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Biomedical subjects

N V Ramkova

Publications and source records attributed to N V Ramkova.

At least 19 recordsLinked to original sources
PubMed1989

[The use of thermal analysis in developing chemical tests of sterilization].

A number of chemicals have been examined to find out whether they can be employed to test the temperature regimens of vapor and hot-air sterilization methods. Test kits for various temperature ranges and different sterilization modes have been selected. It is advisable that stains be used in tests (except the sulfur one) to control vapor (but not hot-air) sterilization.

Hot Temperature↗
PubMed1977

Resistance of stratospheric and mesospheric micro-organisms to extreme factors.

Studies of the stratosphere and mesosphere, by means of special analysers installed on meteorological rockets, have thrown more light on our knowledge of the upper boundary of the biosphere. The presence of the following micro-organisms was registered at heights of 49-77 km: Aspergillus niger, Penicillium notatum, Circinella muscae, Papulaspora anomala, Mycobacterium luteum and Micrococcus albus. The isolated micro-organisms were subjected to the action of gamma-irradiation, high vacuum and UV radiation in order to evaluate the quality of sterilization by gamma-rays (3.2-3.5 Mrad) prior to sampling and the resistance of these micro-organisms to physical factors of the stratosphere and mesosphere. No species with high radio-resistance were detected among the isolated cultures. The D10 index for fungal spores and bacterial vegetative cells, freeze-dried or suspended in a physiological solution, did not exceed 290 krad. These data confirm that sterilization of the analyser with gamma-rays assured the purity of biological experiments during sampling. The isolated micro-organisms were found to be very resistant to high vacuum (10(-9) mmHg) and UV radiation, with the exception of the pigmentless Micrococcus albus. This evidence shows that pigmented micro-organisms can survive in the earth's atmosphere at high altitudes.

Air Microbiology↗
PubMed1976

Effect of extreme factors on micro-organisms used for the control of the effectiveness of sterilization.

Survival of micro-organisms used for control of sterilization procedures was studied under conditions simulating the Martian environment (daily temperature change from +20 degrees to -20 degrees in 99.98% CO2 + 0.02% air at 0.13 x 10(-6) N m-2 pressure, with ultraviolet radiation spanning the whole range of the solar spectrum 300-350 MkW cm-2). The test organisms were four strains of Bacillus subtilis and one strain of Bacillus anthracoides, and were inoculated on to four materials, smooth metal, porous plastic, multilayer composition material and powdered limonite. Some organisms survived on all materials, the greatest on the limonite. The resistance of the survivors to disinfectants was the same as that of the original cultures.

Bacillus↗
PubMed1976

On micro-organisms of the stratosphere.

The lower parts of the biosphere are well studied since various live beings are found in oceans and at the bottom of large hollows. Contrary to this, we have no data about the upper boundaries of the biosphere. Samples were obtained with the help of specially constructed analysers which were installed in meteorological rockets and reached an altitude of 100 km. With the help of methods completely excluding the possibility of contamination of analysers with outside microflora it became possible to prove that earth microbes carried by air currents are present in the stratosphere. At an altitude of 48-77 km Circinella muscae, Asp. niger, Penicillium notatum were found as well as mycobacterium and micrococcus. The correlation of these cultures with external factors is studied and the weight of one conidium or one cell in isolated micro-organisms is estimated. These investigations will continue.

Air Microbiology↗
PubMed1971

Bacterial contamination of confined, sealed space during long-term human occupation.

The long-term presence of human beings in a closed room of small volume is accompanied by the accumulation of a common and hemolytic microflora on their bodies, clothes, in the air, and on the room surfaces. A study was made of the dynamics of the spreading of such microflora in rooms measuring from 5-21 m3 when occupied by 1-3 persons for 5-30 days. With minimal sanitation the skin, after 30-40 days, is covered with several thousands of microbes per cm2, of which the hemolytic staphylococci amount to about 500 cells per cm2. Linen contained tens of thousands of bacteria per cm2, including up to 7000 hemolytic staphylococci per cm2. Generally, air contamination increases during the experiment. The rate of increase depends on many factors, and includes, in addition to common microbes, hemolytic staphylococci, streptococci, including pathogenic ones. The distribution of microbes in the air depends on human activity, and the total number is lowered by improved sanitation. While initial surface contamination depends on preliminary disinfection, there is a steady accumulation of micro-organisms on the chamber surfaces. No Escherichia coli could be found on chamber surfaces. Most bacteria were found on horizontal surfaces, working areas and floors (thousands of microbes per cm2), while ceilings and walls yielded from units to hundreds of cells per cm2.

Air Conditioning↗