Functional mapping and single chain construction of the anti-cytokeratin 8 monoclonal antibody TS1

The anti-cytokeratin (CK) 8 monoclonal antibody (mab) TS1 has been shown to efficiently bind to CK8 expressed in carcinomas in vivo. The anti-idiotypic antibody of TS1, alphaTS1, can be used to regulate the tumor:non-tumor ratio of TS1 by clearing non-tumor binding TS1 from the circulation. If the interaction of TS1 to CK8 and alphaTS1 is fully understood, mutations can be used to improve the tumor:non-tumor ratio. A scFv was made of the mab TS1 and residues earlier identified by Erlandsson et al. as important for the interaction with both its antigen CK8 and its anti-idiotype alphaTS1, were mutated to alanine or amides and expressed in E. coli. The effects of the mutations were studied by ELISA and residues important for the interactions to both CK8 and alphaTS1 were identified as mainly tyrosines, charged residues, a serine and a tryptophan. Altogether, nine amino acid residues in TS1 were found to be important in the interaction to alphaTS1 and six residues for the interaction to CK8. Important residues, clustered together in the modelled protein, were identified as residues from CDR 3 of the heavy chain and the unexpected participation of a residue in CDR 2 of the light chain. Some of the important residues are likely to be hotspots. Hotspots constitute a few residues in an interaction that contribute most to the binding, energetically. Amino acid residues in hotspots often cluster together in the center of the interaction interface, but can also be spread out to the periphery. The hotspots are often surrounded by hydrophobic patches, which are seen in the modelled TS1 protein used in this study. Amino acid residues that increased the affinity when mutated were also identified for both interactions. These residues are likely to be located outside the interacting interface. It can from this study be concluded that it is wise to precede the mutational procedure with experiments that can give guidelines for the selection of which amino acid residues to mutate. If the guidelines from the chemical modifications from Erlandsson et al. not had been used, this study would have left some residues unmutated and thereby missed important information.     

Gaussian prefiltering of 123I DAT SPECT images when using depth-independent resolution recovery

Previously we have investigated a depth-independent compensation for collimator detector response (CDR) included in the OSEM reconstruction, intended for SPECT images that have been corrected for scatter and septal penetration using convolution-based methods. In this work, the aim was to study how different filtering strategies affect contrast as a function of noise when using Gaussian smoothing filters in combination with the above-described CDR compensation. The evaluation was performed for (123)I dopamine transporter (DAT) SPECT images. Prefiltering with 2D Gaussian filter kernels, where the deterioration in resolution is included in the depth-independent CDR compensation, was compared to conventional postfiltering with 3D Gaussian filter kernels. Images reconstructed without filtering are also included in the comparison. It was found that there is little benefit in noise reduction when using CDR compensation. However, this variant of prefiltering gives consistently higher contrasts as a function of noise compared with the postfiltering alternative, and that could be of interest when using other types of filters with contrast improving properties.     

Association between lung function decline and obstructive sleep apnoea: the ALEC study

Sleep and Breathing - To study changes in lung function among individuals with a risk of obstructive sleep apnoea (OSA), and if asthma affected this relationship. We used data from the European...     

Autoradiographic localization of extrastriatal D2-dopamine receptors in the human brain using [125I]epidepride

Epidepride is a benzamide with high affinity for central D₂- and D₃-dopamine receptors. The anatomical distribution of [¹²⁵I]epidepride binding was examined by autoradiography, using postmortem human whole-hemisphere cryosections. The density of [¹²⁵I]epidepride binding sites was high in caudate nucleus and putamen. [¹²⁵I]epidepride also labeled receptors in extrastriatal region such as in the pallidum, some thalamic nuclei, the neocortex, and the substantia nigra. The neocortical binding was heterogeneously distributed. In most cortical regions, binding sites were located in superficial layers (I-II). However, in basal levels of the occipital cortex, [¹²⁵I]epidepride binding was located in a deeper layer, probably corresponding to layer V. Competition studies indicated that most of the [¹²⁵I]epidepride binding represented predominantly D₂-dopamine receptors, in striatal as well as in extrastriatal regions. The presence of extrastriatal D₂-dopamine receptor populations is of particular interest for research on schizophrenia and antipsychotic drug action. © 1996 Wiley-Liss, Inc.     

Addiction on prescribed sedative-hypnotics

This paper reviews the conceptualization of addiction on prescribed sedative-hypnotics medications; its evolution, occurrence, characteristics and validity. Such addictive behaviour is often concurrent with severe anxiety and/or personality disorders and follows a dismal course. The rate of suicide is very high, particularly in health care personnel with access to lethal medications. The risk of developing this kind of addiction is miniscule, considering the mass exposure to these medications in the general population. Yet, moralizing arguments amplified by the media, as well as overzealous government interventions create unnecessary obstacles to proper and effective pharmacotherapy for morbid anxiety and insomnia. © 1996 John Wiley & Sons, Ltd.     

Studies on the effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on central catecholamine neurons in C57BL/6 mice. Comparison with three other strains of mice

The effect of the parkinsonism-inducing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on central catecholamine neurons in C57BL/6 mice has been studied employing neuro- and histochemical techniques. The number of dopamine (DA) cell bodies in substantia nigra pars compacta (SNC) was reduced by 70% in MPTP-treated C57BL/6 mice, as demonstrated both by tyrosine hydroxylase (TH) immunohistochemistry and conventional histology (Cresyl violet staining) and an almost complete loss of DA fibers in striatum was also found. A detailed analysis of the effects of MPTP on endogenous catecholamine levels in various brain regions revealed that MPTP caused a severe reduction of endogenous DA in substantia nigra and striatum (35 and 5% of control) which was accompanied by an increase in the 3,4-dihydroxyphenylacetic acid (DOPAC)/DA ratio. There was also a decrease of DA in nucleus accumbens and the olfactory tubercle to 41 and 44% of control, respectively, without any significant change in the DOPAC/DA ratio and density of TH-positive fibers. Small but significant decreases of the noradrenaline (NA) levels in septum, entorhinal cortex and frontal cortex were seen, although the uptake of [3H]NA in frontal cortex was not significantly changed. Minor MPTP-induced decreases of the serotonin levels in frontal cortex, occipital cortex and spinal cord were also seen. The MPTP treatment also induced a 55% increase of adrenaline levels in hypothalamus, while no changes were seen in pons-medulla and spinal cord. Comparing this with 3 other strains of mice, the MPTP-induced reduction of endogenous DA in striatum was most pronounced in C57BL/6, less in N.M.R.I. and CBA/Ca mice, and least in Swiss-Webster. Concerning the effect of MPTP on cortical NA levels, the same relation was at hand except for C57BL/6, where, as mentioned, the effect was merely detectable. No reduction of DA perikarya in SNC was seen in Swiss-Webster mice. These findings show that in mice major differences exist in sensitivity of catecholamine neurons to MPTP between different strains. The data show that MPTP can produce an almost complete, permanent and relatively selective degeneration of the nigrostriatal DA neurons in C57BL/6 mice similar to that seen in primates. This strain may therefore serve as a useful model for studies on various aspects of MPTP-induced parkinsonism.