Morphogenetic adaptation of the looping embryonic heart to altered mechanical loads.

The biophysical mechanisms that drive and regulate cardiac looping are not well understood, but mechanical forces likely play a central role. Previous studies have shown that cardiac torsion, which defines left-right directionality, is caused largely by forces exerted on the heart tube by a membrane called the splanchnopleure (SPL). Here we show that, when the SPL is removed from the embryonic chick heart, torsion is initially suppressed. Several hours later, however, normal torsion is restored. This delayed torsion coincides with increased myocardial stiffness, especially on the right side of the heart. Exposure to the myosin inhibitor Y-27632 suppressed both responses, suggesting that the delayed torsion is caused by an abnormal cytoskeletal contraction. This hypothesis is supported further by computational modeling. These results suggest that the looping embryonic heart has the ability to adapt to changes in the mechanical environment, which may play a regulatory role during morphogenesis.     

Alterations in cholinergic and non-cholinergic neurotransmitter receptor densities in transgenic Tg2576 mouse brain with beta-amyloid plaque pathology.

Cholinergic deficits in Alzheimer's disease are accompanied by a number of alterations in other transmitter systems including glutamate, noradrenaline and serotonin, suggesting the involvement also of other neurotransmitter systems in the pathogenesis of the disease. To address the question whether beta-amyloid may contribute to these deficits, brain tissue from transgenic Tg2576 mice with Alzheimer plaque pathology at ages of 5 (still no significant plaque load) and 17 months (moderate to high cortical beta-amyloid plaque load) were examined for a number of cholinergic and non-cholinergic markers. Transgenic mice with no significant plaque load demonstrated reduced hemicholinium-3 (HCh-3) binding to choline uptake sites in anterior brain regions as compared to non-transgenic littermates, while in aged transgenic mice with high number of plaque deposits decreased HCh-3 binding levels were accompanied by increased vesicular acetylcholine transporter binding in selected cortical brain regions. In aged transgenic mice GABA(A), NMDA, AMPA, kainate, and beta-adrenergic as well 5-HT(1A)- and 5-HT(2A)-receptor binding levels were hardly affected, whereas alpha(1)- and alpha(2)-adrenoceptor binding was increased in selected cerebral cortical regions as compared to non-transgenic littermates. The development of changes in both cholinergic and non-cholinergic markers in transgenic Tg2576 mouse brain already before the onset of progressive plaque deposition provides in vivo evidence of a modulatory role of soluble beta-amyloid on cortical neurotransmission and may be referred to the deficits in learning and memory observed in these mice also before significant plaque load.     

Antifungal potential of disulfiram.

Disulfiram, an alcohol antagonistic drug has been on the market since 1949 with 80% bioavailability and an established safety profile. Recently it has been reported as a P-glycoprotein efflux pump modulator. Herein we report its antifungal potential. The MIC50 and MIC90 of disulfiram for yeast isolates is 4 and 8 microg/ml, respectively, and the MIC range is 1-16 micro g/ml for both fluconazole sensitive and resistant strains. Interestingly, disulfiram also showed fungicidal activity on Aspergillus spp. with MIC50 and MIC90 of 2 and 8 microg/ml, respectively.     

Der chirurgische Part im Rahmen multimodaler Therapiekonzepte in der Onkologie-Schilddrüse

29. Tagung der ?sterreichischen Gesellschaft für Chirurgie und Ihrer Assoziierten Fachgesellschaften Innsbruck, 2. bis 4. Juni 1988 Herausgeber: E. Bodner und G. Szinicz Abstracts

Der chirurgische Part im Rahmen multimodaler Therapiekonzepte in der Onkologie-Schilddrüse     

Inverse trend between estimated worldwide frequency of major cancers and inferred infectious burdens of populations: possible role of adaptive immune system

Regions of the world subjected to heavy infectious burdens seem to show lower incidence of cancer. The index of infectious burden in this study has been chosen to be poverty, i.e., low GDP, high infantile mortality, poor hygienic conditions, inaccessibility to modern medical infra-structures, etc. When estimates of observed cancer incidence is plotted against the GDP of 24 regions of the world, a trend line is obtained: low GDP (a proxy for high infectious burden) tends to be associated with low incidence of cancer whereas high GDP values herald higher cancer occurrences. Similarly, countries with high infantile mortality rates tend to have a lower incidence of cancer and vice versa. The data are explained in terms of the so-called "hygiene hypothesis": frequent infectious onslaughts, especially in childhood, challenge the immune system and build a strong adaptive immune system and immunological memory which prepare the body to tackle further battles down the line, such as cancer. Within this framework, the role of other factors such as diet, selenium, hardness of water, etc. in the aetiology of cancer is also briefly examined. For rigorous verification of this observation, age-adjusted cancer incidence rates for various countries must be used even though such data are not available for all the countries examined here [Bulletin of World Health Organization 62(2) (1984) 163]; where data are available [Age-adjusted death rates for cancer for selected sites (A classification) in 51 countries in 1974, Segi Institute of Cancer Epidemiology, Nagoya, Japan (Feb. 1979); Global Geocancerology, Churchill Livingstone, New York, 1986], the same trend is also observed for the age-adjusted cancer death rates, which may be used as an index of age-adjusted cancer incidence, subject to qualifications discussed in the text.     

Enhanced molecular volume of conservatively pegylated Hb: (SP-PEG5K)6-HbA is non-hypertensive

Recent studies have suggested that the "pressor effect" of acellular Hb is a consequence of perturbation of the macro-and microcirculatory system in multiple ways, and that PEGylation is an effective approach for controlling the same. In an attempt to confirm this concept, a new and simple thiolation mediated, maleimide chemistry-based conservative PEGylation protocol has been developed to conjugate multiple copies of PEG-chains to Hb. This approach combines the high reactivity of maleimides towards thiols with the propensity of iminothiolane to derivatize the epsilon-amino groups of proteins into reactive thiol groups, with conservation of their positive charge. One of the PEGylated products, namely (SP-PEG5K)6-HbA, that carries on an average six copies of PEG5000 chains per Hb, is non-hypertensive in hamster top load and in rat 50% exchange transfusion models. This hexa-PEGylated-Hb has (i) a hydrodynamic volume corresponding to that of an oligomerized Hb of 256kDa, (ii) a molecular radius of approximately 6.8 nm, (iii) high oxygen affinity, (iv) lowered Bohr effect, and (v) increased viscosity and colloidal osmotic pressure. These properties of (SP-PEG5K)6-HbA are consistent with the emerging new paradigms for the design of Hb based oxygen carriers and confirm the concept that the "pressor effect" of Hb is a multifactorial event. The thiolation mediated maleimide chemistry-based PEGylation protocol described here for the generation of (SP-PEG5K)6-Hb is simple, highly efficient, and is carried out under oxy conditions. The results demonstrate that a non-hypertensive PEG-Hb can be generated by conjugation of a lower number of PEG chains than previously reported.     

Affinity fractionation of lymphocytes using a monolithic cryogel

A new type of continuous, supermacroporous, monolithic, cryogel affinity adsorbent was developed, allowing specific fractionation and separation of human peripheral blood lymphocytes in a chromatographic format. The affinity adsorbent was used to design a novel cell separation strategy, which was based on the interaction of protein A from Staphylococcus aureus with cells bearing IgG antibodies on the surface. After treating lymphocytes with goat anti-human IgG(H+L), the IgG-positive B-lymphocytes were efficiently separated from T-lymphocytes. Protein A covalently coupled to epoxy activated dimethylacrylamide (DMAA) cryogel matrix specifically bound IgG-bearing B-lymphocytes through the Fc region, while non-bound T-lymphocytes passed through the column. More than 90% of the B-lymphocytes were retained in the column while the cells in the breakthrough fraction were enriched in T-lymphocytes (81%). The viability of the T-lymphocytes isolated was greater than 90%. The bound lymphocytes released by human or dog IgG recovered 60-70% of the B-cells without significantly impairing the cell viability. The technique can be applied in general to cell separation systems where IgG antibodies against specific cell surface markers are available.