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Biomedical subjects

G May

Publications and source records attributed to G May.

At least 19 recordsLinked to original sources
PubMed2006

Living kidney donation: anemia and inflammation in the early postoperative period.

Studies on living donor kidney transplantation primarily address the recipients; few publications focus on kidney donors. The aim of the present study was to detect changes in and compensations of defined parameters of anemia and inflammation in the immediate postnephrectomy period. We included six living kidney donors who underwent an open anterior-extraperitoneal nephrectomy. We excluded donors with complications, such as significant blood loss or infection. Blood samples were taken before nephrectomy as well as on postoperative days 1, 3, 5, and 7, and at discharge for measurements of hemoglobin (Hb), serum erythropoietin (Epo), reticulocytes (Reti), pentraxin 3 (PTX3), and C-reactive protein (CRP). There was a significant decrease in Hb (>3 g/dL), reaching a maximum on day 3 followed by a significant threefold increase in Epo levels on day 5 and a nonsignificant elevation of Reti count. CRP increased approximately 80-fold on day 3. PTX3 showed a similar course, peaking on day 3 with an approximate 70-fold increase. After living donor nephrectomy, there was an unexpectedly pronounced inflammatory reaction in the absence of any signs of bacterial infection simultaneous with a significant decrease in Hb. These parameters improved during the hospital stay, in some cases they achieved the prenephrectomy level at discharge. These data may assist in interpreting laboratory results after nephrectomy among living kidney donors.

Aged↗
PubMed2005

What the Aspergillus genomes have told us.

The sequencing and annotation of the genomes of the first strains of Aspergillus nidulans, Aspergillus oryzae, and Aspergillus fumigatus will be seen in retrospect as a transformational event in Aspergillus biology. With this event the entire genetic composition of A. nidulans, the sexual experimental model organism of the genus Aspergillus, A. oryzae, the food biotechnology organism which is the product of centuries of cultivation, and A. fumigatus, the most common causative agent of invasive aspergillosis is now revealed to the extent that we are at present able to understand. Each genome exhibits a large set of genes common to the three as well as a much smaller set of genes unique to each. Moreover, these sequences serve as resources providing the major tool to expanding our understanding of the biology of each. Transcription profiling of A. fumigatus at high temperatures and comparative genomic hybridization between A. fumigatus and a closely related Aspergillus species provides microarray based examples of the beginning of functional analysis of the genomes of these organisms going forward from the genome sequence.

Aspergillosis↗
PubMed2003

A system for studying genetic changes in Candida albicans during infection.

Candida albicans is a diploid yeast with a dimorphic life history. It exists commensally in many healthy humans but becomes a potent pathogen in immunocompromised hosts. The underlying genetic mechanisms by which C. albicans switches from a commensal to a pathogenic form in the host are not well understood. To study the evolution of virulence in mammalian hosts, we used GAL1 as selectable marker system that allows for both positive and negative selection in selective media. We show that the deletion of one or both copies of GAL1 in the C. albicans genome does not change virulence in a systemic mouse model. We obtained estimates for the frequency of mitotic recombination at the GAL1 locus during systemic infection. Our observations suggest that genetic changes such as mitotic recombination and gene conversion occur at a high enough frequency to be important in the transition of C. albicans from a commensal to a pathogenic organism.

Animals↗
PubMed2003

Pancreatitis in HIV infection: predictors of severity.

OBJECTIVES: Acute pancreatitis occurs at greater frequency in HIV-infected patients than in the general population. We set out to determine the frequency of severe acute pancreatitis in HIV-positive patients and to study the accuracy of The Acute Physiology and Chronic Health Evaluation (APACHE II), Ranson, and Glasgow scales for prediction of clinical disease severity. METHODS: A total of 73 HIV-infected patients with acute pancreatitis were identified retrospectively. Demographic and clinical parameters as well as clinical outcomes were established. Sensitivities and specificities of the three scales mentioned above were calculated and compared. RESULTS: Of the patients, 63 (83.6%) had AIDS. The majority of cases were medication-induced (46%) or idiopathic (26%). The incidence seemed to be declining in the late 1990s. Eleven patients (15%) had a severe course as defined by death, admission to the intensive care unit, or local complications requiring surgery. Eighteen case (24.6%) were considered severe as defined by the criteria established at the International Symposium on Acute Pancreatitis in Atlanta in 1992. APACHE II criteria best predicted outcome with an overall accuracy of 75% (Glasgow 69%, Ranson 48%). Maximal accuracy was achieved with cut-offs of 14 for APACHE II and 4 for the Glasgow and Ranson criteria. CONCLUSIONS: HIV-infected patients have a clinical outcome similar to that of the general population. Clinical predictive scales are applicable and useful in this population.

APACHE↗
PubMed2000

Oral 5-aminosalicylic acid for inducing remission in ulcerative colitis.

OBJECTIVES: To assess the efficacy, dose-responsiveness and safety of the newer release formulations of 5-aminosalicylic acid (5-ASA) compared to placebo or sulfasalazine (SASP) for the induction of remission in active ulcerative colitis. SEARCH STRATEGY: A computer-assisted literature search for relevant studies (1981-1998) was performed using MEDLINE, BIOS, the Cochrane Controlled Trials Register and the Science Citation Index, followed by a manual search of reference lists from previously retrieved articles, review articles, symposia proceedings, and abstracts from major gastrointestinal conferences. SELECTION CRITERIA: Studies were accepted for analysis if they were randomized, double-blinded, and controlled clinical trials of parallel design, with treatment durations of a minimum of four weeks. DATA COLLECTION AND ANALYSIS: Based on an intention to treat principle, the outcomes of interest in the treatment of active disease were the failure to induce global/clinical remission, global/clinical improvement, endoscopic remission, or endoscopic improvement. MAIN RESULTS: 5-ASA was superior to placebo with regard to all measured outcome variables. For the failure to induce global/clinical improvement or remission, the pooled Peto odds ratio was 0.51 (95% CI, 0.35 to 0.76). A dose-response trend for 5-ASA was also observed. When 5-ASA was compared to SASP, the pooled Peto odds ratio was 0.87 (CI, 0.63 to 1.21) for the failure to induce global/clinical improvement or remission, and 0.66 (CI, 0.42 to 1.04) for the failure to induce endoscopic improvement. SASP was not as well tolerated as 5-ASA. REVIEWER'S CONCLUSIONS: The newer 5-ASA preparations were superior to placebo and tended towards therapeutic benefit over SASP. However, considering their relative costs, a clinical advantage to using the newer 5-ASA preparations in place of SASP appears unlikely.

Aminosalicylic Acids↗
PubMed2000

Oral 5-aminosalicylic acid for maintaining remission in ulcerative colitis.

OBJECTIVES: To assess the efficacy, dose-responsiveness and safety of the newer release formulations of 5-aminosalicylic acid (5-ASA) compared to placebo or sulfasalazine (SASP) in the maintenance of remission in ulcerative colitis. SEARCH STRATEGY: A computer-assisted literature search for relevant studies (1981-1998) was performed using MEDLINE, BIOS, the Cochrane Controlled Trials Register, the Inflammatory Bowel Disease Trials Register, and Science Citation Index, followed by a manual search of reference lists from previously retrieved articles, review articles, symposia proceedings, and abstracts from major gastrointestinal conferences. SELECTION CRITERIA: Studies were accepted for analysis if they were prospective, randomized, double-blinded, and placebo- or SASP-controlled clinical trials of parallel design with treatment duration of at least six months. DATA COLLECTION AND ANALYSIS: Based on an intention to treat principle, the primary outcome was the failure to maintain clinical or endoscopic remission. Secondary outcomes were the number of patients experiencing adverse events, the number of patients withdrawn due to adverse events, and exclusions or withdrawals after entry into the study (not due to relapse). All data were analyzed using the Peto odds ratio and corresponding 95% confidence intervals (CI). MAIN RESULTS: The Peto odds ratio for the failure to maintain clinical or endoscopic remission (withdrawals and relapses) for 5-ASA versus placebo was 0. 47 (95% CI, 0.36 to 0.62) with an NNT of 6. These values were also calculated for the trials in which SASP and 5-ASA were compared, revealing an odds ratio of 1.29 (95% CI, 1.05 to 1.57), with a negative NNT value (-19), suggesting a higher degree of therapeutic effectiveness for SASP. SASP and 5-ASA had similar adverse event profiles, with odds ratios of 1.16(0.62 to 2.16), and 1.31(0.86 to 1.99), respectively. The NNH values were determined to be 171 and 78 respectively. REVIEWER'S CONCLUSIONS: The newer 5-ASA preparations were superior to placebo in maintenance therapy. However, the newer preparations had a statistically significant therapeutic inferiority relative to SASP.

Administration, Oral↗
PubMed2000

Azathioprine or 6-mercaptopurine for inducing remission of Crohn's disease.

OBJECTIVES: To determine the effectiveness of azathioprine and 6-mercaptopurine in inducing remission of active Crohn's disease. SEARCH STRATEGY: Studies were selected using the MEDLINE data base (1966 - December 1997), abstracts from major gastrointestinal meetings and references from published articles and reviews. The Cochrane Controlled Trials Register and the Inflammatory Bowel Disease Review Group Trials Register was also searched. SELECTION CRITERIA: Eight randomized placebo controlled trials of azathioprine and 6-mercaptopurine therapy in adult patients were identified: five dealt with active disease and three had multiple therapeutic arms. DATA COLLECTION AND ANALYSIS: Data were extracted by three independent observers based on the intention to treat principle. Each study was given a quality score based on predetermined criteria. Extracted data were converted to 2X2 tables (response versus no response and antimetabolite versus placebo) and then synthesized into a summary test statistic using the pooled odds ratio and 95% confidence intervals as described by Cochran and Mantel and Haenszel ('Odds Ratio' in MetaView). MAIN RESULTS: The odds ratio of a response to azathioprine or 6-mercaptopurine therapy compared with placebo in active Crohn's disease was 2.36 (95% CI 1.57-3.53). This corresponded to a number needed to treat of about 5 to observe an effect of therapy in one patient. When the two trials using 6-mercaptopurine in active disease were excluded from the analysis, the odds ratio of response was 2.04 (CI 1.24 - 3.35). Treatment >/= 17 weeks increased the odds ratio of a response to 2.51 (CI 1.63-3. 88). A steroid sparing effect was seen with an odds ratio of 3.86 (CI 2.14 - 6.96), corresponding to a number needed to treat of about 3 to observe steroid sparing in one patient. Adverse events requiring withdrawal from a trial, principally allergy, leukopenia, pancreatitis, and nausea were increased on therapy with an odds ratio of 3.01 (CI 1.30 - 6.96). The number needed to treat to observe one adverse event in one patient treated with azathioprine or 6-mercaptopurine was 14. REVIEWER'S CONCLUSIONS: Azathioprine and 6-mercaptopurine are effective therapy for inducing remission in active Crohn's disease. The odds ratio of response increases after >/= 17 weeks of therapy, suggesting that there is a minimum length of time for a trial of azathioprine or 6-mercaptopurine therapy. Adverse events were more common among patients on therapy.

Antimetabolites↗
PubMed2000

Conidial germination in Aspergillus nidulans requires RAS signaling and protein synthesis.

The dormant spores of Aspergillus nidulans become competent for growth and nuclear division in a process called conidial germination. To analyze the molecular details of conidial germination, we developed a genetic screen in which we identified spore germination-deficient mutants that are blocked in this process at the restrictive temperature. These mutants defined eight genes, of which we identified five. Four of the five were directly involved in translation and protein folding, and the fifth showed a high degree of homology to a malonyl CoA synthetase. These results suggest that out of a wide array of processes occurring during conidial germination, translation is essential if germination is to proceed. We also show that conidia containing a mutant-activated form of rasA, the ras homologue in A. nidulans, germinate in the absence of an inducing carbon source, suggesting an important role for rasA signaling in conidial germination. Together these data suggest a model by which a carbon source activates a ras-dependent sensory mechanism, inducing translation and leading to conidial germination. This study shows that conidial germination in A. nidulans requires protein synthesis and that the initiation of translation is linked, through an as yet to be determined signaling cascade that includes rasA, to a carbon-source-sensing apparatus.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2000

Itraconazole-amphotericin B antagonism in Aspergillus fumigatus: an E-test-based strategy.

We examined an E-test-based strategy for testing the combination of itraconazole and amphotericin B, the latter given either sequentially or concomitantly, in isolates of Aspergillus fumigatus. An antagonistic interaction between the two drugs was noted, especially with the sequential administration of amphotericin B. This in vitro antagonism was reversible.

Amphotericin B↗
PubMed1999

Evolution of poliovirus type I during 5.5 years of prolonged enteral replication in an immunodeficient patient.

Poliovirus type 1 was isolated from an immunodeficient patient 4 days after onset of paresis (IS1) and after 5.5 years of prolonged enteral virus replication (IS2). Antigenic characterization revealed that IS1 was Sabin 1-like, whereas IS2 reacted like poliovirus 1 Mahoney. Complete genomic sequencing demonstrated the phylogenetic relationship (94.9% identity) of IS1 and IS2, which differed from the most closely related Sabin 1 by 5.4 and 8.3%, respectively. Both isolates had revertant-like mutations at nucleotides 480 and 6203. Deduced amino acid sequences indicated significant changes between IS1 and IS2 at the neutralizing antigenic site 1. Prolonged enteral replication, evolution, and shedding of poliovirus by immunodeficient patients should be considered in the poliovirus eradication strategy.

5' Untranslated Regions↗
PubMed1999

The signature of balancing selection: fungal mating compatibility gene evolution.

A key problem in evolutionary biology has been distinguishing the contributions of current and historical processes to the maintenance of genetic variation. Because alleles at self-recognition genes are under balancing selection, they exhibit extended residence times in populations and thus may provide unique insight into population demographic history. However, evidence for balancing selection and extended residence times has almost exclusively depended on identification of transspecific polymorphisms; polymorphisms retained in populations through speciation events. We present a broadly applicable approach for detecting balancing selection and apply it to the b1 mating type gene in the mushroom fungus Coprinus cinereus. The comparison of neutral molecular variation within and between allelic classes was used to directly estimate the strength of balancing selection. Different allelic classes are defined as encoding different mating compatibility types and are thus potentially subject to balancing selection. Variation within an allelic class, where all alleles have the same mating compatibility type, provided an internal standard of neutral evolution. Mating compatibility in this organism is determined by the complex A mating type locus, and b1 is one of several redundantly functioning genes. Consequently, we conducted numerical simulations of a model with two subloci and varying levels of recombination to show that balancing selection should operate at each sublocus. Empirical data show that strong balancing selection has indeed occurred at the b1 locus. The widespread geographic distribution of identical b1 alleles suggests that their association with differing A mating types is the result of recent recombination events.

Alleles↗
PubMed1999

A GATA-2/estrogen receptor chimera functions as a ligand-dependent negative regulator of self-renewal.

The transcription factor GATA-2 is expressed in hematopoietic stem and progenitor cells and is functionally implicated in their survival and proliferation. We have used estrogen and tamoxifen-inducible forms of GATA-2 to modulate the levels of GATA-2 in the IL-3-dependent multipotential hematopoietic progenitor cell model FDCP mix. Ligand-dependent induction of exogenous GATA-2 activity did not rescue cells deprived of IL-3 from apoptosis. However, induction of GATA-2 activity in cells cultured in IL-3 blocked factor-dependent self-renewal but not factor-dependent survival: Cells undergo cell cycle arrest and cease proliferating but do not apoptose. This was accompanied by differentiation down the monocytic and granulocytic pathways. Differentiation occurred in the presence of IL-3 and did not require addition of exogenous differentiation growth factors such as G-CSF or GM-CSF normally required to induce granulomonocytic differentiation of FDCP-mix cells. Conversely, EPO-dependent erythroid differentiation was inhibited by GATA-2 activation. These biological effects were obtained with levels of exogenous GATA-2 representing less than twofold increases over endogenous GATA-2 levels and were not observed in cells overexpressing GATA-1/ER. Similar effects on proliferation and differentiation were also observed in primary progenitor cells, freshly isolated from murine bone marrow and transduced with a GATA-2/ER-containing retrovirus. Taken together, these data suggest that threshold activities of GATA-2 in hematopoietic progenitor cells are a critical determinant in influencing self-renewal versus differentiation outcomes.

Animals↗
PubMed1999

The divergence-homogenization duality in the evolution of the b1 mating type gene of Coprinus cinereus.

The A mating type locus of the fungus Coprinus cinereus is a complex, multigenic locus which regulates compatibility and subsequent sexual development. Genes within the A locus such as the b1 gene studied here exhibit extreme sequence variation. In this work, we asked how b1 alleles have evolved high levels of variation and, at the same time, conserved function. We compared sequence variation in 17 alleles characterized as belonging to seven different compatibility classes. Comparison of sequence variation between representatives of these seven classes shows that different regions of the b1 gene have been subject to varying levels of substitution, recombination, and structural/functional constraints. The N-terminal region of the encoded protein, which has been previously demonstrated to govern self/nonself recognition, exhibited hypervariability with levels of amino acid identity as low as 41%. We used a novel analysis of neutral mutations accumulating in this gene to rule out the possibility that the N-terminal region is hypermutable. In contrast, the C-terminal region displayed heterogeneous levels of variation, with functional motifs being better conserved. In fact, there is a duality in the b1 gene between variability and conservation; recombination events have homogenized the C-terminal region, while recombination events are undetectable in the N-terminal region. The ability to regulate sexual development is maintained in all of the mating compatibility alleles studied, and these data suggest that some functional motifs may tolerate high levels of substitution.

Alleles↗
PubMed1999

Long-term persistence of immunoglobulin A (IgA) and IgM antibodies against human cytomegalovirus in solid-organ transplant recipients.

The retrospective analysis of 494 solid-organ transplant recipients revealed that during the follow-up period (mean duration, 3.2 years) 184 (88%) of 209 anti-human cytomegalovirus (HCMV) immunoglobulin A (IgA)-positive patients remained IgA positive, as did 128 (74.85%) of 171 anti-HCMV IgM-positive patients. We conclude that anti-HCMV IgA and IgM testing for management of clinically relevant HCMV infections in solid-organ transplant recipients is dispensable.

Adolescent↗
PubMed1999

CAREN--Computer Assisted Rehabilitation Environment.

The CAREN project concerns the development of a virtual reality environment in which the agility of healthy subjects and patients can be tested in a variety of reproducible conditions. CAREN is made by customizing hardware and developing software to enable measurements of motion of a subject in detail as a response to a perturbation from the computer driven motion platform. After feeding the data in a human body model simulation, joint moments of force and muscle activation can be calculated. From the time patterns of these responses, inferences can be made concerning the motor programs the subjects launch. Any primary problem in a motor program, resulting in functional failure or inadequacy, can be identified down to the joint and muscle group. Secondary adaptations of patients to a limitation in the periphery (such as lack of muscle force) can be separated from the primary ones. Inadequacy of complete motor programs in children with movement disorders can be classified, recorded and related to progress that may occur. Especially the understanding of compensation strategies in patients may lead to a better therapeutic attitude. CAREN offers not only a test environment with means of almost unlimited exploratory behaviors for patients, but constitutes also a strong tool for motor control research.

Computer Graphics↗