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E Adám

Publications and source records attributed to E Adám.

At least 19 recordsLinked to original sources
PubMed1998

Transcription of Arabidopsis and wheat Cab genes in single tobacco transgenic seedlings exhibits independent rhythms in a developmentally regulated fashion.

Transcription of Cab genes has been previously shown to be regulated by a circadian oscillator coupled to the red light-absorbing plant photoreceptor phytochrome in various plant species. In addition, it has recently been suggested that rhythmic expression of the Cab genes could also be affected by a phytochrome-independent circadian oscillator in a developmentally regulated fashion. This study has shown that a red light-insensitive oscillator and a phytochrome-coupled circadian clock indeed coregulate the oscillating expression of individual Cab genes at the level of transcription at an early developmental stage. The study involved analysing the expression patterns of transgenes, containing short fragments of the Arabidopsis thaliana Cab2 or the wheat Cab-1 promoter fused to the firefly luciferase reporter gene, by a video-imaging system in single, etiolated tobacco seedlings. Germination and red/far-red light treatments applied between 12 and 36 h after sowing lead to the appearance of two independent circadian rhythms. These rhythms coexist, both exhibiting period lengths close to 25 h but phased differently. However, repeated red-light treatments given 60 h or later after sowing synchronize these free-running rhythms and induce a single new circadian oscillation. These data indicate that both oscillators regulate the expression of the Cab genes studied at the level of transcription and that the cis-acting element(s) of the wheat Cab-1 and A. thaliana Cab2 genes mediating these responses are located on short, 250 bp promoter regions. Furthermore, these red-light induced rhythms are also inducible by far-red light treatments alone. Therefore, in tobacco, the phytochrome-coupled oscillator is regulated, at least partially, by the very low fluence response of phytochrome A.

Animals↗
PubMed1997

[New developments and trends in adenovirus research].

Adenovirus infections have been associated with a variety of disorders of the respiratory, ocular, gastrointestinal and urogenital systems. In the last fifteen years, special attention has been given to the adenoviral infections in immunocompromised host, transplant recipients, cancer patients and AIDS patients. Adenoviruses in these patients can cause severe, often generalized illness, with high fatality rate. Data suggest a specific role for adenoviruses in AIDS pathogenesis. From AIDS patients many new and intermediate adenovirus serotypes could be isolated. Considerable effort should be devoted to this area of research in the coming years to understand the molecular mechanism of the interaction between AIDS and adenoviruses. In the last few years recombinant adenoviruses have been widely used as gene delivery vectors in experiments both with curative and preventive purposes. Adenovirus vectors have been used in the experimental gene therapy of genetic disorders, of immuno- and molecular therapy of a variety of cancers. The combination of recombinant adenovirus technology with chemotherapy (pro drug system) seems to be promising, as well as the specific destruction of tumor cells with modified, not recombinant adenoviruses. An the other hand, recombinant adenoviruses appear to be attractive candidates for vaccination against the infectious diseases, too. The current tendency is the construction of second-generation vectors which serve better the different purposes. Potential improvements could be the construction of targated vector by the modification of viral cell-tropism and the suppression of the immune response of the host organism directed against the vector and the vector virus infected cells.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Characterization of adenovirus hexons by their epitope composition.

For the investigation of epitope composition of different adenovirus hexon types sixty-one mouse ascitic fluids containing monoclonal antibodies (MAbs) developed in three different panels were used. The distinction and marking of the different epitopes recognized by the MAbs were carried out by the determination of the composite cross-reactivity pattern, the titer and the correlation coefficient of all the 61 MAbs with 21 different hexon types representing all the six human subgenera, as well as different bovine and simian adenoviruses. The distinct epitopes were marked by two numbers referring the homologous hexon type to which the MAbs were directed and the serial number of the epitope specified by the different members of the given panel of the MAbs. The three panels of MAbs recognized 22 epitopes on the 21 hexon types among them a genus and three type specific ones and 18 different bi- and multilateral intertype (IT) specific epitopes that grouped adenoviruses within the genus, independently from the subgenus they belong to. Considering that the type specific epitope could be present only on the homologous hexon type, the largest number of the different epitopes distinguishable by the MAbs used could be 20 on the homologous hexon and 19 on the heterologous ones. It was found that the total number of IT specific epitopes on the hexons varied between 2 and 18. The distribution of the distinct specific epitopes on the different hexon types was different, as expected. The antigenic structure of the individual hexon types were characterized by the determination of their IT specific epitope spectrum. By pairwise analysis ten human hexon types formed three epitope clusters (types 4 and 19; types 8, 9, 9/13 and 10; as well as all types of subgenus C) showing identical epitope spectra. No clustering was found with human type 7, 12, 13, 18, 26, 27, 35 and 41, as well as with bovine and simian adenovirus hexons studied. However, they displayed a closer or looser antigenic relationship among each other and to members of the epitope clusters. The degree of antigenic relationship could be expressed by the similarity/dissimilarity percentage calculated from the number of the identical and different epitopes present on any two given hexon types.

Adenoviruses, Human↗
PubMed1996

Intertype specific epitopes on the hexons of adenovirus types 1, 2, 5 and 6.

The intertype specificities of the epitopes present on the surface of the hexon types belonging to human adenovirus (Ad h) subgenus C were studied. The reactivity pattern (RP) and the titres of ascitic fluids containing monoclonal antibodies (MAbs) were determined in ELISA. From three panels of MAbs 38 directed against Ad h1, 17 directed against Ad h 35 and 6 MAbs directed against bovine adenovirus type 2 were studied. Twelve of the MAbs proved to be genus or type specific. The rest of the MAbs showed numerous intertype specific RPs in different combinations on the different hexon types according to previous experiments with purified hexons of different Ad h subgenera and animal serotypes. With hexon types 1, 2, 5 and 6 of subgenus C all intertype specific MAbs gave identical RPs and the titres of the individual MAbs with all the four hexon types were generally high, and the most frequently found titres were evenly distributed among them. These results indicate the presence of numerous different intertype specific epitopes on the hexons of subgenus C in identical combination on the four hexon types.

Adenoviruses, Human↗
PubMed1996

Human herpesvirus 8 in classic Kaposi sarcoma.

Recent studies suggest the role of a new human herpesvirus (HHV8) in the pathogenesis of different forms of Kaposi sarcoma (KS). In the present work we investigated the presence of HHV8 sequences in KS tumour tissues from patient with classic KS. Since clear evidences point to the role of immune suppression in the development of AIDS-associated KS or patients receiving immunosuppressive therapy, immunological investigations were also performed. We could show a highly consequent association of HHV8 sequences with classic KS in the large series of patients supporting our previous findings that this virus might be in some way involved in the pathogenesis of this tumour. In addition immunological examination of the patients revealed a mild decrease in the CD4 positive cell number, a significantly reduced CD4/CD8 ratio, a diminished PHA reactivity and leukocyte migration factor production of lymphocytes. The changes observed in the present study are similar, but much less pronounced than those may be observed in HIV infection.

Aged↗
PubMed1995

[Significance of recombinant adenoviruses in experimental gene therapy].

In the past few years recombinant adenoviruses have emerged as promising technology in the gene therapy. They have been used for genetic modification of a variety of somatic cells in vitro and in vivo. They offer several advantages over other vectors. Replication defective vectors can be produced in very high titers (10(11) pfu/ml) thus allowing a substantially greater efficiency of direct gene transfer, they have the capacity to infect both replicating and nonreplicating cells, and the DNA functions in an extrachromosomal fashion, which eliminates the risk of insertional mutagenesis. Several important limitations of adenovirus-mediated gene transfer are also known, such as the relatively short term expression of foreign genes, the dose-related direct toxic effect, and that the host immune response to the viral proteins may substantially inhibit the effect of repeated infection with recombinant adenoviruses. Recombinant adenoviruses of types 2 and 5 are used most frequently as vectors for direct gene transfer. The author's experiments with monoclonal antibodies raised against the adenovirus hexon proteins revealed the existence of a remarkable homogeneity in the antigenic structure among the hexon types of subgenus C (types 1, 2, 5 and 6). Besides the genus and type specific epitopes the presence of at least 15 identical intertype specific epitopes were demonstrated on the surface of the hexons. The data suggest that recombinant adenoviruses constructed from the types of subgenus C cannot be replaced by each other to avoid the host immune response in repeated infections in gene therapy because of their close antigens relationships.

Adenoviridae↗
PubMed1995

Expression of tobacco genes for light-harvesting chlorophyll a/b binding proteins of photosystem II is controlled by two circadian oscillators in a developmentally regulated fashion.

Light-induced expression of genes encoding the light-harvesting chlorophyll a/b binding proteins of photosystem II (Cab) was shown to be controlled by a circadian oscillator coupled to the red-light-absorbing plant photoreceptor phytochrome. Here we show that a red-light-insensitive oscillator is also involved in regulating the expression of the Cab genes. We provide evidence that germination leads, in a light-independent manner, to the setting and/or synchronization of endogenous oscillators and that it induces the expression of Cab genes in a circadian fashion. This circadian oscillator is not coupled to phytochrome, as it cannot be reset by red light for at least 44 h after sowing. Short red light pulses given between 12 and 44 h after sowing, however, induce new rhythms without perturbing the already free-running red-light-independent circadian oscillation. At this stage of development, the phytochrome-coupled and uncoupled circadian rhythms coexist. Both circadian rhythms are expressed and exhibit period lengths close to 24 h but are phased differently. At later stages of development (60 h or later after sowing), red light treatments synchronized these free-running rhythms and led to the appearance of a single new circadian oscillation. These data indicate that during early development the expression of single tobacco Cab genes, particularly expression of the Cab21 and Cab40 genes, is controlled in a developmentally dependent manner by two circadian oscillators.

Base Sequence↗
PubMed1995

Successful simultaneous transplantation of kidney and fetal pancreatic islet masses.

This paper reports our experience with the successful simultaneous transplantation of kidney and fetal pancreatic islets in 46-year-old diabetic man. No detectable C-peptide level was noted and the end-stage nephropathy required hemodialysis. The cadaver kidney and two masses of 8-week-cultured fetal islets were grafted simultaneously. After revascularization of the kidney, the islet masses were placed under the kidney capsule. Following transplantation, islet function was demonstrated by a higher C-peptide level, which subsequently persisted. Twenty-four months after grafting, islet function was provoked by glucagon and glucose, which led to elevations in the C-peptide and insulin levels. The insulin requirement fell from 58 to 24 U/day during the post-transplant period of 24 months. The mean value of HbA1C (5.6% +/- 0.3%) indicated a constantly normal carbohydrate metabolism. Improvements in retinopathy were also noted. Three periods of kidney rejection were diagnosed, but these proved reversible with high-dose steroid treatment. The serum and urine beta-2-microglobulin levels correlated well with rejection and recovery. More than 2 years after grafting, kidney functions is in the normal range. On sonography, the transplanted islet masses were repeatedly clearly visible, and 24 months following transplantation the volume was twice the original one. The results indicate that simultaneous kidney and fetal pancreatic islet grafting is advantageous in end-stage nephropathy secondary to type I diabetes mellitus.

C-Peptide↗
PubMed1995

Antigenic homogeneity among the adenovirus hexon types of subgenus C.

Antigenic relationships of hexons of human adenovirus (Ad h) types 1, 2, 5 and 6 of subgenus C were studied with 61 monoclonal antibodies (MAbs) raised against human Ad h1, Ad h35 and bovine adenovirus 2. The reactivity pattern (RP) and the titers of the MAbs were determined in indirect ELISA. In previous experiments with hexons of different subgenera 49 MAbs displayed numerous different intertype specificities besides genus specific and type specific ones. With the four hexon types of subgenus C all MAbs gave identical RPs except the type specific ones. Data reveal the existence of a remarkable homogeneity in the antigenic structure among the hexon types of subgenus C defined by the presence of identical or closely related intertype specific epitopes on the surface of the hexons. The possible significance of the results in the experimental gene therapy is discussed.

Adenoviruses, Human↗
PubMed1995

Diversity in the antigenic structure of different hexon types among the members of adenovirus subgenus D.

Antigenic relationships of human adenovirus (Ad h) hexon types: 8, 9, 10, 13, 19, 26, 27 and intermediate type 9/13 (I13), belonging to subgenus D were studied with 61 hybridoma ascitic fluids containing monoclonal antibodies (MAbs). The MAbs were produced in three different panels directed against Ad h1, Ad h35, and bovine Ad type 2. The reactivity pattern (RP) and the degree of cross-reactivity (CR) of the MAbs were determined in indirect ELISA. By the 61 MAbs 8 different RPs could be distinguished. The distinct RPs of hexon types of 8, 9, 10, I13 and 19 were identical or nearly identical and the occurrence of the different eight RPs were based mainly on the combinations of positive or negative reactions of different MAbs with the hexon prototypes 13, 26 and 27. According to the different RPs and to the number of reacting and non-reacting MAbs with the different hexon types as well as on the base of the degree of CR three groups of hexon types with diverse antigenic structure could be distinguished. These data revealed the existence of remarkable diversity in the antigenic structure between type 27 and types 8, 9, 10, I13 and 19, as well as an intermediate position of prototypes 13 and 26.

Adenoviridae↗
PubMed1994

[Experience with the molecular genetical detection of the chimera gene of the Philadelphia chromosome].

Molecular genetical techniques could be developed for detection of the chimera gene of Philadelphia chromosome or that of its gene product, due to the relatively conserved structure of the chimera gene. The authors successfully analysed 123 blood/bone marrow samples from 106 patients using these molecular techniques adapted from the literature. Patients were classified by the first diagnosis, 65 CML, 7 AML, 13 ALL patients were studied. 12 patients had the diagnosis of myeloproliferative syndrome, and 9 patients were after bone marrow transplantation. 57% of the total, and by diagnosis, 74% of CML, 28% of AML, 54% of ALL, and 33% of post-transplant samples have shown the chimera gene structure characteristic for Philadelphia chromosome. All patients of myeloproliferative syndrome were negative. In some cases the authors had the opportunity to study simultaneously the peripheral blood and the bone marrow sample of the same patient and of the same date. The ratio of the positivity of the two samples varied from one to infinite. The authors could follow the effect of interferon in one case, the change of clonality of the leukemic cell line in an other case. They had the opportunity to detect two different abnormal gene structures in the sample of an AML patient.

Chimera↗
PubMed1994

Production of antibodies against adenovirus hexons in Escherichia coli by recombinant phages (a note).

For the study of complex antigen structures, such as the adenovirus hexon capsomer, monoclonal antibodies proved to be very useful tools. Production and stabilization of monoclonal antibodies in a larger amount is complicated and requires special infrastructural background, if we apply the convential hybridoma techniques. Recombinant DNA and gene amplification technology, however, has made it possible to clone antibody genes in bacteria, and to produce antibodies in bacterial cultures.

Adenoviridae↗
PubMed1993

[Acute venous liver circulatory disorder caused by blunt abdominal trauma: is it a compartment syndrome?].

Authors describe the case of a 37-year-old female patient who had been operated on for a subcapsular haematoma of the liver that had developed following a blunt abdominal trauma. This manifested as a Budd-Chiari syndrome-like phenomenon that was not recognized until an exploratory operation was performed, when we found that the liver was hard and dark purple in colour and there was considerable ascites in the abdominal cavity. After aspiration of the haematoma, which contained about 1 l of a mixture of fluid and clotted blood, the circulation of the liver rapidly improved. On the basis of the findings, a posttraumatic Budd-Chiari syndrome seems unlikely, since the symptoms caused by the rise in intracapsular pressure are similar to those of a compartment syndrome. No literature data can be found to define such a posttraumatic failure of the liver circulation. Subcapsular and intrahepatic haematomata can be successfully monitored by ultrasonography and managed conservatively if they are asymptomatic. Operation is restricted to lesions with worsening symptoms or increasing danger of haemorrhage.

Adult↗
PubMed1993

Latex agglutination and adenoviruses. II. Detection of antigens.

Latex particles were coated with different monoclonal antibodies (MAbs) reacting with different epitopes of the hexons of adenovirus (AV) type h1 and h35. The coated particles were tested with the purified hexon of 22 different mammalian AV types and were agglutinated by the respective hexon antigen(s) with high specificity. The sensitivity of the reaction was influenced by the amount of MAb adsorbed to latex particles. The latex, coated with a MAb of genus specific reactivity can be a valuable tool in the rapid immunodiagnosis of adenovirus infections.

Adenoviruses, Human↗