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Biomedical subjects

R Pyhälä

Publications and source records attributed to R Pyhälä.

At least 55 records · Page 3Linked to original sources
PubMed1983

Smoking and influenza in the elderly: a sero-epidemiological study.

Two blood samples were taken at an interval of five years in a continuing epidemiological study of a rural population with an age range of 40-64 years at commencement. Paired sera of 111 light smokers and their non-smoker controls, matched for age and sex, and of 68 heavy smokers and their respective controls were tested for haemagglutination inhibiting antibodies against four different influenza strains. Antibodies were detected in the baseline specimens more frequently and in higher titres among the smokers than among the controls. Significant rises in titre between the baseline specimens and the follow-up specimens occurred slightly more frequently among the smokers.

Adult↗
PubMed1982

Seroepidemiology of H1N1 influenza: the range of the affected population is widening.

The H1N1 influenza epidemic during the winter of 1980-81 affected a wider range of the population than the epidemics of 1977-78 and 1978-79. The increasing frequency of infection among elderly people can be explained by the antigenic drift in the surface proteins of the virus. Small children and pregnant women were affected to only a small extent by the first and second outbreaks, but they suffered more in 1980-81. This altered epidemiology may be explained by adaptation of the virus to the human host, but the genetic mechanism remains an open question.

Adolescent↗
PubMed1981

Seroepidemiology of H1N1 influenza: the infection and re-infection rate in winter 1978-79.

It was observed that small children and pregnant women were affected to only a small extent by the H1N1 influenza outbreak of winter 1978-79. This supports earlier findings from the epidemic season of 1977-78 and demonstrates that the evolutionary changes in the epidemic virus were not reflected in any appreciable way in this curious phenomenon. The frequency of elderly subjects possessing antibodies against the epidemic H1N1 virus was low, and virtually equal in the pre-epidemic and post-epidemic sampling. This low attack rate contrasts with observations on young military servicemen, in whom the re-infection rate was high, thus indicating that the infection with the winter 1977-78 virus had conferred only modest protection against the closely related virus which caused the winter 1978-79 outbreak.

Adolescent↗
PubMed1980

Protection by a polyvalent influenza vaccine and persistence of homologous and heterologous HI antibodies during a period of two epidemic seasons.

A split-product influenza A vaccine which contained an influenza B strain (B/Hong Kong/8/73) and two influenza A strains, antigenically identical with A/Fort Dix/741/76 (Hsw1N1) and A/Victoria/3/75 (H3N2), was offered to personnel of the CPHL. Changes in the antibody status were followed with serum samples collected from 153 participants on the day of vaccination and 1, 13 and 18 months thereafter. During the two epidemic seasons in the trial period there were only four serological influenza A infections (2.6%) among the vaccinees. This is one eighth of the corresponding infection rate (22%) in the general population estimated on the basis of other indices. The vaccinees' antibody response was strongly influenced by the age of the individual subjects. During the trial period the decrease in the antibody titres slowed down. The geometric mean titres of homologous HI antibodies were still substantially higher at the end of the period than at the beginning. This also applied to heterologous antibodies against H1N1 viruses in persons born between 1926 and 1952. In participants born after 1952, the vaccine was not able to evoke these antibodies, and in participants born in or before 1925 the boosting effect was poor.

Adult↗
PubMed1980

Evaluation of amantadine in the prophylaxis of influenza A (H1N1) virus infection: a controlled field trial among young adults and high-risk patients.

The usefulness of amantadine in the protection of humans against influenza A (H1N1) virus was evaluated in a double-blind field trial with 555 volunteers in Finland in the winter of 1978. Three populations--patients in a general hospital, adults in a home for the aged, and two groups of military conscripts--were chosen. Epidemic influenza occurred only in the two groups of conscripts: the incidence of serologically verified influenza was 66% and 83% in the groups that received placebo and 43% and 51% in the groups that received amantadine, giving protection rates of 36% (P = 0.05) and 39% (P = 0.001). The evaluation of the effect of amantadine on the occurrence of illness was obscured by concomitant adenoviral infections that caused influenza-like symptoms. No clear difference in the occurrences of side effects was observed between the placebo and amantadine-treated groups; however, a significantly greater number of participants who took 200 mg of amantadine/day (16.9%) stopped medication during the trial as compared with the placebo groups (7.6%) (P < 0.02).

Adult↗
PubMed1980

ABO associated genetic determinant in H1N1 influenza.

Young people, in the winter of 1977-78 lacked all prior antigenic experience with H1N1 influenza. The attack rate among them was observed to be lowest (42%) in blood group O subjects and highest (59%) in blood group AB subjects. This indicates that there is an ABO associated genetic determinant in resistance against H1N1 influenza. The antibody response to the viral hemagglutinin did not vary substantially according to the ABO status.

ABO Blood-Group System↗
PubMed1979

Influenza A(H1N1) viruses of the 1977/78 outbreak: isolation and haemagglutination properties.

During the H1N1 outbreak of 1977/8, the virus was isolated in embryonated eggs from 59 out of 76 patients (78%) with the serologically confirmed infection. A similar isolation frequency has been achieved during a period of six H3N2 outbreaks since 1972/3. The H1N1 strains were isolated less frequently from late specimens (collected 4--6 days from the onset of illness) and more often only in the second passage compared with the H3N2 viruses. The new H1N1 strains resembled those prevalent in the 1950s with respect to their ability to agglutinate erythrocytes of certain laboratory animals and to be eluted from these, and thus differed from the H3N2 viruses.

Disease Outbreaks↗
PubMed1979

Seroepidemiology of H1N1 influenza: striking differences in the attack rate among young people.

The H1N1 influenza outbreak in winter 1977-78 covered the whole of Finland in a uniform fashion, whereas striking differences emerged between various population segments in the susceptible age group. The attack rate was 68 per cent among young servicemen who had been in the armed forces during the epidemic and 33 per cent among those who had entered the service after the epidemic, but only 6 per cent among pregnant women of the same age. Based on routine specimens sent to the laboratory for reasons unrelated to influenza, the attack rate was 4 per cent among children born in 1973-76 and increased by age up to 45 per cent among subjects born in 1957-62. The findings on pregnant women and small children suggest a novel mechanism of innate resistance operating specifically against H1N1 influenza.

Adolescent↗
PubMed1979

Risk of infection among seafarers: a prospective seroepidemiological survey of the crew of a passenger cruiser.

Serial blood specimens for various serological examinations were taken from the crew of a passenger ship which sailed on winter cruises. The study covered 3 successive seasons totalling about 150 years of observation. The figures on the rates of infection were compared with data available from the general population. The study revealed no clear evidence of an increased infection risk among the crew.

Adolescent↗
PubMed1976

IgA deficiency and influenza infection.

A prospective study of influenza was carried out on 90 blood donors deficient for serum IgA as tested with double immunodiffusion. Half of them lacked IgA even by radioimmunoassay (RIA). A correlation existed between serum haemagglutination-inhibiting (HI) antibody and resistance to infection, suggesting that the serum HI antibody was an important determinant of protection. The rate of infection as evidenced by a fourfold or greater rise in HI titre, was about the same in the RIA-negative and RIA-positive donors and slightly higher than the corresponding rate in pregnant women and in a ship's crew.

Adult↗
PubMed1976

Virus antibody levels in IgA deficiency.

IgA-deficient blood donors and their age- and sex-matched controls were compared for the occurrence of complement-fixing antibodies in serum against several viruses. The level in the IgA-deficient persons was slightly higher against several respiratory pathogens (adenoviruses, type B influenza virus, parainfluenza virus, and respiratory syncytial virus) that give rise to localized infections, and against coxsackie B group of viruses. No corresponding difference was observed in mumps, varicella, and cytomegalovirus infections, where viraemia is a characteristic feature, or in Mycoplasma pneumoniae infection.

Adenoviruses, Human↗
PubMed1976

Antibodies to influenza A/swine-like viruses (Hsw1N1) in human sera: antigenic stimulation and changes in antibody status.

Human sera collected at the end of 1975 were studied for HI antibodies to influenza A/Mayo Clinic/103/74 (Hsw1N1). The frequent occurrence of these antibodies in subjects born before 1930 suggested that they are present in about 25% of the Finnish population. During the H3N2 epidemic in winter 1975-76 a low response of antibodies to A/swine-like viruses was recorded in about half of the influenza patients with a pre-existing titre, but not in any of the patients without pre-existing antibodies. A comparison of samples collected in 1969 and 1975 suggested that at the community level the antibodies to A/swine-like viruses have not decreased during the era of the H3N2 subtype.

Adolescent↗
PubMed1976

NDV-O agglutinins and heteroagglutinins in sera of blood donors.

In sera of healthy blood donors advancing age was accompanied by a decrease in the levels of agglutinins against human group O erythrocytes modified by Newcastle disease virus (NDV-O agglutinins) and of heteroagglutinins against sheep, guinea-pig and rabbit erythrocytes. Significant correlations of titres existed between the different heteroagglutinins, but not between these and the NDV-O agglutinins. The origins and interrelations of the natural agglutinins are discussed.

ABO Blood-Group System↗
PubMed1976

The value of complement fixation and haemagglutination inhibition tests in the diagnosis of influenza A.

Antibody response of 133 influenza A patients from three outbreaks since 1972-73 was analyzed by complement fixation (CF) and haemagglutination inhibition (HI) methods. During the first outbreak, a significant response was more often measured by CF than by HI. During the last outbreak HI appeared more useful than CF for routine serological diagnosis; 23% of cases verified by HI were missed by CF. The poor response of CF antibodies was associated with the high level of pre-infection antibodies.

Adolescent↗
PubMed1975

Serum HI antibody and protection against influenza: a follow-up survey at community level of three epidemics caused by different H3N2-variants.

Serial blood specimens from Rh-negative pregnant women sent to laboratory for Rh antibody testing were stored and used for influenza investigations. The study period covered three epidemics, each caused by a different variant of influenza A (H3N2) virus. The relationship between pre-epidemic haemagglutination inhibiting (HI) antibody level against the epidemic virus and serological evidence of infection was analysed. Titre associated with protection was very similar in the three epidemics. In 1973-74 the influenza A epidemic had an exceptional course characterized by prolonged duration. The study revealed data on the rate of infection in one age and sex category that are difficult to obtain using standard indicators of influenza epidemiology.

Antibodies, Viral↗