bluuebunny/crossref_metadata_2025_split huggingface dataset:
Translational repression mechanisms in prokaryotes
Authors: Schlax Paula Jean , Worhunsky David J. 
Published: May 2003

SummaryTranslational repression results from a complex choreography of macromolecular interactions interfering with the formation of translational initiation complexes. The relationship between the rate and extent of formation of these interactions to form repressed mRNA complexes determines the extent of repression. A novel analysis of repression mechanisms is presented here and it indicates that the reversibility of repressed complex formation influences the steady state balance of the distribution of translationally active and inactive complexes and therefore has an impact on the efficiency of repression. Reviewed here is evidence for three distinct translational repression mechanisms, regulating expression of the transcription factor σ32, threonine tRNA synthetase and ribosomal proteins on the α operon in Escherichia coli. Efficient regulation of expression in these systems makes use of specific mRNA structures in quite different ways.
Identification of Candida albicans genes induced during thrush offers insight into pathogenesis
Authors: Cheng Shaoji , Clancy Cornelius J. , Checkley Mary Ann , Handfield Martin , Hillman Jeffrey D. , Progulske‐Fox Ann , Lewin Alfred S. , Fidel Paul L. , Nguyen M. Hong 
Published: May 2003

Summary Candida albicans causes a wide spectrum of diseases, ranging from mucocutaneous infections like oral thrush to disseminated candidiasis. Screening for C. albicans genes expressed within infected hosts might advance understanding of candidal pathogenesis, but is impractical using existing techniques. In this study, we used an antibody‐based strategy to identify C. albicans genes expressed during thrush. We adsorbed sera from HIV‐infected patients with thrush against candidal cells grown in vitro and screened a C. albicans genomic expression library. We identified 10 genes encoding immunogenic antigens and used reverse transcription‐polymerase chain reaction to verify that they were induced within thrush pseudomembranes recovered from a patient. The in vivo induced genes are involved in diverse functions, including regulation of yeast‐hyphal morphogenesis, adhesion to host cells, nutrient uptake, phospholipid biosynthesis and amino acid catabolism. Four genes encode known virulence determinants (HWP1, CST20, CPP1 and RBF1). Another gene, LPD1, for which a role in candidal pathogenesis is unknown, encodes a protein homologous to a bacterial virulence determinant. Most importantly, disruption of CaNOT5, a newly identified gene, conferred defects in morphogenesis, decreased adherence to human buccal epithelial cells and attenuated mortality during murine disseminated candidiasis, proving that our strategy can identify genes encoding novel virulence determinants.
Prevalence and Economic Importance of Cystic Echinococcosis in Slaughtered Ruminants in Burdur, Turkey1
Authors: Umur S. , Kaaden O.‐R. 
Published: May 2003

SummaryThis study was conducted between April 2000 and March 2001, in 12‐month period. During the study, local slaughterhouses were visited periodically for 1 year to examine the internal organs (livers, lungs, spleens and hearts) for the presence of cysts and total 1355 cattle, 218 sheep and 104 goats were examined for the cystic echinococcosis (CE). It was found that 13.5% of cattle, 26.6% of sheep and 22.1% of goats were infected with this disease. While cysts in cattle (P < 0.001) and goats (P > 0.05) were found mostly in lungs (88.5 and 82.6%, respectively), but they were mostly found in livers (P > 0.05) in sheep. In addition to this, three spleens and one heart in cattle were infected with CE. In this study, the prevalence of CE and the number of cysts in ruminants were found different when the cattle, sheep and goats examined were stratified based on age. The prevalence and the number of cysts increased with age approaching an asymptotic prevalence of one in the oldest animals (P < 0.05). The number of cysts in cattle, sheep and goats were increasing at a rate of 0.31, 0.63 and 0.42/year, respectively. The economic decrease in the value of the carcasses because of the discarded liver and lung as a result of CE was estimated as 1.1% ($7.5 per cattle) for cattle, 4.37% ($3.2 per sheep) for sheep and 4.26% ($2.9 per goat) for goats. The minimum total loss for all infected animals was determined to be $583 in infected animals, based on the market prices in the year 2002.
Bulk Tank Milk Analysis: Factors Associated with Appearance ofMycoplasmasp. in Milk
Authors: Fox L. K. , Hancock D. D. , Mickelson A. , Britten A. , Kaaden O.‐R. 
Published: May 2003

SummaryFactors associated with the presence ofMycoplasmasp. in bulk tank milk samples were evaluated from 664 herds during 2.25 years. Milk quality components were not strongly related to the presence ofMycoplasmasp. in bulk tank milk. The presence of other contagious mastitis pathogens,Staphylococcus aureusandStreptococcus agalactiae, was also not related to the presence of mycoplasma, suggesting that the aetiology and transmission of mycoplasma mastitis were different from transmission of other contagious mastitis pathogens. The occurrence of the first isolation of mycoplasma from a bulk tank was not correlated to season of the year. Mycoplasma in bulk tank milk samples were more likely to be found in herds shipping more milk, an indirect measure of herd size. This suggests that larger herds are more likely to have mycoplasma mastitis. However, the first appearance of mycoplasma mastitis in a bulk tank sample was followed by a sample without this pathogen in more than 60% of herds.Mycoplasmasp. was not detected in any herd a year after first isolation. These findings suggest that this pathogen could be controlled and eliminated from herds.
Prominent induction of cyclin B1 in G2/M renal cancer cells with butyrolactone 1
Authors: KASUYA YUTAKA , HOSAKA YOSHIO , MATSUSHIMA HISASHI , GOTO TOSHITAKA , KITAMURA TADAICHI , OKUYAMA AKIRA 
Published: May 2003

AbstractBackground: Butyrolactone 1 (BL) is a cyclin dependent kinase (CDK) inhibitor derived from Aspergillus terreus. None of the present drugs are effective for the treatment of renal cell carcinoma. The use of BL is expected to promote a new type therapy of renal cancer.Methods: We investigated three human renal cancer cell lines: ACHN, OS‐RC‐2 and RCC10RGB, using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and two‐color flow cytometry. Simultaneous measurements of DNA content and cyclin expression allowed us to perform cell cycle specific analysis. Western blot analysis was performed using ACHN to represent cell lines.Results: BL inhibited cell proliferation and caused cell accumulation at G2/M phase associated with the emergence of the third peak. Moreover, BL induced cyclin B1 over‐expression in G2/M cells. These changes were quite definite, whereas cyclins D1, E and A showed no changes at all. Cyclin B1 accumulation was confirmed by western blot analysis. The chronological observation revealed that the emergence of the third peak preceded the regression of the increased cyclin B1 positive G2/M cells. These results suggested that BL accelerated cyclin B1 accumulation in G2/M cells, which then shifted to G1 phase without cell division. New G1 cells started DNA synthesis most likely as endoreduplication to form the third peak and the mechanism of cyclin B1 accumulation converted into down‐regulation.Conclusion: BL induced significant cell kinetic interference in the tested human renal carcinoma cell lines. This might indicate the possibility of a new medical treatment modality for renal cancer.
Cadmium nephrotoxicity and evacuation from the body in a rat modeled subchronic intoxication
Authors: AOYAGI TEIICHIRO , HAYAKAWA KUNIHIRO , MIYAJI KEISUKE , ISHIKAWA HIROMICHI , HATA MAKOTO 
Published: May 2003

AbstractBackground: Cadmium (Cd) is an important industrial pollutant, although its mechanism of toxicity has not been completely clarified. We studied Cd‐induced subchronic nephrotoxicity and the cadmium evacuation system in rats and cultured human renal tubular cells.Methods: Male Sprague–Dawley rats were subcutaneously injected with 0.6 mg Cd/kg per day for periods of 3, 5 and 8 weeks. The concentration of Cd in urine, serum and kidneys was measured by atomic absorption spectrophotometry. Nephrotoxicity was evaluated based on the urinary concentration of β2 microglobulin (B2MG) and histopathological findings. Apoptotic cells were detected by nick‐end labeling and DNA laddering, and were based on the level of caspase‐3 activity. Cadmium‐induced toxicity was also studied in cultured human renal tubular cells.Results: Nephrotoxicity was detected after 4 weeks of exposure to Cd, because Cd and B2MG appeared in urine. The tissue concentration of Cd increased linearly throughout the 8 weeks of exposure to Cd. The concentration of renal Cd did not change in the 3‐week exposure group, but it decreased after withdrawal of Cd in the 5‐week exposure group, suggesting an active Cd excretion mechanism started after the 4th week. The threshold Cd concentration for nephrotoxicity was 150 micrograms/gram wet tissue, at which concentration histological tubular damage started. Although the kidneys presented mainly necrosis, apoptosis was observed at weeks 4 and 5, before renal tubular necrosis occurred. In vitro DNA laddering was observed and peak caspase‐3 activity was detected when the cells were exposed to the threshold concentration of Cd.Conclusion: Cadmium was effectively evacuated from the body by exfoliation of damaged renal tubular cells presenting focal tubular necrosis after the renal Cd concentration reached the threshold. Apoptosis may be involved in the regulation of Cd‐induced nephrotoxicity.
Significance of capsular attachment and invasion of cancer tissues in prostate cancer
Authors: TANAKA MASASHI , SUZUKI NORIYUKI , NAKATSU HIROOMI , MURAKAMI SHINO , MATSUZAKI OSAMU , SHIMAZAKI JUN 
Published: May 2003

AbstractBackground: There is a discrepancy in tumor node metastasis (TNM) staging of capsular attachment and invasion; the condition was classified as pT3 in 1987, then as pT2 in 1992. Because capsular finding associated with radical prostatectomy is an important prognostic factor, the present study was conducted to characterize clinicopathological states of cancer tissues attached to and invading the capsule.Methods: Specimens removed by radical prostatectomy exhibiting pT2 or pT3 from 90 patients who did not receive any treatment before surgery were classified as Loc (24%, cancer tissues localized and apart from capsule), Inv (59%, attached to and invading but not penetrating capsule) and Pen (17%, penetrating capsule). Their clinicopathological profiles were examined.Results: Gleason score, volume of cancer tissues, seminal vesicle invasion, positive surgical margin and regional lymph node metastasis of Inv were distributed between those of Loc and Pen. Postoperative management was decided as routine check‐up or endocrine therapy according to pathological findings. Median follow‐up was 59 months. Prostate‐specific antigen (PSA) relapse occurred in 13 patients, one of whom died of prostate cancer. The remaining of these patients lived. Rate of PSA relapse was not different between Loc and Inv, mainly due to endocrine therapy to Inv with high risk factors.Conclusion: Pathological profile of Inv lies between those of Loc and Pen. Therefore, pT2a (1997) would be subclassified as Loc and Inv. Patients with Inv may be required to receive the respective management according to clinicopathological profile, which would be different to that of Loc.
Association of absence of intestinal oxalate degrading bacteria with urinary calcium oxalate stone formation
Authors: MIKAMI KAZUO , AKAKURA KOICHIRO , TAKEI KAZUSHIRO , UEDA TAKESHI , MIZOGUCHI KEN’ICHI , NODA MASATOSHI , MIYAKE MASAMI , ITO HARUO 
Published: May 2003

AbstractAim: Urinary concentration of oxalate is considered an important factor in the formation of renal stones. Dietary oxalate is a major contributor to urinary oxalate excretion in most individuals. Furthermore, oxalate degrading bacteria have been isolated from human feces. We investigated the significance of oxalate degrading bacteria for urinary oxalate excretion and urinary stone formation.Methods: Twenty‐two known calcium oxalate stone‐forming patients (stone formers) and 34 healthy volunteers (non‐stone formers) were included in the study. Stool specimens were inoculated into pepton yeast glucose (PYG) medium supplemented with oxalate under anaerobic condition at 37 C for one week. After the incubation period, each colony was checked for the loss of oxalate from the culture medium. A 24‐h urine sample was collected in 43 individuals and analyzed for oxalate excretion.Results: Twenty‐eight of 34 (82%) healthy volunteers and 10 of 22 (45%) calcium oxalate stone formers were colonized with oxalate degrading bacteria. Calcium oxalate stone formers were more frequently free of oxalate degrading bacteria (P < 0.01). Urinary excretion of oxalate in those with oxalate degrading bacteria was significantly less than in those without oxalate degrading bacteria (P < 0.05). Hyperoxaluria (> 40 mg/day) was found in four of 27 individuals (15%) with oxalate degrading bacteria compared to seven of 16 (44%) without oxalate degrading bacteria (P < 0.05), suggesting an association between the absence of oxalate degrading bacteria and the presence of hyperoxaluria.Conclusion: The absence of oxalate degrading bacteria in the gut could promote the absorption of oxalate, thereby increasing the level of urinary oxalate excretion. The absence of oxalate degrading bacteria from the gut appears to be a risk factor for the presence of absorptive hyperoxaluria and an increased likelihood of urolithiasis.
Functional evaluation of one‐stage urethroplasty with parameatal foreskin flaps repair of hypospadias using uroflowmetry
Authors: ANWAR AHMED , KUROKAWA YASUSHI , TAKAHASHI MASAYUKI , YAMAMOTO YASUYO , KANAYAMA HIRO‐OMI , KAGAWA SUSUMU 
Published: May 2003

AbstractBackground: Uroflowmetry is a simple, accurate and non‐invasive test. In the present study, we aimed to determine the role of uroflowmetry in the evaluation of the functional results of one‐stage urethroplasty with parameatal foreskin flaps (OUPF) technique.Methods: Twenty‐one children who had undergone OUPF repair at our clinic were selected. Selection criteria were that patients were toilet trained and had no fistula. Uroflowmetry was performed using a rotating disk sensor. The maximum flow rate (Qmax) and average flow rate (Qave) were plotted against body surface related flow rate nomograms. The upper 95% tolerance limits for the 5th, 10th, 15th, 20th and 25th percentiles of the normal population were used for comparison. The flow pattern was classified as bell ring, plateau or intermittent.Results: The median age at the first uroflowmetry was 4.7 years (range 2.5–8.6) and the mean postoperative follow‐up period was 25 months (range 1–58). Twelve children had Qmax above the 25th, six between the 5th and 25th and three less than the 5th percentiles of the normal population. A normal bell‐shaped flow curve was obtained in 17 (80.6%) of the children. Of the three children with Qmax below the 5th percentile, two children had a plateau flow pattern and were found to have a urethal stricture. Dilation was performed successfully, after which the Qmax returned to the normal range and the symptoms disappeared.Conclusion: The OUPF technique provided satisfactory functional results for hypospadias repair. We advocate the use of uroflowmetry for routine postoperative follow‐up.
Bladder smooth muscle cell phenotypic changes and implication of expression of contractile proteins (especially caldesmon) in rats after partial outlet obstruction
Authors: MATSUMOTO SEIJI , HANAI TADASHI , OHNISHI NORIO , YAMAMOTO KAZUHIKO , KURITA TAKASHI 
Published: May 2003

AbstractBackground: The purpose of the present study was to investigate morphological changes in bladder smooth muscle of rats with partial outlet obstruction. We investigated smooth muscle cell phenotypic changes and implication of synthetic phenotype in contractility decrease and bladder compliance after bladder outlet obstruction.Methods: Partial bladder outlet obstruction was introduced in female rats. Bladder were removed at 1, 3, 6, 10 and 20 weeks after the obstruction. Temporal pattern of changes in bladder mass, light microscopic pathogenesis and phenotypic expression of the bladder smooth muscle cells in the electron micrographs were investigated. Expression of contractile protein was also investigated by the immunoblotting method.Results: Marked increase in bladder mass with marked thickening of smooth muscle layer was observed at 1 week after obstruction. The ratio of myocytes exhibiting contractile and synthetic phenotypes was almost constant until 6 weeks after the obstruction, but thereafter, synthetic phenotypes gradually increased and the ratio (synthetic/contractile phenotype) was 1.5‐fold at 20 weeks after the obstruction. Caldesmon was most markedly expressed after the obstruction among contractile proteins examined by the immunoblotting method.Conclusion: Phenotypic changes were confirmed in bladder smooth muscle, and the decrease of the ratio of contractile phenotype was observed after long‐term obstruction of the bladder outlet. Among the contractile proteins in the bladder smooth muscle cell, caldesmon was considered a reliable marker for predicting the pathogenetic conditions of the bladder.
Neurogenesis and aging: FGF‐2 and HB‐EGF restore neurogenesis in hippocampus and subventricular zone of aged mice
Authors: Jin Kunlin , Sun Yunjuan , Xie Lin , Batteur Sophie , Mao Xiao Ou , Smelick Chris , Logvinova Anna , Greenberg David A. 
Published: May 2003

SummaryNeurogenesis, which may contribute to the ability of the adult brain to function normally and adapt to disease, nevertheless declines with advancing age. Adult neurogenesis can be enhanced by administration of growth factors, but whether the aged brain remains responsive to these factors is unknown. We compared the effects of intracerebroventricular fibroblast growth factor (FGF)‐2 and heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF) on neurogenesis in the hippocampal dentate subgranular zone (SGZ) and the subventricular zone (SVZ) of young adult (3‐month) and aged (20‐month) mice. Neurogenesis, measured by labelling with bromodeoxyuridine (BrdU) and by expression of doublecortin, was reduced by ∼90% in SGZ and by ∼50% in SVZ of aged mice. HB‐EGF increased BrdU labelling in SGZ at 3 months by ∼60% and at 20 months by ∼450%, which increased the number of BrdU‐labelled cells in SGZ of aged mice to ∼25% of that in young adults. FGF‐2 also stimulated BrdU labelling in SGZ, by ∼25% at 3 months and by ∼250% at 20 months, increasing the number of newborn neurones in older mice to ∼20% of that in younger mice. In SVZ, HB‐EGF and FGF‐2 increased BrdU incorporation by ∼140% at 3 months and ∼170% at 20 months, so the number of BrdU‐labelled cells was comparable in untreated 3‐month‐old and growth factor‐treated 20‐month‐old mice. These results demonstrate that the aged brain retains the capacity to respond to exogenous growth factors with increased neurogenesis, which may have implications for the therapeutic potential of neurogenesis enhancement in age‐associated neurological disorders.
Evolution of male longevity bias in nematodes
Authors: McCulloch Diana , Gems David 
Published: May 2003

SummaryMany animal species exhibit sex differences in aging. In the nematode Caenorhabditis elegans, under conditions that minimize mortality, males are the longer‐lived sex. In a survey of 12 independent C. elegans isolates, we find that this is a species‐typical character. To test the hypothesis that the C. elegans male longevity bias evolved as a consequence of androdioecy (having males and hermaphrodites), we compared sex‐specific survival in four androdioecious and four dioecious (males and females) nematode species. Contrary to expectation, in all but C. briggsae (androdioecious), males were the longer‐lived sex, and this difference was greatest among dioecious species. Moreover, male lifespan was reduced in androdioecious species relative to dioecious species. The evolutionary theory of aging predicts the evolution of a shorter lifespan in the sex with the greater rate of extrinsic mortality. We demonstrate that in each of eight species early adult mortality is elevated in females/hermaphrodites in the absence of food as the consequence of internal hatching of larvae (matricide). This age‐independent mortality risk can favour the evolution of rapid aging in females and hermaphrodites relative to males.
Involvement of the INK4a/Arf gene locus in senescence
Authors: Collins Carol J. , Sedivy John M. 
Published: May 2003

SummaryThe INK4a/ARF locus encodes two proteins whose expression limits cellular proliferation. Whilst the biochemical activities of the two proteins appear very different, they both converge on regulating the retinoblastoma and p53 tumour suppressor pathways. Neither protein is required for normal development, but lack of either predisposes to the development of malignancy. Both proteins have also been implicated in the establishment of senescence states in response to a variety of stresses, signalling imbalances and telomere shortening. The INK4a/Arf regulatory circuits appear to be partially redundant and show evidence of rapid evolution. Especially intriguing are the large number of biological differences documented between mice and man. We review here the brief history of INK4a/Arf and explore possible links with organismal aging and the evolution of longevity.
Modelling cellular senescence as a result of telomere state
Authors: Proctor Carole J. , Kirkwood Thomas B. L. 
Published: May 2003

SummaryTelomeres in mammalian cells end in large duplex T loops. These loops protect the single‐strand overhangs from degradation and/or interactions with signalling proteins. This protection is sometimes referred to as capping. At each cell division, telomeres shorten and there is a general consensus that telomere shortening triggers cell cycle exit. However, the exact mechanism by which telomere shortening causes cell cycle arrest is not known. Mathematical models of telomere shortening have been developed to help us understand the processes involved. Until now most models have assumed that the trigger for cell cycle arrest is the first telomere or a group of telomeres reaching a critically short length. However, there is evidence that cells stop cycling over a wide range of telomere lengths. This suggests that telomere length per se may not in fact be the trigger for cellular senescence. In this paper we develop a model which examines the hypothesis that uncapping of a telomere is the main trigger. By letting the probability of uncapping depend upon telomere length, we show that the hypothesized model provides a good fit to experimental data.