Publications

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Abstract 1,5-Anhydrohexitol congeners of AZT, D4T and DDC were synthesized. These compounds did not show anti-HIV activity.

Dimensional inspection tasks are often carried out on conventional coordinate measuring machines (CMMs). These CMMs can differ in layout and size depending on the application area. They can have measurement volumes up to 100m3. However, when measuring large objects it is not always possible to bring a large object to these conventional CMMs. That is why for these applications mobile measuring systems are an ideal solution. These systems often measure the dimensions through optical techniques, like interferometry and optical triangulation. After a short survey of common optical measurement techniques for mobile and large-scale measurements, this paper focuses on two industrial cases where different techniques were used to solve a measurement problem. The first case covers the measurement of a large iron casting with an optical LED-based triangulation system. It was possible to predict problems that would occur with the machining of the part, like unfinished surfaces after milling due to material shortage, and adapt the alignment of the part to prevent these problems. The second case covers the measurement of a double-decker train by means of photogrammetry, as an alternative for the currently used total station. Despite some specific drawbacks of photogrammetry systems it was possible to obtain the same accuracy and to reduce the overall inspection time significantly in comparison with the current situation.

Montana Myotis leukoencephalitis virus (MMLV), a virus isolated from bats, causes an encephalitis in small rodents reminiscent of flavivirus encephalitis in humans. The complete MMLV genome is 10690 nucleotides long and encodes a putative polyprotein of 3374 amino acids. The virus contains the same conserved motifs in genes that are believed to be interesting antiviral targets (NTPase/helicase, serine protease and RNA-dependent RNA polymerase) as flaviviruses of clinical importance. Phylogenetic analysis of the entire coding region has confirmed the classification of MMLV in the clade of the flaviviruses with no known vector (NKV) and within this clade to the Rio Bravo branch (both viruses have the bat as their vertebrate host). We have provided for the first time a comparative analysis of the RNA folding of the 3' UTR of the NKV flaviviruses (Modoc, Rio Bravo and Apoi viruses, in addition to MMLV). Structural elements in the 3' UTR that are preserved among other flaviviruses have been revealed, as well as elements that distinguish the NKV from the mosquito- and tick-borne flaviviruses. In particular, the pentanucleotide sequence 5' CACAG 3', which is conserved in all mosquito- and tick-borne flaviviruses, is replaced by the sequence 5' C(C/U)(C/U)AG 3' in the loop of the 3' long stable hairpin structure of all four NKV flaviviruses. The availability of this latter sequence motif allows us to designate a virus as either an NKV or a vector-borne flavivirus.

In accordance with our antiviral drug development attempt, acylhydrazone derivatives bearing amino acid side chains were synthesized for the evaluation of their antiviral activity against various types of viruses. Among these compounds, 8(S) , 11(S) , and 12(S) showed anti-HIV-1 activity with a 50% inhibitory concentration (IC(50)) =123.8 µM (selectivity index, SI>3), IC(50) =12.1 µM (SI>29), IC(50) =17.4 µM (SI>19), respectively. Enantiomers 8(R) , 11(R) , and 12(R) were inactive against the HIV-1 strain III(B) . Hydrazones 8(S) , 11(S) , and 12(S) which were active against HIV-1 wild type showed no inhibition against a double mutant NNRTI-resistant strain (K103N;Y181C). Molecular docking calculations of R- and S-enantiomers of 8, 11, and 12 were performed using the hydrazone-bound novel site of HIV-1 RT.

With the aim of assessing the role that the thymine base of TSAO-T may play in the interaction of TSAO compounds with HIV-1 reverse transcriptase (RT), we have designed, synthesized, and evaluated for their anti-HIV-1 activity a series of 3-spiro sugar derivatives substituted at the anomeric position with nonaromatic rings or with amine, amide, urea, or thiourea moieties that mimic parts or the whole thymine base of TSAO-T. Also, a dihydrouracil TSAO analogue and O-glycosyl 3-spiro sugar derivatives substituted at the anomeric position with methyloxy or benzyloxy groups have been prepared. Compounds substituted at the anomeric position with an azido, amino, or methoxy group, respectively, were devoid of marked antiviral activity (EC50: 10-200 microM). However, the substituted urea sugar derivatives led to an increase in antiviral potency (EC50: 0.35-4 microM), among them those urea derivatives that mimic most closely the intact TSAO-T molecule retained the highest antiviral activity. Also, the dihydrouracil TSAO derivative retained pronounced anti-HIV-1 activity. None of the compounds showed any anti-HIV-2 activity. The results described herein represent the first examples of sugar derivatives that interact in a specific manner with HIV-1 RT. Molecular modeling studies carried out with a prototype urea derivative indicate that a heteroaromatic ring is not an absolute requirement for a favorable interaction between TSAO-T and HIV-1 RT. Urea derivatives, which can mimic to a large extent both the shape and the electrostatic potential of a thymine ring, can effectively replace this nucleic acid base when incorporated into a TSAO molecular framework with only moderate loss of activity.