Complete characterization of molecular dynamics in ultrashort laser fields.

Reaction Microscope-based, complete, and time-resolved Coulomb explosion imaging of vibrating and dissociating D(2)(+) molecules with femtosecond time-resolution allowed us to perform an internuclear distance (R-)dependent Fourier analysis of the corresponding wave packets. Calculations demonstrate that the obtained two-dimensional R-dependent frequency spectra enable the complete characterization of the wave packet dynamics and directly visualize the field-modified molecular potential curves in intense, ultrashort laser pulses.

Elimination of tritium-labelled hyaluronic acid from normal and osteoarthritic rabbit knee joints.

The half-life of [3H]hyaluronic acid in rabbit knee joints was estimated using two methods: (i) by following the [3H]hyaluronan content of the synovial fluid after intra-articular injection and (ii) by following the 3H2O radioactivity of plasma after intra-articular injection of [3H]hyaluronan. For normal rabbits we obtained a half-life of 15.8 hours (method I) and 17.5 +/- 1.0 hours (mean +/- SEM, method II), respectively. The second method was used to estimate the kinetics of the hyaluronan elimination from normal, sham-operated, as well as from osteoarthritic rabbit knee joints (Colombo model of osteoarthritis). Four weeks after injury, during the developing phase of osteoarthritis, the half-life of hyaluronan rose significantly to 23.5 +/- 2.1 hours and returned to normal levels (17.4 +/- 2.7 hours) 12 weeks after the operation (osteoarthritis developed). At the stage of developed osteoarthritis, the clearance rates were considerably higher than in normal rabbits.

[Distribution studies of alpha-L-arabinofuranosidase already unstable at pH 7.0 (37 degrees C) in tumor-bearing mice in connection with its possible use to enhance the selectivity of the chemotherapy of malignant tumors]. / Untersuchungen zur Verteilung einer bereits bei pH 7.0 (37 Grad C) instabilen alpha-L-Arabinofuranosidase in tumortragenden Mäusen im Zusammenhang mit ihrer möglichen Anwendung zur Erhöhung der Selektivität der Chemotherapie maligner Tumoren.

Graffi et al. (1-3) had proposed the use of exogenous enzymes to toxify inactive transport forms of cancerostatic substances. For this purpose, the pH difference between normal tissues and the tumor was to be exploited, which can be essentially increased by the application of glucose and inorganic phosphate (5-7). Earlier studies using alpha-L-arabinofuranosidase obtained from Aspergillus niger have shown that the selectivity of tumor chemotherapy can be increased in this way (4). The alpha-L-arabinofuranosidases known to date are stabile in a wide pH range (9). However, in some moulds we found pH-labile enzymes of this kind that become irreversibly inactivated in the weakly alkaline or neutral pH range (10, 11). Studies on the distribution of the activity of a pH-labile alpha-L-arabinofuranosidase from Glomerella myabana in tumor-bearing mice have shown that this enzyme is rapidly eliminated from the organism, in contrast to the pH-stable alpha-L-arabinofuranosidase from A. niger. Apart from its excretion via kidney and liver, of importance is the inactivation of the enzyme in the normal tissues. The additional application of glucose strongly increased the activity of this enzyme both in the tumor and in normal tissues (12). By injecting alkaline solutions, stronger inactivation in normal tissues than in the tumor was achieved (13). In the present paper, distribution of an alpha-L-arabinofuranosidase from Fusarium species I 50 (11), inactive already at pH 7.0 (37 degrees C), was studied in tumor-bearing mice. The activity of this enzyme could be enriched under various conditions in the tumor, and especially favorable proved to be the additional application of a combination of glucose and inorganic phosphate. Under these conditions, a higher activity than in the tumor was demonstrable only in the kidney, which can possibly be eliminated in larger experimental animals by diuretics or an appropriate alkaline administration. The investigations have shown that the pH-labile alpha-L-arabinofuranosidases, especially those of Fusarium sp., due to their pharmacokinetic behavior are better suited for use in our therapy concept than the hitherto employed enzyme from A. niger. More recently, Tietze (16) has proposed a similar therapy concept, in which also the glucose-increased pH difference between tumor and normal tissue using tumor-own enzymes, exogenous enzymes as well as transport forms of cancerostatic agents spontaneously hydrolysing under weakly acidic pH conditions is to be exploited.

[Experiments on the modification of the distribution of the activity of various alpha-L-arabinofuranosidases following i.v. application in tumor-bearing mice]. / Versuche zur Beeinflussung der Verteilung der Aktivität verschiedener alpha-L-Arabinofuranosidasen nach i.v. Applikation in tumortragende Mäuse.

Graffi et al. have proposed the use of exogenous enzymes for selective cleavage of inactive transport forms of cancerostatic substances in tumor tissue. Enzymes appropriate for this purpose should, if possible, show also a certain enrichment in the tumor tissue. In studies on the pH-labile alpha-L-arabinofuranosidase from G. myabena in tumor-bearing mice, under defined conditions in the tumors there could be demonstrated a higher concentration of the active form of the enzyme than in most of the normal tissues. However, the enzyme activity is eliminated from the organism in a relatively short time through excretion and inactivation. The application of glucose led to a strong increase of activity of the enzyme injected, both in the tumors and in the normal tissues. It has been shown in the present investigations that this increase in the enzyme activity can be curtailed more strongly in normal tissue by alkali application than in the tumors. In this way, a distribution of the enzyme activity favorable for therapy experiments is obtained. Only in the kidney and urine has a higher activity of the applied enzyme been measured than in the tumors. In the second part of this work it has been attempted to achieve accumulation of activity of the pH-stable alpha-L-arabinofuranosidase from A. niger through application of angiotensin, but no positive results have been reached under the various experimental conditions used.

[Pharmacokinetic studies of the activity of a pH-labile alpha-L-arabinofuranosidase following i.v. injection into tumor-bearing mice]. / Pharmakokinetische Untersuchungen der Aktivität einer pH-labilen alpha-L-Arabinofuranosidase nach i.v.-Injektion in tumortragende Mäuse.

In order to increase the selectivity of tumor chemotherapy, Graffi et al. have proposed the application of xenogenic enzymes, which are able to split transport forms of carcinostatics under the pH-conditions in the tumor more vigorously than in the normal tissues. This paper describes the distribution within the body and elimination of the activity of the pH-labile alpha-L-arabinofuranosidase from G. myabena compared with the pH-stable enzyme from A. niger, using tumor bearing mice. In vitro, the pH labile arabinosidase was irreversibly inactivated within a few minutes at pH 7.4 and 37 degrees C; however at pH 6.5 it remained active even after several hours. After injection, this enzyme activity was eliminated from the organism by excretion and inactivation within a few hours. Hereby a relatively favourable distribution of the enzyme activity for therapeutic application was reached after 60 minutes. At this time higher activity than in the tumor was measured only in the kidney. The application of glucose led to a strong increase of the enzyme activity in both tumor and normal tissues. This effect was also seen in tumor free mice. In further experiments it will be tried to find out conditions which reduce the glucose induced acidosis. The activity and distribution of the pH-stabile enzyme from A. niger were not influenced by glucose application.