Biomedical subjects
Publications and source records attributed to F Ambrosch.
A modified microassay procedure, using triphenyltetrazolium chloride as a germination indicator, was compared with a macroassay method proposed by the World Health Organization for determining the level of antibodies before and after immunization with Group A meningococcal polysaccharide vaccine. There was excellent agreement between the results obtained by the two methods. The vaccine used appeared to be safe and immunogenic.
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A multicentre study of cases of acute myocardial infarction was undertaken at 27 departments at teaching and non-teaching hospitals throughout Austria over a period of three years. Altogether 3397 patients were investigated. On classification of the patients according to the number of shock indicators, two comparable groups (B and C) of "mild" infarction with 0, 1 or 2 signs of shock were obtained. These low-risk groups comprised 728 patients. The mortality in group C ("mild" infarction, no streptokinase) was 17.3%, significantly higher (p less than 0.01) than the corresponding figure of 10.5% in group B ("mild" infarct, streptokinase therapy). The decrease in mortality by streptokinase therapy applied both to monitored patients as well as to those who were not monitored. Haemorrhage was a very rare complication, but somewhat more frequent in the streptokinase-treated cases, as expected. The incidence of complications such as stereocardia, asystole, and cardiac insufficiency, as well as the conversion of "mild" cases into a "severe" symptomatology was markedly reduced in the streptokinase-treated group.
The decrease in blood viscosity induced by streptokinase (SK) in the present investigation in proportional to the streptokinase concentration up to a concentration of 2000 IE/ml blood. A maximum decrease in viscosity is attained with a dosage of between 200 and 300 IE/ml blood. The decrease in viscosity is already clearly detectable at 10 minutes at all investigated doses and is completed after 20 to 30 minutes. An increase in SK resistance delays the decrease in viscosity. Prevention of the decrease, however, only seems to occur with a very high SK resistance and a very low SK dosage (50 IE/ml blood). The optimum dosage of SK to achieve a maximum decrease in viscosity is 200 IE/ml blood.
Hyperacute renal allograft rejection is described in a patient suffering from mesangio-proliferative glomerulonephritis. The transplanted kidney was HL-A identical and the direct cytotoxic cross-match between the recipient's serum and donor lymphocytes was negative. Intrarenal consumption of C 3, but not of C 1 q, C 4, total haemolytic complement, IgG or Igm was demonstrated. Immunofluorescence studies exhibited dense granular deposits of C 3, but not of IgG, IgM C 1q or C 4. These findings together with the observation of beta 1 C-beta 1A converting activity in the patient's serum, raised the possibility that the alternative pathway of complement activation induced by nephritic factor could have operated in this case. Further studies will be necessary to clarify the question whether hyperacute rejection of renal allografts is only antibody mediated or not.
The beneficial effects of vaccinations may be calculated by means of special formulas: (formulas: see text). In these formulas R means the risks of the disease with regard to special complications, r the comparable risk of vaccination, p the protection rate and t the duration of protection. A vaccination is beneficial, if N and Q greater than 1 and D greater than 0. Vaccinations which show low levels for N, Q and D must be reevaluated constantly by means of the above mentioned formulas. This control may be performed also by calculation of the border - risk Rlim = r/p.t and the epidemiologic trend. In case of whooping-cough according to the risk given by the WHO vaccination loses its beneficial effect at the end of 1976 and cannot be recommended therefore for general performance in middle Europe. On the other hand BCG-vaccination will have a beneficial effect for about another 30 years on a very low level. However, the beneficial effect is much more expressed, if the prevention of leucemic deaths, as quoted by Davignon and Rosenthal, is taken for granted.
A national study, with participation of 82 paediatricians, was carried out on 9472 children over medium observation periods of between 3.13 and 5.46 years with evaluation of the history of measles, incidence of complications and details of vaccination procedure performed. The protection rate of primary vaccination with live vaccine was 0.89, with split vaccine (3 times) 0.67 and after a combination of split vaccine (3 times) with live vaccine (9 to 12 months later) 0.94. Complications due to measles in unvaccinated children were found in 5.9% of cases. Measles complications after failure of vaccination were found in 2.9% and 2.8% of children vaccinated with live or split vaccine, respectively. No such complications were observed in children vaccinated with a combination of split and live vaccines.
The effect and risks of the vaccination against TBE virus was calculated by means of formulas for Q and D. Q considers the relation between total risk of unvaccinated and vaccinated persons and D the yearly difference in risks between unvaccinated and vaccinated members of a community. In recommendable vaccinations Q should exceed 1,0 and D should be greater than 0. Vaccination against TBE was performed by 2 injections at an interval of 4 weeks followed by a 3rd injection after 9 months. No major side effects were observed in vaccinations of about 50,000 persons. After one injection only, the conversion rate was 76% and Q 4,17, after 2 injections the conversion rate was 96% and Q 25 and after the total course of 3 injections the conversion rate was 98% and Q was calculated to be 50. With respect to morbidity DM was 7,18 X 10(-5) and regarding mortality DL was 1,1 X 10(-6). That means that proper vaccination of persons at risk in Austria could prevent 500-600 cases of encephalitis and approximately 8 deaths due to TBE per year. It was concluded that the new vaccination is effective and recommendable. Revaccinations will be necessary probably at intervals of 2-3 years, the exact time period still being under study.
The efficiency of the vaccination against influenza resp. its assessment depends on methodological factors, on the vaccine in use and on the epidemiological situation. According to serological tests protection rates (p) may be found of 0,8-0,9; a combined clinical and serological evaluation leads to a value of p=0,7 and after clinical estimation p=0,5. For statistical evaluation it is important to know whether the groups of persons to be compared were randomized or selected. Vaccination groups consisting of volunteers were selected in as much as the vaccines apparently exhibited a higher premorbidity than the control groups. Further on the protection rate is influenced by the number of vaccinations performed. Another very important factor is the composition of the vaccine in use, which should be in accordance with the recommendations of the WHO. Concentration of antigen and addition of adiuvant also influences the efficiency of inactivated vaccines. The antigenic composition is also relevant in live attenuated vaccines. Epidemiological factors are of importance in as much as the efficiency of the vaccination rises with the morbidity of the population. However, even in interepidemic periods the vaccination offers a certain degree of clinically observable protection (0,3). The indication for vaccination against influenza is influenced by age. In older persons the vaccination depresses morbidity and mortality rates, in middle aged working people lower morbidity and a drop in days of absence resulted as consequence of a vaccination campaign, whereas in children shedding of virus is prevented by the vaccination.
A single blind study was performed to test the efficiency of influenza-vaccination against various clinical parameters. The parameters "sickness", "rhinitis" and "medication" were reduced significantly during the months of november to march, namely by 64.8%, 19.9% and 39.6%. Apart from the overall reduction of rhinitis especially the severe forms were strongly reduced. However this effect disappeared after five months. The parameters "fever", "cough" and "asthma" showed no difference.
The effect, hazards and risk of vaccinations may be calculated by means of special formulas which determine the value for N, Q and D. The formula for N considers the question whether a vaccination is effective, necessary and valuable and may be recommended on epidemiological grounds. Q considers the individual risk (i. e. relation between total risk of unvaccinated and vaccinated persons) and D the yearly difference in risks between unvaccinated and vaccinated members of a community. If p stands for protection rate of a vaccination, t = time for which the vaccination effect is lasting, R = complications of disease under study in a community in which vaccinations against this disease are not in use and r = comparable complications of vaccination, the following formulas are applicable: (see article) A vaccination may be recommended if N and Q greater than 1 and the value for D is positiv. Application of these formulas to special vaccinations lead to the following conclusions: In case of BCG, measles and poliomyelitis (oral vaccination) the above mentioned values exceed at least 10(1)-10(2) (N), 4-5 (Q) or are highly positiv (D). These vaccinations-if performed correctly-are considered valuable and highly recommendable. Vaccination against pertussis is not recommendable beyond the second year of life. According to the present epidemiologic situation in Austria this vaccination is still rectified in children under 2 years. However, values for N, Q and D are near border-line and should be yearly evaluated. Smallpox vaccination in Europe is still recommendable. Similarly, continuous reevaluations are necessary due to low values of N, Q and D. On the other hand, vaccination against tetanus is available and vaccination against influenza may be recommended.
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During the clinical development of safe, well tolerated and immunogenic vaccines against hepatitis A the persistence of protective antibodies was estimated, based on relatively short observation periods of 18 months to 3 years. We report here on longterm persistence of antibodies in volunteers who participated in one of the early clinical trials on inactivated hepatitis A candidate vaccines. In a randomized trial three groups of altogether 110 healthy adults, initially hepatitis A virus (HAV) seronegative persons were vaccinated with an inactivated hepatitis A vaccine according to the schedule 0-1-2-12 months. One group received 180 ELISA units, one group 360, and one 720 ELISA units per dose. Blood samples were taken prior to the first vaccination and at months 1, 2, 3, 4, 6, 12, 13, 18, 24, 36 and 84. The decrease of antibodies was characterized by two disappearance rates: a rapidly decreasing component and a slower decreasing one becoming predominant ca 12 months after booster vaccination. The disappearance of antibodies could be described by a two-component model which holds for t > or = 13 months. The estimated disappearance rates for the slow component (annual decrease) was found to be 11 and 13% for the 180 and 360 El. U groups, respectively (the 720 El. U group showed no decline, which was probably due to the small sample size). The estimated persistence of antibodies within protective range varied between 24 and 47 years depending on individual titres reached at month 13 and vaccination dose.