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H Vogler

Publications and source records attributed to H Vogler.

At least 19 recordsLinked to original sources
PubMed2006

How far is the preoperative Kattan nomogram applicable for the prediction of recurrence after prostatectomy in patients presenting with PSA levels of more than 20 ng/ml? A validation study.

OBJECTIVE: We present an external validation study investigating the applicability of the preoperative Kattan nomogram for predicting recurrence after prostatectomy in a population of patients with serum prostate-specific antigen (PSA) levels exceeding 20 ng/ml. MATERIALS: In the evaluation of clinical parameters pooled from a total of 191 patients presenting with PSA levels ranging between 20.1 and 100 ng/ml, the PSA-free survival rate 60 months after surgery was calculated according to Kattan nomograms. Subsequently, the results were statistically compared with the corresponding actual survival rates obtained from Kaplan-Meier analysis. For this purpose, the patients were assigned to one of four different risk groups according to predictions derived from the Kattan nomograms, enabling a direct comparison of expected (as predicted by Kattan nomogram) versus actual survival of each patient investigated in our study. RESULTS: Predicted PSA-free survival rates were determined to be as follows: 83% (low risk group); 66% (intermediate risk group); 39% (intermediate-high risk group), and 10% (high risk group) in comparison with the actual survival rates determined to be 63, 62, 40 and 21%, respectively. For PSA levels ranging between 20.1 and 30 ng/ml, 30.1 and 50 ng/ml, and 50.1 and 100 ng/dl, PSA-free survival rates were found to be 57, 37, and 27% (p=0.0017), respectively, during a 5-year post-prostatectomy follow-up. CONCLUSIONS: The Kattan nomogram shows good statistical concordance with actual survival rates in the mean risk quadrants, but considerable differences were demonstrated concerning individuals with either a high or with a low risk of cancer progression.

Aged↗
PubMed2005

[Differential diagnosis of focal liver lesions using contrast-enhanced MRI with SHU 555 A in comparison with unenhanced MRI and multidetector spiral-CT].

PURPOSE: To evaluate the ability of contrast-enhanced MRI with SHU 555 A to provide additional information for characterization of focal liver tumors compared with non-enhanced MRI and multislice spiral CT. MATERIALS AND METHODS: In a prospective manner the images of 45 patients who underwent multislice spiral CT, unenhanced MRI alone and unenhanced and SHU 555 A-enhanced MRI including dynamic imaging at a field strength of 1.0 T were analyzed in a blinded reading. The readers had to determine on a scale from 1 to 5 whether a tumor was benign or malignant. Furthermore, the readers had to give a definitive diagnosis for each lesion. A true cut needle biopsy served as gold standard against which all imaging procedures were compared. RESULTS: The sensitivity for differentiation malignant vs. benign lesion was 77 % with spiral CT, 72 % with unenhanced MRI and 94 % with SHU 555 A-enhanced MRI, respectively (p < 0.05). The specificity for spiral CT was 73 %, for unenhanced MRI 83 % and for contrast-enhanced MRI 83 %, respectively (n. s.). Compared with the histopathologic results, the correct diagnosis was made with spiral CT in 25/45 (56 %), unenhanced MRI in 16/45 (36 %) and contrast-enhanced MRI in 32/45 (71 %) of the patients (p < 0.05). For the subgroup of patients with liver cirrhosis, the correct diagnosis was established with spiral CT in 16/23 (70 %), unenhanced MRI in 9/23 (39 %) and contrast-enhanced MRI in 19/23 (83 %) of the patients (p < 0.05). CONCLUSION: Contrast-enhanced MRI with SHU 555 A has the ability to improve the differential diagnosis of focal liver tumors compared with unenhanced MRI and multislice spiral CT.

Biopsy, Needle↗
PubMed2004

Significance of the time period between diagnosis of muscle invasion and radical cystectomy with regard to the prognosis of transitional cell carcinoma of the urothelium in the bladder.

OBJECTIVE: Standard treatment of muscle-infiltrated transitional cell carcinoma (TCC) of the urothelium consists of radical cystectomy. In some cases there is a delay between the initial diagnosis and a definitive treatment being administered. The objective of this study was to determine the effect of the time window between evidence of muscle invasion and radical cystectomy on the pathological stage and progression-free survival. MATERIAL AND METHODS: Between February 1992 and August 2002, 239 radical cystectomies were carried out as a result of TCC of the bladder. In a total of 189 patients (79%), cystectomy was carried out due to muscle-infiltrated TCC with no evidence of distant metastases (>/=T2, M0). The time between the diagnosis of muscle invasion and cystectomy was determined for all of these patients, who were then divided into two groups on the basis of a 3-month cut-off period. Univariate and multivariate analyses were used to determine the effect of the time period on clinical factors and progression-free survival. RESULTS: The average age of the patients was 63 (range 35-80) years. A median follow-up of 40 months showed a progression-free survival rate of 49% after 5 years. The average time between the diagnosis of muscle invasion and cystectomy was 1.8 (0.3-12.1) months. For a time window of >3 months, 30/42 patients (72%) showed signs of extravesical tumor growth and/or tumor-positive lymph nodes, compared to 89/147 patients (60%) (p = 0.198) for a time window of </=3 months. In terms of the distribution of tumor stages according to the time groups, there were significantly more pT4 stage tumors in patients with delayed cystectomy (p = 0.009). Patients with a time interval of </=3 months between diagnosis of muscle invasion and cystectomy had a significantly better progression-free survival rate (55%) than those with a longer time window (34%) (p = 0.04). In contrast to lymph node status, clinical stage, pathological tumor stage and differentiation level, the prognostic relevance of the time window fell just short of the significance level in Cox's multivariate regression analysis (p = 0.057). Lymph node status (p < 0.001) and pathological tumor stage (p = 0.05) were the only independent prognostic parameters which could be used to predict progression-free survival. CONCLUSION: Patients with a time window of >3 months between diagnosis of muscle invasion and radical cystectomy were associated with an advanced pathological stage and a poorer progression-free survival. These results underline the need for early cystectomy within the 3-month period between diagnosis of muscle invasion and cystectomy.

Adult↗
PubMed2000

Limited correlation between expansin gene expression and elongation growth rate.

The aim of this work was to study the role of the cell wall protein expansin in elongation growth. Expansins increase cell wall extensibility in vitro and are thought to be involved in cell elongation. Here, we studied the regulation of two tomato (Lycopersicon esculentum cv Moneymaker) expansin genes, LeExp2 and LeExp18, in rapidly expanding tissues. LeExp2 was strongly expressed in the elongation zone of hypocotyls and in the faster growing stem part during gravitropic stimulation. LeExp18 expression did not correlate with elongation growth. Exogenous application of hormones showed a substantial auxin-stimulation of LeExp2 mRNA in etiolated hypocotyls and a weaker auxin-stimulation of LeExp18 mRNA in stem tissue. Analysis of transcript accumulation revealed higher levels of LeExp2 and LeExp18 in light-treated, slow-growing tissue than in dark-treated, rapidly elongating tissue. Expansin protein levels and cell wall extension activities were similar in light- and dark-grown hypocotyl extracts. The results show a strong correlation between expansin gene expression and growth rate, but this correlation is not absolute. We conclude that elongation growth is likely to be controlled by expansin acting in concert with other factors that may limit growth under some physiological conditions.

Blotting, Northern↗
PubMed1998

Pathophysiology in endothelin-1 transgenic mice.

Transgenic mice expressing the human endothelin-1 (ET-1) were generated. These mice develop glomerulosclerosis, interstitial fibrosis, and renal cysts but not hypertension. Consequently, a progressive decrease in renal blood flow and/or glomerular filtration rate was observed, demonstrated by altered creatinine clearance and by magnetic resonance imaging. These genetically altered transgenic mice provide an interesting animal model in which to elucidate the role of ET-1 in the modulation of renal hemodynamics and glomerular and tubule functions.

Animals↗
PubMed1997

[An interdisciplinary consensus conference on the diagnosis and therapy of testicular tumors].

In 1988 the German testicular working group was set up by leading experts in the fields of urology, medical and radio-oncology. Since then, the working group has initiated several clinical studies and conferences with the aim of defining current standards in the treatment of testicular germ cell tumours. After a series of preliminary joint meetings with representatives from the AUO, AIO and ARO of the "Deutsche Krebsgesellschaft", a conference was held in May 1996 to agree on a consensus in diagnosis and treatment of testicular germ cell tumours. The standards which have been agreed on at the conference refer to the current international literature and provide recommendations for the majority of clinical situations. Treatment strategies differing from these standards should not be chosen except for well argued individual settings or patients treated in clinical trials. No consensus could be reached for nonseminomatous stage I, IIA and IIB tumours. As a consequence, the differing treatment strategies for these stages are summarized in this paper. A subsequent conference in later years is needed to possibly find an agreement for these tumour stages and to update the current standards according to new clinical experience and knowledge.

Combined Modality Therapy↗
PubMed1997

Magnetic iron oxide particles coated with carboxydextran for parenteral administration and liver contrasting. Pre-clinical profile of SH U555A.

RATIONALE AND OBJECTIVES: To evaluate the physical and pharmacological profiles of SH U555A, a suspension of magnetic iron oxide particles that is designed to enhance the visualization of liver tumors and metastases. MATERIAL AND METHODS: Chemical and physical methods were used to characterize the size and structure of these magnetic iron oxide particles in aqueous solution. The biodistribution and pharmacokinetics of the particles were studied in mice, rats and dogs. The imaging efficacy of the particles was demonstrated by MR imaging in rat liver tumors RESULTS: The SH U555A particles consist of low-molecular-weight carboxydextran-coated iron oxides predominantly of the gamma-Fe2O3 form with a hydrodynamic diameter ranging from 57-59 nm and strong T2 relaxivity of 164 liters x mmol(-1) x s(-1) (water, 0.47 T). In rats the particles exhibited a dose-dependent half-life of between 2 and 3 days in the liver at a dose of 20 micromol Fe/kg and a shorter half-life at lower doses. No major side effects were found. In a rat tumor model the tumor-to-liver contrast was markedly improved after i.v. administration of SH U555A. At a dose of 14 micromol Fe/kg the half-maximal contrast-effect was obtained even in nonoptimized T1-weighted spin-echo images. CONCLUSION: SH U555A is a superparamagnetic MR contrast agent for i.v. administration and has substantial potential for the demarcation of liver tumors.

Animals↗
PubMed1996

Hepatic kinetics and magnetic resonance imaging of gadolinium-EOB-DTPA in dogs.

RATIONALE AND OBJECTIVES: To measure the hepatic uptake and biliary elimination kinetics of gadolinium (Gd)-EOB-DTPA in dogs. METHOD: Two groups of four beagles each were anesthetized and given an intravenous bolus of 25 mumol/kg or 250 mumol/kg of Gd-EOB-DTPA. Blood, hepatic bile, and urine were collected over 140 minutes, and liver samples were obtained immediately after the dogs were killed. Conventional T1-weighted spin echo sequences of the liver were performed on a 1.5-Tesla (T) magnetic resonance imager during sampling. A ninth beagle received a bolus of 25 mumol/kg followed 140 minutes later with a bolus of 250 mumol/kg of Gd-EOB-DTPA. Wedge liver biopsies were obtained for Gd estimation at various times after dosing, and Gd concentration was measured by inductively coupled plasma atomic emission spectroscopy. RESULTS: The plasma concentration of Gd-EOB-DTPA decreased in a biexponential manner with half-lives of approximately 4 minutes and 60 minutes for the distribution and elimination phase independent of the dose given. Gadolinium bile concentration reached peak values between 80 and 140 minutes: 6.3 +/- 1.6 mmol/L for the low dose (LD) and 11.6 +/- mmol/L for the high dose (HD). Bile Gd output was 62.0 +/- 8.8 (LD) and 78.3 +/- 30.2 (HD) nmol/minute-kg 50 to 80 minutes after injection. Gadolinium-EOB-DTPA was excreted by the biliary route to 24.8 +/- 2.6 (LD) and 3.6 +/- 1.2 (HD) percent of the dose within 140 minutes. Liver Gd concentration was 0.43 +/- 0.14 (LD) and 4.3 +/- 0.5 (HD) mmol/kg liver tissue at the conclusion of the studies. Calculated concentrations in the hepatocyte were 60 (LD) and 15 (HD) times higher than in plasma at 25 minutes after dosing. Whereas the low dose exhibited excellent contrast enhancement for the whole period, the high dose displayed a biphasic signal enhancement with a decreasing signal caused by the too-high hepatic gadolinium accumulation. CONCLUSIONS: Transport of the Gd-EOB-DTPA into the hepatocyte exceeded elimination from hepatocyte to bile. The high dose defined a biliary transport maximum for Gd-EOB-DTPA of 78.3 +/- 30.2 nmol/minute-kg. The liver accumulation results from fast transport into the hepatocyte and rate-limited slower transport from hepatocyte to bile. The accumulation occurs against a strong concentration gradient, suggesting energy-dependent active transport into the hepatocyte.

Animals↗
PubMed1995

Pre-clinical evaluation of gadobutrol: a new, neutral, extracellular contrast agent for magnetic resonance imaging.

The Gd(3+)-complex of 10-(2,3-dihydroxy-1-hydroxymethylpropyl)-1,4,7,10-tetraazacyclo dodecane-1,4,7-triacetic acid(gadobutrol) is a new, neutral Gd-chelate for use as an extracellular contrast agent in magnetic resonance imaging (MRI). The blood level in dogs after intravenous (i.v.) injection decreased with a terminal half-life of about 45 min, the clearance was about 3.75 ml/min per kg and the distribution volume of 0.23 l/kg suggested an extracellular distribution. Biodistribution experiments in rats revealed that only a very small amount (0.16%) of the dose was left in the body 7 days after i.v. injection. Measurable amounts of Gd could be detected only in the liver, kidneys and bones. The osmolality (0.57 osmol/kg at 0.5 mol/l and 1.39 osmol/kg at 1 mol/l) is in the range of other low osmolality contrast media for MRI. Only very little interaction with biologically relevant molecules was suggested by a histamine release test and a lysozyme inhibition test. An i.v.-LD50 of 23 mmol/kg in mice combined with a comparatively high T1-relaxivity (5.6 l/mmol per s at 0.47 T and 6.1 l/mmol per s at 2 T) in plasma promises a high margin of safety. In preliminary imaging experiments, gadobutrol caused high enhancement in different lesions (cerebral infarct, brain tumor) of the rat. Tripling of the typical clinical dose of 0.1 mmol/kg was shown to provide additional diagnostic gain in lesions of this type.

Animals↗
PubMed1995

Early MR detection of experimentally induced cerebral ischemia using magnetic susceptibility contrast agents: comparison between gadopentetate dimeglumine and iron oxide particles.

PURPOSE: To evaluate early patterns of MR changes in a rat model of cerebral ischemia using the first pass of two magnetic susceptibility contrast agents. METHODS: One hours after endovascular middle cerebral artery occlusion, all animals were examined in an experimental MR unit. After bolus application of gadopentetate dimeglumine and, 10 minutes later, of iron oxide particles, the MR changes of the first pass of these contrast agents were followed using a T2*-weighted fast low-angle shot sequence. Time-density curves of both contrast agents were analyzed and compared. RESULTS: After bolus injection of either (paramagnetic) gadopentetate dimeglumine or superparamagnetic particles, nonischemic brain parenchyma decreased markedly in signal, whereas the ischemic brain area remained relatively hyperintense (and thus became clearly delineated). Only after application of gadopentetate dimeglumine did a mild reduction in signal occur in the ischemic hemisphere, although the main artery was occluded. An explantation for this phenomenon might be residual capillary perfusion (plasma flow), which is detectable only when the smaller (paramagnetic) contrast molecules are being used. CONCLUSIONS: Cerebral perfusion deficits can be detected 1 hour after vascular occlusion with T2*-weighted fast low-angle shot sequences and bolus injection of paramagnetic or superparamagnetic MR contrast agents. Gadopentetate dimeglumine may be used as a marker of microcirculatory plasma flow.

Animals↗
PubMed1992

Radiotherapy of the rhabdomyosarcoma R1H of the rat: recovery from radiation injury in tumour and skin.

The response of the rhabdomyosarcoma R1H of the rat to fractionated irradiation has been reported to be almost independent of the dose per fraction in the range from 0.43 to 10 Gy. To elucidate whether recovery from radiation injury is impaired in fractionated irradiation or not, tumours were exposed on 5 days per week over 6 weeks either to a single daily dose or to two daily fractions separated by an interfraction interval of 2 h. Tumour response was assessed by net growth delay. Skin damage was scored for comparison. A significant reduction in tumour response (p less than 0.009) and skin damage (p less than 0.001) was observed when the daily dose was administered in a twice daily irradiation regimen, indicating that recovery from radiation injury does occur in the course of fractionated irradiation in our tumour system. A tumour response was almost independent of the dose per fraction for time intervals between fractions of at least 8 h, a possible explanation might be that recovery is compensated by improved reoxygenation.

Animals↗
PubMed1991

A new lipophilic gadolinium chelate as a tissue-specific contrast medium for MRI.

Gd-Ethoxybenzyl-DTPA (Gd-EOB-DTPA) is a highly water-soluble paramagnetic contrast agent. Due to its protein binding of about 10% and its lipophilic residue, Gd-EOB-DTPA exhibits both renal (30% of the dose) and hepatobiliary (70%) excretion in rats. Despite its lipophilic character, the compound displays a low toxicity (LD50 = 7.5 mmol/kg). T1-relaxivity of 5.3 liters mmol-1 s-1 in water, 8.7 liters mmol-1 s-1 in plasma, and 16.9 liters mmol-1 s-1 in rat liver together with the hepatocellular uptake explain the liver-specific contrast enhancement of Gd-EOB-DTPA. The diagnostic dose is considerably lower than the amount of Magnevist used in abdominal imaging. The preclinical studies suggest its clinical role as being a hepatobiliary contrast agent for MRI.

Animals↗
PubMed1991

NMR imaging study of the pharmacodynamics of polylysine-gadolinium-DTPA in the rabbit and the rat.

The pharmacodynamics of polylysine-(Gd-DTPA) (Schering, Berlin, Germany), a new blood pooling contrast agent for MRI, were studied in the rabbit and the rat. Polylysine-(Gd-DTPA) is a compound with high LD50. Due to its high molecular weight (50.000) and physico-chemical properties, it remains in the vascular system; during the first hour, the plasma level is three times higher than for Gd-DTPA. MRI was performed at 1.5 T using a SE sequence with TR/TE = 300/15 or 20 msec. Signal intensities of muscle, liver and kidney were measured before and after intravenous injection of the contrast agent (0.1 mmol/kg) during 8 hours in the rat (n = 3) and up to 2 wk in the rabbit (n = 3). A dose response study in three additional rabbits confirmed that the 0.1 mmol/kg dose was optimal. The pharmacodynamics results show that the effects of polylysine-(Gd-DTPA) are similar in both the rabbit and the rat. The liver signal is enhanced by about 60% immediately after injection in both species. This enhanced signal decays to half its maximal value in about one hour, which makes the contrast agent useful for clinical applications at a dose of 0.1 mmol/kg. In the kidney medulla and cortex the signals are enhanced by much larger factors (about 3 to 4); it takes at least one day for the kidney to clear the contrast agent in both species.

Animals↗
PubMed1991

Influence of treatment time on the response of rat rhabdomyosarcoma R1H to fractionated irradiation.

The aim of this work was to study influence of overall treatment time on response of an experimental tumour to fractionated radiotherapy. Rhabdomyosarcoma R1H of the rat was treated by fractionated irradiation applying 30 fractions in different overall treatment times of 10, 18.5, 29, 39, and 67 days. The doses per fraction ranged from 1.50 to 2.67 Gy. Tumour response was assessed by net growth delay and by an in vitro colony assay. The results indicate that repopulation of the tumour with clonogenic tumour cells slowed down during treatment leading to an average doubling time of clonogenic tumour cells of 8 +/- 1 days, which is considerably longer than that of unirradiated tumours (3 days). The repopulation rate seemed to increase after about 3 weeks of treatment with a doubling time of tumour clonogens of 5 +/- 1 days, which was still lower than in control tumours.

Animals↗
PubMed1991

Radiotherapy of the rhabdomyosarcoma R1H of the rat: split-course versus continuous fractionation.

Fractionated split-course treatments were given with gaps of different length and the effects on tumor response was studied using the rhabdomyosarcoma R1H of the rat. Total doses of 68, 75 and 82 Gy were applied in 30 fractions (five fractions per week). After four weeks, that is after 20 fractions, treatment was interrupted for one or two weeks followed by another ten fractions. The results were compared to those of continuous treatment given in six consecutive weeks. Tumor response was quantified by TCD37% and net growth delay. The TCD37% increased with increasing duration of the gap. A mean repopulated dose of 0.72 Gy per day was obtained. This corresponds to a doubling time of tumor clonogens of 4.2 days during the gap, which is somewhat slower than the volume doubling time of unperturbed tumors (2.5 days) of the same size. The results obtained for the net growth delay support the results of the TCD37% data. It is concluded that a gap during fractionated radiotherapy leads to poorer results since the dose required for tumor control is enhanced and sparing of normal tissue can only be expected for early but not for late reacting tissues.

Animals↗