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Biomedical subjects

V Mĕrka

Publications and source records attributed to V Mĕrka.

At least 19 recordsLinked to original sources
PubMed1989

Prevention of infectious complications in immunocompromised patients. Part II: Selective decontamination.

The method of selective decontamination of the gastrointestinal tract represents a new possibility of protection of immunocompromised patients against infectious complications with frequent lethal issue. The method is based on employment of such antibiotics and chemotherapeutical drugs that eliminate the aerobic gram-negative microflora and yeasts preserving the anaerobic portion of the bowel microflora that is responsible for the so-called colonization resistance of the intestinal tract. Such a treatment provides patients with more resistance against infection and there is no need for strict reverse isolation. The theoretical exposition of the SD mechanism is given along with instruction on how to use this method and summarizing the hitherto clinical results of its employment. The authors' proper more than 6 year experience is compared with the world literature, and the SD method is stated to be a valuable import in preventing infections in hematological patients. Some unresolved problems and future prospects are also discussed.

Animals↗
PubMed1987

Performic acid toxicity studies on stabilized HEp-2 cells.

Since performic acid is used as a potent disinfectant, chemical sterilant and/or skin antiseptics, information related to its toxicity for living tissues was needed to evaluate the degree of its biotolerance and compare it to that of peracetic acid. In tests on cultured HEp-2 cells distinct cytotoxic effects occurred after treatments with 0.05% and higher concentrations. The 0.005% to 0.000,05% concentrations had only minor effects on the morphology of cells, if passaged they were capable of further growth, but were clearly inhibited in their growth ability. The lowest concentration tested (0.000005%) had no appreciable effect on HEp-2 cells. At the same concentration levels, the cells were affected to a greater degree with performic acid than with peracetic acid treatment. The use of cell cultures as a tool to study in vitro toxicity of various materials is discussed.

Cell Division↗
PubMed1981

Disinfecting properties of performic acid against bacteriophage phi X 174 as a model of small envelope--free viruses.

Performic acid HCOOH (PFA) is a wide-spectrum disinfectant. It inactivates viruses, bacteria and bacterial spores, mycobacteria as well as microscopic fungi. Its main drawback is its instability, which makes it a logical necessity that it is to be prepared prior to use from its components HCOOH and H2O2. The mixing of 8 ml HCOOH of the concentration 850 ml/l and 17 ml H2O2 of the concentration 300 ml/l in a 100 ml-volume reagent bottle with a ground-in glass stopper gives, after an 1-hour rest at room temperature and after another 1 hour in a refrigerator, a stock solution that contains about 50 ml/l of PFA the actual concentration of which is determined iodometrically. Bacteriophage phi X 174 (host E. coli C) is characterized by cubic ikosahedral-type symmetry of particles free of envelope, has 27 mm in diameter and contains single-strand cyclic DNA; formerly was classed among Parvoviridae. The possibility of plaque assay-based quantitative determination of the number of infectious particles makes if it a feasible model for assessing disinfectant action on small hydrophilic viruses under conditions close to those of practical disinfection procedures. PFA stock solution diluted to 1 X 10(-3) (0.05 ml/l of effective component) inactivates the model virus of a concentration 10(8) pfu/ml aqueous suspension within 5 min so that no virus is detectable; the drop in the number of pfu amounts to 7 log orders of magnitude. In the presence of 400 ml/l of serum, the identical effect is achieved within 5 min by PFA stock solution diluted to 5 X 10(-3). The lowest PFA concentration that reliably inactivates bacteriophage phi X 174 in aqueous suspension is identical with the lowest concentration inactivating Coxsackie B 1 virus in tissue cultures. On textile, glass, plastic, rubber and metal carriers contaminated by swabbing or by a dried drop of bacteriophage suspension containing about 1 X 10(9) pfu/ml, the lowest reliably effective concentrations of PFA range within 0.25-0.025 ml/l, i.e. PFA stock solutions diluted to 5 X 10(-3)-5 X 10(-4), depending on the type of carrier and the type of contamination.

Bacteriophage phi X 174↗
PubMed1979

Clinical use of reverse isolation in a protected environment.

The therapeutic method of reverse isolation in patients using an aseptic environment in the Life Island or Laminar Air Flow Unit apparatus systems is described on the basis of data from the literature and the authors' experience. A historical summary of views on treatment in an aseptic environment is followed by a description of the method of work with the system of reverse isolation, including important technical, operational and other data. The main indications for treatment are given and the authors' experience with the reverse isolation of 36 patients suffering from blood diseases who were treated in this way over the past four years is evaluated. The experience gained confirms data from the literature that reverse isolation is unequivocally successful in reducing the number of infections in immunologically weakened persons. Other aspects have not yet been definitely assessed.

Cross Infection↗
PubMed1976

[Reverse isolation of patients with blood diseases in a near germ-free environment].

On the basis of literary data and own experiences the therapeutic method of the reversed isolation of the patients in the aseptic milieu is discussed. After introduction and historical review the working method with the system of reversed isolation (Life Island, Laminar Air Flow Unit) with the clinical results and perspective of a further use in practice is described. Own experiences confirm the literary data in the fact that the reversed isolation is unambiguously successful in the decrease of the number of infections in the immunologically weakened persons. Up to now the other questions cannot be answered definitely.

Asthma↗