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Biomedical subjects

F Meyer

Publications and source records attributed to F Meyer.

At least 109 records · Page 6Linked to original sources
PubMed1998

Rose: generating sequence families.

MOTIVATION: We present a new probabilistic model of the evolution of RNA-, DNA-, or protein-like sequences and a software tool, Rose, that implements this model. Guided by an evolutionary tree, a family of related sequences is created from a common ancestor sequence by insertion, deletion and substitution of characters. During this artificial evolutionary process, the 'true' history is logged and the 'correct' multiple sequence alignment is created simultaneously. The model also allows for varying rates of mutation within the sequences, making it possible to establish so-called sequence motifs. RESULTS: The data created by Rose are suitable for the evaluation of methods in multiple sequence alignment computation and the prediction of phylogenetic relationships. It can also be useful when teaching courses in or developing models of sequence evolution and in the study of evolutionary processes. AVAILABILITY: Rose is available on the Bielefeld Bioinformatics WebServer under the following URL: http://bibiserv.TechFak.Uni-Bielefeld.DE/rose/ The source code is available upon request. CONTACT: folker@TechFak.Uni-Bielefeld.DE

Algorithms↗
PubMed1998

Effect of supramaximal cerulein stimulation on mitochondrial energy metabolism in rat pancreas.

Hyperstimulation with the cholecystokinin analogue cerulein induces mild edematous pancreatitis in rats. It is believed that an impaired energy metabolism diminishes the cellular defense capacity in the inflamed pancreatic tissue and, therefore, contributes to the injuries in acinar cells. In the present study, changes in the capacity of oxidative phosphorylation were quantified within the first 24 h after subcutaneous cerulein injections. Serum amylase level and pancreatic water content were maximally elevated 5 h after the first injection. The capacity of mitochondrial respiration was reduced in isolated acinar cells to 69 and 44% at 5 and 24 h, respectively, compared to that in saline controls. Simultaneously, glutamate dehydrogenase (GLDH) activity dropped to 70 and 46%. The respiration rates of acinar cells and of isolated mitochondria related to GLDH activities were not different from controls. This suggests that the major portion of the mitochondrial population within the acinar cell is inactivated in the course of cerulein treatment. After 24 h, the reduced population of functionally intact mitochondria restricted the rate of phosphorylating respiration in acinar cells (52%), which resulted in a diminution of cellular ATP to 57%. It is concluded that cerulein hyperstimulation induces a drastic and long-lasting reduction of the capacity for mitochondrial ATP production which may adversely affect energy-requiring reactions of the gland during regeneration.

Adenosine Triphosphate↗
PubMed1998

Initial experiences with percutaneous endovascular repair of popliteal artery lesions using a new PTFE stent-graft.

PURPOSE: To report the percutaneous endovascular management of popliteal artery lesions with a new polytetrafluoroethylene (PTFE) stent-graft. METHODS AND RESULTS: Three patients have undergone endovascular treatment in the popliteal region owing to: (1) an iatrogenic false aneurysm with arteriovenous fistula, (2) entrapment syndrome, and (3) an isolated arterial aneurysm. In each case, arterial occlusion was treated initially with thrombolysis. The underlying vascular lesions then were stented using the new Hemobahn endograft, a nitinol stent covered internally with PTFE. Each percutaneous procedure was completed successfully without major complications. During early follow-up (6 to 7 months), no signs of intimal hyperplasia, occlusion, or stent migration have been observed. CONCLUSIONS: Based on these early experiences, percutaneous treatment of stenotic and aneurysmal lesions in the popliteal artery using the Hemobahn endograft appears feasible and effective. Further experience and longer follow-up are required to evaluate this new prosthesis.

Aged↗
PubMed1998

Quebec prostate cancer mortality dropped in 1996.

OBJECTIVE: To monitor incidence and mortality rates of prostate cancer in the province of Quebec. DESIGN: Population-based incidence and mortality trends. SETTING: Entire population of the province of Quebec between 1979 and 1996. MAIN OUTCOME MEASURES: Age-standardized incidence rates and mortality for prostate cancer. RESULTS: Prostate cancer mortality increased regularly until 1989, were stable between 1989 and 1995 and dropped in 1996 by 15%. Incidence rates increased steadily from 1989 until 1993 by an average of 9% per year. CONCLUSION: The rise in incidence is due to the increasing use of prostate specific antigen as a screening test for prostate cancer. The reasons for the reduction in prostate cancer mortality are unknown but are likely to reflect improved treatment modalities.

Age Factors↗
PubMed1998

Dietary fat and advanced prostate cancer.

PURPOSE: We identify the dietary factors, particularly fat intake, associated with advanced prostate cancer. MATERIALS AND METHODS: We performed a case series analysis restricted to prostate cancer cases recruited in a hospital based, case control study evaluating the influence of diet on the development of prostate cancer. Patients eligible for study inclusion were 45 years old or older with prostate cancer who had been hospitalized for initial surgical treatment or radiotherapy between October 1990 and December 1992 at 1 of 8 hospitals in the Quebec City area. A diet history questionnaire was administered to 427 patients with prostate cancer of whom 384 (90%) had completed a reliable questionnaire, including 142 with advanced and 242 with local stages I and II disease. Logistic regression analysis was used to evaluate the associations between dietary intake and advanced prostate cancer. Odds ratios and trend odds ratios were adjusted for patient age, energy intake, method of cancer detection and cancer treatment. RESULTS: There was a moderate, not statistically significant relation to total fat (trend odds ratio 1.15, confidence interval [CI] 0.95 to 1.39). Cases in the highest quartile of saturated fat consumption had a statistically significant odds ratio of 2.15 (CI 1.14 to 4.04). In addition, the relation increased proportionally and significantly with saturated fat intake (trend odds ratio 1.24, CI 1.02 to 1.51). Inverse associations of borderline significance were observed between advanced cancer, and polyunsaturated fat (trend odds ratio 0.88, CI 0.73 to 1.07) and linoleic acid intake (trend odds ratio 0.86, CI 0.71 to 1.04). A positive trend was observed for total animal fat intake (trend odds ratio 1.20, CI 0.99 to 1.46), while a negative trend was noted for total vegetable fat intake (trend odds ratio 0.84, CI 0.70 to 1.01). CONCLUSIONS: This study suggests an association between saturated fat consumption and prostate cancer progression. If cohort studies performed on patients with local prostate cancer confirm these results, dietary fat intake modification may be a promising intervention to prevent prostate cancer progression.

Aged↗
PubMed1998

Ruptured cervical aneurysm of the carotid artery--case report of a rare disease.

Rupture of a cervical carotid artery aneurysm is a rare but life-threatening event. The diagnostic evaluation and therapeutic management of a 55-year-old woman with such a lesion are described. In this case, the aneurysmal rupture was complicated by localized Staphylococcus aureus infection confirmed by bacteriologic culture of excised tissue, septicemia, and prevertebral and intraspinal abscess. Definitive diagnosis was a ruptured mycotic aneurysm of the extracranial carotid artery. The origin of the infection was probably the patient's previously infected vascular prosthesis for hemodialysis.

Aneurysm, Infected↗
PubMed1998

[Rhinologic aspects in the diagnosis of recurrent epistaxis].

Severe and frequently occurring epistaxis is a common problem in the praxis of the general practitioner. It may be a symptom of another disease which should be found. A specific pharmacological history has to be taken. This article tries to review the most important rhinologic aspects for the general practitioner that the development of the rhinologic disease works as guidance for the differential diagnosis of recurrent epistaxis.

Epistaxis↗
PubMed1998

[Fas/Fas ligand mRNA are expressed in Helicobacter pylori infected mucosa].

Helicobacter pylori (Hp) seems to possess an inflammatory as well as immun-modulatory potential. The investigation revealed that both Fas and FasLigand are expressed in the gastric mucosa independently of the Hp infection status and with no significant difference to the expression profile in PBMC. In conclusion, Fas-FasLigand interaction could play a role in immune regulation of Hp gastritis and induction or mediation of epithelial injury.

Adult↗
PubMed1997

[Venous angiomatous hamartoma of the mesenteric root. Therapy of chylous ascites abd chylothorax--case report].

Hamartomas are rare benign tumors appearing very often without any symptoms. In case of diagnostic detection the operative exploration is indicated for a correct histological diagnosis and resection. In this report we describe a very rare case of mesenterial hamartoma. During the late postoperative course a refilling chylothorax and chylous ascites occurred. With total parenteral nutrition, excluding short- and long-chain fatty acids, chylous leakage was successfully treated. The chylous exudation was stopped totally; only intraabdominally did minimal ascites persist. The therapy was continued by a oral Ceres diet nutrition. The conservative therapy involving total parenteral nutrition permitted us to avoid the peritoneovenous Le Veen shunt and the associated complications.

Adult↗
PubMed1997

Dietary energy and nutrients in relation to preclinical prostate cancer.

Previous studies of diet and prostate cancer have focused on advanced disease and have suggested a positive association with saturated fat intake. We report a study assessing the relationship between diet and preclinical prostate cancer. A total of 215 men with preclinical prostate cancer and 593 controls with no evidence of cancer participated in a case-control study conducted in Quebec City between October 1990 and May 1993. The study population comprised two groups: men treated surgically for benign prostatic hypertrophy and participants in a prostate cancer screening program. Trained nutritionists interviewed the participants on their usual diet using a diet history questionnaire. Odds ratios for prostate cancer associated with quartiles of dietary intake and P values for trend were estimated by logistic regression while controlling for age, education, group, and family history of prostate cancer. A positive association was observed between total energy intake and preclinical prostate cancer (p = 0.004). The odds ratios for prostate cancer increased with each quartile of energy intake: 1.00, 1.77, 1.90, and 2.67. After adjustment for energy, nutrients were not associated with prostate cancer. This study provides some evidence that total energy intake is related to preclinical prostate cancer and suggests that diet could be involved earlier than thought in the occurrence of prostate cancer.

Aged↗
PubMed1997

Diagnostic accuracy of urinary cytology, and deoxyribonucleic acid flow cytometry and cytology on bladder washings during followup for bladder tumors.

PURPOSE: We evaluated the diagnostic accuracy of cytology on urine and bladder washings, and deoxyribonucleic acid (DNA) flow cytometry on bladder washings compared to cystoscopy during followup for bladder tumors. MATERIALS AND METHODS: A cross-sectional analysis was performed on 166 patients with a history of bladder tumor for the initial visit when cytology and DNA flow cytometry results were available for urine and bladder washing samples. There were 114 bladder tumor events and 52 negative controls (normal cystoscopy). A prospective study was conducted among the 66 patients with no tumor detected by cystoscopy at the initial visit and for whom the 3 test results were available. The patients were followed from this visit until tumor recurrence or the end of the followup period. Cytological examination was considered positive only when interpreted as malignant. Suspicious examinations were considered negative for the purpose of our study. RESULTS: Sensitivity and specificity of urinary cytology were 59 and 85%, respectively. Sensitivity was increased to 66% using bladder washing cytology whereas specificity was moderately decreased to 83%. The sensitivity and specificity of DNA aneuploidy were 45 and 87%, respectively. Inclusion within the aneuploid category of hyperdiploid samples (defined as more than 7% of cells in the S + G2M phase) increased sensitivity to 77%, while specificity decreased to 42%. Kaplan-Meier analysis of tumor-free survival in patients initially free of bladder cancer at cystoscopy showed an inability of DNA flow cytometry to predict recurrence, whereas positive urine or bladder washing cytology predicted a shorter time to recurrence (log-rank test p <0.01). CONCLUSIONS: These results show that DNA flow cytometry and cytology on bladder washing samples add little information to that obtained from voided urine cytology.

Cross-Sectional Studies↗
PubMed1997

[Modification of energy supply by pancreatic mitochondria in acute experimental pancreatitis].

A disturbed energy metabolism in pancreatic acinar cells is discussed as factor contributing to the development of acute pancreatitis (AP). In this study, we investigated to what extent the mitochondrial ATP producing capacity is impaired in the pancreatic tissue of rats with experimental AP. For preparation of mitochondria from rat pancreas, routine isolation procedures (tissue homogenization and differential centrifugation) were applied. Mitochondria were isolated from rats with edematous pancreatitis produced by hyperstimulation with caerulein, and from rats with mild necrotizing acute pancreatitis. The latter form of AP was induced by a temporary occlusion of the biliary pancreatic duct accompanied by a simultaneous intravenous injection of caerulein plus secretin and an intraabdominal administration of ethanol. As functional parameters of oxidative phosphorylation, the respiration rate, the mitochondrial membrane potential, and the activity of the complex I of the respiratory chain were determined. Mitochondria from rats with caerulein AP showed an enhanced respiration (61% vs. saline control) and a diminished membrane potential (-17 mV) if respiring with succinate in the non-phosphorylating state. This indicates an increased proton leak across the mitochondrial inner membrane. In the mild necrotizing AP, mitochondria were characterized by a decreased respiration with NAD(+)-linked substrates (-33% vs. sham-operated animals). This inhibition of respiration was confirmed by the reduced activity measured for the NADH-cytochrome c reductase (-32%). In both models of experimental AP the potency of mitochondria to produce ATP was significantly diminished. The stronger impairment of mitochondrial functions were found in the necrotizing form of AP. Reactive oxygen species may lead to the observed alterations--to the enhanced permeability of the mitochondrial inner membrane as well as to the inhibition of the complex I of the respiratory chain.

Acute Disease↗
PubMed1997

Acute subdural hematoma associated with nontraumatic aneurysm rupture.

Five cases of subdural hematoma due to aneurysm rupture and their surgical treatment are reviewed. One patient recovered completely, one was severely disabled and 3 patients died. The literature regarding subdural hematomas associated with nontraumatic aneurysm rupture is reviewed and our therapeutical strategy is discussed. We conclude that severe neurological deficit and uncal herniation can be reversible if surgery is performed early.

Aneurysm, Ruptured↗
PubMed1997

Generating benchmarks for multiple sequence alignments and phylogenetic reconstructions.

We present a new probabilistic model of evolution of RNA-, DNA-, or protein-like sequences and a tool rose that implements this model. By insertion, deletion and substitution of characters, a family of sequences is created from a common ancestor. During this artificial evolutionary process, the "true" history is logged and the "correct" multiple sequence alignment is created simultaneously. We also allow for varying rates of mutation within the sequences making it possible to establish so-called sequence motifs. The results are suitable for the evaluation of methods in multiple sequence alignment computation and the prediction of phylogenetic relationships.

Amino Acid Sequence↗
PubMed1997

Human platelet antigen frequencies of platelet donors in the French population determined by polymerase chain reaction with sequence-specific primers.

To prevent human platelet alloimmunization, Blood Transfusion Centres have to develop a strategy close to the erythrocytes' one. The first step of this strategy is to perform the HPA typing of donors with an accurate method. We applied the PCR-SSP to type 800 platelet donors in the HPA-1 and HPA-5 systems and 350 in the HPA-2 and HPA-3 ones. This study reports the human platelet antigen frequencies of four platelet-specific alloantigen systems in the French population. The results are quite similar to those currently published for Caucasian population frequencies. Low prevalences are observed for the HPA-1b, (2%), HPA-2b (0.6%) and HPA-5b (2%) groups. Furthermore, this study confirms the need to type donors and recipients in the HPA-1 system at least, in case of post-transfusion pupura and platelet refractoriness to platelet transfusion therapy.

Antigens, Human Platelet↗
PubMed1996

Plasma metabolites, volume and electrolytes following 30-s high-intensity exercise in boys and men.

It has been shown that boys recover faster than men following brief, high-intensity exercise. Better to understand this difference, plasma metabolite concentration, volume, electrolyte concentration [electrolyte], and hydrogen ion concentration [H+] changes were compared in five prepubescent boys [mean age 9.6 (SD 0.9) years] and 5 men [mean age 24.9 (SD 4.3) years] following 30-s, all-out cycling. Blood was collected prior to, at the end, and at the 1st, 3rd and 10th min following exercise. At the 10th min of recovery, the men's lactate concentration was 14.2 (SD 1.8) mmol.l-1 and [H+] was 66.1 (SD 5.9) nmol.l-1, compared with 5.7 (SD 0.7) mmol.l-1 and 47.5 (SD 1.2) nmol.l-1 respectively, in the boys (P < 0.01 for both). The glycerol concentration was higher in the boys at the end of exercise and until the 3rd min of recovery. Plasma volume (PV) decreased more in the men [16.9 (SD 3.0)%] than in the boys [9.4 (SD 2.8)%]. In both groups, [electrolyte] increased after exercise, tending to be higher in the men. Recovery of plasma [electrolyte] and PV started earlier in the boys (1st min) than in the men (3rd min). These findings would support the notion of a lesser reliance on glycolytic energy pathways in children and may explain the faster recovery of muscle power in boys compared to men.

Adult↗
PubMed1996

[Immuno-hemolytic transfusion reactions. III. Report of 61 cases].

Blood transfusion is mainly bound to immunological and infectious risks. The immunological risk originates from an incompatibility between the blood of the donor and that of the recipient; this risk remains insufficiently assessed. A multicentre study has been carried out by the French Blood Transfusion Society and the National Institute for Blood Transfusion. Sixty-one accidents due to an erythrocyte incompatibility were found: 26 cases with ABO incompatibility, and 35 cases with alloantibodies of other blood group systems. For the former category of accidents, the most frequent cause was due to a failure in the realization of the bedside ABO check. For the latter, the main problem was the achievement and the interpretation of antibody screening. The long term follow-up shows no chronic after-effects of immunological accidents. For each accident, errors have been identified and analysed. It was proven that they all originate from health care establishments.

ABO Blood-Group System↗