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Biomedical subjects

M Ryba

Publications and source records attributed to M Ryba.

At least 55 records · Page 3Linked to original sources
PubMed1982

Arterial blood--spinal fluid oxygen gradient diminishes during alkalaemia in hyperoxic man.

We investigated the effect of intravenous sodium bicarbonate (2 mmol x kg-1) on the arterial blood-spinal fluid PO2 gradient in twelve anaesthetized hyperoxaemic human subjects who were in preparation for surgical procedures The steady-state samples of arterial blood and lumbar fluid were withdrawn for the assessment of the acid-base status and electrolyte content in both fluid compartments before and after NaHCO3 injection. We found that NaHCO3 increased the arterial pH and PCO2, and decreased the blood-spinal fluid PO2 gradient significantly. The latter was a result of an increase in spinal fluid PO2 and a decrease in PaO2. The diminished PO2 gradient can be accounted for by the specific effect of carbamate and bicarbonate, distinct from that of pH, lowering the affinity of haemoglobin for oxygen. This might favor the maintenance of an adequate oxygen supply in the brain tissue under unfavorable conditions.

Adult↗
PubMed1982

Study of persistence of maternal antibodies to varicella-zoster virus by indirect haemagglutination, with result control by radioimmunoassay.

The persistence of maternal antibody against varicella-zoster virus was studied by the method of indirect haemagglutination (IH) and a control of the results was performed by radioimmunoassay (RIA). The findings were analysed with reference to the constant half-life of passively acquired IgG and the titre range and frequency of antibodies in 220 persons of fertile age representative of the normal population. Statistical analysis of expected and the experimentally obtained data was performed. Among the normal population, the expectancy is a gradual decrease in maternal IH antibody titres to negativity during the first 10 months of life and 100% sero-negativity by the 11th and 12th month. The experimental data showed a decrease in IH seropositivity from the initial 100% in 1-month infants to 27% in 6-month and 7% in 12-month infants. Nine out of twelve of the experimentally found positive titres in infants during the second half of their first year of life deviated from the normal population sample. The results obtained by both of the methods used were in good agreement.

Antibodies, Viral↗
PubMed1980

Cell-mediated immunity to varicella-zoster virus as assessed by the migration inhibition test.

The migration inhibition method was used to test cell-mediated immunity to varicella-zoster (VZ) virus in 10 varicella and 11 herpes zoster patients. Control groups consisted of eight children susceptible to VZ infection on serological evidence and 49 normal persons of different age categories. Depending on the positivity criterion adopted, positive results during disease were obtained in 43% or 90% or all tests performed in varicella patients and 47% or 74% in herpes zoster patients. Irrespective of which criterion of positivity was applied, a high rate of positive results was obtained in the normal control groups; in the age range from 20--44 years it was comparable to that for patients. This finding would suggest a high activity of VZ virus among the human population. Since a positive result in migration inhibition test offers evidence of recent contact with antigen, either exogeneous contact with VZ infection or endogenous contact with latent VZ virus must have been involved.

Adult↗
PubMed1979

Radioimmunoassay for antibodies in varicella-zoster virus serology.

The method of RIA for antibodies was employed with success in VZ virus serology. The method is suitable for testing VZ antibodies in the course of varicella or herpes zoster disease as well as for determining anamnestic titres. Its advantages are stability of antigen, objective reading of results and applicability to testing large serum sets.

Adult↗
PubMed1979

Testing the properties of an experimental batch of zoster immune gammaglobulin (ZIG).

The methods of indirct haemagglutination (IH) and precipitation in gel (ID) were employed to test the level of varicella-zoster (VZ) antibodies in an experimental batch of zoster gammaglobulin (ZIG). The titre of indirect haemagglutinating antibodies in ZIG was about 64 times higher than in the ordinary batches of normal immunoglobulin and about 8 times higher in comparison with the level of the initial plasma pool. In the reaction of precipitation in gel, ZIG produced 5 to 6 zones. In comparison with the initial pool of convalescent plasma, ZIG also showed an 8-fold concentration of precipitating antibodies. ZIG was administered preventively to 6 children with risk diagnoses. None of the children fell ill with varicella. According to the results of subsequent serological examination in the reactions of indirect haemagglutination and radioimmunologic analysis, only 3 children were definitely susceptible to VZ infection. In two other children (very low antibody titres) the risk could not be excluded. No substantial increase in the levels of IH and RIA antibodies was observed in the 4 children under serological observation in a period of 6 months following the administration of ZIG. ZIG was administered therapeutically to four children with varicella. The effect of ZIG therapy was very suggestive, especially in two newborn infants lacking maternal antibodies, where the dose of ZIG per 1 kg body weigt was unusually high.

Antibodies, Viral↗
PubMed1977

Studies on reflex control of breathing in pigs and baboons.

In 8 pigs and 4 baboons, spontaneously breathing, anaesthetized with halothane, Hering-Breuer reflex was tested by means of a total obstruction of the airway preventing either inspiration or expiration. Subsequently animals were paralysed and maintained on phrenic nerve driven servo-respirator. The response of phrenic motoneurone output to various degree of lung inflation, introduced for one breath only, was then carefully studied. This was achieved by varying the gain of servorespirator. Additionally in baboons, identical series of gain manoeuvres was performed against a background of different levels of the initial gain setting. Changes in both inspiratory time and peak amplitude of phrenic signal were monoexponentially dependent on gain of servorespirator and linearly dependent on tidal volume (all negatively correlated). The relationship between inspiratory time T(1) and subsequent expiratory duration T(E )existed only within a range of growing T(1). Vagal positive feedback phenomenon was apparent in pigs and negligible in baboons. It is postulated that inspiratory cut-off mechanism terminates inspiration when excitatory function are outbalanced by their integral.

Animals↗
PubMed1976

Indirect haemagglutination reaction (LH)-the method of choice for the detection of anamnestic antibodies to varicella - zoster (VZ) virus.

The method of indirect haemagglutination is a sensitive quantitative serological reaction for the detection of anamnestic titres of VZ antibodies. The curve obtained by the examination of a representative population sample has shown that the occurrence of VZ antibodies increases with the age so that 60% of children of under-school age and 90% of 15-year-old children have antibodies to varicella-zoster virus. In adult age groups, seropositivity ranges between 90--100%. The incidence and level of antibodies are identical in both sexes and do not decrease in old age groups. The mean titre of indirect haemagglutinating antibodies was 1 : 128.

Adolescent↗