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F Berger

Publications and source records attributed to F Berger.

At least 73 records · Page 4Linked to original sources
PubMed2001

Paternal chromosome incorporation into the zygote nucleus is controlled by maternal haploid in Drosophila.

maternal haploid (mh) is a strict maternal effect mutation that causes the production of haploid gynogenetic embryos (eggs are fertilized but only maternal chromosomes participate in development). We conducted a cytological analysis of fertilization and early development in mh eggs to elucidate the mechanism of paternal chromosome elimination. In mh eggs, as in wild-type eggs, male and female pronuclei migrate and appose, the first mitotic spindle forms, and both parental sets of chromosomes congress on the metaphase plate. In contrast to control eggs, mh paternal sister chromatids fail to separate in anaphase of the first division. As a consequence the paternal chromatin stretches and forms a bridge in telophase. During the first three embryonic divisions, damaged paternal chromosomes are progressively eliminated from the spindles that organize around maternal chromosomes. A majority of mh embryos do not survive the deleterious presence of aneuploid nuclei and rapidly arrest their development. The rest of mh embryos develop as haploid gynogenetic embryos and die before hatching. The mh phenotype is highly reminiscent of the early developmental defects observed in eggs fertilized by ms(3)K81 mutant males and in eggs produced in incompatible crosses of Drosophila harboring the endosymbiont bacteria Wolbachia.

Aneuploidy↗
PubMed2001

Polycomb group genes control pattern formation in plant seed.

Transcriptional activators of the Trithorax group (TRX-G) and repressors of the Polycomb group (Pc-G) are involved in multiple aspects of embryogenesis in Drosophila and the mouse [1, 2] and appear to have a conserved role in the zygotic control of the development of the anterior-posterior axis [3, 4, 5]. In the model plant Arabidopsis, three Pc-G genes have been isolated and characterized to date. CURLY LEAF (CLF) represses the expression of a floral homeotic gene in vegetative tissues but does not appear to have a role in plant embryogenesis [6]. Two other Pc-G genes, FIS1/MEDEA [7, 8, 9], and FIS3/FIE [8, 10] have been characterized in studies of mutants that produce seeds in the absence of fertilization. Seeds resulting from autonomous development in fis mutants do not contain an embryo but only endosperm, the second product of double fertilization in flowering plants [11, 12]. Thus, FIS genes are considered to be repressors of endosperm development before fertilization. We report that when fis ovules are fertilized, the endosperm patterning along the major polar axis is perturbed. Posterior structures develop in more anterior domains of the endosperm. This correlates with the ectopic expression of a posterior molecular marker. FIS genes appear to be potent regulators of the establishment of the anterior-posterior polar axis in the endosperm.

Arabidopsis↗
PubMed2001

p53 Status and gene transfer experiments using CMV enhancer/promoter.

Comparison of transfection efficiencies between different commercial reagents or methods is a matter of major concern in the field of gene therapy. Transfection efficiencies are usually evaluated by the quantification of a reporter gene expression (i.e., luciferase or lacZ) whose expression is usually driven by the CMV promoter. However, this experimental approach does not consider the possible effects of the transfection on the activity of the promoter used to drive reporter genes expression. Using p53 null fibroblasts we show that transfection efficiency estimated by the use of pCMV-luc or pCMV-betagal plasmids may be dramatically affected by the cell p53 status. These data highlight the fact that differences in p53 levels may be one of the parameters involved in the variation of transfection efficiencies observed with different cell lines. Furthermore, they point to the fact that comparison of transfection efficiencies should distinguish differences in the efficiency of transfection from differences in the level of transcription of the transgene. Finally they suggest that the known p53 down-regulation of the CMV promoter should be considered in order to avoid the nonintentional construction of transfer vectors in which the expression of a transgene down-modulates its own promoter.

Animals↗
PubMed2001

Masked left ventricular restriction in elderly patients with atrial septal defects: a contraindication for closure?

The impact of an atrial septal defect in the elderly with reduced diastolic elasticity of the left ventricle is unclear. We studied the hemodynamic changes during balloon occlusion of atrial septal defects in patients over 60 years of age. In 18 patients (61-78 years old; median, 70), the left atrial pressure and the mitral valve inflow was measured during complete balloon occlusion of the defect and after deflation of the balloon. In seven patients, the left atrial pressure and the E/A ratio of the mitral valve inflow increased markedly (P = 0.02). Mean atrial pressures reached values of 27 mm Hg and the v-wave peak values of 55 mm Hg. Two patients received a transcatheter device closure and developed congestive heart failure. In the elderly, an atrial septal defect can have a decompressive impact on the left ventricle. Therefore, caution appears to be warranted if atrial septal closure is planned.

Aged↗
PubMed2001

Maternal control of seed development.

Maternal control of higher plant seed development is likely to involve female sporophytic as well as female gametophytic genes. While numerous female sporophytic mutants control the production of the ovule and the embryo sac true maternal effect mutations affecting embryo and endosperm development are rare in plants. A new class of female gametophytic mutants has been isolated that controls autonomous development of endosperm. Molecular analyses of these genes, known as FIS class genes, suggest that they repress downstream seed development genes by chromatin remodelling. Expression of the FIS genes in turn is modulated by parent specific expression or genomic imprinting which in turn is controlled by DNA methylation. Thus maternal control of seed development is a complex developmental event influenced by both genetic and epigenetic processes.

Arabidopsis Proteins↗
PubMed2001

[Acute left heart failure after interventional occlusion of an atrial septal defect].

Congestive left ventricular failure after surgical closure of an atrial septal defect (ASD) has been repeatedly reported, particularly in the elderly. We present a case of left ventricular failure after a successful transcatheter closure of an ASD, which to our knowledge has not been described before. In a 78-year-old woman (50 kg, 160 cm) with well-preserved left ventricular function (ejection fraction 65%) and without coronary artery disease or arterial hypertension, an ASD (Qp/Qs 1.6:1) was closed with an Amplatzer Septal Occluder without a residual shunt. Two hours after the procedure, she developed pulmonary edema due to left ventricular failure (increase of end-diastolic diameter from 42 mm to 54 mm, ejection fraction 20%), had to be mechanically ventilated for 24 hours and needed catecholamines for 4 days. High doses of diuretics were supplied until the ejection fraction normalized (32%). The patient could not be discharged until two weeks after intervention. A reduced preload for decades may predispose acute left ventricular failure, particularly in the elderly with compromised ventricular compliance.

Aged↗
PubMed2001

Molecular and clinical differences between adenocarcinomas of the esophagus and of the gastric cardia.

Adenocarcinoma of the esophagus (ADCE) with Barrett's mucosa and adenocarcinoma of the cardia (ADCC) are often reported as a single pathological entity. In this study we have used strict anatomical-pathological criteria to distinguish between these two lesions and we have investigated their differences in TP53 mutations, MDM2 gene amplification, and cytokeratin expression. DNA was extracted from the tumor areas of formalin-fixed, paraffin-embedded sections in 26 ADCC and 28 ADCE patients. TP53 mutations were detected by temporal temperature gradient electrophoresis and identified by sequencing. MDM2 amplification was assessed by differential polymerase chain reaction. The expression of cytokeratins 4, 7, and 13 was examined by immunohistochemistry. In ADCC, the male to female ratio was 1.8:1, compared to 27:1 in ADCE. Five ADCC patients had a history of other neoplasms, compared to only one ADCE patient. The two types of tumor differed in the prevalence of TP53 mutations (31% in ADCC and 50% in ADCE) and of MDM2 gene amplification (19% in ADCC and 4% in ADCE), and in the pattern of expression of cytokeratin 7 (positive in 100% of ADCE and in 41% of ADCC) and cytokeratin 13 (positive in 81% of ADCE and in 36.5% of ADCC). ADCE and ADCC differ in their clinical characteristics, in the prevalence of TP53 mutations and MDM2 amplifications, and in the patterns of cytokeratin expression. These results support the notion that ADCC and ADCE are distinct pathological entities.

Adenocarcinoma↗
PubMed2001

Endothelial cell marker expression in dysplastic lesions of the liver: an immunohistochemical study.

BACKGROUNDS/AIMS: Hepatocellular carcinoma usually contains continuous capillary vessels lacking the differentiation markers specific for normal sinusoidal endothelial cells. We therefore aimed to search for alterations in endothelial cell marker expression in precancerous liver lesions. METHODS: Expression of the endothelial cell markers CD31, CD34 and BNH9 was analyzed in 138 dysplastic lesions from 40 cirrhotic patients (20 with and 20 without hepatocellular carcinoma). RESULTS: No expression of the three endothelial cell markers was detected in cirrhotic nodules and in non dysplastic regenerative macronodules. The three markers were detected in 29.8% of dysplastic lesions and 47% of hepatocellular carcinomas. At least one marker was detected in 75% of dysplastic lesions and 100% of hepatocellular carcinomas. The three markers were more frequently expressed in areas of small cell than of large cell change (34 vs 10%). No correlation was found with the grade of dysplasia, the occurrence of arterialization and the association with hepatocellular carcinoma. CONCLUSIONS: Alterations in the hepatic microcirculation comparable to those observed in hepatocellular carcinoma are present in a significant proportion of dysplastic lesions of the liver and may be indirect markers of the process of liver carcinogenesis.

Adult↗
PubMed2001

Feasibility of transcatheter closure of multiple defects within the oval fossa.

BACKGROUND: Multiple perforations in the floor of the oval fossa may be an obstacle for transcatheter closure. Thus, we analyzed the interventions in 33 patients with more than one interatrial communication in comparison with 370 procedures with a single defect. METHODS AND RESULTS: A diagnostic catheterization, which included a balloon-sizing maneuver, was performed. We implanted a total of 46 occluders, made up of 42 Amplatzers and 4 CardioSEALs. In 20 patients, the defects were closed with a single occluder, namely 18 Amplatzer and 2 CardioSEAL devices. Complete closure was achieved in 15 patients, while a tiny residual shunt remained in 5 patients. In 13 patients, two devices were implanted, without any residual shunt being found immediately after implantation. In 3 patients, the occluders did not touch each other. In 10 patients, their rims overlapped. In comparison with the control group, the group with multiple defects did not differ in the distribution of age, gender, and indications for device closure. The mean time of the procedure, and the time required for fluoroscopy, however, were significant longer (P<0.001). These times ranged from 45 to 250 minutes with a median of 140 minutes, and from 0.0 to 39.2 minutes, with a median of 12.0 minutes, respectively. Also, the association with an atrial septal aneurysm was significantly more frequent (61 vs. 17%; P<0.001). The times taken during insertion of double devices were also significantly longer than those needed for insertion of a single device (P<0.001). CONCLUSIONS: Transcatheter closure of multiple defects within the oval fossa is feasible with currently available occluders, albeit than, in selected cases it is necessary to implant two devices.

Adolescent↗
PubMed2001

Quantification of morphologic and hemodynamic severity of coarctation of the aorta by magnetic resonance imaging.

OBJECTIVE: As the morpholgic severity of coarctation of the aorta is difficult to assess, especially after previous repair, the value of the technique of multiplanar reconstruction of magnetic resonance imaging data to achieve a 3-dimensional reconstruction of the aortic arch was evaluated and compared to hemodynamic measurements. METHODS AND RESULTS: We performed 30 examinations in 27 patients aged from 6 to 54 years, with a mean of 21 years, by magnetic resonance imaging using a 1.5Tesla scanner with a standard body coil. Measurements of flow across the coarctation were performed using phase shift velocity mapping, and peak velocity was calculated at the site of stenosis. Aortic cross-sectional area before, at, and beyond the stenosis was reconstructed 3-dimensionally to calculate a percentage degree of stenosis. Morphologic severity of stenosis was correlated to invasively assessed hemodynamic gradients and morphologic data from biplane angiography in 23 patients. Among the 30 examinations, 24 patients had been previously treated by either surgery, in 17 patients, or balloon dilation, while 6 had native coarctation. 3-dimensional reconstruction was possible in all and better delineated the anatomy concerning the hemodynamic relevance of stenoses even as compared with biplane angiography. The correlation between severity of narrowing assessed by diameter measurements in the biplane angiography and 2-dimensional magnetic resonance imaging was r = 0.94, and multiplanar reformation with 2-dimensional magnetic resonance imaging was r = 0.87 with a tendency of higher grading with the 3-dimensional technique (p = 0.0001). The correlation of 2-dimensional magnetic resonance imaging with invasively measured hemodynamic gradients was r = 0.67 versus r = 0.74 for the areas assessed by multiplanar reformation, indicating that the hemodynamic relevance of a morphological approach to evaluate the degree of a stenosis should better be assessed 3-dimensionally. CONCLUSIONS: The 3-dimensional reconstruction of the morphologic severity of coarctation offers additional information over conventional imaging especially in patients with kinking, complex geometry, or collaterals, in whom hemodynamic measurements can become unreliable.

Adolescent↗
PubMed2001

[Options for interventional heart catheterization in congenital heart disease].

Parallel to the rapid advances in the surgical options in treating congenital heart defects pioneering innovations in interventional cardiology could establish alternative treatment to surgery for these patients. On the one hand there is a trend to interventionally cure simple heart defects, but on the other hand interventional procedures can often only support surgical treatment. This review gives a limited overview over the recent possibilities and problems of the interventional cardiology and therefore focuses on balloon dilatation of congenital valve or vessel stenoses, on device closure of intracardiac defects and on the implantation of stents for the enlargement of elastic or long stenoses.

Angioplasty, Balloon, Coronary↗
PubMed2001

Efficient retrovirus-mediated transduction of primitive human peripheral blood progenitor cells in stroma-free suspension culture.

Retroviral transduction of hematopoietic cells has resulted in unsatisfactory gene marking in clinical studies. Since cytokine-stimulated stem cells have engrafted poorly in animal models, we investigated phenotypic changes during culture of peripheral blood progenitor cells (PBPC). Human CD34(+) HLA-DR(low) cells, immunomagnetically separated from PBPC collections, were found to extrude rhodamine-123, which is characteristic for primitive hematopoietic cells. Cells were grown in suspension cultures supplemented with cytokines. While interleukin-3-containing factor combinations promoted cell proliferation they caused loss of rhodamine-123 extrusion and reduced the frequencies of cobblestone area-forming cells (CAFC). Several other cytokines failed to stimulate cell divisions, which are required for retroviral transduction. A combination including Flt-3 ligand (FL), interleukin-6 and stem cell factor (SCF) preserved an immature phenotype for 5 to 6 days and stimulated cell divisions, which was improved upon addition of leukemia inhibitory factor and interleukin-11. Furthermore, the CAFC frequency among cells treated with these cytokines was increased as compared with widely used cocktails containing interleukin-3, interleukin-6 and SCF. Rhodamine-123 appeared to be a particularly sensitive indicator for differentiation of PBPC. For analysis of gene transfer, amphotropic retroviruses conferring an MDR1 cDNA were added repeatedly for 6 days to cytokine-treated PBPC stroma-free cultures. Proviral cDNA was detected by polymerase chain reaction in 68% of cobblestone areas derived from CD34(+)HLA-DR(low) cells that had been exposed to Flt-3 ligand, interleukin-6 and SCF. In summary, conditions were identified that facilitate efficient transduction of early PBPC with amphotropic retroviruses while preserving a primitive phenotype for extended periods.

Antigens, CD34↗
PubMed2001

Orthotopic liver transplantation for idiopathic portal hypertension: indications and outcome.

BACKGROUND: Idiopathic portal hypertension is a rare clinical syndrome which may be associated with a spectrum of histological lesions, including nodular regenerative hyperplasia and incomplete septal cirrhosis. Here, we report eight adult patients with idiopathic portal hypertension who experienced an unusually severe clinical evolution characterized by the development of progressive hepatic failure requiring orthotopic liver transplantation. Our aims are: (a) to stress the distinctive clinical presentation of these patients, (b) to describe their biological and histopathological features, and (c) to evaluate the results of orthotopic liver transplantation in this rare indication. METHODS: Complete clinical charts and histological data were available in all patients. All patients were male. Their age at diagnosis ranged from 17 to 59 years. Complications of portal hypertension revealed the disease in all cases. Medical treatment was performed in all patients and portosystemic shunt in three. RESULTS: The development of progressive hepatic failure led to the indication of liver transplantation after a delay ranging from 3 to 10 years. Explanted livers showed pure nodular regenerative hyperplasia in three patients and incomplete septal cirrhosis in five. Recovery was uneventful. All patients are alive, without recurrence of the disease. CONCLUSIONS: This report points to the existence of severe cases of idiopathic portal hypertension occurring without underlying or associated systemic disease and characterized by a poor clinical course and requiring liver transplantation.

Adolescent↗
PubMed2001

Expression of hMLH1 and hMSH2 and assessment of microsatellite instability in testicular and mediastinal germ cell tumours.

The aim of this study was to investigate DNA mismatch repair deficiency in male germ cell tumours. We analysed the expression of two mismatch repair proteins, human mutL homologue 1 (hMLH1) and human mutS homologue 2 (hMSH2), and evaluated the frequency of microsatellite instability with 10 mononucleotide and two dinucleotide repeat sequences, in 39 paired tumour/normal DNA samples obtained from 17 testicular and two mediastinal germ cell tumours. In all 19 cases, hMLH1 and hMSH2 both showed nuclear immunolocalization in invasive and testicular in-situ tumours. In non-neoplastic seminiferous tubules, hMLH1 was expressed only in premeiotic germ cells, while hMSH2 was seen in all stages of spermatogenesis. Genetic analysis of dinucleotide markers revealed loss of heterozygosity in one of two testicular yolk sac tumours at D18S58 and an allelic shift at D2S123 in two of three testicular embryonal carcinomas, while none of the 12 seminomas exhibited a genetic abnormality at these loci. No abnormalities were demonstrated with the 10 mononucleotide markers. The two mediastinal germ cell tumours showed no genetic instability or allelic loss with all 12 markers. We suggest that genetic alterations as assessed by microsatellite analysis in germ cell tumours may reflect tissue maturation and phenotypic differentiation rather than tumour progression. In addition, we suggest that hMLH1 and hMSH2 genes may not be implicated in the genesis of germ cell tumours.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Pathologic and clinical features of 77 Hodgkin's lymphoma patients treated in a lymphoma protocol (LNH87): a GELA study.

Between 1987 and 1993, 77 of 2855 lymphomas included in the LNH87 protocol of the GELA as non-Hodgkin lymphoma (NHL) and reviewed by a panel of pathologists had a diagnosis changed to Hodgkin lymphoma (HL). Some of these lymphomas had been initially interpreted as anaplastic large-cell lymphoma Hodgkin-like (ALCL-HL subtype). The purpose of this study was to analyze the histologic pitfalls initially encountered, to define more clearly the diagnostic criteria of lymphomas placed in the gray zone around HL, and to follow the survival of these 77 patients affected with HL and initially treated with NHL regimens. The 77 cases of HL were reviewed by three hematopathologists and immunostained with a large panel of antibodies, including CD30, CD15, CD3, CD20, CD45, CD43, LMP-1, EMA, BNH-9, TiA1, and ALK1. Each case was classified according to the Lukes-Rye system and the British National Lymphoma Investigation (BNLI) grading. The initial clinical presentation of patients was analyzed, and the overall and event-free survival rates of the 77 patients were estimated. Among the 77 HLs, 46 were misinterpreted as NHL by primary individual pathologists (12 as ALCL, 8 as ALCL-HL, 12 as peripheral T-cell lymphoma (PTCL), 6 as B-cell lymphoma, and 8 as unclassifiable NHL). The other 31 cases had been first considered by the panel as consistent with ALCL-HL (n = 18) or with PTCL (n = 13) and were changed later in view of an immunophenotype concordant with HL. Fifty-five percent of the patients completed the full NHL treatment. The 5-year event-free and overall survival rates were 54% and 77%, respectively. The current results indicate that lymphomas initially called ALCL-HL should not be regarded as a variant of ALCL, but as HL. The clinical consequences of misdiagnoses seem to be a lower event-free survival rate compared with that of classical HL, probably because of more relapses of initially inappropriately treated HL.

Adolescent↗