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G Adam

Publications and source records attributed to G Adam.

At least 199 records · Page 11Linked to original sources
PubMed1996

[Detectability of focal liver lesions: comparison of MRI at 1.5 T and dynamic spiral CT].

PURPOSE: To compare dynamic spiral CT with MR imaging in the detectability of focal liver lesions. MATERIAL AND METHODS: Thirty-one patients with 62 focal liver lesions (27 benign) were evaluated retrospectively. Dynamic spiral CT scans were compared with T1- and T2- weighted spin-echo (SE) sequences and in part with multi slice 2-D-FLASH and single-shot slice-selective inversion recovery Turbo-FLASH sequences at 1.5 T. RESULTS: Dynamic spiral CT detected 89% of all lesions and was superior to each sequence alone (56-70%), and also to MRI overall (79%) regardless of lesion size, localization, and histology. However, statistical significance (p < 0.05) was only found for the differences between CT and the T1-weighted SE sequence. CONCLUSION: Compared to conventional SE and GE MR imaging sequences, dynamic spiral CT scanning seems to be more effective in the detection of focal liver lesions.

Adenoma, Liver Cell↗
PubMed1996

[Superparamagnetic iron oxide particles: what value has the T1 effect in the MR diagnosis of focal liver lesions?].

PURPOSE: To evaluate the T1 effect of superparamagnetic iron oxide (SPIO) in MR imaging of focal hepatic lesions. METHODS: 21 patients with 34 liver lesions (18 benign) were examined before and immediately after infusion of SPIO particles (Endorem) with a T1-weighted GRE- and SE sequence and a double echo SE sequence at 1.5T. Changes of lesion signal intensity and contrast-to-noise (C/N) ratio were measured in addition to a qualitative analysis of changes in liver vessel signal. RESULTS: In all cases a marked increase of liver vessel signal intensity was observed on T1-weighted images after SPIO infusion. In contrast to malignant lesions, haemangiomas and adenomas showed significant signal changes (p < 0.05) on T1-and T2-weighted images. Highest signal changes were achieved for haemangiomas on T1-GRE images (+80%) followed by T1-SE (+41%) and T2-SE (-42%). Malignant liver lesions exhibited highest C/Ns on T2-weighted postcontrast images. CONCLUSION: The T1-effect of Endorem offers no benefits in respect of detectability of malignant liver lesions. However, it is helpful in characterising haemangiomas and their differentiation from liver tumours.

Adenoma↗
PubMed1996

[MRT of experimental liver abscesses: a comparison of a new blood pool contrast medium with gadolinium-DTPA in animal experiments].

PURPOSE: In an experimental pyogenic liver abscess model, the signal intensities were compared intraindividually and interindividually after the application of a new blood pool contrast agent, 24-gadolinium-DTPA (diethylenetriamine-pentaacetic acid) cascade polymer, and after the application of gadopentetate dimeglumine. METHODS: In 20 rabbits with experimentally induced liver abscesses, the relative signal intensities of the liver, abscess centre, abscess wall and portal vein were assessed before and between 30 seconds and 60 minutes after injection of a 25 mumol/kg dose of gadolinium polymer and of 100 mumol/kg of gadolinium-DTPA, respectively. Measurements were performed at 1.5 Tesla, using a head coil and a Flash-2-D sequence. RESULTS: The interindividual comparison (unpaired T-test, p < 0.05) yielded significant differences of the relative signal intensities of the abscess centre (at any time point after contrast-media application), abscess wall (between 15 and 60 minutes after contrast media application), and portal vein (between 30 seconds and 7.5 minutes after contrast media application). The interindividual comparison showed a significantly higher abscess centre-liver contrast (between 30 seconds and 12.5 minutes after contrast media application) and a significantly higher abscess wall-centre contrast (between two and 7.5 minutes after contrast media application) after the application of gadolinium polymer compared with gadopentetate dimeglumine. CONCLUSION: In this animal model, the higher abscess centre-liver contrast after the application of gadolinium polymer was the basis for a better and prolonged visibility of the abscesses, as compared with images acquired after injection of gadopentetate dimeglumine.

Animals↗
PubMed1996

Computed tomography of experimental liver abscesses using a new liposomal contrast agent.

RATIONALE AND OBJECTIVES: Evaluation of computed tomographic enhancement characteristics of a new liposomal contrast agent (liposomal iodixanol [LI]) in a pyogenic liver abscess model in 17 rabbits. METHODS: Eight to 14 days after abscess induction (Escherichia coli), density-time curves were calculated for regions of interest in liver, abscess wall and center, spleen, portal vein, abdominal aorta, inferior vena cava, and kidney. Images were obtained every minute between 1 and 10 minutes, every 5 minutes between 15 and 60 minutes, and 75 minutes after 200 mg/kg LI application (group A: 7 rabbits) and after 600 mg/kg iopentol application (group B: 10 rabbits), and 90, 105, and 120 minutes after LI. RESULTS: The abscess wall-liver contrast after LI lasted from 10 to more than 120 minutes with a maximum of 30 delta Hounsfield Units (HU) at 45 minutes. For iopentol, the abscess wall-liver contrast lasted from 2 to 7 minutes with a maximum of 8 delta HU at 5 minutes. The abscess wall-center contrast after LI lasted from 1 to more than 120 minutes with a maximum of 112 delta HU at 40 minutes. For iopentol, the abscess wall-center contrast lasted from 1 to 75 minutes with a maximum of 79 delta HU at 1 minute. The liver-portal vein contrast after LI lasted from 1 to more than 120 minutes with a maximum of 100 delta HU at 20 minutes. For iopentol, the liver-portal vein contrast lasted from 1 to 8 minutes with a maximum of 38 delta HU at 2 minutes. An abscess wall was detected in a higher percentage of the LI images (86% LI, 56% iopentol), and images in the LI group correlated better with histopathology. CONCLUSIONS: The diagnostic value of LI exceeds that of iopentol in terms of overall abscess contrast and duration of the diagnostic interval. The higher hepatic vessel contrast allows better abscess localization.

Animals↗
PubMed1996

Differentiation of spontaneous canine breast tumors using dynamic magnetic resonance imaging with 24-Gadolinium-DTPA-cascade-polymer, a new blood-pool agent. Preliminary experience.

RATIONALE AND OBJECTIVES: The author assess the enhancement characteristics over time of spontaneous breast tumors in dogs comparing gadopentetate dimeglumine with a new blood-pool agent (24-gadolinium [Gd]-DTPA-cascade polymer). METHODS: Eighteen dogs with spontaneous breast tumors (5 carcinomas, 4 adenomas, and 9 benign mixed-tissue tumors) underwent dynamic magnetic resonance imaging after intravenous injection of gadopentetate dimeglumine and the blood-pool agent. Signal intensity time curves were followed up to 30 minutes after injection of both agents in the same animal. A nonlinear fitting routine enabled calculation of the delivery and clearance half lives of the contrast agent kinetics in each tumor. RESULTS: For gadopentetate dimeglumine, a fast signal increase was found immediately after intravenous injection, with a subsequent signal decay in all tumors. No difference was observed between the enhancement kinetics of different tumor types after gadopentetate dimeglumine application. Similar kinetics were found in benign lesions after injection of the blood-pool agent. However, in carcinomas the blood-pool agent displayed a slower delivery, delayed peak enhancement, and slower tumor tissue clearance or even a signal plateau of more than 30 minutes. CONCLUSIONS: Dynamic magnetic resonance imaging of breast neoplasms using a blood-pool agent may help to better differentiate between benign and malignant lesions because it demonstrates the enlarged interstitial space and increased capillary permeability in carcinomas.

Adenoma↗
PubMed1996

Hemodialysis fistulas and grafts: use of cutting balloons to dilate venous stenoses.

To evaluate percutaneous transluminal angioplasty (PTA) with a cutting balloon performed in stenosed hemodialysis fistulas and grafts, 19 venous lesions in 15 patients were treated with a cutting balloon with an inflated diameter of 3-6 mm. The grade of stenosis ranged from 40% to 90% (mean, 65% +/- 15 [standard deviation]). Cutting PTA was performed before conventional PTA in seven patients and was followed with conventional PTA with larger balloons in seven patients. The balloon expanded completely in all patients, and no balloon waist remained. The mean grade of stenosis decreased to 14% +/- 9. Cutting PTA increased the technical success of balloon dilation of hemodialysis fistulas and grafts.

Aged↗
PubMed1996

Laparoscopic bilateral ureterolysis in Ormond's disease.

We report a case of retroperitoneal fibrosis with dilation of the upper urinary tract on both sides and impaired renal function in a 66-year-old female. The patient was successfully treated by laparoscopic ureterolysis and intraperitonealization of both ureters with subsequent immunosuppressive medication. Due to intraoperative subcutaneous emphysema, surgical therapy had to be performed as a two-step procedure but postoperative morbidity was minimal with quick recovery. Laparoscopic ureterolysis is a reconstructive procedure and the ureters are accessible in full length either transperitoneally or retroperitoneally.

Aged↗
PubMed1996

Hydrodynamic thrombectomy of haemodialysis grafts and fistulae: results of 51 procedures.

PURPOSE: To describe efficacy of hydrodynamic thrombectomy for occluded dialysis native and graft fistulae in 51 instances. MATERIALS AND METHODS: Fifty-one hydrodynamic thrombectomies of 34 native and graft a-v fistulae were performed. There were 32 thrombectomies in PTFE grafts and 19 procedures in native Brescia-Cimino fistulae. Multiple thrombectomies were performed in 11 of 34 fistulae. The estimated occlusion time was 36.4+/-22 h. The length of the occluded segment ranged from 2 to 50 cm (mean 28.8 cm). In all cases, a 7 F hydrodynamic thrombectomy catheter was used. Double-cannulation technique was used for graft fistulae, single-cannulation for native fistulae. Additionally, balloon dilatation was performed in all 51 cases, stenting in six, and aspiration thrombectomy in two cases. RESULTS: Arterialized flow was re-established by hydrodynamic thrombectomy and PTA in 43 of 51 cases (84%). By additional use of other techniques, technical success improved to 46 of 51 procedures (90%). Early re-thrombosis occurred in six cases within 24 h of thrombectomy (11%). Clinical success was achieved in 39 of 46 technically successful cases (85%). Cumulative patency was calculated at 63% after 1 week, 57% after 1 month, 48% after 3 months, 37% after 6 months, and 32% after 12 months. Patency of native fistulae after thrombectomy was better than patency of grafts. CONCLUSIONS: Hydrodynamic thrombectomy is an effective percutaneous technique for declotting haemodialysis fistulae and grafts recently thrombosed.

Adult↗
PubMed1995

Expression, promoter usage and parental imprinting status of insulin-like growth factor II (IGF2) in human hepatoblastoma: uncoupling of IGF2 and H19 imprinting.

We have studied the promoter utilization and parental imprinting status of human IGF2 in three genetically informative hepatoblastomas from patients ranging in age from 9 months to 3 years. In all three cases, there is a downregulation of promoter P1 in the tumor tissues while the P2 and P3 promoters are upregulated compared to the normal liver. One of three patients displayed loss of imprinting (LOI) of IGF2 in the tumor tissue. We also investigated the expression of the H19 gene in all three cases and the methylation pattern in H19 from the patient with LOI of IGF2. The expression of H19 was greatly reduced in all tumors. Monoallelic H19 expression however, was retained even in the case which showed LOI of IGF2. Unlike the situation in Wilms' tumor, no differences in the methylation pattern between the normal liver and tumor tissues were observed in the H19 promoter or 3' region, using HpII analysis. We show here, that in contrast to the situation in Wilms' tumor, H19 expression is not a prerequisite for maintaining a monoallelic IGF2 expression.

Alleles↗
PubMed1995

N-substituted oxazolo[5,4-b]pyridin-2(1H)-ones: a new class of non-opiate antinociceptive agents.

A series of 1-(aminoalkyl)- and 1-[(4-aryl-1-piperazinyl)alkyl]oxazolo[5,4-b]pyridin-2(1H)-one derivatives of oxazolo[5,4-b]pyridin-2(1H)-one, incorporating modifications to the length of the alkyl side chain and to the amino or 4-aryl-1-piperazinyl substituents, were tested for safety and analgesic efficacy in mice and rats. Some compounds with 4-(substituted or nonsubstituted phenyl)-1-piperazinyl substituents and a 3-4-carbon alkyl side chain had significantly greater analgesic activity than that of the oxazolo[4,5-b]pyridin-2(3H)-one analogs. To reduce the metabolic N-dealkylation of the piperazine observed in our previous work on oxazolo[4,5-b]-pyridin-2(3H)-ones, analogs of the most active compounds with steric hindrance on the alkyl side chain were prepared and tested. The compound with the maximal combination of safety and analgesic efficacy was 1-[[4-(4-fluorophenyl)-1-piperazinyl]propyl]oxazolo[5,4-b]pyridin- 2(1H)-one (compound 3b), with ED50 values of 5.6 mg/kg po (mouse, phenylquinone writhing test) and 0.5 mg/kg po (rat, acetic acid writhing test). Compound 3b is a potent, rapid-acting, non-opioid, nonantiinflammatory analgesic with low acute toxicity and sustained effect.

Analgesics↗
PubMed1995

Mutation analysis of ten exons of the CFTR gene in Greek cystic fibrosis patients: characterization of 74.5% of CF alleles including one novel mutation.

To initiate the complete characterization of mutations in the CFTR gene in Greek cystic fibrosis (CF) patients, we screened 184 patients for six relatively common mutations (delta F 508, G542X, G551D, 621 + 1 G-->T, N1303K, W1282X) using allele-specific hybridization and, in addition, analyzed exons 4, 5, 7, 8, 10, 11, 17b, 19, 20 and 21 using the method of denaturing gradient gel electrophoresis (DGGE). Six mutations accounted for 65.9% of the CF alleles in Greek patients, of which the delta F 508 mutation had a frequency of 52.7%. A further 15 previously described mutations accounted for another 8.3% CF alleles and one previously undescribed mutation (3272-4A-->G) was found in one chromosome. The W1282X mutation was not detected at all. Thus, so far, we have identified 21 mutations in the CFTR gene in Greek CF patients, accounting for 74.5% of the CF alleles.

Alleles↗
PubMed1995

Gadopentetate-dimeglumine-enhanced MR imaging of osteonecrosis and osteochondritis dissecans of the elbow: initial experience.

Magnetic resonance imaging (MRI) was performed on seven patients with aseptic osteonecrosis (n = 4) and osteochondritis dissecans (OCD; n = 3) of the elbow. Precontrast MRI was superior to plain radiographs, which did not show any abnormality in three cases of osteonecrosis. On gadopentetate-dimeglumine-enhanced T1-weighted images, which were obtained in three patients with osteonecrosis and three patients with OCD, all cases of osteonecrosis demonstrated homogeneous enhancement of the lesions. All cases of OCD were diagnosed on plain radiographs. On MRI one showed significant enhancement of the loose body. In another case an incompletely enhancing loose body was surrounded by a diffusely enhancing region. In the third patient only a small marginal enhancement of the defect was observed. Our results suggest that MRI can improve the accuracy in diagnosis of aseptic osteonecrosis of the elbow. The use of gadopentetate dimeglumine allows the viability of the lesions or the loose bodies to be demonstrated and reparative tissue to be detected.

Adolescent↗
PubMed1995

Selenium in serum and whole blood in patients with surgical interventions.

Selenium values of serum and whole blood were determined for two groups of patients undergoing large surgical interventions (e.g., gastrectomy) and receiving a total parenteral nutrition (TPN). All patients showed low selenium values at the beginning of TPN. The first group received a supplementation of selenium, and it was established that selenium levels normalized after 6-7 d. The balances of selenium turned out to be positive in all cases. The second group, which was not administered selenium supplementation, showed significantly lower values of selenium. It can, therefore, be concluded that a substitution of selenium prior to large surgical interventions following TPN clearly helps patients combat the increase in the oxidant stress reactions.

Aged↗
PubMed1995

Changes of the methylation pattern of the c-myc gene during in vitro aging of IMR90 human embryonic fibroblasts.

DNA modification by cytosine methylation has received considerable interest in the context of mammalian cell differentiation but is discussed controversially with respect to cellular aging. As the expression of c-myc affects strongly cellular aging and terminal differentiation, we have analysed the sequence-specific methylation pattern of the c-myc gene during proliferative aging in vitro of human embryonic fibroblasts. In this study, both, 5-methylcytidine sensitive restriction enzymes as well as genomic sequencing were used. The overall methylation pattern was found essentially stable during proliferative aging. However, specific hypermethylation of exon II during aging was observed. Furthermore, one specific cytidine located in the consensus sequence of the DNA binding factor PEBP2 was found completely methylated during most of the course of proliferative aging of the cells but became demethylated as the cells reached the end of their proliferative life span. Our results indicate the importance of establishing the sequence-specific changes of the methylation pattern of the genome during in vitro aging.

Base Sequence↗