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M Fuss

Publications and source records attributed to M Fuss.

At least 37 records · Page 2Linked to original sources
PubMed1999

[The simultaneous determination of the arterial input function for dynamic susceptibility-weighted magnetic resonance tomography of the A. carotis interna and the A. cerebri media].

PURPOSE: The determination of the arterial input function (AIF) is necessary for absolute quantification of the regional cerebral blood volume and blood flow using dynamic susceptibility contrast MRI. The suitability of different vessels (ICA--internal carotid artery, MCA--middle cerebral artery) for AIF determination was compared in this study. METHODS: A standard 1.5 T MR system and a simultaneous dual FLASH sequence (TR/TE1/TE2/alpha = 32/15/25/10 degrees) were used to follow a bolus of contrast agent. Slice I was chosen to cut the ICA perpendicularly. Slice II included the MCA. Seventeen data sets from ten subjects were evaluated. RESULTS: The number of AIF-relevant pixels, the area under the AIF and the maximum concentration were all lower when the AIF was determined from the MCA compared to the ICA. Additionally, the mean transit time (MTT) and the time to maximum concentration (TTM) were longer in the MCA, complicating the computerized identification of AIF-relevant pixels. Data from one subject, who was examined five times, demonstrated that the intraindividual variance of the measured parameters was markedly lower than the interpersonal variance. CONCLUSIONS: It appears to be advantageous to measure the AIF in the ICA rather than the MCA.

Adult↗
PubMed1999

Clinical relevance of thiamine status amongst hospitalized elderly patients.

BACKGROUND: The prevalence and the consequences of thiamine deficiency among elderly patients admitted to acute geriatric wards are not known. OBJECTIVES: (1) To assess the prevalence of thiamine deficiency in patients admitted to a geriatric ward compared to age-matched ambulatory outpatients; (2) to identify their diseases and problems associated with thiamine deficiency, and (3) to determine the relationship between the thiamine status and the cognitive and functional status of these patients. MATERIALS AND METHODS: 118 aged hospitalized patients (83 +/- 7 years; mean age +/- SD) were prospectively enrolled on admission to the geriatric ward. Their cognitive status was assessed using the Mini-Mental State Examination (MMSE) and their ability to perform their activities of daily living (ADL) using ADL scales. The effect of exogenous thiamine pyrophosphate (TPP) addition on the blood transketolase (TK) activity (TPP TK effect) served to estimate thiamine deficiency. Socioeconomic data, diseases and treatment were identified as potential associated risk factors. This group of hospitalized patients was divided according to their thiamine status to characterize the conditions associated with thiamine deficiency. Thirty-five outpatients without any functional or cognitive impairment served as a control group. RESULTS: Of 118 inpatients, 46 (39%) presented with a TPP TK effect of >15%, and 6 with values of >22%, indicating moderate and severe thiamine deficiency, respectively. Only 6 of 30 outpatients (20%) exhibited a TPP TK effect of >15% and none of them reached values of >18%. Although it tended to be lower in outpatients, the mean TPP TK effect did not statistically differ from the mean of inpatients. Thiamine-deficient inpatients comprised a larger proportion of institutionalized subjects than nondeficient inpatients (87 versus 47%, p < 0.001). Functional status, cognitive functions and the occurrence of delirium did not differ according to their thiamine status. By contrast, thiamine-deficient inpatients exhibited a higher proportion of Alzheimer's disease, depression, cardiac failure and falls. Furosemide was more frequently taken by thiamine-deficient patients. CONCLUSIONS: Severe thiamine deficiency remained quite low among the hospitalized elderly. The prevalence of moderate thiamine deficiency approached 40%. Institutionalized subjects were at particular risk of developing thiamine deficiency. Its clinical relevance on functional status and on cognitive function remained not significant. By contrast, a high proportion of falls, Alzheimer's disease, depression, cardiac failure and furosemide use could have been related to thiamine deficiency.

Activities of Daily Living↗
PubMed1998

Assessment of neuropsychological changes in patients with arteriovenous malformation (AVM) after radiosurgery.

PURPOSE: The purpose of this study was to investigate neuropsychological effects of radiosurgery in patients with cerebral arteriovenous malformation (AVM), with special focus on attention and memory. This report describes the study setup and presents the first results during a follow-up of up to 1 year. MATERIALS AND METHODS: Seventy-nine patients were studied before, acutely after radiosurgery, and during the regular follow-up (subacute phase: Weeks 6-12, chronic phase: Months 6-12). Radiosurgery was performed using a modified linear accelerator (minimum doses to the target volume: 15-22 Gy, median 20 Gy). Estimated whole brain dose was 0.5 to 2 Gy. Neuropsychological testing included assessment of general intelligence (Wechsler Adult Intelligence Scale), attention (modified Trail-Making Test A, Digit Symbol Test, D2 Test, Wiener Determination Machine) and memory (Rey Auditory Verbal Learning Test, Benton Visual Retention Test). During follow-up, alternate test versions were used. Neuropsychological deficits were defined as a test score of at least one standard deviation (SD) below the mean of the normal distribution. RESULTS: The pretherapeutic evaluation revealed marked deviations from the normal population; 24% had deficits in intelligence (range 23-31% in different subtests), attention (35%, 23-59%) and memory (48%, 31-61%). The overall percentage of aberrant results was reduced by 12% (memory) to 14% (attention) in the chronic phase up to 12 months after therapy. The improvement in test scores was significant (p < 0.05) in 3 of 4 subtests of attention functions. CONCLUSIONS: The acute tolerance of radiosurgery seems to be very good in these patients, showing no relevant increase in number of patients with neuropsychological deficits. Although the long-term follow-up needs to be further increased, our data indicate a tendency to slight improvement in the overall neuropsychological performance of AVM patients in the chronic phase after radiosurgery.

Adult↗
PubMed1998

[The radiosurgery of glioblastoma multiforme in cases of recurrence. The Heidelberg experiences compared to the literature].

AIM: To describe the clinical results a prospective phase II study of radiosurgically treated patients with recurrent glioblastoma multiforme. PATIENTS AND METHOD: Since 1986, 62 patients were irradiated stereotactically. Including criteria were residual tumor < or = 5 cm and Karnofsky performance score > or = 70. Twenty-seven patients (mean age 50 years) were treated for recurrent tumor. The planning target volume was defined by the contrast enhancing region demonstrated by magnetic resonance imaging (MRI) scans which were performed in treatment position. A safety margin of 2 to 5 mm was added. The mean dose was 17 Gy. The median interval from the time of initial diagnosis and therapy to radiosurgery for recurrent tumor was 9.6 months. Initial therapy consisted of surgery and irradiation (60 Gy). Survival curves were calculated according to the Kaplan Meier method. Quality of life was evaluated using objective criteria such as neurological findings, frequency of seizures and steroid medication. RESULTS: The median survival calculated from the time of diagnosis was 18 months, calculated from the time of radiosurgery 9 months. 4.5 months after therapy, 50% of the patients showed improved or stable quality of life. CONCLUSION: Radiosurgery demonstrates efficacy in selected patients suffering from recurrent glioblastoma multiforme.

Adult↗
PubMed1998

[Value of radiosurgery in first-line therapy of glioblastoma multiforme. The Heidelberg experience and review of the literature].

AIM: To describe the clinical results and the feasibility of a phase II dose escalation study of small boost target volumes with a radiosurgical technique in patients with positive early postoperative MRI scans. PATIENTS AND METHOD: Since 1986, 35 patients were treated within a concept for first line therapy. Including criteria were residual tumor < or = 5 cm and Karnofsky performance score > or = 70. The mean age was 54.5 years. The treatment concept included an operation for reduction of tumor volume and a postoperative irradiation. The postoperative irradiation was divided in 2 parts: first, a hyperfractionated (1.8 Gy single dose twice a day, 54 Gy total dose) irradiation was performed containing the tumor and the edema with a 2 cm safety margin. Secondly, a radiosurgical boost dose was delivered. The target volume of this radiosurgery was the contrast enhancing residual tumor in early postoperative MRI scans. The median boost dose was 15 Gy. Survival curves were calculated according to the Kaplan-Meier method. Quality of life was evaluated using objective criteria such as neurological findings, frequency of seizures and steroid medication. RESULTS: The median survival calculated from the time of diagnosis was 10.1 months. The 1- and 2-year survival rate were 35% and 6%, respectively. Young age tended to longer survival, patients younger than 53 years had a median survival of 10.4 months whereas patients older than 53 years showed a median survival of 9.2 months. The mean value of the boost volume was 22 cm3. Patients with smaller volumes had a median survival of 10.1 months and patients with bigger volumes showed a median survival of 9.9 months, 4.5 months after therapy, 75% of the patients showed improved or stable quality of life. CONCLUSION: The feasibility of a radiosurgically delivered boost dose after postoperative irradiation could be demonstrated. The observed survival rate is comparable to the survival rates reported in the literature. Whether or not the radiosurgery after postoperative irradiation is able to prolong survival can only be evaluated in a randomized phase III trial.

Adult↗
PubMed1998

[Stereotactic conforming irradiation of choroid metastases].

UNLABELLED: The aim of our study was to develop noninvasive stereotactic radiotherapy for patients with choroidal metastases. METHODS: The head of the patient was immobilized by an individual cast mask. The target volume and adjacent critical structures were three-dimensionally segmented based on ophthalmological findings and MRI. The beam angles were optimized by a beam's eye view technique with a micro-multileaf collimator. We use a linear accelerator with 6-MeV photons. A patient was treated in a phase I/II trial with a single dose of 22.5 Gy. RESULTS: The accuracy of stereotactic positioning of the eye was 0.8 mm. The dose gradients were 15% mm. It was possible to spare the lens and the lacrimal gland in all cases. The treatment with four to six fields took 35-50 min and was tolerated without acute complications. CONCLUSIONS: We introduce a new method to treat choroid metastases by stereotactic radiotherapy. This method allows to concentrate the dose to the target and to spare adjacent critical structures. One of the advantages of this noninvasive treatment is the short treatment time. The clinical role of this method has to be evaluated based on long-term results of tumor control and visual outcome in these patients.

Adenocarcinoma↗
PubMed1998

Radiosurgery alone or in combination with whole-brain radiotherapy for brain metastases.

PURPOSE: Evaluation of the treatment outcome after radiosurgery (RS) alone or in combination with whole-brain radiotherapy (WBRT) with special attention to prescribed dose and its influence on local control and survival. PATIENTS AND METHODS: Between September 1984 and January 1997, 236 patients with 311 brain metastases treated with radiosurgery met the following inclusion criteria: one to three brain metastases per patient; no previous WBRT; and Kamofsky performance status (KPS) > or = 50%. One hundred fifty-eight patients treated only with RS received a median dose of 20 Gy prescribed to the 80% isodose line; 78 patients received RS with a median dose of 15 Gy/80% and an additional course of WBRT. RESULTS: For the entire series, overall median survival was 5.5 months, with control of CNS disease achieved in 92% of the treated brain metastases; the results were not significantly different between patients treated by RS with or without WBRT. However, in patients without evidence of extracranial disease, median survival was increased for patients who received WBRT (15.4 vs 8.3 months; P=.08). Additionally, there was a suggestion that increased doses for patients treated with RS only resulted in improved outcome. Four lesions were suspicious for radiation necrosis by magnetic resonance imaging (MRI); in one of the four lesions, radiation necrosis was confirmed histologically. The incidence of transient low-grade toxicity was 18%; symptoms could be treated by the temporary administration of steroids. CONCLUSION: RS is an effective, noninvasive means of controlling brain metastases when used alone or in combination with WBRT. There is a trend for superior local control and especially in patients without extracranial disease for superior survival when RS is used in conjunction with WBRT. Randomized trials would seem to be warranted, comparing the benefit of RS with or without additional WBRT.

Brain Neoplasms↗
PubMed1997

Intracranial meningeomas: time- and dose-dependent effects of irradiation on tumor microcirculation monitored by dynamic MR imaging.

The purpose of this study was the characterization of the time- and dose-dependent effects of irradiation on tumor microcirculation by means of dynamic MR imaging and correlation of the estimated data with tumor response in patients with meningeomas. Dynamic MR imaging studies were performed in 20 patients with intracranial meningeomas prior to (n = 20) and at 6 (n = 17), 18 (n = 17), and 50 wk (n = 14) after the end of radiotherapy. In seven of these patients, dynamic measurements were also performed during fractionated radiotherapy after approximate 20 Gy and 54 Gy. During and after short-time infusion of gadopentetate dimeglumine, the kinetics of lesion response was resolved using a strongly T1-weighted saturation recovery TurboFLASH (SRTF) sequence. The signal-time courses of the suspected lesions were analyzed using a pharmacokinetic two-compartment model. The calculated parameters amplitude A (reflecting gadopentetate dimeglumine accumulation in the extracellular space) and exchange rate constant k21 (depending on vascular permeability and blood flow) were displayed as color-coded images and analyzed as a function of time of therapy and radiation dose. All meningeomas showed a high exchange rate constant k21 (median, 5.7 min-1; range, 1.9-23.0 min-1) and a high amplitude A (median, 1.5 arbitrary units; range, 1.1-2.7) prior to X-ray treatment. During radiotherapy we found a dose related significant (p < .01) increase of k21 accompanied by an increase of the amplitude A as compared to the pretreatment values. Analysis of tumor volume 6, 18, and 50 wk after X-ray treatment revealed two different groups. In the responder group (n = 13) the median of the tumor volume decreased from 10.0 to 7.5 cm3. For this group, we found a significant drop (p < .01) of the median of the amplitude A and a decrease of the exchange rate constant k21. In the nonresponder group (n = 4) the median of the tumor volume increased after radiation from 3.5 to 4.5 cm3. The pharmacokinetic analysis revealed a decrease of the amplitude A-and an increase of the exchange rate constant k21. The response of meningeomas to radiotherapy is influenced by the effect of X-rays on tumor microcirculation. This effect on tumor microcirculation can be derived by analysis of pharmacokinetic maps obtained from dynamic MR images. Furthermore, these pharmacokinetic maps can possibly be used to differentiate groups of patients who respond or do not respond to radiotherapy and, thus, could benefit from another treatment modality.

Contrast Media↗
PubMed1996

[Blood volume changes after the radiotherapy of the central nervous system].

BACKGROUND: The pathogenesis of late delayed radiation damage in normal brain tissue is most likely due to damage to the vascular endothelium. The mitotic activity of gliomas was shown to correlate with the tumor induced angiogenesis. Dynamic susceptibility contrast MR imaging (DSC MRI) allows the measurement of the cerebral hemodynamics based on the indicator dilution theory. We describe theory and technique of the method and present our experience with blood volume measurements after irradiation of the CNS. METHODS: We established a double slice technique on a standard 1.5 T MR system without hardware modifications, which allows an absolute quantification of the blood volume in regions of interest (ROI) within the brain. Fifty-five T2* weighted double slice images were acquired before, during and after bolus injection of Gd-DTPA (0.1 mmol/kg in 5 sec.) using a SD FLASH sequence (simultaneous dual fast low angle shot, TR/TE1/TE2 31/16/25, flip angle 10 degrees). Concentration-time curves were calculated from the measured signal-time curves. Blood volume values in tissue were normalised and calculated in absolute values (ml/100 g) based on the knowledge of the arterial input function (AIF), which was measured in the brain supplying arteries. The whole procedure requires only 2 to 3 minutes, the time for post processing is about 15 to 20 minutes. RESULTS: Blood volume parameter images of representative cases demonstrate the blood volume changes after radiotherapy. A reduction in blood volume could be observed in normal brain tissue and low-grade gliomas, while recurrent tumors were accompanied by a local increase in blood volume. CONCLUSIONS: Radiation induced blood volume changes in the CNS can be measured using dynamic susceptibility contrast MR imaging. The measurements in normal brain tissue allow a functional in-vivo analysis of late delayed radiation reactions of the CNS. The definite value of intratumoral blood volume measurements for determination of the therapeutic success and for differentiation of recurrences versus radionecroses remains to be clarified in further studies.

Adult↗
PubMed1994

Paget's disease of bone: five regimens of pamidronate treatment.

The efficacy of five therapeutic regimens using (3-amino-1-hydroxypropylidene)-1,1- bisphosphonate (APD or pamidronate) was assessed in patients with Paget's disease of bone. These regimens were as follows: (a) pamidronate 600 mg/day given orally during six months; (b) iv infusion of 20 mg daily for 10 days; (c) iv infusion of 40 mg daily for 5 days; (d) iv infusion of 10 mg daily for 4 days and (e) a single iv infusion of 10 mg. Six months after the initiation of therapy, urinary excretion of hydroxyproline and serum alkaline phosphatase activity (expressed as percent of their initial value) were: Group a: 30 +/- 10 (mean +/- SE) and 30 +/- 6, Group b: 55 +/- 8 and 46 +/- 6, Group c: 54 +/- 7 and 57 +/- 6, Group d: 53 +/- 7 and 69 +/- 4, and Group e: 85 +/- 10 and 98 +/- 4 respectively. Oral route was accompanied by digestive intolerance. On the contrary, except for rare and transient "flu-like syndromes", the iv treatment was not associated with any serious secondary effect. Intravenous infusion of pamidronate, 20 mg for 10 days or 40 mg for 5 days, appears as an interesting alternative to the oral route in the treatment of Paget's disease of bone.

Administration, Oral↗
PubMed1993

Measurement of guanine nucleotide-binding protein activation by A1 adenosine receptor agonists in bovine brain membranes: stimulation of guanosine-5'-O-(3-[35S]thio)triphosphate binding.

Signal transduction by A1 adenosine receptors was investigated by measuring the modulation by adenosine agonists of guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTP[S]) binding to guanine nucleotide-binding proteins (G proteins). The extent of stimulation of [35S]GTP[S] binding was dependent on the presence of high concentrations of Mg2+ (1-10 mM), GDP (10 microM), and NaCl (100 mM). Under optimal conditions, the agonist (R)-N6-phenylisopropyladenosine [(R)-PIA] stimulated binding of [35S]GTP[S] to G proteins approximately 2.3-fold. All adenosine receptor agonists tested stimulated the binding of [35S]GTP[S] with a rank order of potency typical of A1 adenosine receptors in bovine tissues, (R)-PIA > 2-chloro-N6-cyclopentyladenosine > (S)-PIA > 5'-N-ethylcarboxamidoadenosine > 2-[4-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosin e. The EC50 values for G protein activation correlated with the Ki value of agonists for inhibition of radioligand binding to the high affinity state of the A1 adenosine receptor. The inclusion of 100 mM NaCl as well as increasing GDP concentrations led to a parallel increase of Ki values and EC50 values. In addition, both compounds induced a shift of A1 adenosine receptors from the high affinity state for agonists to the low affinity state.

Animals↗
PubMed1992

Longitudinal study of bone metabolism after ethanol withdrawal in alcoholic patients.

The pathogenesis of osteopenia in chronic alcoholism remains unclear, and many ethanol-related abnormalities have been advocated to explain bone loss. A direct inhibitory effect of ethanol on osteoblast function was suggested by in vivo and in vitro studies. We measured biochemical markers of bone turnover in 12 alcoholic men before and during a 2 week period of alcohol withdrawal, and we compared the results with those obtained in 15 nonalcoholic men. Our alcoholic patients presented with (1) decreased serum concentrations of bone gla protein (BGP), suggesting decreased bone formation; (2) increased urinary excretion of hydroxyproline, suggesting increased bone resorption; (3) increased renal threshold of phosphate excretion without modification of serum PTH concentration, suggesting a direct effect of ethanol on the renal handling of phosphate. The rapid increase in serum BGP concentrations following ethanol withdrawal suggests that low serum BGP concentrations in alcoholics may result from a direct toxic effect of ethanol on osteoblast function and/or numbers.

Adult↗
PubMed1992

Calcium and vitamin D metabolism in granulomatous diseases.

Overproduction of the active metabolite of vitamin D 1,25-dihydroxyvitamin D (1,25(OH)2D) has been described in sarcoidosis and other granulomatous diseases. High circulating concentrations of 1,25(OH)2D lead to increased intestinal absorption of calcium, possibly to enhanced bone resorption, and may result in hypercalcaemia and/or hypercalciuria. Data obtained in vivo and in vitro demonstrated that the unregulated production of 1,25(OH)2D lies within the granulomatous tissue and is controlled by glucocorticoids. This abnormal production of 1,25(OH)2D seems to be a general phenomenon of granulomatous processes, which is not exceptional in sarcoidosis, but appears seldom in tuberculosis. These abnormalities, however, are not pathognomonic of granulomatous processes, since they have been described in other diseases such as lymphomas.

Calcium↗
PubMed1992

[Persistent and recurrent hyperparathyroidism following parathyroidectomy].

In a series of 416 parathyroidectomies for primary or secondary hyperparathyroidism, 19 were reoperations for persistence (17 cases) on recurrence (2 cases) of the disease. (1) Preoperative localisation studies were useless in half of the cases. (2) In re-explorations, 72% only of parathyroid glands were discovered, 46% of them in ectopic locations. In reoperations for primary hyperparathyroidism, 56% of cases had more than one pathological gland. (3) Long term results have been less satisfactory after re-explorations than after the first operations.

Adult↗
PubMed1991

Calcitonin secretion in idiopathic renal stone formers.

Several studies demonstrated a reduction in bone mineral content (BMC) in idiopathic renal stone formers (RSF). We found this reduction in association with a chronic low-calcium diet. Low calcium intake could theoretically result in calcitonin deficiency, responsible for increased bone resorption. This hypothesis was tested in 22 male RSF eating a low-calcium diet (350 +/- 72 SD mg/day) for 2 years or more, who showed a significant reduction in their BMC. When compared to 15 normal male subjects eating a free diet, RSF showed increases in serum alkaline phosphatase activity and fasting urinary excretion of hydroxyproline and calcium, suggesting increased bone turnover. Plasma calcitonin levels were measured by radioimmunoassay following an extraction-concentration technique (exCT). Basal plasma exCT levels were higher (P less than 0.005) in RSF (4.1 +/- 0.8 SEM pg/ml) than in normal subjects (2.8 +/- 0.4). Following a 5 minute infusion of 2 mg elemental calcium per kg, levels of plasma exCT tended to increase more, although not significantly, in RSF (51.3 +/- 9.4 pg/ml) than in normal subjects (36.6 +/- 9.7). The CT secretory response, taking into account changes in serum calcium concentration (delta exCT/delta Ca), was higher (P less than 0.05) in RSF (50.0 +/- 10.0) than in normal subjects (25.6 +/- 6.6). Our study thus demonstrates that RSF chronically fed a low-calcium diet have increased basal plasma CT levels and increased CT cells responsiveness. CT deficiency cannot therefore be considered a cause for the low BMC associated with a chronic low-calcium diet in RSF.

Adult↗
PubMed1991

Stimulation of calcitonin secretion by an oral calcium load test in normal subjects and in idiopathic renal stone formers.

Circulating concentrations of calcitonin (CT) have been found high in idiopathic renal calcium stone formers (RSF). It has been postulated that this could result from increased serum calcium concentrations following calcium-containing meals. To verify this hypothesis, 15 male idiopathic RSF and 15 male normal subjects underwent plasma CT measurements, following an extraction-concentration technique (exCT), in basal state and during an oral calcium load test. Most RSF exhibited increased excretion of calcium following oral calcium loading, suggesting overabsorption of calcium, but serum calcium did not increase more in RSF than in normal subjects. Basal plasma exCT concentrations were normal in RSF. ExCT plasma concentrations following calcium loading, and the area under the curve of exCT levels, tended to be higher in RSF than in normal subjects, but not significantly. Our results thus do not support the hypothesis that increased plasma CT levels in RSF result from increased serum calcium concentrations following calcium-containing meals.

Administration, Oral↗