Search PubMed⌕ Search

Biomedical subjects

G Adam

Publications and source records attributed to G Adam.

At least 271 records · Page 15Linked to original sources
PubMed1991

Triterpene glycosides from Schefflera octophylla.

In addition to 3-epi-betulinic acid, three triterpene glycosides were isolated from leaves of Schefflera octophylla. The structures of the glycosides have been determined as 28-O-[alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl(1----6)-be ta-D- glucopyranosides of 3 alpha-hydroxy-lup-20(29)-ene-23,28-dioic acid, 3 alpha,11 alpha- dihydroxy-lup20(29)-ene-23,28-dioic acid and 3-epi-betulinic acid by spectroscopic data and chemical transformations. The last two compounds were found for the first time in the plant kingdom.

Carbohydrate Sequence↗
PubMed1991

A sulphated triterpenoid saponin from Schefflera octophylla.

Dried leaves of Schefflera octophylla afforded a new sulphated triterpene glycoside. From spectroscopic data and chemical transformations the structure of the new constituent was determined as 3-epi-betulinic acid 3-O-sulphate 28-O-[alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl (1----6)]-beta-D-glucopyranoside.

Acetylation↗
PubMed1991

Microbial degradation of 2 alpha, 3 alpha-dihydroxy-5 alpha-cholestan-6-one by Mycobacterium vaccae.

2 alpha,3 alpha-Dihydroxy-5 alpha-cholestan-6-one (3), which had the substitution pattern of brassinosteroids in the A/B-ring moiety, was transformed by Mycobacterium vaccae to give 2 alpha,3 alpha,6 alpha-trihydroxy-5 alpha-androstan-17-one (4) and 2 alpha-hydroxyandrost-4-ene-3,17-dione (5). The structures of these compounds were determined by spectroscopic methods, especially 1H nuclear magnetic resonance studies.

Biotransformation↗
PubMed1991

[Contrast-enhanced MRT of malignant melanoma of the uvea].

Twenty-one patients with malignant melanoma of the uvea or iris, some with intra-ocular bleeding, were examined by MRT before and after the administration of Gd/DTPA. In 13 patients, several examinations were performed over a period of 1.5 to 20 months after irradiation of the melanoma. After Gd-DTPA there was an average increase of 13% in the signal intensity from all non-irradiated melanomas (17 cases). Three months following radiation therapy, there was an average increase in signal intensity after Gd-DTPA of 65.7%, and after seven months of 100%. Amelanotic melanomas (two cases) showed a primary increase in intensity of 100%. Two melanomas of the iris were demonstrated by sonography; of these, only one could be shown with certainty by MRT. Small tumours and tumour residues after irradiation were better defined after contrast. In the presence of suspected intra-ocular bleeding, the examination should always be performed after the administration of Gd-DTPA.

Adult↗
PubMed1991

[Angiography of the a. pudenda and its branches in erectile dysfunction. A modified angiographic technic and optimized use of vasodilator substances].

A new simplified technique for evaluating the internal pudendal artery and the penile vessels is described using a new catheter configuration with a very short 90 degrees-angled tip. In 30 consecutive patients, a superselective catheterisation of the internal pudendal artery was achieved in 93%. To improve visualisation of the penile arteries, the selective intraarterial application of 0.2 mg nitroglycerin in addition to the mandatory intracavernous injection of papaverin or prostaglandin E1 has proved to be of value. Examination of the blood blow velocity in the dorsal penile artery with Doppler ultrasound 2 minutes after intra-arterial application of 0.2 mg nitroclyerin showed a mean elevation of the Doppler amplitude by the factor 2.4 (range 0.4-9). With regard to the maximal increase of the blood velocity (range 1-6 minutes), a high interindividual difference was observed.

Arteries↗
PubMed1991

In vitro ablation of normal and diseased vascular tissue by a fiber-transmitted holmium laser.

An in vitro study was performed to test the ablative potential of a fiber-transmitted pulsed holmium laser (2.1 microns) applied to normal vascular wall, lipomatous plaques, and calcified plaques. Different fluences per pulse of 42, 80, 205, and 315 J/cm2 were used. Ablation of normal tissue and lipomatous plaques was achieved with all power settings. Effective ablation of calcified plaques, however, occurred only after a minimum fluence of 205 J/cm2, and the effect was significantly less pronounced compared to ablation of soft lesions.

Angioplasty, Laser↗
PubMed1991

Cloning and sequencing of the S RNA from a Bulgarian isolate of tomato spotted wilt virus.

Libraries of cloned cDNA were prepared from complete genomic RNA and isolated S RNA of the Bulgarian L3 isolate of tomato spotted wilt virus (TSWV-L3). Northern blotting of TSWV genomic RNA detected clones specific for the L, M and S RNAs in the library from complete RNA. S RNA-specific clones selected from both libraries covered approximately 2.8 kb (about 95%) of the S RNA. Sequencing of these clones showed TSWV-L3 S RNA to be ambisense. It contains two open reading frames (ORFs); one of 1401 nucleotides located on the viral RNA encodes an Mr 52,400 (52K) protein, and the other of 774 nucleotides on the complementary strand encodes an Mr 28,900 (29K) protein. Expression of the 29K ORF in bacteria and immunological analysis of the fusion protein synthesized confirmed that the 29K protein is the N protein of TSWV-L3. Comparison with the published sequence for the S RNA of a Brazilian TSWV isolate, CNPH1, revealed almost complete identity in the amino acid sequences for the 29K protein, but several clustered amino acid exchanges in the putative 52K protein. In addition, the separating non-translated intergenic region of the S RNA of the Bulgarian isolate is 81 nucleotides longer than that of CNPH1.

Amino Acid Sequence↗
PubMed1991

The Saccharomyces cerevisiae ADR1 gene is a positive regulator of transcription of genes encoding peroxisomal proteins.

Expression of the CTA1 gene of Saccharomyces cerevisiae, encoding catalase A, the peroxisomal catalase of this yeast, is sensitive to glucose repression. A DNA fragment cloned as a multicopy plasmid suppressing the glucose repression of CTA1 transcription was demonstrated to contain the ADR1 gene. Multiple copies of ADR1 increased catalase A formation not only on 10% glucose, but also on ethanol medium and in the presence of oleic acid, an inducer of peroxisome proliferation. Compared with wild-type cells, adr1 null mutants produced by disruption of the gene exhibit reduced CTA1 expression. This demonstrates that ADR1 is a true positive regulator of CTA1. Further experiments showed that it acts directly on CTA1. Alcohol dehydrogenase II, which is under ADR1 control, was excluded as a mediator of the effect on CTA1; deletion of bases -123 to -168 of CTA1 reduces expression and eliminates the response to the ADR1 multicopy plasmid without eliminating fatty acid induction; and gel retardation experiments demonstrated that ADR1 binds to a CTA1 upstream fragment (-156 to -184) with limited similarity to the ADR1 binding site of ADH2. Northern hybridization experiments further demonstrated that expression of two genes encoding enzymes of peroxisomal beta-oxidation (beta-ketothiolase, trifunctional enzyme) and of a gene involved in peroxisome assembly (PAS1) is also negatively affected by the adr1 null mutation. These findings demonstrate that the ADR1 protein has much broader regulatory functions than previously recognized.

Base Sequence↗
PubMed1991

Rheumatoid arthritis of the knee: value of gadopentetate dimeglumine-enhanced MR imaging.

In an attempt to differentiate among joint effusion, synovitis, pannus, and subchondral sclerosis in patients with clinically proved chronic rheumatoid arthritis, we used gadopentetate dimeglumine-enhanced MR imaging to examine 23 patients with acute knee symptoms. All patients had had rheumatoid arthritis for more than 6 months and satisfied four or more of the criteria of the American Rheumatism Association for rheumatoid arthritis. MR imaging was performed on a 1.5-T machine by using unenhanced T1-weighted spin-echo imaging, unenhanced T2*-weighted gradient-echo imaging, and unenhanced and enhanced T1-weighted gradient-echo imaging. Signal intensities of the synovium and bone marrow were measured with the region-of-interest technique on unenhanced and enhanced T1-weighted gradient-echo scans. Conventional radiographs were available for each patient. Joint effusion, synovitis, intraarticular pannus, subchondral sclerosis, and subchondral pannus had the same signal intensities on unenhanced T1-weighted spin-echo, unenhanced T1-weighted gradient-echo, and unenhanced T2*-weighted gradient-echo MR images, and could not be differentiated from one another. On enhanced T1-weighted gradient-echo sequences, pannus and synovitis showed marked enhancement in 15 patients, whereas joint effusion and sclerosis did not. Synovitis was diagnosed if the synovial membrane showed high enhancement; pannus was diagnosed if enhancing masses were seen within the joint space or in the subchondral area. In eight of the 23 joints, there was no enhancement of the synovium or intraarticular or subchondral tissue. We conclude that gadopentetate dimeglumine-enhanced MR imaging allows differentiation between synovitis and joint effusion and between subchondral pannus and subchondral sclerosis. Enhancement of the synovium and pannus indicates acute inflammation of the joint.

Adolescent↗
PubMed1991

Post-translational arginylation and intracellular proteolysis.

Cellular proteins may be designated to fast degradation by their N-terminal amino acids, and especially a N-terminal arginine residue should have an extremely destabilizing effect on cytosol proteins. We investigated the post-translational arginylation of cytosol proteins and especially of ornithine decarboxylase (ODC) by the cytosolic enzyme arginyl transferase by incubation with radioactive L-arginyl-tRNA and isolation of ODC with our monoclonal antibody. Arginylated ODC had a specific radioactivity 8600 times that of the bulk of cytosolic proteins and Edman-degradation of this ODC showed that the post-translational arginylation occurred only at the L-amino-end of the enzyme. The inhibitor of arginyltransferase, L-Glutamyl-L-Valyl-L-Phenylalanine, increased the half-life of ODC in cultured hepatocytes from 39 min to more than 90 min. This post-translational arginylation of ODC and also of other cytosol proteins is reversible. At least 25 different cytosol proteins in addition to ODC can be arginylated in hepatocytes, and at least 15 different proteins can be arginylated in Dictyostelium discoideum. The arginylated proteins are much more rapidly degraded by cellular proteinases, especially by calpains, than those cytosolic proteins which are not arginylated.

Acyltransferases↗
PubMed1991

[Differential intraocular tumor diagnosis in MRI using gadolinium DTPA: value in comparison with other ophthalmologic examination procedures].

To improve the tissue characterizing information obtained by MRI we examined 35 patients with 43 different intraocular lesions by applying Gadolinium-DTPA for the first time. Histology was available in seven cases. Twenty patients were diagnosed as having a malignant uveal melanoma, 2 had a melanoma of the ciliary body and the iris, 3 patients were found to have a naevus of the uvea and 3 patients suffered metastatic uveal infiltrates, 4 patients had a senile maculopathy and 10 patients had either a vitreal or a subretinal haemorrhage, 1 patient had an angioma and another a lymphoma of his vitreous. Ruthenium plaques were applied to 13 out of 20 melanoma patients. These patients were followed-up by MRI examinations at regular intervals after therapy. The pretherapeutic signals of melanotic melanomas were high before applying Gadolinium-DTPA and demonstrated a further increase after contrast enhancement. Following ruthenium therapy the drop of the precontrast signal was more pronounced than the postcontrast signal. In complicated clinical situations MRI offers additional information to enable the differentiation between intraocular tumors and haemorrhages.

Adult↗
PubMed1990

Cross-sectional anatomy of the knee.

Frozen knee joints from cadavers were cut into 7 mm slices. The anatomical structures of representative slices were described in detail in order to provide us with information of the topography of the anatomical structures as possible. The detailed description is thought to be helpful for the interpretation of MR images of the knee joint.

Humans↗
PubMed1990

Cystic fibrosis in Greece: typing with DNA probes and identification of the common molecular defect.

The relative frequency of the delta F508 mutation in the Greek population is 54.1%; this is similar to that reported in other Southern European populations and contrasts with the considerably higher frequencies encountered in Northern Europe and North America. The low frequency is in agreement with the linkage disequilibrium already reported between cystic fibrosis and haplotype B in this country. In contrast to the common association of pancreatic insufficiency with the homozygous delta F508 genotype, the present study revealed two homozygous children with no evidence of pancreatic failure.

Chromosome Deletion↗
PubMed1990

Gadolinium-DTPA-enhanced MRI of intraocular tumors.

The value of gadolinium-enhanced MRI in 30 patients with intraocular lesions has been evaluated. Seventeen patients had a uveal melanoma, two a ciliary body melanoma, three had uveal metastases, one lymphoma, four had senile macula degenerations, and three uveal nevi. Twelve of 17 patients with melanoma were followed up by MRI after ruthenium plaque therapy on 2-4 occasions. Melanomas showed high precontrast signal intensities and only a slight enhancement after intravenous Gd-DTPA was given. After ruthenium plaque therapy precontrast signal intensities (SI) decreased while a moderate signal increase on postcontrast scans was noted. Scars or tumor residues were better delineated on enhanced images. All other tumors than melanotic melanomas showed low SI on precontrast scans and a high signal increase after Gd-DTPA administration. Small amelanotic tumors were better delineated on postcontrast scans. In addition Gd-DTPA-enhanced MRI allowed differentiation between tumor and hemorrhage. No signal increase after Gd-DTPA application was seen in subretinal or vitreous hemorrhages of varying ages.

Adult↗
PubMed1990

[Laser angioplasty and the removal of calcified plaques. An in vitro study].

The ablative potentials of five different lasers on normal and diseased vascular tissue were tested in vitro. Post-mortem aortic specimens of normal wall, lipomatous and calcified plaques were exposed to both continuous wave lasers (argon, neodymium-YAG 1064 nm) coupled to hot-tipped or sapphire tipped fibres and pulsed lasers (Excimer 193 nm, CO2, erbium-YAG). Histomorphological changes and penetration were evaluated microscopically. Pulsed lasers of all wavelengths used were able to ablate vascular tissue of all stages including heavily calcified plaques. Thermal lasers were able to penetrate the normal wall and lipomatous plaques, but did not reach any evident reaction on calcified plaques. Thermal lasers may have only limited potentials in angioplasty, since ablation of calcified plaques is not possible.

Angioplasty, Balloon↗