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Biomedical subjects

U Fink

Publications and source records attributed to U Fink.

At least 163 records · Page 9Linked to original sources
PubMed1988

Magnetic resonance imaging of normal and pathological white matter maturation.

Fifty children between 3 months postnatal and 16 years of age were examined by means of a 1.5 T superconductive magnet, run at 0.35 and 1.0 T. The myelination was studied qualitatively and quantitatively (relaxation times, proton densities, image contrast). With increasing age, a decrease of T1 and proton density of white matter was found, which was complete at one year of age. In regions with a slow progression of myelination, gray/white matter contrast showed an increase up to the end of the first decade. Pathological white matter maturation was diagnosed either as an abnormal transformation of myelin (characterized by abnormal relaxation values), or as a deficient or delayed myelin formation (in comparison with age-matched controls).

Adolescent↗
PubMed1988

[Bioactive materials. A critical review].

The bioactive materials should be divided into osteoinductive and osteostimulative materials according to their effect in bone regeneration. Already this statement requires a definition of the words used, in order to assure a real discussion. By means of the recommendations for definitions this paper is a basis for those discussions. In order to classify the bioactive materials into types of materials the potential effect onto the bone regeneration process should be considered. On the other hand the synthetic or biological origin, and the physical or biochemical structure are of great significance. Beside the classification made by the above called criteria the types of materials with their advantages and disadvantages are described. In the following discussion some problems are described like the mechanical and chemical instability, the coating of metallic substrata, the sterilization and the possibilities for the analytic characterization of hydroxylapatite.

Biocompatible Materials↗
PubMed1988

[Nuclear magnetic resonance tomographic appearance of disseminated encephalomyelitis in relation to clinical diagnosis].

The MRI findings in 149 patients with a clinical diagnosis of disseminated encephalomyelitis (D.E.) were related to the diagnostic criteria of McAlpine (definite, probable, possible). The most common pattern in all three groups was a mixed peri- and para-ventricular distribution of foci. The findings in 'possible' D.E., compared with 'definite' D.E., showed fewer confluent lesions, but were characterised by peri- and para-ventricular as well as solitary foci. The results of the present study permit better classification and evaluation of the MRI findings if the clinical diagnosis of D.E. is only suspected (probable or possible).

Adolescent↗
PubMed1988

[Clinical use of gradient echo sequences of longer repetition times].

Studies designed to optimise image contrasts of gradient echo sequences showed, that especially repetition times between 250 and 500 ms in combination with adequate echo times and flip angles provide new image contrasts. The clinical purpose of gradient echo sequences with longer TR was systematically evaluated in 450 patients. A major advantage of GE sequences was the low signal intensity of fat and bone tissue. On the other hand different pathologic changes showed a high signal intensity in comparison to T2 weighted spin echo sequences as well. With the possibility of multiple slices GE sequences were of outstanding diagnostic value especially in MR of soft tissue and of the musculoskeletal system. T2 weighted SE sequences provided no additional informations and could therefore be omitted in a great number of examinations.

Abdomen↗
PubMed1988

Indications for the use of Gd-DTPA in MRI of the central nervous system. Experiences in patients with cerebral and spinal diseases.

A total of 209 intracranial and spinal diseases were evaluated before and after administration of the paramagnetic contrast agent Gd-DTPA. The results justify the use of Gd-DTPA in intracranial and spinal tumors for better visualization of location and extent of a lesion and for better tissue differentiation. In inflammatory diseases Gd-DTPA allows the differentiation between active and chronic lesions.

Brain Neoplasms↗
PubMed1987

[Perioperative chemotherapy in squamous cell carcinomas of the esophagus].

In the majority of patients with esophageal cancer local tumor infiltration and/or distant metastases are responsible for the poor prognosis. Therefore to improve life expectancy additional modalities - chemotherapy alone or in combination with simultaneous radiation - have been introduced perioperatively. In spite of a possible increase of resectability convincing data are lacking which could argue for an uncontrolled introduction of the neoadjuvant approach outside investigational studies.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Postoperative controls in surgically treated hormonactive pituitary adenomas by use of magnetic resonance imaging.

The search of reliable imaging methods to detect the substrate for persisting hypersecretion in patients operated on for hormonactive pituitary adenoma prompted us to study the possibilities of the newly available Magnetic Resonance Imaging (MRI) technique in this regard. Pre- and postoperative MRI-studies where performed in 5 patients with persisting GH excess following transsphenoidal surgery as well as in 3 patients with micro- and 2 patients with macroprolactinomas. The MRI-findings were correlated with the results of the endocrinological examinations. Two acromegalic patients and three cases with microprolactinomas, who were successfully operated upon as defined by the functional criteria were also included to obtain a baseline for normal postoperative findings. The MRI-study was positive in all of the five patients with persisting GH-overproduction. In prolactinomas, the substrate of hypersecretion could only be detected, when the PRL-value exceeded 2,000 microU/ml. MRI may present an important diagnostic method for evaluating further treatment options in patients with remaining hormonal hypersecretion following transsphenoidal adenomectomy, particularly with regard to a second surgical approach.

Acromegaly↗
PubMed1987

Cytotoxic effects of ether lipids and derivatives in human nonneoplastic bone marrow cells and leukemic cells in vitro.

The effects of 2-lysophosphatidylcholine (2-LPC), the alkyl lysophospholipid derivatives (ALP) 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) and 1-O-hexadecyl-sn-glycero-3-phospho-trimethyl-ammonio-hexanol, the 2-acetamide analog of platelet-activating factor (PAF) 1-O-octadecyl-2-acetamide-sn-glycero-3-phosphocholine, the thioether lysophospholipid derivative (TLP) BM 41.440 and the ether-linked lipoidal amine CP-46,665 on tritiated thymidine uptake and trypan blue dye exclusion were tested in vitro in various freshly explanted cell samples from human nonneoplastic bone marrow and human leukemias. In both assay systems, a dose range of 1-20 micrograms/ml of the compounds was tested after 24, 48 and 72 hr of coincubation with the cells. The trypan blue dye exclusion revealed statistically significant preferential cytotoxicity in leukemic cells for three compounds with the order of quantitative selectiveness: ET-18-OCH3 greater than BM41.440 greater than 2-acetamide analog of PAF. CP-46,665 was the most toxic compound, but did not reveal significant differences between nonneoplastic bone marrow and leukemic cells when added in concentrations greater than 1 microgram/ml. The trimethyl-ammonio-hexanol compound showed only minor activity in the majority of tests, when added at concentrations less than 20 micrograms/ml. 2-LPC was rather ineffective. The tritiated thymidine uptake showed only preferential antiproliferative effects towards leukemic cells of ET-18-OCH3 and, sometimes, within the dose time frame tested of BM 41.440. All compounds tested except 2-LPC and the trimethyl-ammonio-hexanol compound were active also in this assay (inhibition of uptake greater than 50% of the controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗
PubMed1987

Structure-cytotoxicity studies on alkyl lysophospholipids and some analogs in leukemic blasts of human origin in vitro.

Eleven lipids have been tested for cytotoxic (trypan blue dye exclusion) activity in cells from eight freshly explanted human leukemias in vitro. 4-Aminomethyl-1-[2,3-(di-N-decyloxy)N-propyl]-4-phenylpiperidine (CP-46,665), 1-mercapto-hexadecyl-2-methoxymethyl-rac-glycero-3-phosphocholine (BM 41.440), the 2-acetamide analog of platelet-activating factor (PAF) and 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) were found among the most active compounds. 2-Lysophosphatidylcholine (2-LPC) showed the lowest activity. However, in addition there was variation among the results regarding the activity of the 1-octadecyl-rac-glycero-3-phosphocholine (ET-18-OH) and its D- and L-forms, but a significantly higher cytotoxic activity of D-ET-18-OH compared with L-ET-18-OH on the basis of 2-LPC as control after an incubation time of 48 hr. We conclude that with the limited number of structures available, this type of study is not sufficient to yield further information about the mode of the accumulation and toxicity of this type of lipids.

Antineoplastic Agents↗
PubMed1987

Antineoplastic activity of the thioether lysophospholipid derivative BM 41.440 in vitro.

Thioether lysophospholipid derivatives (TLP) inhibited the in vitro uptake of [3H]thymidine into blasts of eight leukemias and cells of 12 different solid tumors of human origin. This effect correlated with trypan blue dye exclusion, which was used to assess cell damage. Cytostatic and cytotoxic effects of TLP were dependent on dosage and incubation time. Destruction of leukemic blasts was completed with greater than 5 micrograms/ml after an incubation of greater than 48 hr, but 10 to 20 micrograms/ml were necessary in solid tumors. Ester-linked 2-lysophosphatidylcholine was ineffective in the same dose range, which points to the requirement of the alkyl moiety in sn-1 and a stable sn-2 substitution of the molecule for the antineoplastic effect. To assess putative antileukemic selectivity, the cytotoxicity (trypan blue dye exclusion) of TLP was compared in human cell samples of 19 non-neoplastic bone marrows and 9 leukemias. Results revealed a significantly higher activity of the TLP BM 41.440 in leukemic blasts.

Antineoplastic Agents↗
PubMed1987

Clinical phase I pilot study of the alkyl lysophospholipid derivative ET-18-OCH3.

Sixteen patients suffering from widespread malignant disease, the majority pretreated and found in poor general health, were treated in a phase I pilot study with the alkyl lysophospholipid derivative 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3). Eleven patients were treated intravenously, and five were given oral therapy. Prolonged IV administration of 15-20 mg/kg/day at a concentration of 5 mg ET-18-OCH3 per 1 ml 20% human serum albumin could be continued safely. The maximum-tolerated dose was either 50 mg/kg as a single injection or 20 mg/kg during daily dispensions. Grade 2-4 toxicity, as pulmonary edema and impairment of hepatic function, then occurred during daily treatment. Toxicity was reversible. Mitogen stimulation and mixed lymphocyte culture studies revealed possible immunosuppressive effects of higher doses of ET-18-OCH3. There were no chromosomal changes in cytogenetic studies. Frequent post-mortem examinations revealed no further toxicity. IV and oral treatment showed few encouraging response data since there were two partial remissions in non-small cell lung cancers and a reduction of leukemic blasts to less than 10% in an acute myelomonocytic leukemia.

Administration, Oral↗
PubMed1987

[Magnetic resonance imaging in craniopharyngiomas. The differential diagnosis of cystic intra- and suprasellar space-occupying lesions].

Seven patients with confirmed craniopharyngiomas were examined via magnetic resonance imaging. The various tumour components (whether solid, cystic or calcified) were evaluated separately. Three types of cysts were observed that can be distinguished by their signal intensity in various pulse sequences. This could be explained largely by an analysis of the T1 and T2 image contrast. The reason for the various types of cysts is determined by their cholesterol content. MR imaging is not as useful as CT for demonstrating the solid and calcified portions of the tumour and this reduces its value in diagnosing the type of tumour. Against that, it is superior with regard to separating the tumour from its neighbouring structures. The differential diagnosis, which must be considered in using MR, is summarised in a table at the end of the paper.

Craniopharyngioma↗
PubMed1987

Disseminated testicular cancer with bulky disease: results of a phase-II study with cisplatin ultra high dose/VP-16/bleomycin.

This is a preliminary analysis of the AIO-Testicular Tumour Study Group trial in patients with disseminated bulky testicular cancer. Treatment plan: cisplatin 35 mg/m2 days 1-5, VP-16 120 mg/m2 days 1-5 (two daily divided doses), bleomycin 15 mg/m2 days 1, 8, 15. Of 98 patients at present evaluable 63% had complete remission or have no evidence of disease (CR/NED), 30% had partial remission (PR) and 7% had no change or progressive disease (NC/P). Relapse-free survival is 93% for the CR/NED group after a median follow up of 2.2 years: the overall survival for the entire patient population is 70%. Toxicity included predominantly granulocytopenic fever and infection with septicaemia, thrombocytopenia, nausea, vomiting, neurotoxicity and lung toxicity, with 7% fatal toxicity. A prospective randomized trial is warranted to evaluate the apparent superior activity of ultra high dose cisplatin in combination with VP-16 and bleomycin.

Adolescent↗
PubMed1987

Benefit and costs of follow-up programs in nonseminomatous germ cell tumors of the stages IIb-IV: the Munich experience.

Since 1979 we have seen 197 patients with nonseminomatous germ cell tumors (NSGCT) of the stages IIb-IV. 185 of these are evaluable (3 lost to follow-up, 9 still in treatment). The majority of the patients was given platinum-vinblastine-bleomycin treatment (PVB). 138/185 (74.6%) have achieved a first complete remission (CR), and 131/185 (70.8%) are currently found with no evidence of disease (NED). All patients in CR have been followed by physical examinations, blood chemistry including tumor markers, and chest X ray (years 1 and 2: 8 times; year 3: twice; years 4 and 5: twice) and by abdominal computer tomography (CT; years 1 and 2: 6 times; year 3: twice; years 4 and 5: twice). So far this follow-up procedure has been performed for a total of 326 patient years costing approximately $215,000. 18/138 patients (13%) were found in the first relapse. 13/18 could achieve a 2nd CR under salvage therapy. 2 of these patients were found in a 2nd relapse and 1 of these was brought into a third CR. 1 patient died in CR from reasons unrelated to NSGCT. The 20 first and second relapses were detected with clinical symptoms (6 times), chest X ray (6 times), abdominal CT (5 times), and tumor marker elevation (3 times). This represents 14 relapses detected by follow-up examinations without clinical symptoms. Only 1/6 patients complaining of clinical symptoms as a first sign of the 1st recurrence achieved a second CR, and 5/6 died of progressive disease, whereas all 12 patients with first relapses detected without clinical symptoms during follow-up could be brought into second CR. Although this is a retrospective analysis and 3/6 patients with symptomatic relapses had additional brain lesions, these data, with due caution, tend to argue in favor of close follow-up programs with monitoring additional to physical examination for patients with NSGCT in CR. Furthermore, 15/18 first relapses (83%) were found within the first 2 years and 3/18 later. Since all 3 patients detected with a late recurrence achieved a second CR, at least 5 years of follow-up seem justified.

Cost-Benefit Analysis↗