Recombinant human erythropoietin increases blood pressure, platelet aggregability and platelet free calcium mobilisation in uraemic children: a possible link?

Recombinant human erythropoietin was administered to 10 uraemic children on chronic haemodialysis, all of whom responded by correcting their haemoglobin. In addition, they showed an increase in blood pressure; platelet aggregations, subnormal before therapy, improved during treatment. The intracellular free calcium concentration in platelets after thrombin stimulation also increased significantly during erythropoietin administration. We hypothesize that the effect of erythropoietin on platelet aggregability and on blood pressure may be due to an increase in the intracellular free calcium mobilisation in platelets and possibly in smooth muscle cells respectively.     

Absence of detectable immunoreactive alpha melanocyte stimulating hormone in plasma in various types of Cushing's disease.

We have measured alpha-MSH in plasma of normal subjects and subjects with various diseases of the pituitary-adrenocortical system using a radioimmunoassay with a sensitivity of 1.2 pmol/l. No alpha-MSH could be detected in plasma of normal subjects (n = 6), in plasma of patients with Addison's disease (n = 3), Nelson's syndrome (n = 2), bromocriptine responsive (n = 2) and unresponsive (n = 5) Cushing's disease and in plasma of psychiatric patients on chronic treatment with the dopamine antagonist haloperidol (n = 5). Plasma alpha-MSH remained undetectable in 2 patients with Cushing's disease after iv injection of 60 micrograms/kg haloperidol. In contrast, alpha-MSH was detectable in plasma of normal dogs (n = 2) and dogs with pituitary dependent hyperadrenocorticism (n = 2), whereas the iv injection of halo peridol was associated with a rise of plasma alpha-MSH. Thus we are unable to detect circulating alpha-MSH in man despite the use of a sensitive radioimmunoassay.     

In-situ photopolymerization of oriented liquid-crystalline acrylates, 3. Oriented polymer networks from a mesogenic diacrylate

Synthesis, mesomorphism, orientation and photo-initiated chain crosslinking of the liquid-crystalline diacrylate 1,4-phenylene bis{4-[6-(acryloyloxy)hexyloxy]benzoate} ( 1 ) are studied. Monomer 1 exhibits a broad nematic phase between 108 and 155°C and a monotropic smectic phase below 88°C. The monomer is uniaxially oriented in its nematic phase at a substrate which has been coated with polyimide and unidirectionally rubbed with tissue. At the transition temperature to the smectic phase the order parameter is measured to be 0,7. During polymerization, the ordering of the mesogens is frozen-in, yielding a uniaxially crosslinked network. The clear films of oriented poly( 1 ) exhibit a birefringence Δn between 0,12 and 0,15, depending on the polymerization temperature. In the highest oriented state of 1 a small reduction of the degree of order is observed during the crosslinking reaction, whereas at higher temperatures and lower ordering of 1 , the uniaxially orientation increases upon reaction. A special feature of the oriented networks is that the ordering is maintained while heating at high temperatures. The polymerization of the acrylate groups in the mesomorphic phases proceeds fast and to high conversion. Below 90°C the polymerization behaviour is similar to that of conventional isotropic diacrylates. Above 90°C the polymerization reaction of the liquid-crystalline diacrylate proceeds faster than that of an isotropic diacrylate.     

Hospital-related outbreak of infection with multidrug-resistant Streptococcus pneumoniae in the Netherlands.

Multidrug-resistant strains of Streptococcus pneumoniae were isolated over a two-year period (July 1995 until August 1997) from the sputum of 36 patients who were hospitalized in a Dutch medical centre. Nosocomial transmission was confirmed by typing of the bacterial isolates: all 36 multidrug-resistant isolates shared the same genotype, serotype, and displayed overlapping drug resistance profiles. Thirty-two of the 36 (89%) patients had chronic obstructive pulmonary disease (COPD). The outbreak was initiated by a 76-year old patient, who had been colonized with the same strain since 1993. Because staff screening of the hospital and pulmonary function department was negative, patient-to-patient spread was the most likely cause of this outbreak. The epidemic ceased following the commencement of barrier nursing, a treatment course of ceftriaxone, and a five-day rifampicin eradication therapy for the positive patients. The outbreak resulted from failure to recognize quickly the rapid transmission of this multidrug-resistant pneumococcal clone. We conclude that patients with COPD are at high risk of acquiring multidrug resistant pneumococci, and suggest that COPD patients who are colonized or infected with multidrug-resistant pneumococci should be isolated to prevent future transmission.     

Synthesis of 4-Azido-N-[2-(diethylmethylammonium)ethyl]benzamide Iodide: A Photolabile Derivative of Procainamidethobromide

In order to identify polypeptides interacting with organic cations like PAEB the photolabile derivative 4-azido-N-[2-diethyl([³H]methyl)ethyl]benzamide iodide with a specific radioactivity of 4.3 Ci/mmol was synthesized. Photolysis of this derivative using a Rayonet RPR 100 reactor with a maximum emission at 300 nm obeyed first order kinetics with t_1/2 = 13.5 min. The photochemical properties of this azido-derivative of PAEB indicate that it may be well suited for the identification of binding polypeptides by photoaffinity labeling studies.     

In-situ photopolymerization of oriented liquid-crystalline acrylates, 5.. Influence of the alkylene spacer on the properties of the mesogenic monomers and the formation and properties of oriented polymer networks

The photoinitiated bulk polymerization of macroscopically oriented 1,4-phenylene bis{4-(ω-acryloyloxyalkyloxy)benzoate} produces densely crosslinked oriented polymer networks. The influence of the length of the alkylene spacer between the aromatic central core and the polymerizable acrylate end-groups on the mesomorphic behaviour of the monomer, the molecular orientation in the monomeric and polymeric state and the process of photoinitiated polymerization in the ordered state is studied. Some optical properties of the oriented networks are presented.     

In situ photopolymerization of an oriented liquid-crystalline acrylate, 2

During the photo-initiated free-radical bulk polymerization of 4-biphenylyl 4-(6-acryloyloxy-hexyloxy)benzoate ( 1 ) in the liquid-crystalline state, the ordering is maintained, leading to an oriented liquid-crystalline side-chain polymer. The course of the photopolymerization depends on the phase of monomer 1 . In the monotropic smetic-A and in the monotropic nematic phase the polymerization rate and conversion are affected by crystallization during polymerization. In the stable nematic phase the bulk polymerization is fast and complete. In this temperature region the transition from nematic 1 to smectic poly( 1 ) is passed during which temporary segregation may occur, affecting the molecular ordering. Starting with isotropic 1 , the polymerization proceeds considerably more slowly.