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Biomedical subjects

G Wiedermann

Publications and source records attributed to G Wiedermann.

At least 127 records · Page 7Linked to original sources
PubMed1977

[Changes in the benefit of immunization].

The beneficial effects and the risks of vaccinations may be calculated by means of special formulas (N,Q,D). Changes in the effect of vaccinations may be substantiated by constant (eventually computerized) reevaluation of the present epidemiologic situation with the help of the above mentioned formulas. Another possibility lies in the calculation of the epidemiologic trend and determination of Rlim, the latter meaning the borderline number of complications of a certain disease, when risks as consequence of the disease or of the vaccination are about equal (D = 0). The follow-up of the epidemiologic situation over many years allows the estimation when this will be the case or, in other words, when the vaccination against the disease in question is not meaningful any more and has lost its beneficial effect and practical importance. In case of smallpox the risk of importation of the disease is practically zero; this means that N and Q less than 1 and D less than 0 thus underlining the view that the compulsory vaccination of the newborn is obsolete. A follow up of the case mortality of whooping cough in Austria over the past 15 years leads to the conclusion that Rlim, when calculated according to Ehrengut (that means that deadly risks of vaccination, r, are considered to be 2,4 x 10(-5), has been reached already in 1971. When calculated according to the WHO(r = 0,1 x 10(-5)) this will be the case by the end of 1976. In case of BCG vaccination the borderline mortality (Rlim) is not yet reached in Austria. The total number of deaths from tuberculosis that have been prevented by vaccination is already very low. The beneficial effect of this vaccination is much more expressed however when the prevention of leucemic deaths, as quoted by Davignon et al. (1970, 1971) and Rosenthal et al. (1972), is taken for granted. More observations will be necessary to clarify that point.

Adult↗
PubMed1977

[Hyperacute rejection of an HL-A identical renal allograft (author's transl)].

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.

Acute Disease↗
PubMed1977

[Trendobservation of beneficial effects of vaccinations (author's transl)].

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.

Adolescent↗
PubMed1976

[Epidemiological investigations on measles in unvaccinated and vaccinated children (author's transl)].

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.

Adolescent↗
PubMed1976

[Effect, hazards and risks of the new vaccination against tick-borne encephalitis (TBE) as calculated by special formulas (author's transl)].

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.

Encephalitis, Tick-Borne↗
PubMed1976

[Assessment of the efficiency of vaccination against influenza (author's transl)].

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.

Adjuvants, Immunologic↗
PubMed1976

[BPO-Specific, complement-dependant cell-lysis of differently sensitized sheep red cells: evaluation of haptenic groups and their influence on IgM and IgG-induced lysis (author's transl)].

Sheep erythrocytes were coated with bencylpenicilloyl-(BPO)groups. Different incubation periods resulted in erythrocyte preparations with different hapten density. Complement dependent lysis induced by IgM or IgG antibodies was studied with the cell preparations. The calculation of hapten density on the erythrocyte surface was not possible by direct measurement of coupled radioactive BPO since more than 90% of radioactive material was found in the soluble supernatant after osmotic cell lysis and less than 10% was fixed to the cellular membrane. Measurement of membrane bound immunologically relevant BPO-groups was achieved, therefore, by comparison of the inhibitory capacity of the test cells with that of a standard cell preparation. The latter consisted of tannic acid treated erythrocytes coated with protein complexed radioactive BPO. Surface hapten density of the different target cell preparations varied between 1.9 x 10(5) and 4.8 10(5) BPO-groups per cell depending on the time of incubation. Complement dependent antibody mediated cell lysis was significantly reduced by reduction of haptenic sites per target cell, IgG induced lysis being much more affected than hemolysis induced by IgM antibodies. Statistical calculations led to the conclusion that 18,000 protein islets per cell bearing 4 or more BPO-groups are not sufficient for hemolysis induced by IgG antibodies. 48,000 protein islets with this hapten density are necessary for "optimal" sensitization. IgG antibodies must be apparently bound to the cell surface in bivalent form.

Cell Membrane↗
PubMed1975

Influence of surface hapten density of sheep red blood cells on the hemolytic or blocking activity of IgG antibodies.

The hapten density on the surface of sheep red cells, coated with benzylpenicilloic acid (BPO) was determined. This was achieved by comparison of the inhibitory capacity of the test cells with that of a standard cell preparation of known antigen density. IgG-induced hemolysis was much more affected by the recution of haptenic sites/cell than IgM-induced hemolysis. It was concluded that more than 18,000 protein islets on the sheep red cell surface bearing at least four haptenic sites were necessary for IgG-induced lysis. Target cells with 190,000 BPO groups/cell could be protected by anti-BPO-IgG against the lytic effect of simultaneously added IgM. Using target cells with 240,000 haptenic groups/cell or more a synergistic hemolytic action of IgG-and IgM-anti-BPO antibodies could be observed.

Animals↗
PubMed1975

[Mathematical methods to judge the efficiency of protective vaccinations (author's transl)].

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.

BCG Vaccine↗