Protein adsorption onto poly(ether urethane ureas) containing Methacrol 2138F: a surface-active amphiphilic additive

Surface characterization and protein adsorption studies were carried out on a series of additive dispersed and additive coated poly(ether urethane ureas), PEUUs, to characterize early events in the blood compatibility of these materials. A hypothesis that is based on surface hydrophilicity, surface flexibility, and adsorption media has been developed to understand the modulated adsorption of plasma proteins by PEUU additives. Electron spectroscopy for chemical analysis (ESCA) and contact angle analysis were performed on two PEUU formulation as well as on PEUU formulations modified with Methacrol 2138F (co[diisopropylaminoethyl methacrylate (DIPAM)/decyl methacrylate (DM)][3/1]) or acrylate or methacrylate polymer or copolymer analogs of Methacrol 2138F. Methacrol 2138F is a commercially used amphiphilic copolymethacrylate. ESCA showed that the PEUUs loaded with Methacrol 2138F or with its hydrophilic component, homopoly (DIPAM) (h-(DIPAM)), had a higher percentage of nitrogen at their surfaces than did the base PEUUs. Contact angle analysis also showed that the air side of PEUU formulations loaded with Methacrol 2138F were more hydrophobic than was the air side of base PEUUs when films were cast from dimethylacetamide. However, during contact angle testing, the air side of PEUU films loaded with Methacrol 2138F rapidly became more hydrophilic than did the air side of the base PEUU films. A radioimmunoassay and whole or diluted human plasma were also used to characterize the presence of the proteins fibrinogen, immunoglobulin G, factor VIII/von Willebrand factor, Hageman factor (factor XII), and albumin, on the surface of the same PEUUs as analyzed by ESCA and contact angle. The protein adsorption assay showed that PEUU films loaded or coated with Methacrol 2138F, with a copolyacrylate analog of Methacrol 2138F (co(diisopropylaminoethyl acrylate [DIPAA]/decyl acrylate [DA]) [3/1]), or with the hydrophilic polyacrylate or polymethacrylate component analogs of Methacrol 2138F (h-DIPAM or h-DIPAA) adsorbed significantly lower amounts of the proteins than did either the base PEUU formulations or the homopoly(decyl methacrylate) (h-DM) or homopoly(decyl acrylate) (h-DA) coated or loaded PEUUs.     

Iron reserves in the female body and susceptibility to colds

Levels of temporary invalidity because of catching cold were analyzed in 101 working women over two years and these women's levels of serum iron, total iron-binding capacity of the serum, transferrin saturation with iron, serum ferritin, and red cell ferritin measured. Women with stable iron reserves in the body virtually have no sick leaves because of catching cold, whereas in those with iron deficiency susceptibility to catching cold is increased, and if iron metabolism intensity in the body grows, invalidity periods are much longer. Normalization of not only iron reserves in the body, but correction of iron metabolism as well should be regarded as a factor exerting a favorable effect on body resistance to catching cold.     

Sensitivity of B- and C-DNA forms to modifications by O-methylhydroxylamine

Effects of high concentrations of lithium, cesium and ammonium chlorides on the reaction ability of free CMP and cytosine in free DNA of CD phage with respect to O-methylhydroxylamine (OMHA) are studied. CMP reaction in all the cases takes place mainly for 24 hours. Like classical B-form, native DNA, having C-form in high ionic strength solution (as estimated from circular dichroism data), is not modificated. Thus, the access of some cytosine residues in intraphage DNA to OMHA is due not to the decreased DNA hydratation in situ, but to the presence of differently ordered regions in DNA.     

Study of the sensitivity of different strians of the influenza A2 virus of rimantadine

The sensitivity of different influenza A2 (H3N2) virus strains to rimantadine in ovo was studied. The reference strains of influenza virus A/Hong Kong/1/68, A/England/42/72, A/Scotland/840/74 as well as new epidemic strains isolated in the USSR and Mongolia in 1974-1975 antigenically related to influenza A/Port Chalmers/1/73 virus were found to be sensitive to rimantadine.     

Respiratory insufficiency in neuronopathic and neuropathic disorders

Twenty-nine patients with a neuronopathic or neuropathic disorder were referred for assessment of respiratory insufficiency between 1978 and 1994. Diagnoses included spinal muscular atrophy (6), chronic idiopathic demyelinating neuropathy (4), Vialetto-van Laere syndrome (3), hereditary motor and sensory neuropathy (3) and a miscellaneous group (5). We also describe seven patients with Guillain-Barré syndrome (GBS) who required long-term ventilatory support for over 6 months to 7 years after the initial illness. Respiratory insufficiency occurred as a consequence of respiratory muscle weakness, impaired bulbar function and restrictive lung defects. In some groups presentation was with progressive nocturnal hypoventilation culminating in acute respiratory failure. Five patients with GBS or chronic idiopathic demyelinating neuropathy were weaned from ventilatory support up to 18 months after the initial illness. The remaining 24 patients required continuous or nocturnal ventilatory support using intermittent positive-pressure ventilation (13), negative pressure ventilation (4), nasal-mask-delivered intermittent positive-pressure ventilation (4), nasal-mask-delivered continuous positive-pressure ventilation (3), mouthpiece-assisted ventilation by day (2) and rocking bed (1). None have been weaned from support after a period of ventilation ranging from one month to 10 years. Eight patients have subsequently died.