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Biomedical subjects

M Fattal-German

Publications and source records attributed to M Fattal-German.

33 records · Page 2Linked to original sources

Monitoring of the response of elderly individuals to pneumococcal vaccination with the aid of a novel ELISA.

An ELISA for assessing pneumococcal anticapsular antibodies in human sera is described. Sensitization was carried out by adding to avidin-coated polystyrene plates biotinylated capsular polyosides. This ELISA was used for the determination of anticapsular antibody levels in pre- and post-immunization sera from 20 elderly individuals. The anticapsular antibody titres differed significantly in sera taken prior to and after vaccination. Eighteen of the 20 sera tested showed mean fold increases of the antibody level greater than 2 (2.1 to 21.0) as a result of vaccination. Since morbidity and mortality rates from S. pneumoniae infections are high in the elderly, immunization should be systematically performed. However, the elderly subject is frequently immunosuppressed, and it is therefore advisable to control the result of the vaccination, using a simple procedure, such as the one described here.

Aged↗

Use of live Saccharomyces cerevisiae cells as a biological response modifier in experimental infections.

A short-term oral administration of live Saccharomyces cerevisiae cells, strain Sillix Hansen DSM 1883, resulted in enhanced resistance of mice toward infections with K. pneumoniae. S. pneumoniae and S. pyogenes A produced by intranasal inoculation. Yeast pre-treatment also increased the efficacy of antibiotic therapy in bacterial infections and of antiviral drugs in viral infections. Yeast treatment of animals stimulated phagocytosis, activated the complement system and induced interferon which are likely to represent the main mechanisms of action whereby pretreatment of mice with live S. cerevisiae cells increases resistance to infection. It is concluded that preventive administration of live Saccharomyces cerevisiae cells should be used for increasing resistance to bacterial infections, in particular of the respiratory tract, or to viral infections, as well as an adjunct to antibiotic and antiviral drug therapy.

Adjuvants, Immunologic↗

[Prevention and therapeutical trials of a few current viral diseases].

Vaccines afford now good prevention of many viral diseases including Hepatitis B. In revenge, attempts of immunization against Herpes Virus types I and II did not result in large scale application of vaccination. Research for a vaccine against HIV encounters many difficulties due to virus variability and host reactions. The introduction of nucleosides analogues represented a great advance for antiviral chemotherapy. Weakly toxic drugs although efficacious against Herpes Virus replication are now available but they do not seem to prevent viral recurrences. As for HIV, its sensitivity to drugs like AZT has raised great hopes which were limited by their intrinsic toxicity. However, research and trials for more efficacious but less toxic drugs are further being developed.

HIV Infections↗

Potentiation by nonspecific immunostimulation of the efficacy of antibiotics in the treatment of experimental bacterial infections.

In the present investigation, mouse infection models with either intracellular or extracellular bacteria were designed in order to assess the effect of nonspecific immunostimulation with the C. granulosum-derived P40 immunomodulator on infection treatment, performed with doses of antibiotics achieving a low percentage of cures. The results obtained showed that nonspecific immunostimulation was able to significantly enhance antibiotic therapy efficacy. In addition, combined treatments of bacterial infections should allow for a reduction in dosages of antibiotics while at the same time, achieving increased efficacy. Possible mechanisms for the potentiating effect of nonspecific immunostimulation on antibiotic therapy effectiveness are discussed.

Adjuvants, Immunologic↗

Sensitivity and specificity of viral immunoglobulin M determination by indirect enzyme-linked immunosorbent assay.

Four sources of error associated with virus-specific immunoglobulin M (IgM) determination by indirect enzyme-linked immunosorbent assay were recognized and analyzed. First, competitive inhibition due to specific IgG was demonstrated by experiments involving addition and subtraction of rubella-specific IgG. Second, the interference due to rheumatoid factors (RFs) of the IgM class (IgM-RFs) was studied thoroughly, and it appeared that the level of false positivity was more dependent on specific IgG titers than on IgM-RF titers. Third, it was found that some IgM-RFs, differing from conventional IgM-RFs in that they reacted only with isologous IgG, were responsible for further cases of false positivity. Fourth, the interference of an IgM reacting with some virus-unmasked cellular antigens was demonstrated for some uninfected individuals. All four interfering factors could be readily eliminated by simply premixing serum samples with a sheep anti-human gamma-chain serum. This single pretreatment was shown to eliminate false-negatives as well as false-positives in a further 2,004 sera tested for six viruses. These results also emphasize the frequency of RFs and their heterogeneity.

Antibodies, Viral↗

The Corynebacterium granulosum-derived P40 immunomodulator exerts a synergistic effect on the activity of antiviral drugs in the treatment of experimental viral infections.

Comparative studies have been carried out on the effects on 2 viral-infection models (Herpes virus and influenza virus) of treatments consisting of either C. granulosum-derived immunomodulator P40, or of vidarabin or amantadine as antiviral drugs, or of combinations of vidarabin or amantadine with P40. According to the modalities of administration of the P40 or of the antiviral drugs, the anti-infectious effect was more or less marked. In contrast, the combinations of P40 and antiviral drugs did not result in a cumulative effect but in significant synergy of the effects of each component of the treatments.

Adjuvants, Immunologic↗

Potentiating the effectiveness of influenza vaccination by a combined immunostimulation with P40 immunomodulator: an experimental study in mice.

Influenza vaccination is highly desirable in view of the epidemic character of this infection and of the severity that it can assume in high-risk and in elderly persons. Its effectiveness varies from 40-90%. Moreover, strains can undergo an antigenic drift in the course of an epidemic. Consequently, reinforcement of the immunogenicity of vaccines is required for achieving a more complete immunization coverage. Combination of an immunomodulator, the C. granulosum-derived P40 fraction, with influenza vaccine resulted in significant potentiation of vaccine immunogenicity. In addition to its adjuvant action, the P40 is also likely to exercise a protective effect by stimulating the non-specific immune defenses of the organism.

Adjuvants, Immunologic↗

[Humoral and cellular immunologic reactions in various forms of chronic psychiatric diseases].

Studies on the status of the immune system in mental disorders have mostly provided contradictory results. For example, some authors have reported dramatic increases of immunoglobulin G in schizophrenic patients, and others a decrease of immunoglobulin G in the same patients. This prompted us to undertake a study on a large cohort of psychiatric patients (120 schizophrenics, 30 manic-depressives, 8 epileptics, 48 cases of Alzheimer and vascular dementia, 23 cases of alcoholic dementia, 14 cases of childhood psychosis, 47 encephalopaths, and 21 chronic alcoholics), all chronically hospitalized. Plasma antitetanus antibodies were assayed in 238 previously immunized patients, the tuberculin test was performed on 302 patients, and the candidine test on 287 patients. Furthermore, 21 patients had an antitetanus vaccine booster injection with antibodies assayed before the injection and one month later, and 31 patients had 2 tuberculin tests with a year or more between them. The results show no major abnormal immune disorders in the patients. Nevertheless some particular features have been found. The first is a very significant relation between the age and the weakness of the immune defences. The second is a large scattering of the blood tetanus antibodies titers in schizophrenic patients, specially in the paranoid subgroup (20.6% of abnormally high or low titers). And the third is the existence of inpredictable variations in the responses when stimulations, or tests, are repeated. These results can raise the hypothesis of a state-dependent component of the immune response in mentally ill patients, but further in, depth studies are needed for better understanding the nature of our findings.

Adult↗