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Biomedical subjects

K Koch

Publications and source records attributed to K Koch.

At least 109 records · Page 6Linked to original sources
PubMed1985

[New possibilities in radiotherapy of endobronchial tumors using the afterloading method in combination with laser technics].

New possibilities for radiotherapy of bronchial carcinomas are provided by the combined application of the recently introduced afterloading method used hitherto in the treatment of stenosing processes of bronchial carcinomas and the neodyme-YAG laser which opens the stenosis in such a manner that the afterloading probe can be inserted. This new method allows to perform without complications or disadvantages further combined therapies such as percutaneous irradiation (telecobalt, linear accelerator or betatron). An irradiation scheme leading to a decisive tumor regression can be established due to the fast reventilation of the lung obtained by both methods. Surprisingly, three patients could be submitted despite the small-field radiotherapy to rather important lung operations such as lobectomy and pneumonectomy which were performed without complications or disadvantages. The patients were not operable without laser and afterloading therapy. This method was applied several times in the treatment of other diseases such as oesophageal cancer and stenosing cancer of the antrum. In these cases, a normal ingestion due to tumor regression was obtained rapidly.

Brachytherapy↗
PubMed1984

Filtration for free drug level monitoring: carbamazepine and valproic acid.

Free carbamazepine and valproic acid monitoring using the EMIT FreeLevel filtration system was evaluated and compared with reference equilibrium dialysis and gas chromatographic (GC) techniques. For carbamazepine, free levels after filtration or dialysis were essentially identical (mean 1.74 vs. 1.77 mg/L, r = 0.940, n = 28, EMIT assay). Free levels were 16% higher by EMIT than by GC, possibly due to cross-reaction with carbamazepine-10,11-epoxide. Free fractions were not significantly different using any combination of filtration or dialysis with EMIT or GC (means 0.24-0.26). There was a significant correlation between epoxide and parent-drug free fractions (r = 0.642). Free fraction varied from 0.20 to 0.41 among 61 patient samples and was independent of total drug concentration. For valproic acid, there was a strong correlation between filtration and dialysis results for free level (r = 0.974) and free fraction (r = 0.892), but filtration values were 6-7% higher. Free fraction was concentration dependent (r = 0.597), and lower free fractions by dialysis were attributed to dilution of total drug concentration. Free fraction varied from 0.01 to 0.14 among 50 patient samples. For carbamazepine and valproic acid the EMIT FreeLevel filtration system compared favorably with equilibrium dialysis, and had the advantage of being rapid.

Blood Proteins↗
PubMed1984

Orbital pseudotumor in Crohn's colitis.

A 17-year-old woman presented with orbital pain, diplopia, ptosis, and upper lid swelling due to an orbital pseudotumor involving the superior rectus-levator complex. Although she had no prior symptoms of chronic inflammatory bowel disease, diagnostic evaluation revealed Crohn's colitis. Diagnostic evaluation of patients with "idiopathic" orbital pseudotumor should include testing to rule out chronic inflammatory bowel disease.

Adolescent↗
PubMed1983

[Effects of extracorporeal blood irradiation on the lymphocyte population in chronic lymphadenosis].

The surface markers of lymphocytes were detected in 18 patients with chronic lymphatic leukemia (CLL), with 9 of them being treated by means of extracorporeal blood irradiation (ECIB) and 9 of them being without any treatment. We found that B-lymphocytes were eliminated by ECIB to a higher degree than it can be recognized by the decrease of lymphocytes. As to their percentage B-cells with ME-receptors or EAC-receptors respectively were partially diminished to a higher degree than the total population of B-cells. Moreover, the pathological Ig-type could be shown to be affected predominantly. The changes of marker profiles and absolute values achieved by ECIB revealed an approach of values in treated patients to those of untreated patients. The investigations make it clear that the determination of lymphocyte subpopulation can be used not only for diagnosis and differential diagnosis of lymphatic system diseases, also for evaluating therapy effects.

Chronic Disease↗
PubMed1981

Pharmacokinetics of 14C-activity after the administration of 14C-azimexone in rats.

The pharmacokinetics of 14C-activity were studied in male Sprague-Dawley rats over 24 and 288 h periods after oral i.v. administration respectively. After oral administration rapid and complete absorption of azimexone occurred. The elimination of radioactivity from plasma after i.v. administration could be best described by an open four-compartment-system yielding a terminal half-life of 74.45 h indicating the existence of deep compartment for azimexone or its metabolites. The renal clearance of 14C-activity decreased considerably after i.v. administration with progressing time. This points to an extensive metabolism of azimexone. Fifty-seven and sixty-seven per cent of the given 14C-activity could be recovered in urine within 24 h after i.v. and p.o. administration respectively and in both cases less than 1% of the doses in feces. Studies on the distribution of the labelled substance 24 h after i.v. administration showed highest concentration in gastric contents, spleen thyroid gland and bone marrow. Twelve days after i.v. administration the ratio of the 14C-content in organ/plasma was greatly increased for spleen, thymus, lung, bone marrow and thyroid gland as compared with the conditions 24 h after administration. Thus it can be assumed that the target organs for the immunomodulating activity of the drug belong to the deep compartment of azimexone or its metabolites.

Adipose Tissue↗
PubMed1981

[A contribution to the recovery of poliomyelitisvirus from digested sewage sludge dependent on pH-value (author's transl)].

For later investigations on the influence on virus in digested municipal sewage sludge four different methods were tested to recover virus of poliomyelitis from the sludge. The best results were obtained by elution with 3% beef-extract at pH 9, followed by ultrasonic-treatment. The recovery-rate is not significantly influenced by the final concentration of beef-extract. Poliovirus inoculated to anaerobic digested sludge shows a 90% reduction within 7 hours at room-temperature.

Anaerobiosis↗
PubMed1981

[Removal of polio- and parvovirus in sewage-sludge by lime-treatment (author's transl)].

Lime (CaO) applied as conditioner for dewatering municipal sewage sludge in filter-presses is suitable to disinfect sewage sludge with respect to virus. A pH-rise to more than 12 followed by release of ammonia inactivates Polio- and Bovine Parvovirus. Addition of 3 kg CaO and more per m3 of raw sludge inactivates Poliovirus within 30 minutes. 7.5 kg CaO per m3 of anaerobically digested sludge are required to inactivate Polio-virus within 5 days and Bovine Parvovirus within 24 hours. Parvovirus seems to be more sensitive against free ammonia than Poliovirus, but less sensitive against high pH-values.

Calcium↗
PubMed1981

Extrarenal clearance, distribution volume, and elimination rate of digoxin and metildigoxin in anuric patients.

The pharmacokinetics of 3H-labeled digoxin and metildigoxin were compared in six anuric patients. The following means +/- s.e.m. were obtained: extrarenal clearance of digoxin, 43.3 +/- 5.4 ml/min, of metildigoxin, 30.3 +/- 2.9 ml/min; distribution volume of digoxin, 315 +/- 29 1, of metildigoxin, 258 +/- 22 1; rate constant for elimination of digoxin, 0.0086 +/- 0.0013 h-1, of metildogixon, 0.0071 +/- 0.0007 h-1. The elimination rates correspond to half-lives of 80 h for digoxin and of 97 h for metildigoxin. From our investigations and published data a weighed mean of 47 ml/min was calculated for the extrarenal clearance of metildigoxin. This is not significantly different from the mean extrarenal clearance of 40 ml/min reported for digoxin. A total body clearance of 40 ml/min and a daily intravenous dose of 0.1 mg correspond to an average steady-state glycoside concentration of 1.74 ng/ml.

Anuria↗
PubMed1980

Characteristics of Crassulacean Acid Metabolism in the Succulent C(4) Dicot, Portulaca oleracea L.

Crassulacean acid metabolism (CAM) was investigated in leaves and stems of the succulent C(4) dicot Portulaca oleracea L. Diurnal acid fluctuations, CO(2) gas exchange, and leaf resistance were monitored under various photoperiod and watering regimes. No CAM activity was seen in well watered plants grown under 16-hour days. Under 8-hour days, however, well watered plants showed a CAM-like pattern of acid fluctuation with amplitudes of 102 and 90 microequivalents per gram fresh weight for leaves and stems, respectively. Similar patterns were also observed in detached leaves and defoliated stems. Leaf resistance values indicated that stomata were open during part of the dark period, but night acidification most likely resulted from refixation of respiratory CO(2). In water-stressed plants maximum acid accumulations were reduced under both long and short photoperiods. At night, these plants showed short periods of net CO(2) uptake and stomatal opening which continued all night long during preliminary studies under natural environmental conditions. Greatest acid fluctuations, in P. oleracea, with amplitudes of 128 microequivalents per gram fresh weight, were observed in water-stressed plants which had been rewatered, especially when grown under short days. No net CO(2) uptake took place, but stomata remained open throughout the night under these conditions. These results indicate that under certain conditions, such as water stress or short photoperiods, P. oleracea is capable of developing an acid metabolism with many similarities to CAM.

Journal Article↗
PubMed1980

Enzymatic inhibition assay for fluorometric determination of allopurinol and oxipurinol in serum and urine.

An enzymatic inhibition assay for the xanthine oxidase (XOD) inhibitors allopurinol and oxipurinol is described. 2-Amino-4-hydroxypteridine is used as sensitive fluorogenic substrate, which is oxidized to highly fluorescent isoxanthopterin by XOD. Increasing concentrations of allopurinol (Ap) or oxipurinol (Ox) prevent conversion of 2-amino-4-hydroxypterdine to isoxanthopterin. Assay conditions of XOD-inhibition are different for Ap and Ox. In the presence of xanthine both Ap and Ox inhibit XOD to the same degree; absence of xanthine results in inactivation by Ap only. Thus rapid and convenient determination of Ap and Ox is possible without prior separation of the substances. The limit of detection is about 0.5 nmol/ml (50 micrograms/ml) in serum and 25 nmol/ml (2.5 micrograms/ml) in urine.

Allopurinol↗
PubMed1980

Binding of technetium-99m to plasma proteins: influence on the distribution of Tc-99m phosphate agents.

Plasma protein binding of Tc-99m was assessed in man after injection of various Tc-99m-labeled bone imaging agents. Of the five methods in which plasma proteins were precipitated to determine protein binding no correlation between them could be established. The ammonium sulfate method seemed to correlate well with dialysis filtration. Plasma obtained from patients injected with Tc-99m phosphate compounds was reinjected to rats. The bone uptake in these animals correlated linearly with the unbound activity in the injected plasma. Provided that no protein binding would occur, the bone uptake as well as the urinary excretion proved to be identical for Tc-99m HEDP, MDP, and PPi. Electrophoresis of Tc-99m PPi indicated that the intact complex may be uncharged, whereas at low ligand concentrations uncharged as well as negatively charged Tc-99m species are formed. Better methods are needed, however, to establish the presence of various Tc-99m species and their relative role in the kinetics of these compounds, and plasma protein binding.

Animals↗
PubMed1980

[Problem of so-called pseudotumor cerebri].

A brief survey on the concept of the so-called pseudotumour cerebri is given, referring to a great number of synonyms. On the basis of the clinical data of 70 patients with diseases of the intra- and extracranial organs and without a recognisable basic disease, a continous development of the increase in the brain pressure from only subjective complaints to the syndrome of the benign intracranial hypertension in an extended sense and the most severe disease pictures with a lethal outcome are discussed. For lethal courses the term of malignant intracranial hypertension is suggested and the importance of computer tomography in the differential diagnosis and supervision of unclear brain pressure increases is pointed out.

Adolescent↗