the budding yeast, is the most thoroughly studied eukaryote at the cellular, molecular, and genetic levels. Yet, until recently, we knew very little about its ecology or population and evolutionary genetics. In recent years, it has been recognized that S. cerevisiae occupies numerous habitats and that populations harbour important genetic variation. There is therefore an increasing interest in understanding the evolutionary forces acting on the yeast genome. Several researchers have used the tools of functional genomics to study natural isolates of this unicellular fungus. Here, we review some of these studies, and show not only that budding yeast is a prime model system to address fundamental molecular and cellular biology questions, but also that it is becoming a powerful model species for ecological and evolutionary genomics studies as well.
Rare arctic‐alpine plants of the European Alps have different immigration histories: the snow bed species Minuartia biflora and Ranunculus pygmaeus
Authors: SCHÖNSWETTER P. , POPP M. , BROCHMANN C. 
Published: February 2006

Abstract Minuartia biflora and Ranunculus pygmaeus are circumarctic plants with a few isolated occurrences in the European Alps. We analysed amplified fragment length polymorphism (AFLP) and chloroplast DNA sequence data to unravel the history of their immigration into the Alps and to provide data on their circumpolar phylogeography. In spite of the similar ecological requirements of the two species, they exhibit strikingly different immigration histories into the Alps. In M. biflora, the Alpine populations are most probably derived from source populations located between the Alpine and Scandinavian ice sheets, in accordance with the traditional biogeographic hypothesis. In contrast, the Alpine populations of R. pygmaeus cluster with those from the Tatra Mountains and the Taymyr region in northern Siberia, indicating that the distant Taymyr area served as source for the Alpine populations. Both species showed different levels of genetic diversity in formerly glaciated areas. In contrast to the considerable AFLP diversity observed in M. biflora, R. pygmaeus was virtually nonvariable over vast areas, with a single phenotype dominating all over the Alps and another, distantly related one dominating the North Atlantic area from Greenland over Svalbard to Scandinavia. The same pattern was observed in chloroplast DNA sequence data. Thus, postglacial colonization of R. pygmaeus was accompanied by extreme founder events.
Detecting the signature of selection on immune genes in highly structured populations of wild sheep (Ovis dalli)
Authors: WORLEY K. , CAREY J. , VEITCH A. , COLTMAN D. W. 
Published: February 2006

AbstractThe confounding effects of population structure complicate efforts to identify regions of the genome under the influence of selection in natural populations. Here we test for evidence of selection in three genes involved in vertebrate immune function — the major histocompatibility complex (MHC), interferon gamma (IFNG) and natural resistance associated macrophage polymorphism (NRAMP) — in highly structured populations of wild thinhorn sheep (Ovis dalli). We examined patterns of variation at microsatellite loci linked to these gene regions and at the DNA sequence level. Simple Watterson's tests indicated balancing selection at all three gene regions. However, evidence for selection was confounded by population structure, as the Watterson's test statistics from linked markers were not outside of the range of values from unlinked and presumably neutral microsatellites. The translated coding sequences of thinhorn IFNG and NRAMP are fixed and identical to those of domestic sheep (Ovis aries). In contrast, the thinhorn MHC DRB locus shows significant evidence of overdominance through both an excess of nonsynonymous substitution and trans‐species polymorphism. The failure to detect balancing selection at microsatellite loci linked to the MHC is likely the result of recombination between the markers and expressed gene regions.
Interspecies mating in sympatric species ofSyngnathuspipefish
Authors: WILSON A. B. 
Published: February 2006

AbstractHybridization is thought to be an important source of novel genetic variation, and interspecific hybridization may increase the adaptive potential of wild populations. While hybridization has not been previously reported in syngnathid fishes (seahorses and pipefish), the sympatric occurrence of closely related species at high densities increases the probability of interspecies mating in this group. Southern California is home to five species ofSyngnathuspipefish, and these species frequently co‐occur in near‐shore eelgrass beds along the California coast. Recent work has identified exceptionally high levels of genetic diversity in southern populations ofSyngnathus leptorhynchus, a widespread species which ranges from Mexico to Alaska. Microsatellite genotyping and mitochondrial sequence data are used here to study the population genetics ofS. leptorhynchusandS. auliscusat a site in San Diego Bay where they are found to co‐occur at high densities. While no adult hybrids were detected in the study population, analysis of male broods indicates that interspecies mating is occurring between the two species. The lack of premating isolating mechanisms between these two relatives suggests that hybridization may be common in sympatric species ofSyngnathus.
Outcome after kidney transplantation in children with thrombotic risk factors
Authors: Kranz Birgitta , Vester Udo , Nadalin Silvio , Paul Andreas , Broelsch Christoph E. , Hoyer Peter F. 
Published: February 2006

Abstract:  Background:  According to the data from the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS), vascular thrombosis accounts for 11.6% of graft losses in pediatric renal transplantation. In adults, inherited and acquired thrombophilic risk factors, e.g. factor V Leiden mutation, have been associated with early graft loss and increased rejection episodes. Data on the impact of these factors on the outcome of children after renal transplantation are rare.Methods/patients:  Sixty‐six pediatric patients awaiting renal transplantation (mean age 10.1 yr) were screened for inherited and acquired risk factors for hypercoagulable disorders (protein C, S, and antithrombin III deficiency, antiphospholipid antibodies, factor V Leiden, prothrombin, and MTHFR mutation) in order to intensify anticoagulation in those with an increased risk for thrombophilia: intravenous heparin was administered with a partial prothrombin time (PTT) prolongation of 50 s for 14 days and switched to low‐molecular‐weight heparin for another 8 wk before aspirin was introduced for the first year. Patients without hypercoagulable risk factors were treated with heparin without PTT prolongation for 14 days and switched to aspirin immediately afterwards.The results on graft survival, incidence of acute rejection episodes, and long‐term renal graft function were analyzed between recipients with and without hypercoagulable risk factors.Results:  Thrombophilic risk factors were identified in 27.3% of our patients. No thrombosis occurred. One serious bleeding complication led to a second surgical intervention. The rate of acute rejection episodes was not increased in patients with and without thrombotic risk factors after 90 days (16.7 vs. 25%), 1 yr (22.2 vs. 33.3%), and 3 yr (38.9 vs. 41.7%) of follow‐up, respectively (p = n.s.). After a mean follow‐up of 3 yr the kidney function was comparable in both groups, with 63.1 in recipients with and 69.8 mL/min/1.73 m2 in recipients without hypercoagulable risk (p = n.s.). At latest follow‐up, three graft losses were found not to be attributed to thrombotic risk factors.Interpretation:  Children with thrombophilic risk factors were identified and treated with an intensified anticoagulation regimen after renal transplantation. An increased risk for graft failure, acute rejection episodes, or impaired renal function for pediatric renal transplant recipients with hypercoagulable status was not found.
CDX‐2 homeobox gene expression in human gastric carcinoma and precursor lesions
Authors: KIM HYUNG‐SEOK , LEE JI‐SHIN , FREUND JEAN‐NOEL , MIN KYUNG‐WHAN , LEE JEONG‐SOO , KIM WAN , JUHNG SANG‐WOO , PARK CHANG‐SOO 
Published: February 2006

AbstractBackground:  Recent studies have demonstrated that CDX‐2 is expressed in the intestinal metaplasia of the stomach and intestinal‐type gastric cancer. To address the role of CDX‐2 in carcinogenesis of gastric carcinomas of intestinal type, the expression of CDX‐2 in gastric carcinoma and precursor lesions were examined using immunohistochemistry.Methods:  A total of 160 specimens diagnosed as gastric carcinomas or non‐invasive neoplasia from 158 patients were analyzed for CDX‐2 expression by immunochemical methods. Patients were classified into histopathologic subgroups according to the Padova international classification: 60 cases of low‐grade non‐invasive neoplasia, 55 cases of high grade, and 45 cases of invasive intestinal‐type adenocarcinoma. The CDX‐2 expression in non‐neoplastic gastric mucosa including intestinal metaplasia was also evaluated in the areas included in the histologic sections.Results:  The CDX‐2 expression was localized in the epithelial cell nuclei in the area of intestinal metaplasia with or without dysplasia and carcinoma, consistent with its role as a transcriptional regulator. No CDX‐2 reactivity was noted in the normal mucosa in all cases. The CDX‐2 expression was detected in 73.3% of low‐grade cases, 85.5% of high‐grade cases and 91.1% of intestinal‐type adenocarcinoma cases. In the gastric mucosa with intestinal metaplasia, 89.7% of the samples were positive. The CDX‐2‐expressing cells in intestinal metaplasia were more prevalent than in dysplasia and carcinoma. Expression of CDX‐2 showed a statistically significant positive correlation with increasing grade of dysplasia and carcinoma.Conclusions:  These findings suggest that CDX‐2 expression in stomach cancer may be a marker of the progression of gastric carcinogenesis, and that its activation may represent an early event.© 2005 Blackwell Publishing Asia Pty Ltd
Serum levels of transforming growth factor β1 are significantly correlated with venous invasion in patients with gastric cancer†
Authors: LIN YINGSONG , KIKUCHI SHOGO , OBATA YUKI , YAGYU KIYOKO ,   THE TOKYO RESEARCH GROUP ON PREVENTION OF GASTRIC CANCER
Published: February 2006

AbstractBackground and Aim:  The significance of serum levels of transforming growth factor (TGF)‐β1 in the development of gastric cancer is unclear. The purpose of this study is to determine whether serum TGF‐β1 correlated with the clinicopathological findings of patients with gastric cancer.Methods:  Transforming growth factor‐β1 levels in the serum of 275 gastric cancer patients and 275 gender‐ and age‐matched healthy controls were measured with enzyme‐linked immunosorbent assay (ELISA) using a commercially available kit.Results:  The mean level of serum TGF‐β1 of gastric cancer patients (15.9 ± 5.9 ng/mL) was significantly higher than that (13.9 ± 7.4 ng/mL) of healthy controls (P < 0.01). The odds ratio for the subjects in the highest quartile (16.7 ng/mL or more) was 4.03 (95% confidence interval, 2.14–7.58), as compared with that for the subjects in the lowest quartile (0–9.5 ng/mL). Patients with venous invasion compared to those without venous invasion had significantly elevated serum TGF‐β1 (17.3 ± 7.2 vs 15.0 ± 5.1 ng/mL; P = 0.04). There were no statistically significant differences between the two groups categorized by histological type, lymph node metastasis and distant metastasis. Logistical regression analysis showed that venous invasion was significantly correlated with elevated serum TGF‐β1 levels (P = 0.02).Conclusions:  The present study showed that an elevated serum TGF‐β1 level may be significantly correlated with venous invasion in gastric cancer patients.© 2005 Blackwell Publishing Asia Pty Ltd
Analysis of cytotoxic T lymphocyte associated antigen 4 gene polymorphisms in patients with ulcerative colitis
Authors: LANKARANI KAMRAN B , KARBASI ASHRAF , KALANTARI TAHEREH , YARMOHAMMADI HOOMAN , SABERI‐FIROOZI MEHDI , ALIZADEH‐NAEENI MAHVASH , TAGHAVI ALI R , FATTAHI MAHAMMAD R , GHADERI ABBAS 
Published: February 2006

AbstractBackground and Aim:  Ulcerative colitis (UC) is a multifactorial disease associated with dysregulated immunity. Recently, cytotoxic T lymphocyte associated antigen 4 (CTLA‐4) gene polymorphisms have been reported in association with several autoimmune diseases in several populations. In the present study, the possible implication of the CTLA‐4 gene as a risk factor for UC in the Iranian population was investigated.Methods:  One hundred UC patients and 100 healthy subjects were studied. CTLA‐4 exon 1 position 49 (A/G: codon 17: Thr/Ala) polymorphisms were investigated by polymerase chain reaction single strand confirmation polymorphism method. Four of the patients and one of the healthy controls were excluded from the study because of incomplete DNA extraction.Results:  The allele frequencies of A and G in 96 patients (A: 66.1%; G: 33.9%) were not significantly different from the 99 control subjects (A: 63.1%; G: 36.9%, P > 0.05). No significant differences in the distribution of genotype frequencies were observed between A + 49G gene polymorphisms and UC in the Iranian population (P > 0.05).Conclusion:  CTLA‐4 polymorphism is not associated with UC in the Iranian population.
Discordant influence of amphotericin B on epirubicin cytotoxicity in primary hepatic malignant cells collected by a new primary culture technique
Authors: LIN ZU‐YAU , CHUANG WAN‐LONG , CHUANG YEN‐HWANG , YU MING‐LUNG , HSIEH MING‐YUH , WANG LIANG‐YEN , TSAI JUNG‐FA 
Published: February 2006

AbstractBackground: The purpose of this prospective study was to investigate whether amphotericin B (AmB) had any potential role in the systemic chemotherapy of primary hepatic malignancy using cancer cells collected by the authors’ method of primary culture.Methods: The specimens obtained by ultrasound‐guided fine‐needle aspiration biopsy (22 G) from 15 patients with hepatocellular carcinoma (HCC) and one with cholangiocarcinoma were plated into culture flask without disaggregation by trypsin‐ethylenediamine tetra‐acetic acid solution. Six patients with HCC and one patient with cholangiocarcinoma (7/16, 44%) had successful culture and the cancer cells at the 4th passage were continuously exposed to therapeutic ranges of epirubicin (0, 0.5, 1.0, 1.5, 2.0 µg/mL) with or without the combination of 2.5 µg/mL AmB for 24 h. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay was applied to evaluate the effects of the drugs. A human HCC cell line (HA 22T/VGH) was studied for comparison.Results: Addition of AmB showed no influence on epirubicin cytotoxicity in two patients (one partial resistant HCC and one epirubicin‐sensitive cholangiocarcinoma; 25%), augmentation of the epirubicin cytotoxicity in two patients (one total resistant HCC, partial resistant HA 22T/VGH cell line and one epirubicin‐sensitive HCC; 37.5%), and decrease of epirubicin cytotoxicity in the remaining three (one partial resistant and two epirubicin‐sensitive HCC; 37.5%).Conclusions: Amphotericin B has a discordant influence on epirubicin cytotoxicity in primary cultured hepatic malignant cells. Application of AmB in the systemic chemotherapy of primary hepatic malignancy should be limited to patients with positive AmB effect evaluated by anin vitrosensitivity test such as the present method.
Gender‐related differences in visceral perception in health and irritable bowel syndrome
Authors: KIM HYUN SEO , RHEE POONG‐LYUL , PARK JUNGHO , LEE JUN HAENG , KIM YOUNG‐HO , KIM JAE JUN , RHEE JONG CHUL 
Published: February 2006

AbstractBackground:  Irritable bowel syndrome (IBS) is more common in female subjects, and IBS patients generally exhibit reduced pain thresholds to rectal distension. The aim of the present paper was to determine gender‐related differences in rectal perception in both healthy controls and IBS patients.Methods:  Fifty‐nine IBS patients (age 20–65 years; mean, 39.2 years; 31 women, 28 men) with symptoms that fulfilled Rome‐II criteria and 21 healthy controls (age 25–58 years; mean, 37.8 years; 11 women, 10 men) were recruited. Participants completed a questionnaire regarding bowel symptoms and psychological distress, and maximal tolerable pressures were evaluated via barostat tests.Results:  Although healthy women appear to have lower perception thresholds than men, significant gender differences in pain sensitivity were not detected (P > 0.05). In addition, female patients with IBS also exhibited no enhanced colorectal perception, as compared with male IBS patients (P > 0.05).Conclusions:  No gender differences in visceral perception were determined to exist between the healthy controls and the IBS patients. Therefore, the increased prevalence of IBS in women may be related to another set of pathophysiological factors, and not to gender‐related differences in visceroperception.
Antitumor effects of all‐trans‐retinoic acid on cultured human pancreatic cancer cells
Authors: Guo Junming , Xiao Bingxiu , Lou Yanru , Yan Chunhong , Zhan Li , Wang Donghui , Zhao Weihong 
Published: February 2006

AbstractBackground and Aim:  Although it is uncommon, pancreatic cancer is known to have a poor prognosis. The aim of the present study was to determine the inhibitory effects of all‐trans‐retinoic acid (ATRA) on cell growth, cell cycle and alkaline phosphatase (ALP) activity in the human pancreatic cancer cell line PANC‐1 in vitro.Methods:  Human pancreatic cancer PANC‐1 cells were treated by various concentrations of ATRA, and then the cell growth was determined by MTT viability assay. Cell cycle distribution and ALP activity were analyzed by flow cytometry and chemical analyzer, respectively.Results:  ATRA inhibited the growth of PANC‐1 cells grown in culture; a dose‐dependent inhibitory influence was found. ATRA arrested PANC‐1 cells at G2/M phase. The ALP activity of PANC‐1 cells was significantly increased by 1–50 µmol/L ATRA.Conclusions:  The antitumor effects of ATRA on human pancreatic cancer cells are associated with G2/M phase arrest and increased ALP activity.