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F Vogel

Publications and source records attributed to F Vogel.

At least 19 recordsLinked to original sources
PubMed2000

Effects of hydrogen peroxide scavenger Catalase on villous microcirculation in the rat small intestine in a model of inflammatory bowel disease.

This study was conducted to quantify the effect of systemic Catalase, a hydrogen peroxide scavenger, on villous microcirculation in the inflamed small intestine of the rat. Intestinal inflammation was induced with s.c. application of Indomethacin. Intravital fluorescence microscopy and FITC-labeled erythrocytes were used to quantify erythrocyte velocity and arteriolar diameter in the main arteriole of the villi in the terminal ileum following i.v. application of Catalase in the inflamed intestine, and the blood flow was calculated. Control groups were formed for Ringer's lactate, Catalase and Indomethacin, respectively. We found that villous blood flow was significantly increased in the in the inflamed intestine. Application of Catalase led to a significant decrease in villous perfusion, but had no effect in the control group. The increase in villous blood flow was accompanied by changes in the diameter of the main arteriole. This effect on arteriolar diameter was reversed by i.v. Catalase. Our results provide evidence that systemic application of Indomethacin leads to vasodilatation of the main arteriole of the villus in the rat ileum and hyperemia in the mucosa. Hyperemia and the vascular diameter of the main arteriole were significantly reduced by H(2)O(2)-scavenger Catalase, suggesting that endogenous H(2)O(2) may be one of the mediators of hyperemia in the mucosa in this animal model of intestinal inflammation.

Animals↗
PubMed1999

[Linkage studies of a familial spastic paraplegia pedigree from Tibet].

OBJECTIVE: To study the location of disease-related gene in a hereditary spastic paraplegia family with autosomal dominant inheritance in Tibet. METHODS: The AD-HSP family in Tibet was analyzed by linkage studies using 9 highly polymorphic microsatellite DNA markers at three chromosomal regions. RESULTS: The maxium Lod- Score of D14S264 was 0.5163(theta=0.05); of D14S75, 2. 1072 (theta=0);+D14S69, 0.2840 (theta=0.10); of D14S266, 0.9311 (theta=0);of D14S66, 0.7991(theta=0);OF GABRB3, 0(theta =0.40);of D15S128, 0(theta=0.40); of D2S2255, 0 (theta=0.40);and of D2S2347,0(theta=0.40). CONCLUSION: In this Tibetian family, the disease-related gene is linked to D14S75 locus of SPG3 region.

Female↗
PubMed1999

Indomethacin-induced disturbances in villous microcirculation in the rat ileum.

Indomethacin is a widely used nonsteroidal antiphlogistic compound used-among others-for the treatment of rheumatoid arthritis in humans. Common side effects of indomethacin in the gastrointestinal tract include ulcerative lesions and petechial bleeding in the mucosa. In the rat, oral intake of indomethacin induces ulcerations in the mucosa of the stomach and, if administered systemically, edema, petechial bleeding, and ulcerations in the small intestine. In order to determine if systemic administration of indomethacin may induce changes in villous perfusion, we assessed the effect of indomethacin on erythrocyte velocity and the diameter of the main arteriole in the villi of the rat ileum. We found that indomethacin led to a significant decrease in mean arteriolar blood flow (6.3 +/- 0.8 vs 5.0 +/- 1.2 nl/min, means +/- SD) 7 days after administration. Mean diameter of the main arteriole remained unchanged (control, 7. 8 +/- 0.8 vs indomethacin, 7.0 +/- 0.9 microm). In conclusion, systemic application of indomethacin leads to a decrease in blood supply to the mucosa. We previously found an increase in villous perfusion when assessed 24 h after administration of indomethacin, accompanied by an increase in arteriolar diameter of the main arteriole. In summary, different regimens of application of indomethacin lead to varying observations in microcirculatory parameters in single villi. Further studies are required to identify the underlying mechanisms.

Animals↗
PubMed1999

Grepafloxacin: a review of its safety profile based on clinical trials and postmarketing surveillance.

The safety profile of grepafloxacin has been characterized in a number of preclinical and clinical studies. Preclinical investigations have shown that its toxicologic profile is similar to that of other fluoroquinolones, and phase I studies in humans have confirmed these data. A photosensitivity study demonstrated equivalence with ciprofloxacin, and a study in elderly patients taking the highest clinical dose of grepafloxacin indicated that prolongation of the QTc interval by grepafloxacin was less than 2 ms, 15 times less than that observed in a study of erythromycin. In phase II and III clinical investigations conducted in the United States and the United Kingdom, safety data have been gathered from more than 3000 patients with either community-acquired pneumonia or acute bacterial exacerbations of chronic bronchitis. The most common adverse events with grepafloxacin 400 or 600 mg were gastrointestinal, such as nausea, vomiting, and diarrhea. The frequency of these adverse events was similar to that seen with ciprofloxacin. Significantly more patients reported a mild, unpleasant metallic taste with grepafloxacin than with ciprofloxacin, but <1% of patients withdrew from therapy because of this. Headache was observed significantly more often in ciprofloxacin-treated patients than in grepafloxacin-treated patients. Recent postmarketing data confirm the good tolerability and safety profile of grepafloxacin. These data, from a case-report study of more than 9000 patients in Germany, demonstrated that only 2.3% of patients reported adverse events when grepafloxacin was used in routine clinical practice. The most frequently reported events were nausea (0.8%) and gastrointestinal symptoms (0.4%). Dizziness was reported by only 0.3% of patients, and only 4 patients (0.04%) reported photosensitization. Adverse events did not appear to be either dose dependent or related to diagnosis. More than 400,000 patients world-wide have received grepafloxacin treatment. No new safety issues have arisen from the spontaneous-report data and, with the exception of rare reports of an unpleasant taste, the most commonly reported events have been the same as those seen in clinical studies. These data support grepafloxacin as a well-tolerated fluoroquinolone suitable for the treatment of community-acquired respiratory tract infections.

Animals↗
PubMed1999

Randomized, double-blind study of short-course (5 day) grepafloxacin versus 10 day clarithromycin in patients with acute bacterial exacerbations of chronic bronchitis.

The efficacy and safety of grepafloxacin were compared with clarithromycin in a randomized, double-blind, multicentre clinical trial of 805 patients with acute bacterial exacerbations of chronic bronchitis (ABECB). Patients were randomized to receive grepafloxacin 400 mg od for either 5 (n = 273) or 10 days (n = 268) or clarithromycin 250 mg bd for 10 days (n = 261). Patients were assessed pre-treatment, 3-5 days during treatment, 1-3 days post-treatment and at follow-up (21-28 days post-treatment). The clinical success rates for the evaluable patients were 91% in the 5 day grepafloxacin group, 95% in the 10 day grepafloxacin group and 86% in the clarithromycin group. At follow-up, respective rates were 72%, 81% and 73%. A total of 513 pathogens were isolated from the pre-treatment sputum specimens of 400 (49%) patients. The primary pathogens were Haemophilus influenzae (36% of isolates), Haemophilus parainfluenzae (27%), Moraxella catarrhalis (12%), Streptococcus pneumoniae (11%) and Staphylococcus aureus (3%). Pathogens were eradicated or presumed eradicated at post-treatment in 85%, 91% and 58% of evaluable patients treated with grepafloxacin for 5 days, grepafloxacin 10 days and clarithromycin 10 days, respectively. The eradication rates in both grepafloxacin groups were significantly greater than the clarithromycin group (P<0.001). All treatments were well tolerated and incidence of drug-related adverse events in each group was comparable. This study demonstrates that both a 5 and a 10 day regimen of grepafloxacin 400 mg od are as clinically and bacteriologically effective as in the treatment of ABECB clarithromycin 250 mg bd. for 10 days.

Acute Disease↗
PubMed1999

Yeast cells allow high-level expression and formation of polyomavirus-like particles.

Polyomavirus-derived virus-like particles (VLPs) have been described as potential carriers for encapsidation of nucleic acids in gene therapy. Although VLPs can be generated in E. coli or insect cells, the yeast expression system should be advantageous as it is well established for the biotechnological generation of products for human use, especially because they are free of toxins hazardous for humans. We selected the yeast Saccharomyces cerevisiae for expression of the major capsid protein VP1 of a non-human polyomavirus, the hamster polyomavirus (HaPV). Two entire HaPV VP1-coding sequences, starting with the authentic and a second upstream ATG, respectively, were subcloned and expressed to high levels in Saccharomyces cerevisiae. The expressed VP1 assembled spontaneously into VLPs with a structure resembling that of the native HaPV capsid. Determination of the subcellular localization revealed a nuclear localization of some particles formed by the N-terminally extended VP1, whereas particles formed by the authentic VP1 were found mainly in the cytoplasmic compartment.

Animals↗
PubMed1999

Lack of effects of recombinant human GH on spermatogenesis in the adult cynomolgus monkey (Macaca fascicularis).

OBJECTIVE: The effects on male reproductive parameters after 1 year of treatment with recombinant human GH to the cynomolgus monkey were investigated. DESIGN: Twenty-four male cynomolgus monkeys were given daily subcutaneous doses of 0 (vehicle) (n=7), 0.4 (n=5), 2.0 (n=5) and 10.0 (n=7) IU/kg bodyweight for 52 weeks. At completion of the treatment period two control and two high-dose animals were left for a 12-week treatment-free period. METHODS: Before and during the treatment period and during the recovery period, sperm analyses, testicular volume measurements and hormone analyses of prolactin (PRL), LH, FSH, testosterone and IGF-I in serum, and analysis of serum antibodies against human GH were performed. Testicular morphology was monitored by biopsies, predose and on day 15 of the study, and with light microscopy on organ samples collected at time of death, at the end of the treatment, and during recovery periods respectively. RESULTS: Of all studied parameters, alterations were observed only in serum levels of IGF-I and PRL. IGF-I showed a dose-dependent increase throughout the treatment, with a normalisation during the treatment-free period. PRL decreased significantly in animals given 10.0IU/kg per day from week 14 of treatment and throughout the study but with a normalisation upon cessation of treatment. Spermatogenesis, as judged from semen analysis, testicular volume measurements and testicular morphology was not affected. CONCLUSION: This controlled preclinical study demonstrates that high doses of human GH do not alter male reproductive parameters in a non-human primate model.

Animals↗
PubMed1998

Interplay between humans and infective agents: a population genetic study.

The genetic composition of present day human populations is determined largely by the interaction between the human host and infective agents. Therefore, theoretical analysis of the host-infective-agent system is required in order for us to be able to understand human evolution. Classical population genetics has been confined largely to analysing the interplay of various mechanisms, such as selection, mutation and drift, in one species at a time. Unfortunately, there have been few studies of such interactive systems. In the present investigation, these studies have been enlarged, with problems of human genetics in mind, by mathematical examination of a model in which a diploid host with three alleles interacts with a haploid infective agent with two alleles. The results are compared with those obtained from simpler models analysed in the past. The assumptions inherent in such "gene for gene" models and our results are discussed. An increase in the number of alleles appears to enhance the chances for the establishment of permanent genetic polymorphisms, improving genetic "elasticity" of a population for coping with changing challenges by various infective agents. Interaction between two haploid species leads to a loss of polymorphism in both of them and, hence, to a severe loss of evolutionary elasticity. The hypothesis that the evolution of diploidy might have been favoured by a selective advantage of diploid organisms interacting with environmental challenges, such as infective agents, is supported.

ABO Blood-Group System↗
PubMed1997

Introduction of plasmid DNA into isolated mitochondria by electroporation. A novel approach toward gene correction for mitochondrial disorders.

Mitochondrial disorders are a large group of phenotypically heterogeneous diseases. An understanding of their molecular basis would benefit greatly from the ability to manipulate the mitochondrial genome and/or to introduce functional exogenous DNA into mitochondria. As a first step toward this approach, we have used electroporation to introduce a 7.2-kilobase plasmid DNA into isolated functional mitochondria. Transfer of the DNA at field strengths between 8 and 20 kV/cm was investigated by Southern blot analysis. Maximal plasmid internalization was achieved at a field strength of 14 kV/cm. The functional integrity of the mitochondria after electroporation was verified by enzymatic assays of specific mitochondrial marker enzymes and by measuring respiratory control. At field strengths above 12 kV/cm, an increasing mitochondrial destruction was observed. 12 kV/cm was found to be optimal for the most efficient plasmid internalization while still retaining the functional integrity of the mitochondria. At this field strength, about half of the internalized plasmid was found in the inner membrane or mitochondrial matrix, as determined by immunoelectron microscopy and Southern blot analysis of electroporated mitochondria treated with digitonin. We estimate that on average one plasmid molecule/mitochondrion reaches the matrix or inner membrane.

Animals↗
PubMed1997

Inducible membranes in yeast: relation to the unfolded-protein-response pathway.

Overproduction of an endoplasmic reticulum (ER)-resident membrane protein (cytochrome P450 52A3) and of a secretory protein (invertase) was used to study the regulation of the luminal ER protein Kar2p under conditions that lead to ER proliferation and secretory overload, respectively. In both cases we found (i) a significant increase of Kar2 protein and mRNA levels, (ii) a transcriptional regulation based on the the function of the 22 bp unfolded-protein-response element of the KAR2 promoter and (iii) an essential role of the transmembrane kinase Ire1p for upregulation of KAR2 gene expression. These results show that the same mechanism operates when KAR2 induction is triggered by overproduction of cytochrome P450 or invertase and that this mechanism shares the known features of the unfolded-protein-response pathway. Disruption of the IRE1 gene resulted in a marked decrease of the invertase protein levels produced. In contrast, a functional IRE1 gene was not required to reach high-level production of the integral membrane protein cytochrome P450 52A3, Moreover, IRE1 gene disruption did not prevent P450-induced ER proliferation. We suggest that Ire1p-mediated KAR2 induction is, in the case of cytochrome P450 52A3 overproduction, a process which follows on ER proliferation, thereby monitoring the increase of ER size and adjusting the level of Kar2p accordingly.

Cytochrome P-450 Enzyme System↗
PubMed1997

Another pedigree with pure autosomal dominant spastic paraplegia (AD-FSP) from Tibet mapping to 14q11.2-q24.3.

The mutant in a family with autosomal-dominant spastic paresis in Northern Tibet was mapped by linkage analysis with several microsatellite markers to a gene locus at 14q11.2-q24.3, an area to which a few mutants leading to a condition with similar clinical signs have previously been mapped. The mutant observed in this pedigree probably arose de novo. Gene loci at 2p21-p24 and 15q, which have been found for other pedigrees with dominant spastic paresis, were excluded. The data in this pedigree do not contradict the hypothesis proposed by another group that there might be anticipation.

Adult↗
PubMed1997

Protein quality--a determinant of the intracellular fate of membrane-bound cytochromes P450 in yeast.

To elucidate mechanisms determining the intracellular localization of cytochromes P450, authentic and mutant cytochromes P450 52A4 (P450Cm2) and P450 52A5 (P450Alk2A) were heterologously expressed in Saccharomyces cerevisiae and the ultrastructure of the respective transformants was investigated by means of immunoelectron microscopy. As a result, overproduction of both wild-type P450 forms resulted in a massive proliferation of tubular membrane structures distributed over the whole cytoplasm. In contrast, all mutant P450Cm2 and Alk2A forms tested were mainly localized within stacks of paired membranes which often occurred in close vicinity to the nucleus. As found by serial sectioning of a single cell, these stacked membranes bearing the mutant P450 actually represented plates of consecutive membranes arranged one upon the other. A tubular network of endoplasmic reticulum membranes as observed after expression of the wild-type proteins could not be detected. Generally, the kind of mutation introduced into the P450 forms did not influence the morphology of the induced membranes. Even single amino acid exchanges in the cytosolic domain caused the formation of membrane stacks. The common feature of all mutant P450 forms causing the formation of stacked membranes was, however, their lower protein stability after heterologous expression in the S. cerevisiae host cells, compared to the stability of the authentic cytochromes P450. Furthermore, the proliferated membranes containing the different P450 forms were characterized by means of subcellular fractionation experiments. Using this approach, clear differences in the distribution of spectrally active and inactive P450 molecules were found. The results obtained suggest the presence of an intracellular sorting mechanism based on the protein quality, which finally leads to the differences in the intracellular distribution of wild-type and mutant cytochromes P450.

Candida↗
PubMed1997

Sequential therapy with cefuroxime followed by cefuroxime axetil in acute exacerbations of chronic bronchitis.

A prospective, multicentre, randomized, open-label, parallel group study compared the efficacy, safety and tolerability of cefuroxime 750 mg iv administered either twice daily (bd) or three times daily (tds) for 48-72 h, followed by oral cefuroxime axetil 500 mg bd for 5-7 days in a sequential therapy regimen for the treatment of acute exacerbations of chronic bronchitis. A total of 628 adult patients entered the study; 323 in the cefuroxime tds group and 305 in the cefuroxime bd group. For clinically evaluable patients, the post-treatment clinical response rate was 86% and 88% in the cefuroxime tds and bd groups, respectively. Cure was maintained at follow-up (14-28 days after treatment completion) in 85% of the cefuroxime tds group and 84% of patients in the cefuroxime bd group. A total of 189 pathogens was isolated, the most common being Haemophilus influenzae (17%), other Haemophilus spp. (15%), Streptococcus pneumoniae (15%) and Enterobacteriaceae (23%). At the post-treatment assessment, 66% and 70% of pathogens were cleared in the cefuroxime tds and bd groups, respectively. Both treatment regimens were well tolerated. The incidence of drug-related adverse events was 7% in the cefuroxime tds group and 6% in the cefuroxime bd group; the most common side-effects were gastrointestinal. Qualitative and quantitative markers were used to determine the optimal time to switch from iv to oral therapy and, of these, peak expiratory flow rate was shown to be the most useful in the present study. In conclusion, the findings of this study support the use of a bd dosing schedule of cefuroxime in a sequential therapy regimen with oral cefuroxime axetil, demonstrating it to be clinically equivalent to the standard tds dosage currently used, as well as being simpler and more convenient to administer at a lower cost.

Adolescent↗
PubMed1997

Sequential therapy with cefuroxime followed by cefuroxime axetil in community-acquired pneumonia.

STUDY OBJECTIVES: To compare the efficacy of two sequential therapy regimens of IV cefuroxime followed by oral cefuroxime axetil for the treatment of community-acquired pneumonia (CAP). DESIGN: Prospective, multicenter, randomized, open-label, parallel-group study. SETTING: Sixty-six centers in 11 countries (Belgium, Canada, Czech Republic, Germany, Hungary, Ireland, Israel, Poland, Portugal, South Africa, and the United Kingdom). PATIENTS: Six hundred thirty-six adults with CAP requiring hospitalization and initial IV antibiotic treatment. INTERVENTIONS: Cefuroxime, 1.5 g IV tid or bid for 48 to 72 h followed by oral cefuroxime axetil, 500 mg bid for 7 days. MEASUREMENTS AND RESULTS: For clinically evaluable patients, the clinical response rates were equivalent for cefuroxime tid and bid groups posttreatment (cure/improvement, 79% and 84%, respectively) and at follow-up (maintained cure, 87% and 82%, respectively). All signs and symptoms of pneumonia showed improvement at the time of switch from IV to oral therapy. A total of 111 pathogens were isolated, the most common being Streptococcus pneumoniae (23%), Haemophilus influenzae (18%), and Enterobacteriaceae (15%). Bacteriologic clearance was obtained posttreatment in 47 of 49 and 36 of 42 of bacteriologically evaluable patients in the cefuroxime tid and bid groups, respectively. Both regimens were well tolerated with a low incidence of drug-related adverse events, the most common being GI. CONCLUSIONS: Twice daily IV cefuroxime followed by oral cefuroxime axetil is a simple and effective sequential therapy regimen for the treatment of CAP. It offers potential cost savings and can replace the current tid regimen in this indication.

Administration, Oral↗
PubMed1996

Importin provides a link between nuclear protein import and U snRNA export.

Importin-alpha mediates nuclear protein import by binding nuclear localization signals and importin-beta. We find approximately 30% of SRP1p, the yeast importin-alpha, in a nuclear complex with the Saccharomyces cerevisiae nuclear cap-binding protein complex (CBC). Similarly, a large fraction of Xenopus CBC is associated with importin-alpha in the nucleus. CBC promotes nuclear export of capped U snRNAs and shuttles between nucleus and cytoplasm. The CBC-importin-alpha complex binds specifically to capped RNA, suggesting that CBC might shuttle while bound to importin-alpha. Strikingly, importin-beta binding displaces the RNA from the CBC-importin-alpha complex. Thus, the commitment of CBC for nuclear reentry triggers the release of the export substrate into the cytoplasm. We provide evidence for a mechanism that ensures that importin-mediated RNA release is a specifically cytoplasmic event.

Amino Acid Sequence↗