[Sustained ventricular tachycardia in a patient with a single ventricle of the heart and a pheochromocytoma].

A pheochromocytoma is a rare tumor that develops from adrenomedullary chromaffin cells and produce ones or more catecholamines, including adrenaline, norepinephrine, and dopamine. On rare occasions a pheochromocytoma is hormonally inactive. Cyanotic heart disease is also a relatively rare pathology. One of its least frequently occurring variants is the single ventricle of the heart. Presumably, in patients with cyanotic heart defects, the occurrence of pheochromocytes and paragangliomas will be higher due to the presence of certain germinative and somatic mutations. In cyanotic heart defects, the development of malignant arrythmias is one of the frequent causes of death. A combination of a pheochromocytoma with a single ventricle of the heart is extremely rare: only eight such cases have been described in the literature. This article describes a young patient with a unique case of a single ventricle of the heart, pheochromocytoma and sustained ventricular tachycardia. The cause of the ventricular tachycardia, in all likelihood, was inappropriate medical care - in this case, a prescription for verapamil. The surgical excision of the pheochromocytoma and the referral of the patient for cardiac surgery became possible only after correcting the antihypertensive and antiarrhythmic therapy. Verapamil was replaced with a combination of doxazosin and amiodarone, resulting in relatively satisfactory blood pressure readings and sinus rhythm.

[TYPE 1 MULTIPLE ENDOCRINE NEOPLASIA SYNDROME AND FAMILIAL ISOLATED HYPERPARATHYROIDISM].

Type 1 multiple endocrine neoplasia syndrome (MEN-1) is a rare autosomal dominant disorder caused by mutation in the MEN-1 gene and manifest as a combination of tumours of parathyroid glands, endocrine pancreas, and adenohypophysis. Familial isolated hyperparathyroidism (FIHP) is another rare autosomal dominant disorder characterized by the development ofparathyroid tumours as the sole endocrinopathy within a single family. The notion of FIHP encompasses different hereditary forms of primary hyperparathyroidism, such as a variant of MEN-1 syndrome. This paper is a brief literature review of the problems related to primary hyperparathyroidism, MEN-1, and FIHP. Also, It describes a family presenting with genetically confirmed MEN-1 syndrome, manifest as primary hyperparathyroidism.

Origin of visible photoluminescence from arrays of vertically arranged Si-nanopillars decorated with Si-nanocrystals.

Arrays of vertically aligned Si-nanopillars, with average diameters of 100 nm and 5 µm length, have been prepared by wet chemical etching of crystalline silicon in a special manner. Samples with smooth- and porous-walled nanopillars have been studied. In the case of the latter, Si-nanocrystals, passivated with SiO(x), decorating the surface of the nanopillars are identified by the means of TEM and FTIR. When excited by UV-blue light, the porous-walled Si-nanopillars are found to have a strong broad visible emission band around 1.8 eV with a nearly perfect Gaussian shape, µs luminescence lifetimes, minor emission polarization and a non-monotonic temperature dependence of luminescence. The Si-nanocrystal surface is found to be responsible for the luminescence. The red-shift of the emission maximum and the luminescence quenching induced by oxidation in UV-ozone confirm this assumption. A model of luminescence involving UV photon absorption by Si-nanocrystals with subsequent exciton radiative recombination on defect sites in SiO(x) covering Si-nanocrystals has been proposed. Possible applications of the nanopillar arrays are discussed.

Measurements of neutron fluxes with energies from thermal to several MeV in near-Earth space: SINP results.

Neutron measurement results obtained at SINP MSU since 1970 are presented. These measurements were made using techniques based on neutron moderation and subsequent detection in a Li6I(Eu) crystal or a He3 coronal counter. The measurements were mainly carried out in orbits with inclination of 52 degrees and altitudes of 200-450 km. The spatial and angular distributions of the measured neutron fluxes were studied. The albedo neutron flux was estimated according to the count rate difference for opposite detector orientations towards Earth and away from it. This flux is comparable to the local neutron flux outside the Brazil anomaly region, where local neutrons dominate. Neutron fluxes, generated by solar protons, were detected during a solar flare on June 6, 1991 for the first time. Their spectrum was estimated as a power law with alpha>2.

Specific features of electron distributions at altitudes of 400 km.

New experimental data obtained on the orbital station 'MIR' in 1991 during solar maximum are discussed. Electron fluxes with Ee>75 keV were registered for three different directions as well as for electrons with Ee>300 and 600 keV. Spatial and time distributions of electron fluxes in the trapping region are presented. In the inner radiation belt an additional maximum is observed at L=1.25-1.35, and the fluxes in the 22-05h MLT interval are 2-3 orders of magnitude smaller, than during other local times. In this region a flattening of the electron spectrum is observed. The results obtained were compared with the AE-8 model.

[Investigation of the microstructure of biological systems by triplet label]. / Issledovanie mikrostruktury biologicheskikh sistem metodom tripletkh metok.

A method for investigating the microstruct and dynamics of biological systems by means of triplet-excited molecules is suggested. The method is based on the phenomenon of triplet excitation disactivation by exchange-resonance triplet-triplet energy transfer to the acceptor or by intercombination conversion induced by interaction of an excited molecule with a paramagnetic center. The disactivation efficiency was measured by registrating the phosphorescense decay kinetics. The interaction of the triplet label eosin isothiocyanate, covalently coupled with albumine, lysozyme, sarcoplasmic reticulum membrane and Ca-Mg-dependent sarcoplasmic reticulum ATPase, with O2, the stable nitroxide radicals and ions of Mn2+ was investigated to analyse the potentialities of this method. As a model system the eosin phosphorescence quenching by the same quenchers in glycerine-aguaous solutions was studied. The method permits to investigate the microviscosity and microstructure of biological objects in the label attached region on interaction of the label with a sound-quencher with constants being 10(4) divided by 10(9) M-1 sec-1 and to measure the lateral diffusion of molecules in highly viscosity media (10 divided by 10(5) santypuas).