Some aspects of structural disturbances in the DNP complex when damaged by N-nitroso-N-methylurea

The effect of solubilization of deoxyribonucleoproteins (DNP) in a medium of near-physiological ionic strength after treatment with the mutagen N-nitroso-N-methylurea (NMU) is highly dependent on the NMU concentration. To convert DNP into a soluble state, the critical number of groups in the DNA and protein must evidently be modified. On the basis of data obtained by the circular dichroism method and by viscosimetry it is concluded that after treatment with NMU the DNP complex becomes soluble in solvents with near-physiological ionic strength largely as a result of labilization and dissociation of the DNA-protein bonds.Laboratory of Biophysics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR. Sector of Kinetics of Chemical and Biological Processes, Institute of Chemical Physics, Academy of Sciences of the USSR. Laboratory of Physical Methods of Investigation, D. I. Ivanovskii Institute of Virology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. S Debov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 6, pp. 674–677, June, 1976.     

Technical aspects of gaseous formaldehyde as a sterilant

The design of a sterilizer for sterilization of heat sensitive items using gaseous formaldehyde and steam is described. The sterilizer is able to create a constant formaldehyde-steam concentration over a period of at least one hour. It is further able to operate at formaldehyde concentrations close to saturation with only small residues on sterilized plastic materials. The autoclave is used for measurement of formaldehyde solubility in polyolefines and poly(vinyl chloride) being approx. 15 and 250 ppm, respectively, at 70 degrees C and 30 mg HCHO I-1. The diffusion coefficient of formaldehyde in poly(vinyl chloride) is measured and is in the same order of magnitude as for ethylene oxide in poly(methyl methacrylate) i.e. 10(-10) cm2 s-1. Measurements of airborne formaldehyde in front of different sterilizers show that it is possible to design facilities meeting occupational exposure limits.     

Some aspects of occupational asthma

The behaviour of forty-four patients, taken from a group of 133 cases of extrinsic pulmonary granulomatoses (EPG), who before developing the disease had no history of atopy and after being affected presented asthma-like symptoms, is analysed. Some of these patients had simultaneously clinical signs of rhinitis which proved to be due to lesions identical to those found in the bronchial mucosa. From the presented results, the author concludes that the clinical manifestations of these patients are not of the classical allergic type but bronchial and nasal reactions of the EPG in which, at least, a type III hypersensitivity reaction is involved. This is supported by the results of bronchial provocation tests performed on twenty-three patients with suberosis.     

Influence of nonideal flow conditions in haemodialysers on mass-transfer theories

The flow conditions in some commonly used haemodialysers have been investigated. For the blood compartment, it is found that considerable differences in height occur. This improves the mass transfer in a coil dialyser, but has a negative effect on the mass-transfer process in plate dialysers. In some designs, an effective mixing of the dialysate has been obtained, leading to a reduced mass-transfer resistance.     

Investigation of the free formaldehyde content when poliomyelitis virus is inactivated with formalin

Summary The quantitative diffusion method of determihation of free formaldehyde has established that, inactivating poliomyelitis virus by Salk's method, the average free formaldehyde level at the end of the process was 0.08 g/l.Formaldehyde in the virus fluid is combined mainly with amino acids passing into the fluid from the 199 medium. The free formaldehyde concentration is an easily controlled condition of inactivation.This is confirmed by the stability of the chemical indices, the level of total nitrogen and amino nitrogen, reflecting the level of the substances interacting with formaldehyde in the virus fluid.Presented by Active Member AMN SSSR A. E. Braunshtein     

Some aspects of thermoregulation during pregnancy

Summary The peculiarities of thermoregulation were studied at various periods of pregnancy (on the 4th, 12th and 21st days) in administration of aminazine (chlorpromazine) and the action of low environmental temperature. The results of experiments demonstrated that the sensitivity of rats to low temperature and to the administration of aminazine (0.55 mg per 100 gms of body weight) is changed in the opposit direction at the end of pregnancy, i. e. it is increased under the effect of low temperature and decreased as a result of administration of aminazine. In simultaneous action of aminazine and low environmental temperature there is almost no difference in the effect produced by these agents on the gravid and nongravid animals.Presented by Active Member Acad. Med. Sci. USSR, A. I. Serebrov     

Some aspects of neuroendocrine pathology.

The advent of modern microscopical investigative methods for the determination of neuroendocrine differentiation has increasingly given credence to the original concept of a "diffuse endocrine system". These methods include a variety of silver impregnation techniques, technologically advanced light and electron microscopical immunocytochemistry, and, lately, the ability to localise specific binding sites by in vitro autoradiography and mRNA species by in situ hybridisation. Further insight has been gained into the possible role of regulatory peptides contained in the so called "diffuse endocrine system" and into the nature of disease processes by investigating the role of the system in benign and malignant disease.