Serum levels of intercellular adhesion molecule-1 in squamous cell carcinoma of the head and neck

Soluble intercellular adhesion molecule-1 (s-ICAM-1) was measured in the sera of 131 patients with primary and 50 patients with recurrent squamous cell cancer of the head and neck (HNSCC). 30 patients with benign ear, nose and throat diseases served as controls. s-ICAM-1 levels in serum are high in patients with HNSCC, particularly in the advanced tumor stages (UICC IV). Highest levels can be measured at the time of tumor recurrence and locoregional lymph node metastases. The sensitivity (95% specificity) of s-ICAM-1 (cutoff-level: 473 ng/ml) is 4% at primary diagnosis and 12% for recurrent disease. A coefficient of correlation for s-ICAM-1 in combination with SCC, carcinoembryonic antigen and CYFRA 21-1 indicates that no correlation can be found of s-ICAM-1 compared with traditional tumor markers. Due to overlapping values in control and patient groups s-ICAM-1 is not suitable for a specific clinical use in HNSCC.

[Arteriovenous fistula with cardiac insufficiency disclosing kidney cancer]

A 66 year-old woman free of any coronary and valvular heart disease presented to our hospital with acute and severe congestive heart failure associated with increased blood flow-angiography showed an intraparenchymatous arteriovenous fistula of the left kidney and a kidney cancer. The patient was discharged after nephrectomy and complete heart recovery as assessed from the normality of the hemodynamic exploration of the right ventricle.

Size effects in Kauffman type evolution for rugged fitness landscapes

Millions of sites are simulated in an NK fitness model of evolution and coevolution. We find a logarithmic size dependence of the number of hill-climbing iterations needed to reach a local fitness optimum (Nash equilibrium). We also check for chaotic behavior and determine the size of the damage clouds or avalanches. Random noise (simulated annealing) is shown to increase appreciably the fitness.

Dynamic light-scattering studies on the effect of heat and disinfectants on spores of Bacillus cereus

The relative stability of spores of Bacillus cereus grown at three different temperatures was examined by using quasi-elastic light scattering (q.l.s.) in conjunction with turbidity and scanning electron microscopy (s.e.m.). Cultures grown at 20, 30 and 40 degrees C (BC20, BC30 and BC40 respectively) were compared in terms of (i) their effective hydrodynamic radius, rH, as determined from q.l.s. and (ii) their gross morphology, as determined from s.e.m. The effects of autoclaving at 121.1 degrees C on both these properties was also examined. We observed (1) that cultures BC20 and BC30 appeared to have similar values for rH, whereas that of BC40 appeared some 50% higher, and (2) BC40 had a correspondingly much lower heat resistance (its structural integrity was lost after about 20 min autoclaving, whereas that of BC20 and BC30 was retained even after 80 min autoclaving). These data were in good agreement with independent measurements of heat-resistance coefficients. Changes in the hydrodynamic radius, polydispersity (both using q.l.s.) and turbidity were monitored with time on addition of the disinfectants sodium hypochlorite and peracetic acid; again BC40 appeared to have a lower resistance.

On computer simulation methods used to study models of two-component lipid bilayers

We show that the use of a computer simulation method introduced to calculate the equilibrium thermodynamic properties of a model of a two-component lipid bilayer membrane [Freire, E., & Snyder, B. (1980) Biochemistry 19, 88-94] is incorrect. This is done by comparing the method to that of Metropolis, which has been proven to generate equilibrium distribution of that model, and by showing that back-processes have been omitted in the implicit master equation of Freire and Snyder. We have illustrated this explicitly by first generating distributions according to the method of Freire and Snyder and then allowing the system to relax via the Kawasaki method, which uses the technique of Metropolis. We show that relaxation to a different distribution occurs. We also remark that the cluster distributions generated by the Freire-Snyder method are substantially different from those occurring in equilibrium distributions. Thus, conclusions about equilibrium thermodynamic properties such as specific heats and transition enthalpies or about transport properties or cluster properties at equilibrium cannot be drawn from the results obtained by using this method. Finally, we point out that the method of Freire and Snyder is appropriate to so-called aggregation models, which have been used to study irreversible growth; and we suggest biological systems that might be simulated by their method.

Lateral diffusion of gramicidin S, M-13 coat protein and glycophorin in bilayers of saturated phospholipids. Mean field and Monte Carlo studies

We have developed a general model that relates the lateral diffusion coefficient of one isolated large intrinsic molecule (mol. wt. greater than or approximately 1000) in a phosphatidylcholine bilayer to the static lipid hydrocarbon chain order. We have studied how protein lateral diffusion can depend upon protein-lipid interactions but have not investigated possible non-specific contributions from gel-state lattice defects. The model has been used in Monte Carlo simulations or in mean-field approximations to study the lateral diffusion coefficients of Gramicidin S, the M-13 coat protein and glycophorin in dimyristoyl- and dipalmitoylphosphatidylcholine (DMPC and DPPC) bilayers as functions of temperature. Our calculated lateral diffusion coefficients for Gramicidin S and the M-13 coat protein are in good agreement with what has been observed and suggest that Gramicidin S is in a dimeric form in DMPC bilayers. In the case of glycophorin we find that the 'ice breaker' effect can be understood as a consequence of perturbation of the lipid polar region around the protein. In order to understand this effect is necessary that the protein hydrophilic section perturb the polar regions of at least approx. 24 lipid molecules, in good agreement with the numbers of 29-30 measured using 31P-NMR. Because of lipid-lipid interactions this effect extends itself out to four or five lipid layers away from the protein so that the hydrocarbon chains of between approx. 74 and approx. 108 lipid molecules are more disordered in the gel phase, so contributing less to the transition enthalpy, in agreement with the numbers of 80-100 deduced from differential scanning calorimetry (DSC). An understanding of the abrupt change in the diffusion coefficient at a temperature below the main bilayer transition temperature requires an additional mechanism. We propose that this change may be a consequence of a 'coupling-uncoupling' transition involving the protein hydrophilic section and the lipid polar regions, which may be triggered by the lipid bilayer pretransition. Our calculation of the average number of gauche bonds per lipid chain as a function of temperature and distance away from an isolated polypeptide or integral protein shows the extent of statically disordered lipid around such molecules. The range of this disorder depends upon temperature, particularly near the main transition.